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  • 1.
    Abbasi, M.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Backstrom, J.
    Mid Sweden Univ, FSCN Mat Phys, Dept Nat Sci, SE-85170 Sundsvall, Sweden..
    Cornell, Ann M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Fabrication of Spin-Coated Ti/TiHx/Ni-Sb-SnO2 Electrode: Stability and Electrocatalytic Activity2018Inngår i: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 165, nr 9, s. H568-H574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel three-layer anode having the composition Ti/TiHx/Ni-Sb-SnO2 (Ti/TiHx/NATO) was successfully prepared by a spin-coating and pyrolysis process aiming at a long service lifetime and good electrocatalytic properties for ozone formation. The TiHx as an interlayer was produced by electrochemical cathodic reduction of a coated layer of the TiOