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  • 4301.
    Ye, Pengcheng
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Sjöberg, Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Correction: Air Separation at Cryogenic Temperature Using MFI membranes2014In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 197, p. 359-Article in journal (Refereed)
    Abstract [en]

    In the present work, zeolite membranes were for the first time evaluated for separations at cryogenic temperatures. MFI membranes were evaluated with a feed of synthetic air, at varying feed pressures between 1– 5 bar and a sweep stream of helium at a constant pressure of 1 bar for temperatures in the range 77 to 110 K. When the feed pressure was 1 bar, the highest O2/N2 separation factor was 3.9, corresponding to a separation selectivity of 4.1, with an oxygen permeance of 6.7×10-7 mol m-2 s-1 Pa-1 at the optimum temperature 79 K. This membrane performance is just above the upper bound in the 2008 Robeson selectivity- permeability plot for polymeric membranes. As the feed pressure increased, the maximum separation factors for O2/N2 decreased while the optimum separation temperatures increased. It is inferred that the separation is governed by condensation and effective transport of oxygen in the zeolite pores under these conditions. However, the adsorption of nitrogen, and thereby the transport of nitrogen, likely increases as the pressure is increased, which reduce the selectivity. To test this hypothesis, the feed was diluted with 33% helium and the total feed pressure was maintained at 1 bar, corresponding to a partial pressure of air of 0.66 bar. In this case, the maximum separation factor increased to 4.3, which supports the proposed separation mechanism.

  • 4302.
    Ye, Xinchen
    KTH, School of Chemical Science and Engineering (CHE).
    Nanocomposites Based on Whey Protein Nano-Fibrils and Matrix2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The inclusion of nanoparticles has opened new possibilities to enhance and tune the properties of biobased materials. We here explored an approach to create protein homo-nanocomposites in which the nanoparticles and matrix are made from the same raw material. Whey protein isolate, as the raw material, are known to self-assemble into highly ordered nanofibrils under certain conditions. 2.5 - 15 % of protein nanofi brils solution was mixed with non-fibrillar matrix and 33 % glycerol as plasticizer. Tensile tests indicated increased elastic modulus and decreased  maximal elongation as function of increasing amounts of nanofibrils. The ultimate strength was less affected. It can be explained by the growth of  strongly  hydrogen-bonded peptide group in P-s heets observed by  IR  spectroscopy.  The  undulating  surface  and exifoliated P-sheets a lso have influence on the mechanical properties of the films.  Taken together, our study shows that it is possible to control the mechanical properties  of protein­  based materials  by addition  of protein nanofibrils.

  • 4303.
    Ye, Xinchen
    et al.
    KTH, Stockholm, Sweden.
    Junel, Kristina
    RISE - Research Institutes of Sweden, Bioeconomy.
    Gällstedt, Mikael
    SIG Combibloc.
    Langton, Maud
    SLU, Uppsala, Sweden.
    Wei, Xin-Feng
    KTH, Stockholm, Sweden.
    Lendel, Christofer
    KTH, Stockholm, Sweden.
    Hedenqvist, Mikael S.
    KTH, Stockholm, Sweden.
    Protein/Protein Nanocomposite Based on Whey Protein Nanofibrils in a Whey Protein Matrix2018In: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 6, no 4, p. 5462-5469Article in journal (Refereed)
    Abstract [en]

    This article describes nanocomposite films with separately grown protein nanofibrils (PNFs) in a nonfibrillar protein matrix from the same protein starting material (whey). Tensile tests on the glycerol-plasticized films indicate an increased elastic modulus and a decreased extensibility with increasing content of PNFs, although the films are still ductile at the maximum PNF content (15 wt %). Infrared spectroscopy confirms that the strongly hydrogen-bonded β-sheets in the PNFs are retained in the composites. The films appear with a PNF-induced undulated upper surface. It is shown that micrometer-scale spatial variations in the glycerol distribution are not the cause of these undulations. Instead, the undulations seem to be a feature of the PNF material itself. It was also shown that, apart from plasticizing the protein film, the presence of glycerol seemed to favor to some extent exfoliation of stacked β-sheets in the proteins, as revealed by X-ray diffraction.

  • 4304.
    Yin, Bo
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Functional PVC Additives: Core-Shell Nanoparticle and Renewable Resource Plasticizers2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Several functional poly(vinyl chloride) (PVC) additives were designed: PVC plasticizers made from renewable resources as alternatives to traditional phthalate plasticizers and core-shell nanoparticle-plasticizers with the aim to design an additive that can improve several mechanical properties simultaneously. Monomeric and oligomeric PVC plasticizers based of isosorbide and glucose were synthesized. Their structures and molecular weights were determined by SEC, NMR, FTIR and LDI-MS. PVC was blended with the different plasticizers and miscibility, mechanical properties and thermal properties of the blends were analyzed. PVC/isosorbide dihexanoate (SDH) films exhibited similar properties as PVC/diisooctyl phthalate (DIOP) blends. PVC films plasticized by oligo(isosorbide suberate) (OSS) and oligo(isosorbide adipate) (OSA) showed better thermal stability and higher mechanical strength, but lower strain compared to the PVC/DIOP and PVC/SDH blends. Glucose ester plasticizers with slightly different chemical structures were synthesized by applying different reaction times. Results revealed that the plasticization efficiency was improved by larger number of hexanoate units on the glucose ring. Altogether the glucose esters showed great potential as renewable PVC plasticizers.

    Core-shell nanoparticle-plasticizers were designed with the aim to simultaneously improve both the stiffness and toughness of the materials. Halloysite, kaolin and silicon dioxide nanoparticles were surface-grafted by poly(butylene adipate) (PBA). The surface-grafting was confirmed by FTIR and the amount of grafting was determined by TGA. PVC/nanoparticles binary blends and PVC/PBA/nanoparticle ternary blends were prepared by solution casting. The dispersion of nanoparticles in the PVC matrix, as observed by SEM, was remarkably improved by the surface-grafting. The tensile stress at break for the PVC films containing 5 wt-% surface-treated halloysite nanoparticles (St-Halloy-5) increased 15 % compared with the material containing same amount of untreated halloysite nanoparticles (untreated Halloy-5) films. The St-Halloy-5 films also exhibited 30 times higher strain at break values compared to untreated Halloy-5 films. The PVC films containing 5 wt-% surface-treated silicon dioxide nanoparticles (St-SiO2-5) exhibited remarkably higher strain at break values even though the strength was slightly lower compared to the material with same amount untreated SiO2 particles. The nanoparticle surface treatment also improved the mechanical properties of PVC/PBA/nanoparticle ternary blends. PBA/St-Halloy exhibited most obvious improvement compared to PBA/Halloy, the values increased more than 100% for both stress at break and strain at break The results show that the designed nanoparticle-plasticizers could simultaneous improve the stiffness and toughness of PVC materials.

  • 4305.
    Yin, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Aminlashgari, Nina
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Glucose based green PVC plasticizersManuscript (preprint) (Other academic)
  • 4306.
    Yin, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Core-shell nanoparticle-plasticizers for design of high-performance polymeric materials with improved stiffness and toughness2011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 24, p. 8670-8677Article in journal (Refereed)
    Abstract [en]

    Core-shell nanoparticle-plasticizers were synthesized and blended with PVC in an attempt to simultaneously improve the toughness and stiffness of the resulting materials. Halloysite, kaolin and silicon dioxide nanofillers, representing acicular, layered and spherical morphologies, were surface-grafted with poly(butylene adipate) (PBA). The surface-grafting was confirmed by FTIR and the amount of PBA grafted on the surface was determined by TGA. In the case of halloysite and silicon dioxide nanoparticles their dispersion and miscibility in the PVC matrix were remarkably improved by the surface-grafting as shown by SEM, tensile testing and DMA. The tensile stress at break for the PVC films containing 5 wt% surface-treated halloysite nanoparticles increased 15%, modulus by 65% and the strain at break was 30 times higher compared to PVC containing 5 wt% untreated halloysite nanoparticles. The PVC films containing 5 wt% surface-treated silicon dioxide nanoparticles exhibited remarkably higher strain at break values compared to plain PVC/silicon dioxide composites, but also somewhat lower stress at break values probably due to the considerably higher amount of PBA grafted on the silicon dioxide surfaces. The higher storage modulus for PVC with surface modified silicon dioxide, however, still indicates higher stiffness for the material containing surface treated nanoparticles. Altogether the results show that the nanoparticle-plasticizer concept could be applied to simultaneously improve the toughness and stiffness of the materials and further improvements could be achieved after optimization of the number of PBA chains and their molecular weight.

  • 4307.
    Yin, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Flexible and strong ternary blends of poly(vinyl chloride), poly(butylene adipate)and nanoparticle-plasticizers2013In: Materials Chemistry and Physics, ISSN 0254-0584, E-ISSN 1879-3312, Vol. 139, no 2-3, p. 734-740Article in journal (Refereed)
    Abstract [en]

    Multiple property enhancement was achieved for ternary blends of PVC, poly(butylene adipate) (PBA) plasticizer and PBA-grafted nanofillers as compared to ternary blends with untreated nanofillers. The blends with surface modified halloysite, kaolin or silicon dioxide nanofillers all exhibited higher stress at break and higher strain at break as compared to the corresponding composites with untreated nanoparticles. The strain at break was similar or improved compared to binary PVC/PBA blends. Most significant improvement was observed for the films containing surface treated halloysite nanofillers. Over 100% increase in stress at break and strain at break was obtained when compared to the corresponding nanocomposite containing untreated halloysite fillers. In addition to tensile testing the prepared films were characterized by DSC, SEM, TGA and FTIR imaging to evaluate the miscibility and thermal properties. Interestingly the FTIR imaging analysis revealed that the surface grafting of halloysite resulted not only in improved dispersion of halloysite filler, but also in more homogenous distribution of PBA plasticizer in the blends. During aging in contact with aqueous solution the films containing kaolin exhibited the smallest weight loss. This is explained by the plate like structure of kaolin which prevents the migration of PBA molecules.

  • 4308.
    Yin, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Green Plasticizers from Liquefied Wood2014In: Waste and Biomass Valorization, ISSN 1877-2641, E-ISSN 1877-265X, Vol. 5, no 4, p. 651-659Article in journal (Refereed)
    Abstract [en]

    Green plasticizers were designed from liquefied wood flour, a non-edible biobased waste product. Wood flour was liquefied to low molecular weight polyols by acid catalyzed reaction. The resulting polyol mixture, including the remaining liquefaction solvents glycerol and diethylene glycol, was further utilized for the synthesis of low molecular weight ester plasticizers. Monomeric (MLWP) and oligomeric (OLWP) plasticizers were prepared by esterification of the polyols by hexanoic acid or a mixture of hexanoic and adipic acid, respectively. Liquefied wood polyol mixture and the synthesized plasticizers were characterized by size exclusion chromatography, electrospray ionization-mass spectrometry and fourier transform infrared spectroscopy. MLWP, OLWP and traditional dioctyl phthalate (DIOP) plasticizer were blended with poly(vinyl chloride) (PVC) and tensile testing was performed to evaluate the plasticizing efficiency of the new plasticizers. In addition PVC blends containing model disaccharide ester, sucrose octaacetate (SOA), were prepared and tested. Highest strain at break was obtained after addition of SOA ester, which clearly shows the potential of sugar esters as PVC plasticizers. Addition of MLWP also resulted in slightly higher strain at break as compared to films plasticized with same amount of phthalate plasticizer, DIOP. Differential scanning calorimetry showed one concentration dependent glass transition temperature for all the studied blends indicating good miscibility. Our novel plasticizers are attractive environmentally friendly alternatives for phthalate plasticizers and could be prepared from biomass waste from agriculture and forest industry.

  • 4309.
    Yin, Bo
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Hakkarainen, Minna
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymer Technology.
    Oligomeric Isosorbide Esters as Alternative Renewable Resource Plasticizers for PVC2011In: Journal of Applied Polymer Science, ISSN 0021-8995, E-ISSN 1097-4628, Vol. 119, no 4, p. 2400-2407Article in journal (Refereed)
    Abstract [en]

    Oligo(isosorbide adipate) (OSA), oligo(isosorbide suberate) (OSS), and isosorbide dihexanoate (SDH) were synthesized and evaluated as renewable resource alternatives to traditional phthalate plasticizers. The structure of the synthesized oligomers was confirmed by nuclear magnetic resonance spectroscopy (H-1-and C-13-NMR), and molecular weight was determined by size exclusion chromatograph. The plasticizers were blended with poly(vinyl chloride) (PVC), and the miscibility and properties of the blends were evaluated by differential scanning calorimetry, fourier transform infrared spectroscopy, tensile testing, and thermogravimetry. Especially the blends plasticized with SDH had almost identical properties with PVC/diisooctyl phthalate (DIOP) blends. The blends containing OSA and OSS plasticizers, based on dicarboxylic acids, had somewhat lower strain at break but higher stress at break and better thermal stability compared to the PVC/DIOP or PVC/SDH blends. All the synthesized isosorbide plasticizers showed potential as alternative PVC plasticizers.

  • 4310.
    Yin, Litao
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing.
    FEM Modelling of Micro-galvanic Corrosion in Al Alloys Induced by Intermetallic Particles: Exploration of Chemical and Geometrical Effects2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Localized corrosion, such as pitting, crevice corrosion or galvanic corrosion, is a long-standing phenomenon that can greatly limit the life of metallic materials. For decades experimental methods have been used to try to understand the underlying physical, chemical and electrochemical processes that control localized corrosion in order to find effective protection methods against its propagation. The complexity of the phenomenon and its small geometric size have often severely restricted the basic understanding of local corrosion. In recent decades, computational methods have been developed as an alternative to the experimental methods. Compared to experimental methods, modeling and numerical simulation enable complicated systems to be systematically investigated without considering the inherent constraints of experimental methods.

        In the current Doctoral thesis, advanced calculation methodology has been used to study galvanic corrosion of an aluminum alloy with geometric resolution at micrometer level. The computational platform has been a commercial FEM-based software, COMSOL Multiphysics, which was combined with another software, Matlab. The current model system consists of a semi-spherical intermetallic particle, surrounded by a pure aluminum matrix. The aluminum surface is covered by an inert passive film, except for a ring-shaped surface around the particle itself. By assuming that the particle is electrochemically more noble than aluminum, it acts as a cathode and the surrounding aluminum ring as anode. By utilizing the FEM-based software, it has been possible to incorporate important physicochemical reactions, including the electrochemical anode and cathode reactions of the individual phases, mass transport of various chemical compounds formed during ongoing electrochemistry, homogeneous reactions in the electrolyte, as well as deposition of corrosion products consisting of Al(OH)3 along parts of the anodic area.

        What has made this study a significant step forward is that not only chemical changes but also geometrical changes have been taken into consideration in the simulation of ongoing micro-galvanic corrosion. Particularly challenging has been to mathematically master the gradual deposition of compact Al(OH)3 on an aluminum surface which gradually dissolves anodically. In the initial modeling work, the deposition of Al(OH)3 was assumed to occur only on the electrode surface, resulting in a gradual blockage of surface activity. In an even more advanced stage, the modeling has also sought to simulate the effect of a deposited porous film of Al(OH)3, formed through homogeneous reactions in the electrolyte. By taking into account inhibited diffusion and migration of chemical products that the porous film causes, its sterically inhibiting effect has for the first time been quantitatively interpreted. The porous corrosion product can most closely resemble the lid experimentally observed above local corrosion attacks, which leads to an even more diminished surface activity in electrochemical reactions compared with the deposition of only compact corrosion products on the anode surface.

        The kinetic model has resulted in a significantly deeper insight into the mechanism of micro-galvanic corrosion of the investigated system. The simulation has been shown to predict the time-dependent geometric changes of the anodically dissolved aluminum surface as well as the flow and distribution of generated chemical products. Contrary to the widely accepted perception that Al(OH)3 is not stable in the occluded acidified electrolyte environment, the calculations predict a higher local pH in the occluded electrolyte. This means that insoluble Al(OH)3 can be deposited on the electrode surface, the blocking effect of which may lead to a termination of the micro-galvanic corrosion. If the ring width is initially 0.5 μm or less, transport of OH- ions from the cathode surface to the occluded electrolyte environment is limited, leading to a local acidification within the occluded dissolving volume. At a given anodic ring width, an increased radius of the cathodic particle instead leads to an increased anodic dissolution rate by formation of a larger area for the cathode reaction. Variation of the chemical parameters in the electrolyte also shows that the simulated micro-galvanic corrosion rate of aluminum has a minimum at pH = 6. Both more acidic and more alkaline conditions result in an elevated anodic dissolution of aluminum. When pH ≤ 4, the deposition of Al(OH)3  becomes negligible, and the micro-galvanic corrosion will continue uninterrupted, completely in accordance with experimental data.

  • 4311.
    Yin, Litao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. Univ Sci & Technol Beijing, China.
    Jin, Ying
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    A FEM model for investigation of micro-galvanic corrosion of Al alloys and effects of deposition of corrosion products2016In: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 192, p. 310-318Article in journal (Refereed)
    Abstract [en]

    A finite element method model has been elaborated aiming at a deeper insight into the influence of microstructure on micro-galvanic corrosion of Al alloys. The model considers a dynamic corroding surface and takes into account kinetic data from local electrochemical reactions, transport of O-2 and ionic species (e.g., Al3+, H+, Cl-), homogeneous reactions in the electrolyte, deposition of reaction products and its influence on both anodic and cathodic reactions. As a first step, an Al matrix with a micrometer-sized cathodic intermetallic particle exposed in 0.1 M NaCl has been considered. The simulation predicts the dynamic changes of the corroding surface, and the flow and distribution of ionic species and of O-2 in space and time. The calculated pH of the electrolyte inside and nearby the occluded corroding volume suggests the formation of insoluble Al(OH)(3) on both the cathodic and anodic areas. This results in blocking effects of anodic and cathodic reactions and in eventual termination of the micro-galvanic corrosion. The predicted deposition of corrosion product is in good agreement with in-situ atomic force microscopy measurements.

  • 4312.
    Yin, Litao
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science. University of Science and Technology Beijing, China.
    Jin, Ying
    Leygraf, Christofer
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Numerical Simulation of Micro-Galvanic Corrosion of Al Alloys: Effect of Chemical Factors2017In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 164, no 13, p. C768-C778Article in journal (Refereed)
    Abstract [en]

    A finite element model for simulating the propagation of micro-galvanic corrosion of Al alloys induced by intermetallic particle was established to reveal the dynamic changes including a moving dissolution boundary, deposition of reaction products and their blocking effect. This model has previously been used to study the influence of geometrical factors such as the particle size and width of the anodic ring. In this work, we explore effects of chemical factors including pH and bulk concentration of O-2 by using chemical-dependent electrochemical kinetics as input parameters. The simulations reveal that the micro-galvanic corrosion rate is slowest at pH = 6. For pH > 6, the rise of pH increases the dissolution rate of Al and also the deposition rate of Al(OH)(3), leading to a faster but more short localized Al dissolution. For pH < 6, the decline of pH accelerates Al dissolution and inhibits Al(OH)(3) deposition, leading to a faster and more long lasting Al dissolution. At pH <= 4, deposition of Al(OH)(3) becomes negligible, and localized corrosion will propagate continuously. Within the O-2 concentration range relevant for atmospheric conditions, a lower O-2 concentration in the solution leads to a slower rate of micro-galvanic corrosion.

  • 4313.
    Ying, Zhong-Shu
    et al.
    Department of Engineering Chemistry, Chalmers University of Technology.
    Gevert, Börje
    Department of Engineering Chemistry, Chalmers University of Technology.
    Otterstedt, Jan-Erik
    Department of Engineering Chemistry, Chalmers University of Technology.
    Sterte, Johan
    Hydrodemetallisation of residual oil with catalysts using fibrillar alumina as carrier material1997In: Applied Catalysis A: General, ISSN 0926-860X, E-ISSN 1873-3875, Vol. 153, no 1-2, p. 69-82Article in journal (Refereed)
    Abstract [en]

    Hydroprocessing catalysts were prepared using fibrillar aluminas as carrier materials and sulphides of nickel and molybdenum as active substances. The fibrillar aluminas were obtained from fibrillar boehmite samples prepared at three different synthesis conditions resulting in different fibril sizes. After extrudation and deposition of metals, catalysts combining large surface areas with large average pore diameters were obtained. The catalysts were tested for hydrodemetallisation of an atmospheric residue and the results were compared with those obtained for a commercial reference catalyst with a similar loading of nickel and molybdenum. Two of the catalysts prepared using fibrillar alumina as carrier material were more active than the commercial catalyst. The third catalyst containing the largest alumina fibrils was inferior to the other catalysts in all respects. Catalyst deactivation was investigated in a long-term hydroprocessing experiment using a heavy vacuum residue containing large amounts of metals as a feed oil. The catalyst prepared using fibrillar alumina used in this test showed a constant level of hydrodemetallisation even after 500 h on stream whereas the reference catalyst was completely deactivated after 350 h.

  • 4314.
    Ying, Zhong-Shu
    et al.
    Chalmers University of Technology, Department of Engineering Chemistry.
    Gevert, Börje
    Chalmers University of Technology, Department of Engineering Chemistry.
    Otterstedt, Jan-Erik
    Chalmers University of Technology, Department of Engineering Chemistry.
    Sterte, Johan
    Large-pore catalysts for hydroprocessing of residual oils1995In: Industrial & Engineering Chemistry Research, ISSN 0888-5885, E-ISSN 1520-5045, Vol. 34, no 5Article in journal (Refereed)
    Abstract [en]

    Hydroprocessing catalysts were prepared using fibrillar alumina and attapulgite as carrier materials and nickel and molybdenum as active substances. With fibrillar alumina as primary particles, a carrier material was obtained which combined a large surface area (138 m2/g) with a large average pore diameter (252 Å). Due to side-by-side association of the fibers, attapulgite did not yield a catalyst carrier with as large pores as was expected. The catalysts were tested for hydroprocessing of an atmospheric petroleum resid, and the results were compared with those obtained for a commercial catalyst with similar loading of nickel and molybdenum. The catalyst prepared using fibrillar alumina as carrier material was more active than the commercial catalyst for hydrodemetalization, equally active for hydrodesulfurization, and less active for hydrodenitrogenation. The catalyst prepared using attapulgite as carrier material was inferior to the other two catalysts in all respects. © 1995 American Chemical Society.

  • 4315. Ylitervo, Päivi
    et al.
    Franzen, Carl Johan
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Ethanol production at elevated temperatures using encapsulation of yeast2011In: Journal of Biotechnology, ISSN 0168-1656, E-ISSN 1873-4863, Vol. 156, no 1, p. 22-29Article in journal (Refereed)
    Abstract [en]

    The ability of macroencapsulated Saccharomyces cerevisiae CBS 8066 to produce previous termethanolnext term at previous termelevatednext termprevious termtemperaturesnext term was investigated in consecutive batch and continuous cultures. Prior to cultivation previous termyeastnext term was confined inside alginate–chitosan capsules composed of an outer semi-permeable membrane and an inner liquid core. The encapsulated previous termyeastnext term could successfully ferment 30 g/L glucose and produce previous termethanolnext term at a high yield in five consecutive batches of 12 h duration at 42 °C, while freely suspended previous termyeastnext term was completely inactive already in the third batch. A high previous termethanolnext termprevious termproductionnext term was observed also through the first 48 h at 40 °C during continuous cultivation at D = 0.2 h−1 when using encapsulated cells. The previous termethanolnext termprevious termproductionnext term slowly decreased in the following days at 40 °C. The previous termethanolnext termprevious termproductionnext term was also measured in a continuous cultivation in which the previous termtemperaturenext term was periodically increased to 42–45 °C and lowered to 37 °C again in periods of 12 h. Our investigation shows that a non-thermotolerant previous termyeastnext term strain improved its heat tolerance upon previous termencapsulationnext term, and could produce previous termethanolnext term at previous termtemperaturesnext term as high as 45 °C for a short time. The possibility of performing fermentations at higher previous termtemperaturesnext term would greatly improve the enzymatic hydrolysis in simultaneous saccharification and fermentation (SSF) processes and thereby make the bioethanol previous termproductionnext term process more economically feasible.

  • 4316.
    Yoshikawa, Masahiro
    et al.
    Central Research Institute of Electric Power Industry, Energy Engineering Research Laboratory, Kanagawa, Japan.
    Bodén, Andreas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sparr, Mari
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Lindbergh, Göran
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Experimental determination of effective surface area and conductivities in the porous anode of molten carbonate fuel cell2006In: Journal of Power Sources, ISSN 0378-7753, E-ISSN 1873-2755, Vol. 158, no 1, p. 94-102Article in journal (Refereed)
    Abstract [en]

    Stationary polarization curves and electrochemical impedance spectroscopy of a porous nickel anode in a molten carbonate fuel cell were obtained in order to determine the active surface area and conductivities with varying degree of electrolyte filling for two anode feed-gas compositions, one simulating operation with steam reformed natural gas and the other one gasified coal. The active surface area for coal gas is reduced by around 70-80% compared to the standard gas composition in the case of Li/Na carbonate. Moreover, an optimal degree of electrolyte filling was shifted toward higher filling degree in the case of operation with coal gas.In order to evaluate the experimental data a one-dimensional model was used. The reaction rate at the matrix/electrode interface is about five times higher than the average reaction rate in the whole electrode in case of 10% electrolyte filling. This result suggests that the lower limit of the filling degree of the anode should be around 15% in order to avoid non-uniform distribution of the reaction in the electrode. Therefore, in the case of applying Li/Na carbonate in the MCFC, an electrolyte distribution model taking into account the wetting properties of the electrode is required in order to set an optimal electrolyte filling degree in the electrode.

  • 4317. Yoshimura, Takeshi
    et al.
    Hayashi, Akiko
    Handa-Narumi, Mai
    Yagi, Hirokazu
    Ohno, Nobuhiko
    Koike, Takako
    Yamaguchi, Yoshihide
    Uchimura, Kenji
    Kadomatsu, Kenji
    Sedzik, Jan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. National Institutes of Natural Sciences, Japan.
    Kitamura, Kunio
    Kato, Koichi
    Trapp, Bruce D.
    Baba, Hiroko
    Ikenaka, Kazuhiro
    GlcNAc6ST-1 regulates sulfation of N-glycans and myelination in the peripheral nervous system2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 42257Article in journal (Refereed)
    Abstract [en]

    Highly specialized glial cells wrap axons with a multilayered myelin membrane in vertebrates. Myelin serves essential roles in the functioning of the nervous system. Axonal degeneration is the major cause of permanent neurological disability in primary myelin diseases. Many glycoproteins have been identified in myelin, and a lack of one myelin glycoprotein results in abnormal myelin structures in many cases. However, the roles of glycans on myelin glycoproteins remain poorly understood. Here, we report that sulfated N-glycans are involved in peripheral nervous system (PNS) myelination. PNS myelin glycoproteins contain highly abundant sulfated N-glycans. Major sulfated N-glycans were identified in both porcine and mouse PNS myelin, demonstrating that the 6-O-sulfation of N-acetylglucosamine (GlcNAc-6-O-sulfation) is highly conserved in PNS myelin between these species. P-0 protein, the most abundant glycoprotein in PNS myelin and mutations in which at the glycosylation site cause Charcot-Marie-Tooth neuropathy, has abundant GlcNAc-6-O-sulfated N-glycans. Mice deficient in N-acetylglucosamine-6-O-sulfotransferase-1 (GlcNAc6ST-1) failed to synthesize sulfated N-glycans and exhibited abnormal myelination and axonal degeneration in the PNS. Taken together, this study demonstrates that GlcNAc6ST-1 modulates PNS myelination and myelinated axonal survival through the GlcNAc-6-O-sulfation of N-glycans on glycoproteins. These findings may provide novel insights into the pathogenesis of peripheral neuropathy.

  • 4318. Youngsukkasem, Supansa
    et al.
    Rakshit, Sudip K.
    Taherzadeh, Mohammad J.
    University of Borås, School of Engineering.
    Biogas production by encapsulated digesting bacteria2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 1, p. 56-65Article in journal (Refereed)
    Abstract [en]

    Encapsulation of methane producing bacteria was performed to enhance the rate of biogas production, using natural as well as synthetic membranes. A one-step liquid-droplet-forming method was employed for the natural membrane, resulting in spherical capsules with an average diameter and a membrane thickness of 4.3 and 0.2 mm, respectively. The capsules were made from alginate, with chitosan or Ca2+ as counter-ions, with addition of carboxymethylcellulose (CMC). For synthetic capsules, the Durapore® membrane (hydrophilic PVDF), with a pore size of 0.1 µm, was used for capsules of the sizes 3×3 and 3×6 cm, holding the bacteria. During the digesting process the dissolved substrates penetrated through the capsule membranes, and biogas developed inside the capsules, escaping by diffusion. The results indicate that encapsulation is a promising method of digestion, with a high density of anaerobic bacteria. The method holds a considerable potential for further development of membranes and their applications.

  • 4319.
    Yu, Fiona
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH).
    Sulfur Addition to Reduce CO Emissions2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In autumn 2017, an experiment was conducted for the reduction of carbon

    monoxide (CO) emissions commissioned by Holmen Paper Braviken, one

    of the world’s most production-efficient paper mills. Digitalization has increased

    in recent years, which has resulted in a decreased demand for graphic

    paper. The goal of finding cost-reducing solutions in the manufacturing process

    has been increased in Holmen Paper Braviken to meet the rising price

    pressure and strengthen competitiveness. Braviken consumes large quantities

    of steam in the paper machines and some of this steam is produced in

    the solid fuel boiler. The solid fuel boiler combusts bark, wood chips, and

    water treatment sludge. When adding sulfur-rich water treatment sludge to

    the fuel mix, it has been observed that CO levels decrease without increasing

    NOx levels. To control the amount of sulfur addition, it has been proposed

    that pure sulfur can be microdosed into the fuel mix. A previous short-term

    experiment was conducted in Braviken during autumn 2016 with a successful

    result.

    The present study was conducted with the aim of mapping the effects of

    sulfur addition to the solid fuel boiler in Braviken concerning CO emissions.

    The possibility to operate the plant and interaction with the water treatment

    sludge have also been investigated. The study was performed through

    the construction of a microdosing system and a long-term attempt of sulfur

    addition.

    The result shows that the optimal sulfur concentration of Braviken’s solid

    fuel boiler for reducing CO emissions is 6 kg/h S (1.03 kg S/ton C). The

    interaction between elemental sulfur with the sulfur-rich water treatment

    sludge is complex, but with sulfur dosage a reduction of 42% CO can be

    achieved. NOx levels have not shown any change on the addition of sulfur.

    The study shows that CO emissions are at a more stable level with sulfur dosing.

    The result becomes difficult to analyze because the parameters varied.

    The effects of parameters should be investigated with the recommendation

    to perform a more prolonged experiment on sulfur addition.

  • 4320.
    Yu, Junchun
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Yao, Mingguang
    Gröbner, Gerhard
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundqvist, Bertil
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Tonpheng, Bounphanh
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Liu, Bingbing
    Andersson, Ove
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Buckminsterfullerene: A Strong, Covalently Bonded, Reinforcing Filler and Reversible Cross-Linker in the Form of Clusters in a Polymer2013In: ACS Macro Letters, ISSN 2161-1653, Vol. 2, no 6, p. 511-517Article in journal (Refereed)
    Abstract [en]

    A Buckminsterfullerene/polyisoprene (C60/PI) composite was synthesized at high-temperature, high-pressure (HP&HT) conditions. The composite has significantly improved tensile strength and Young’s modulus, by up to 49% and 88% per wt % C60, respectively, which is much higher than for corresponding composites with carbon nanotube (CNT) fillers. The reinforcing action of C60 fillers is different from that of CNTs as C60 becomes covalently bonded to PI chains, and C60 clusters in PI form C60–C60 covalent bonds. The latter are reversible and break by heating at 1 bar, which suggests improved recyclability of the material and indicates that carbon nanostructures can be used as strong reversible cross-linkers (“vulcanizers”) in elastomers.

  • 4321.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ultra-thin MFI membranes for removal of C3+ hydrocarbons from methane2018In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 551, p. 254-260Article in journal (Refereed)
    Abstract [en]

    The removal of propane and heavier hydrocarbons (C3+) from natural gas is an important part of natural gas upgrading. In the present work, ultra-thin MFI zeolite membranes with a thickness of 400 nm and an estimated Si/Al ratio of 152 were evaluated for separation of C3H8 and n-C4H10 from binary and ternary mixtures with CH4. The membranes were selective towards the heavier hydrocarbons and showed high permeance at all investigated temperatures. At room temperature, the n-C4H10/CH4 separation selectivity was 25, coupled with an n-C4H10 permeance of 31 × 10−7 mol m−2 s−1 Pa−1 for a 10/90 n-C4H10/CH4 binary feed mixture. As the temperature was decreased to 281 K, the separation selectivity increased to as high as 55 with an n-C4H10 permeance of 25 × 10−7 mol m−2 s−1 Pa−1. The separation selectivities for a 10/90 C3H8/CH4 binary mixture were 9.5 and 19, with C3H8 permeances as high as 54 and 37 × 10−7 mol m−2 s−1 Pa−1 at 297 and 271 K, respectively. The higher selectivities observed for n-C4H10 containing mixtures was ascribed to stronger adsorption of n-C4H10 than C3H8 in MFI, thus resulting in higher adsorption selectivities of the n-C4H10 containing mixtures over CH4. For a 10/10/80 n-C4H10/C3H8/CH4 ternary mixture, the highest sum selectivity of (n-C4H10 + C3H8)/CH4 was 48 and the corresponding sum permance of (n-C4H10 + C3H8) was 26 × 10−7 mol m−2s−1 Pa−1 at 283 K, which were similar to the separation results of n-C4H10/CH4 binary mixture at the same conditions. The n-C4H10/CH4 and C3H8/CH4 separation selectivities from the ternary mixture were of course lower, but still as high as 32 and 16 at 283 K, with n-C4H10 and C3H8 permeances of 17 and 8 × 10−7 mol m−2 s−1 Pa−1, respectively. The results show that ultra-thin MFI zeolite membranes are promising candidates for separation of C3+ hydrocarbons from natural gas. 

  • 4322.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ye, Pengcheng
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ultra-thin MFI membranes for olefin/nitrogen separation2017In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 524, p. 428-435Article in journal (Refereed)
    Abstract [en]

    The recovery of light hydrocarbons such as propylene and ethylene from vent streams in polymer plants is desirable since it opens up for more efficient conversion of the monomers with high economic value. Consequently, polymer membrane vapour-gas separation systems have been used for this purpose for decades [1,2]. However, an alternative is zeolite membranes. In this work, ultra-thin MFI zeolite membranes (0.5 µm) were used to separate propylene or ethylene from binary 20/80 olefin/nitrogen mixtures at different temperatures. The membranes were olefin selective with high permeance at all investigated temperatures. At room temperature, the permeance of propylene was 22×10-7 mol m-2 s-1 Pa-1 and the separation factor was 43, which corresponds to a separation selectivity of around 80. For a mixture of 20 mol.% ethylene in nitrogen, the maximum separation factor was 6 (corresponds to a separation selectivity of 8.4) at 277 K with an ethylene permeance of 57×10-7 mol m-2 s-1 Pa-1. The membrane selectivity was governed by more extensive adsorption of olefin, especially propylene, as compared to nitrogen. Comparing with ethylene, propylene has higher heat of adsorption, which probably caused the higher propylene/nitrogen selectivity compared to ethylene/nitrogen selectivity. The permeance and the selectivity for propylene were much higher than for commercial polymeric membranes. For ethylene, the permeance was much higher, and the selectivity was comparable to commercial polymeric membranes. Modelling showed that the pressure drop over the support limited the flux through the membranes especially at higher temperatures and in particular for the ethylene/nitrogen system with high flux. Further, modelling indicated that the result obtained at high temperatures, where the flux was high, was also affected by concentration polarization. However, for the propylene/nitrogen system at the optimum separation temperature, the pressure drop over the support and the concentration polarisation were small. The results show that ultra-thin MFI zeolite membranes are promising candidates for light olefins/nitrogen separation in polymer plants.

  • 4323.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Biogas upgrading by zeolite membranes2016Conference paper (Other academic)
  • 4324.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Highly permeable CHA membranes prepared by fluoride synthesisfor efficient CO2/CH4 separation2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 16, p. 6847-6853Article in journal (Refereed)
    Abstract [en]

    All-silica CHA nanocrystals, much smaller (20–200 nm) than previously reported, were prepared by an improved method developed in the present work. The nanocrystals are prepared by adding milled crystals to a fluoride synthesis mixture and we observed that much smaller crystals are obtained by adding a much higher fraction of milled crystals. In the next step, CHA membranes with a thickness of ca. 1.3 μm were prepared by hydrothermal treatment of a monolayer of nanocrystals supported on porous graded alumina discs in a fluoride synthesis gel. Finally, the membranes were calcined at 480 °C. The highest measured single gas CO2 permeance was 172 × 10−7 mol m−2 s−1 Pa−1 at room temperature. The highly permeable membranes were evaluated for separation of CO2 from an equimolar mixture with CH4 at varying temperatures. The highest observed CO2 mixture permeance was 84 × 10−7 mol m−2 s−1 Pa−1 at 276 K with a separation selectivity of 47 at 9 bar feed pressure and atmospheric permeate pressure. At room temperature, the CO2 mixture permeance was also as high as 78 × 10−7 mol m−2 s−1 Pa−1 with a separation selectivity of 32. To the best of our knowledge, these CO2 permeances are by far the highest reported for CHA membranes, while the selectivity is similar to that reported previously at comparable test conditions.

  • 4325.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Korelskiy, Danil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Very High Flux MFI Membranes for Alcohol Recovery via Pervaporation at High Temperature and Pressure2015In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 153, p. 138-145Article in journal (Refereed)
    Abstract [en]

    Ultra-thin MFI membranes (0.5 μm) were evaluated for recovery of alcohols from dilute aqueous mixtures by pervaporation at high temperature and pressure for the first time. The feed pressure was sufficiently high to keep the feed in liquid state at high temperature, while the permeate pressure was kept at atmospheric and a low flow of sweep gas was used to reduce the partial pressure on the permeate side. Atmospheric pressure on the permeate side is more practical than vacuum. High feed temperature and pressure result in high fugacity in the liquid feed, which, in combination with lower permeate pressure, results in a large driving force. Consequently, the membrane exhibited very high fluxes for feeds comprised of 10 wt% ethanol/water and 5 wt% n-butanol/water mixtures at 110 °C and 140 °C, respectively. The flux observed for 10 wt% ethanol/water mixtures was as high as about 52 kg m-2 h-1, i.e., 6 times higher than the highest previously reported flux for this separation using zeolite membranes in pervaporation. For 5 wt% n-butanol/water mixtures, the flux was 40 kg m-2 h-1, which is 11 times higher than the highest previously reported flux for this separation by zeolite membranes. At these conditions, the membrane displayed separation factors for ethanol/water and n-butanol/water mixtures of 5 and 16, respectively. However, after about 6 hours of operation, the separation factor decreased significantly and the flux increased due to formation of defects in the membrane when the feed was saturated with silica. Lower membrane stability was observed for silica free feeds. The work has shown that it is possible to obtain high flux in pervporation by using ultra-thin membranes in combination with high feed temperature. The observed membrane selectivity was not excellent, due to pressure drop over the support as well as likely concentration polarization on the feed side resulting from the high flux. Membrane stability was also an issue at these conditions, however it was shown that stability could be improved by saturating the feed with silica.

  • 4326.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Liu, Dong
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Yan, Baili
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Zeng, Changfeng
    College of Mechanic and Power Engineering, Nanjing Tech University.
    Wang, Chongqing
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemistry and Chemical Engineering, Nanjing University of Technology.
    Zhang, Lixiong
    State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology.
    A Universal Biological-materials-assisted Hydrothermal Route to Prepare Various Inorganic Hollow Microcapsules in the Presence of Pollens2016In: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 301, p. 26-33Article in journal (Refereed)
    Abstract [en]

    A universal bio-economical hydrothermal route has been developed to prepare various inorganic hollow microcapsules with the help of rapeseed pollens for the first time. The pollens were used without any modifications. TiO2, ZnO, zeolite ZSM-5, BaTiO3 and ZnS were prepared by this route using the regular synthesis solutions added with rapeseed pollens. The obtained products were examined by scanning and transmission electron microscopy, X-ray diffraction, FT-IR, N2 adsorption and thermogravimetric analysis. The hollow microcapsules are composed of inorganic particles around the derivations of pollens. And the diameter of the hollow has been demonstrated almost the same size as the derivations microspheres. The derivations were decomposed in high temperature crystallization procedure; therefore, no additional procedure is needed to remove the templates for the hollow structure. The hollow microcapsules prepared with rapeseeds have much higher specific surface area. The formation mechanism can be ascribed to the template effect of derivative microspheres formed from decomposition of these pollen grains. Furthermore, other pollens are also used in the preparation by the universal hydrothermal route. Still, inorganic hollow microcapsules but with different hollow diameters were obtained probably resulting from the different size of the derivations.

  • 4327.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing, 210009, PR China.
    Zeng, Changfeng
    College of Mechanic and Power Engineering, Nanjing Tech University.
    Wang, Chongqing
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing.
    Zhang, Lixiong
    State Key Laboratory of Materials-Oriented Chemical Engineering, College of Chemical Engineering, Nanjing Tech University, Nanjing.
    In situ impregnation−gelation−hydrothermal crystallization synthesis of hollow fiber zeolite NaA membrane2017In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 244, p. 278-283Article in journal (Refereed)
    Abstract [en]

    Chitosan-assisted in situ impregnation−gelation−hydrothermal (IGH) crystallization process has been developed for the preparation of hollow fiber zeolite NaA membranes. Firstly, chitosan-zeolite NaA composite hollow fibers were prepared successfully by assistance of a simple homemade tube-in-orifice spinneret. The composite hollow fibers were initially prepared by in situ impregnation–gelation–hydrothermal transformation of chitosan-silica hollow fibers in aluminate solution. Zeolite NaA membranes can be subsequently obtained on the outer surface of chitosan-zeolite NaA composite hollow fibers by in situ microwave hydrothermal treatment. The zeolite crystals in the composite hollow fibers serve as seeds for the growth of zeolite membrane. Moreover, the chitosan-silica hollow fibers were prepared by solidification of chitosan hollow fibers, which were formed in the tube-in-orifice spinneret from a chitosan-silica sol viscous aqueous solution, in the sodium hydroxide solution. Pervaporation for separation of 90 wt% ethanol aqueous solution was employed to examine the obtained membranes. The hollow fiber membranes showed high permeation flux and high stability.

  • 4328.
    Yu, Q. Z.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Brage, Claes O.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Nordgreen, Thomas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Sjöström, Krister
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Effects of Chinese dolomites on tar cracking in gasification of birch2009In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 88, no 10, p. 1922-1926Article in journal (Refereed)
    Abstract [en]

    To minimize tar in the producer gas from birch gasification at 700, 750 and 800 degrees C, four Chinese dolomites (Zhenjiang, Nanjing, Shanxi, Anhui) and a Swedish dolomite (Sala) used as reference were studied in a laboratory-scale atmospheric fluidized bed gasifier. The gasifier was equipped with a downstream fixed catalyst bed. The results imply that all dolomites but Anhui dolomite effectively decompose tar into gases. Anhui dolomite showed a low catalytic capacity to crack tar produced at 700 and 800 degrees C. The influence of various ratios of steam to biomass on tar content in the producer gas after passing over dolomite was studied. The tar cracking efficiency of the dolomites did not improve significantly with the ratio of steam to biomass in the region 0.11-0.52.

  • 4329.
    Yu, Wenbin
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Reitberger, Torbjörn
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology.
    Hjertberg, T.
    Oderkerk, J.
    Costa, F. R.
    Gedde, Ulf W.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Antioxidant consumption in squalane and polyethylene exposed to chlorinated aqueous media2012In: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 97, no 11, p. 2370-2377Article in journal (Refereed)
    Abstract [en]

    Squalane stabilized with 0.2 wt.% of Irganox 1010 and a medium-density polyethylene containing 0.1 wt.% of the same antioxidant were exposed to two different aqueous media (water solutions containing either 10 ppm Cl-2 or 10 ppm ClO2, both buffered to pH = 6.8) at different temperatures between 30 and 70 degrees C. The squalane phase was characterized by differential scanning calorimetry (oxidation induction time, OIT) and infrared spectroscopy, and the aqueous media were analysed after concentrating the analytes using liquid-liquid extraction by liquid chromatography, mass spectrometry and infrared spectroscopy. OIT measurements were carried out on the polyethylene samples after exposure to the chlorinated aqueous media. Exposure of the squalane systems to water containing ClO2 resulted in discolouration by the formation of quinoid structures and a faster depletion of the antioxidant than exposure to water containing Cl-2. The activation energy for the loss of antioxidant activity on exposure to ClO2-water was very low (<10 kJ mol(-1)) in the squalane test (no diffusion control) and 21 +/- 2 kJ mol(-1) at a depth of 1-2 mm from the surface of polyethylene plaques (diffusion control). Calculation from earlier published OIT data from a HDPE exposed to Cl-2-water yielded an activation energy for the loss antioxidant activity of 68 kJ mol(-1). The antioxidant degradation products obtained from the exposure to the ClO2 aqueous medium were found at a higher concentration, were more polar and exhibited a higher proportion of low molar mass species than those obtained after exposure to the Cl-2 aqueous medium. The important chemical difference between ClO2 and Cl-2 is that the former is a one-electron oxidant whereas the latter preferentially reacts by hydrogen substitution. Possible further reactions, in agreement with the observations made, are proposed.

  • 4330. Yu, Xinhai
    et al.
    Wen, Zhenzhong
    Lin, Ying
    Tu, Shan-Tung
    Wang, Zhengdong
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Intensification of biodiesel synthesis using metal foam reactors2010In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 89, no 11, p. 3450-3456Article in journal (Refereed)
    Abstract [en]

    This study presents a technology for continuous and high-efficiency alkali-catalyzed biodiesel synthesis using a metal foam reactor combined with a passive mixer. A metal foam reactor with higher pore density produces smaller droplets that result in higher efficiency of biodiesel synthesis. Compared with conventional stirred reactors, the time for high methyl ester conversion can be shortened remarkably by the use of metal foam reactors. Experimental results reveal that a metal foam reactor of 50 pores per inch exhibits an energy consumption per gram biodiesel of 1.01 J g(-1), merely 1.69% and 0.77% of energy consumption of the zigzag micro-channel and conventional stirred reactors, respectively. Moreover, biodiesel yield per reactor for the metal foam reactor is approximately 60 times that of the zigzag micro-channel reactor, thus overcoming the problem of numbering up an excessive number of reactors in the application. These results indicate the great potential of metal foam reactors in small-fuel biodiesel processing plants for distributive applications.

  • 4331.
    Yu, Xinhai
    et al.
    E China Univ Sci & Technol, China.
    Yang, Jie
    Univ Shanghai Sci & Technol, China.
    Lu, Haitao
    E China Univ Sci & Technol, China.
    Tu, Shan-Tung
    E China Univ Sci & Technol, China.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Royal Inst Technol, Stockholm, Sweden.
    Energy-efficient extraction of fuel from Chlorella vulgaris by ionic liquid combined with CO2 capture2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 160, p. 648-655Article in journal (Refereed)
    Abstract [en]

    Algae-sourced feedstocks remain confined to commercialization because of the high cost and energy consumption of biomass cultivation and feedstock extraction. In this study, to reduce the energy consumption required for algae extraction, experiments with Chlorella vulgais extraction by ionic liquids (ILs) combined with CO2 capture were conducted considering that captured CO2 by ILs can compensate the energy consumption of extraction. The results showed that the addition of CO2 to [BMIM][BF4] increased the lipid yield of Chlorella vulgaris from 68.0% to 75.6%. The properties of synthesized biodiesel from C vulgaris lipids met the UNE-EN 14214 European biodiesel standard except for oxidative stability. Protein denaturation and degradation were found during the lysis of algae cells. Approximately 82.2 wt.% of the total extracted proteins could be precipitated during both algae lysis and supernatant liquid drying. A microalgae-to-biofuel route including C vulgaris extraction and CO2 capture was proposed that involves wet algae input and delivery outputs of water, biodiesel, pyrolysis oil, proteins, sugars, biogas and glycerol. Fossil energy ratios (FER) based on the overall energy balance were 3.30 (n = 1, n is the volume ratio of IL to wet algae) and 3.84 (n = 2) for [BMIM][BF4] with CO2 capture, approximately 2.5 times those based on commercially available technologies. The possibilities of synthesizing novel ILs that show both high CO2 absorption and good abilities in cell wall breakage are discussed. More progress is greatly needed to reduce IL recovery loss. (C) 2015 Elsevier Ltd. All rights reserved.

  • 4332.
    Yu, Ziyun
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Rasmuson, Åke Christoffer
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Transport Phenomena.
    Selective desorption of carbon dioxide from sewage sludge for in-situ methane enrichment – modeling of the desorption processIn: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909Article in journal (Other academic)
  • 4333.
    Yuan, Kang
    et al.
    Linköping University, Department of Management and Engineering.
    Peng, Ru
    Linköping University, Department of Management and Engineering.
    Li, Xin-Hai
    Finspang, Sweden.
    Johansson, Sten
    Linköping University, Department of Management and Engineering.
    Hot Corrosion Behavior of HVOF-sprayed CoNiCrAlYSi Coatings in a Sulphate Environment2015In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 122, no part A, p. 47-53Article in journal (Refereed)
    Abstract [en]

    HVOF-sprayed CoNiCrAlYSi coatings were tested at 900 °C in a hot corrosion environment containing sodium–potassium sulphates. The HVOF spraying caused the typical splat-on-splat structure. The results after the hot corrosion testing showed that the corrosion preferentially occurred at the coating surface and the splat boundaries. The oxidation along the splat boundaries can isolate the splat from the underlying coating matrix. In those isolated splats or coating parts, internal oxidation and nitridation of Al took place, following that the Al-depleted coating fragments were then oxidized to spinels. For those coatings which had a worse splat boundary quality (i.e. with higher porosity and intersplat oxides) or had a worse coating surface quality (i.e. with more small coating fragments therefore more interfaces), heavier corrosion attack was observed on those coatings due to the corrosion of the splats or the coating fragments. The results indicated that the as-sprayed coating quality including porosity and surface morphology was important for the hot-corrosion resistance of the coatings.

  • 4334. Yurindatama, D.
    et al.
    Barsoum, Imad
    KTH, School of Engineering Sciences (SCI), Aeronautical and Vehicle Engineering, Lightweight Structures. The Petroleum Institute, United Arab Emirates.
    Constitutive model and failure locus of a polypropylene grade used in offshore intake pipes2017In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 57, p. 245-259Article in journal (Refereed)
    Abstract [en]

    BorECO®™ BA212E is a polypropylene block co-polymer which has become a common material in the manufacturing of large diameter non-pressurized gravity offshore intake pipelines. These lines are used for transportation of sea water for cooling of petrochemical process plants. The pipe sections are joined by butt heat fusion welding to create the pipeline. Recently a few premature failures of such pipelines have been reported in the field. Hence, there is a need to characterize the constitutive behavior of the pipe and weld material in order to properly design these pipes. The aim of this work is to determine the material constitutive behaviors of the pipe material and the welded joint material. Uniaxial tensile tests of both the pipe and weld joint material are conducted at various strain rates. Both the pipe and weld material show a rather high strain rate dependency, with the weld material having about half the yield strength than that of the pipe material. An analytical constitutive material model is developed for both the pipe and weld material, incorporating the effect of strain rate. The failure locus, expressed in terms of the equivalent plastic strain at failure vs. the stress triaxiality, for both materials is also determined as part of the constitutive model using notched dumbbell specimens. The constitutive model and failure loci for the pipe and weld material are implemented in a finite element model (FEM) and are validated by conducting a series of independent four-point bend experiments on both material types. The validation is carried out by comparing the FEM results of the four-point bend model with the experimental results, which show a rather good agreement.

  • 4335. Yusuf, Abdul Aleem
    Improvement of Oxygen Barrier Properties by Enzyme Technology2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 4336. Zaccone, Alessio
    et al.
    Soos, Miroslav
    Lattuada, Marco
    Wu, Hua
    Bäbler, Matthäus
    Department of Chemistry and Applied Biosciences, Institute for Chemical and Bioengineering, ETH Zurich.
    Morbidelli, Massimo
    Breakup of dense colloidal aggregates under hydrodynamic stresses2009In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 79, no 6, p. 061401-Article in journal (Refereed)
    Abstract [en]

    Flow-induced aggregation of colloidal particles leads to aggregates with fairly high fractal dimension (d(f) similar or equal to 2.4-3.0) which are directly responsible for the observed rheological properties of sheared dispersions. We address the problem of the decrease in aggregate size with increasing hydrodynamic stress, as a consequence of breakup, by means of a fracture-mechanics model complemented by experiments in a multipass extensional (laminar) flow device. Evidence is shown that as long as the inner density decay with linear size within the aggregate (due to fractality) is not negligible (as for d(f) similar or equal to 2.4-2.8), this imposes a substantial limitation to the hydrodynamic fragmentation process as compared with nonfractal aggregates (where the critical stress is practically size independent). This is due to the fact that breaking up a fractal object leads to denser fractals which better withstand stress. In turbulent flows, accounting for intermittency introduces just a small deviation with respect to the laminar case, while the model predictions are equally in good agreement with experiments from the literature. Our findings are summarized in a diagram for the breakup exponent (governing the size versus stress scaling) as a function of fractal dimension.

  • 4337.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, University of Tabriz.
    Nikjoo, Dariush
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science. Physical Chemistry Department, University of Tabriz.
    Liquid-Liquid and Liquid-Liquid-Solid Equilibrium of the Poly(ethyleneglycol) Dimethyl Ether 2000 + Sodium Sulfate + Water System2008In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 53, no 11, p. 2666-2670Article in journal (Refereed)
    Abstract [en]

    The phase diagram for the poly(ethylene glycol) dimethyl ether (PEGDE) + Na2SO4 + H2O system at298.15 K using PEGDE with a molar mass of 2000 was determined. Compositions of the liquid-liquid and the liquid-liquid-solid equilibria were determined using calibration curves of refractive index of the solutions, and atomic absorption (AA) and X-ray diffraction analyses were made on the solids. The solid phase in equilibrium with the biphasic region was anhydrous Na2SO4. An empirical nonlinear three-parameter expression developed by Merchuk was used for reproducing the experimental binodal data at T ) (288.15,298.15, 308.15, and 318.15) K, and the fitting parameters were obtained for the corresponding temperatures.The effects of temperature on the binodal curve were also studied, and it was observed that the area of the biphasic region increased slightly with an increase in temperature. The experimental tie-line compositions at the aforementioned temperatures were fitted to both the Othmer-Tobias and Bancroft and Setschenowtypeequations. Correlation coefficients for all equations are reported.

  • 4338.
    Zafarani-Moattar, Mohammed Taghi
    et al.
    Physical Chemistry Department, Faculty of Chemistry (Excellence of Science for New Materials and Clean Chemistry) University of Tabriz.
    Nikjoo, Dariush
    Physical Chemistry Department, University of Tabriz.
    Phase Diagrams for Liquid-Liquid and Liquid-Solid Equilibrium of the TernaryPoly(ethylene glycol) Dimethyl Ether 2000 + Sodium Carbonate + Water System2009In: Journal of Chemical and Engineering Data, ISSN 0021-9568, E-ISSN 1520-5134, Vol. 53, no 11, p. 2666-2670Article in journal (Refereed)
    Abstract [en]

    The complete phase diagram for the poly(ethylene glycol) dimethyl ether 2000 (PEGDME2000) + Na2CO3+ H2O system at 298.15 K was determined. Experimental liquid-liquid equilibrium phase diagrams, tielines, and plait points were obtained for the ternary system. Compositions of the liquid-liquid and the liquid-liquid-solid equilibria were determined from calibration curves of refractive index of the solutions, and atomic absorption (AA) and X-ray diffraction analyses were made on the solids. Binodal curves were described using the Merchuk equation at T ) (288.15, 293.15, 298.15, 308.15, and 318.15) K, and the fitting parameters were obtained for the corresponding temperatures. The effects of temperature on the binodal curve were also studied, and it was observed that the area of the biphasic region increased slightly with increase in temperature. Also, the tie lines were fitted to both the Othmer-Tobias and Bancroft andSetschenow-type equations. Correlation coefficients for all equations are reported.

  • 4339.
    Zagorodni, Andrei
    KTH, Superseded Departments, Materials Science and Engineering.
    Evaluation of results obtained by analysis of fractions2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 512, no 2, p. 251-256Article in journal (Refereed)
    Abstract [en]

    The paper discusses treatment of experimental data obtained from the monitoring of continuous processes by a series of batch analyses (i.e. by analysis of fractions sequentially collected during the process). Common errors that are committed when graphically representing and fitting such data are shown. An approach for identification of such errors in published data is presented. One error results from the incorrect positioning of the analysis results along the X-axis when plotting data. In the case of equal fractions, this results in a systematic error along the X-axis. For non-equal fractions, the error in the coefficients of the fitting equation can be both systematic and random. A correct representation does not introduce any error if the actual function is linear in the region of the fraction collection. This plotting method is also a satisfactory procedure for low curvature functions. Another error originates because of the incorrect application of the least squares method. The reason lies in the fact that the analysis of each fraction does not represent an instant value of the measured parameter, but rather the averaged value over some period of time or over some volume. The actual error depends on the curvature of the fitting function. Furthermore, a reader encounters difficulties when evaluating published scientific information because many authors do not explain the methods by which their data were plotted and fit. The presented approach to the evaluation of graphical data makes it possible to identify the described errors.

  • 4340.
    Zaidi, Syed Faraz Ali
    et al.
    Mälardalen University, School of Sustainable Development of Society and Technology.
    Sudthanom, Juthatip
    Mälardalen University, School of Sustainable Development of Society and Technology.
    To Analyze The Relationship between BOD, Nitrogen And Phosphorus Contents at Constant Dissolved Oxygen Concentration In Municipal Wastewater Treatment2011Independent thesis Advanced level (degree of Master (One Year)), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [en]

    In this report, the application of Principle Component Analysis (PCA) and Partial Least Square (PLS)  regression analyzing methods used to understand the relationship of interdependent loads in municipal wastewater treatment plant. Two different wastewater treatment plants were chosen for analysis of  the relationship between interdependent loads. Firstly, the collected data of incoming wastewater and outgoing water from both Västerås and Eskilstuna wastewater treatment plants were analyzed to find some relationship or correlation between contents and compare the data of both the plants. Secondly, the correlated contents were used to generate the regression model for predicting the value in the future, in this report we have focussed only on ammonium nitrogen value for regression model. The PCA study shows the variation between incoming and outgoing wastewater’s characteristics  given by  Västerås and Eskilstuna plant.   

  • 4341. Zakrzewska, A.
    et al.
    Zaleśny, R.
    Kolehmainen, E.
    Ośmiałowski, B.
    Jȩdrzejewska, B.
    Ågren, Hans
    KTH, School of Biotechnology (BIO), Theoretical Chemistry and Biology.
    Pietrzak, M.
    Substituent effects on the photophysical properties of fluorescent 2-benzoylmethylenequinoline difluoroboranes: A combined experimental and quantum chemical study Dedication: This publication is dedicated to the memory of Prof. Jerzy Pa̧czkowski.2013In: Dyes and pigments, ISSN 0143-7208, E-ISSN 1873-3743, Vol. 99, no 3, p. 957-965Article in journal (Refereed)
    Abstract [en]

    In this study, we demonstrate a successful synergy between theory and experiment and report on the photophysical properties of a recently synthesized series of substituted 2-benzoylmethylenequinoline difluoroboranes with a view towards the effect of substitution on their properties. In general difluoroboranes are known to have a bright fluorescence but for some analogs the properties are not fully understood. Quantum chemistry methods have been applied in order to explain a complex structure of the absorption and emission spectra and to gain an insight into the charge redistribution upon the excitation of the investigated molecules. We demonstrate that the spectra of this important class of compounds can be satisfactorily simulated using quantum chemistry methods. In particular, the absorption and emission band structure was resolved and the spectral features were assigned to C-H wagging and skeletal vibrations of the polycyclic core.

  • 4342.
    Zamani, Akram
    University of Borås, School of Engineering.
    Superabsorbent Polymers from the Cell Wall of Zygomycetes Fungi2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The present thesis presents new renewable, antimicrobial and biodegradable superabsorbent polymers (SAPs), produced from the cell wall of zygomycetes fungi. The cell wall was characterized and chitosan, being one of the most important ingredients, was extracted, purified, and converted to SAP for use in disposable personal care products designed for absorption of different body fluids. The cell wall of zygomycetes fungi was characterized by subsequent hydrolysis with sulfuric and nitrous acids and analyses of the products. The main ingredients of the cell wall were found to be polyphosphates (4-20%) and copolymers of glucosamine and N-acetyl glucosamine, i.e. chitin and chitosan (45-85%). The proportion of each of these components was significantly affected by the fungal strain and also the cultivation conditions. Moreover, dual functions of dilute sulfuric acid in relation to chitosan, i.e. dissolution at high temperatures and precipitation at lowered temperatures, were discovered and thus used as a basis for development of a new method for extraction and purification of the fungal chitosan. Treatment of the cell wall with dilute sulfuric acid at room temperature resulted in considerable dissolution of the cell wall polyphosphates, while chitosan and chitin remained intact in the cell wall residue. Further treatment of this cell wall residue, with fresh acid at 120°C, resulted in dissolution of chitosan and its separation from the remaining chitin/chitosan of the cell wall skeleton which was not soluble in hot acid. Finally, the purified fungal chitosan (0.34 g/g cell wall) was recovered by precipitation at lowered temperatures and pH 8-10. The purity and the yield of fungal chitosan in the new method were significantly higher than that were obtained in the traditional acetic acid extraction method. As a reference to pure chitosan, SAP from shellfish chitosan, was produced by conversion of this biopolymer into water soluble carboxymethyl chitosan (CMCS), gelation of CMCS with glutaraldehyde in aqueous solutions (1-2%), and drying the resultant gel. Effects of carboxymethylation, gelation and drying conditions on the water binding capacity (WBC) of the final products, were investigated. Finally, choosing the best condition, a biological superabsorbent was produced from zygomycetes chitosan. The CMCS-based SAPs were able to absorb up to 200 g water/g SAP. The WBC of the best SAP in urine and saline solutions was 40 and 32 g/g respectively, which is comparable to the WBC of commercially acceptable SAPs under identical conditions (34-57 and 30-37 g/g respectively).

  • 4343.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Birbas, Daniella
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Márquez Montesino, Francisco
    niversidad de Pinar del Río, Departamento de Quimica, Pinarde de Río, Cuba,.
    Preparation of Activated Carbon: Forest residues activated with Phosphoric Acid and ZincSulfate2011In: VII EDICIÓN DE LA CONFERENCIA CIENTÍFICA INTERNACIONAL MEDIOAMBIENTE SIGLO XXI, MAS XXI 2011, 2011Conference paper (Refereed)
    Abstract [en]

    This paper describes the preparation of activated carbon by chemical activation. The selected biomass used as precursor is sawdust from both Cuban and Swedish Pine tree. Phosphoric acid and Zinc Sulphate are the chemical reagents. The objective is to study the influence of acid concentration, impregnation ratio and activation temperature on adsorption performance of the obtained activated carbon.

    The experiments with phosphoric acid activation show that treatment with 40% acid concentration at 400 °C produce an activated carbon with good properties for ammonia adsorption and good iodine number. If a 30% phosphoric acid is used for activation, an activation temperature of 500 °C is recommended. With an impregnation ratio of 1, good adsorption was obtained in the activated carbon produced from Swedish pine while using Cuban pine a higher adsorption was obtained with an impregnation ratio of 2.

    The experiments with Zinc Sulphate activation show that activation conditions of 20% zinc sulphate concentration, 400 °C and impregnation ratio: 1 are enough to produce an activated carbon with good properties for ammonia adsorption. The adsorption of carbon tetrachloride was lower. Activated carbons produced with 10 % zinc sulphate concentration, 0.5 impregnation ratio and 400 °C activation temperature (the mildest studied conditions) show already good iodine number and BET surface area.    

  • 4344.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Björnbom, Emilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Reaction Engineering.
    Grimm, Alejandro
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Reaction Engineering.
    Biosorbentes para la remoción de cobre (II) en soluciones acuosas2005Conference paper (Refereed)
  • 4345.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Majari, Mehdi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Björnbom, Emilia
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Reaction Engineering.
    Biomass pre-treatment by torrefaction2008Conference paper (Refereed)
  • 4346.
    Zanzi Vigouroux, Rolando
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Technology.
    Tsyntsarski, B.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Budinova, T.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Petrov, N.
    Institute of Organic Chemistry, Bulgarian Academy of Sciences.
    Influence of the chemical composition of agricultural by-products on their behavior during thermal treatment2008Conference paper (Refereed)
  • 4347.
    Zarazua Mujo, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences.
    In-vitro study of antibiotic and strontium release from hydroxyapatite spheres and its PMMA composite2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of this project was to study the in vitro release of cephalothin, vancomycin and strontium from hydroxyapatite particles and its PMMA composite. The hydroxyapatite spheres containing strontium were prepared in the laboratory. The in vitro release study for the hydroxyapatite was carried out in phosphate buffer saline solution (PBS) with differing pH value at 37 °C for five days and the PMMA composites for 21 days.

    All of the releases showed a burst release within the first 24 hours followed by a slow release. The pH value of the release medium had influence on the release rate to some extent for the antibiotic release and the acidic solution had a more significant impact on the strontium release. All of the composite groups had a much lower strontium release rate than the strontium release from the hydroxyapatite spheres.

  • 4348.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Andersson, Fredrik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Almesåker, Ann
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences, Engineering and Mathematics.
    Removal of dissolved and colloidal substances from mechanical pulping white waters by flotation2011In: 16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC / [ed] Wang, L. et al., Tianjin: China Light Industry Press , 2011, p. 1238-1242Conference paper (Other academic)
    Abstract [en]

    Various sorts of process water, foaming agents and a new chelating surfactant have been investigated in the chemical optimization of flotation ofwaters generated at laboratory and white water from mechanical pulping. Turbidity measurements, the Orcinol method for quantitative carbohydrate analysis and total organic carbon (TOC) as well as gas chromatography (GC) of extractives, have been carried out to determine theremoval and characteristics of Dissolved and Colloidal substances (DisCo). The tests have been realized under different conditions, such as using different flotation cells, foaming agents and complexing agents at different temperatures and pH values. It was found that a reduction of thewhite water turbidity of 70% and a 50% removal of the lipophilic substances from the white water can be obtained in a single-stage flotationunit, and that the selection of suitable flotation equipment, foaming agents and solution conditions plays a very important role in the removalcapacity of the unwished substances.

  • 4349.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Removal of lipophilic extractives and manganese ions from spruce TMP waters in a customized flotation cell2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 2, p. 2376-2392Article in journal (Refereed)
    Abstract [en]

    The influence of a chelating surfactant, different foaming agents, cationic polyelectrolytes, pH value, and temperature on the purification efficiency of process waters from a mechanical pulp mill has been studied by flotation in a 1 L customized unit. Turbidity measurements and gas chromatography (GC) were carried out to determine the removal and characteristics of dissolved and colloidal substances (DisCo). The manganese ion content in the process waters before flotation and the metal chelate removal capacity by flotation were determined by Inductively Coupled Plasma (ICP) and Atomic Absorption Spectrometry (AAS) measurements. It was found that a 99% removal of complex bound manganese ions and a 94% decrease in turbidity of the TMP water produced at the laboratory can be achieved in a single-stage flotation with a chelating surfactant and a foaming agent. Furthermore, a 91% decrease in turbidity, the removal of up to 96% of resin and fatty acids, and 93% of triglycerides from TMP water can be obtained after application of a foaming agent.

  • 4350.
    Zasadowski, Dariusz
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Hedenström, Erik
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Edlund, Håkan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Norgren, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of applied science and design.
    Use of a Voith flotation cell for removal of lipophilic extractives and Mn ions from spruce thermomechanical pulping process waters2012In: BioResources, ISSN 1930-2126, E-ISSN 1930-2126, Vol. 7, no 3, p. 2784-2126Article in journal (Refereed)
    Abstract [en]

    The effects of a chelating surfactant and different foaming agents on the efficiency of cleaning process waters from a thermomechanical pulp (TMP) mill were studied in a Voith flotation cell. Turbidity measurements and gas chromatography were used to determine the removal extent and characteristics of dissolved and colloidal substances (DisCo). The metal ion content in the process waters before flotation and the metal chelate removal after flotation were determined using inductively coupled plasma-optical emission spectrometry (ICP-OES). FiberLab (TM) equipment was used to characterize changes in the size of fibers present in the process waters. The results indicate that a decrease in turbidity of up to 91% and the removal of 80% of lipophilic extractives in the TMP water could be obtained using a single-stage flotation unit. Furthermore, the foam fraction was within 5% of the initial volume, and 100% of the Mn2+/chelating surfactant complex added to the TMP water was removed.

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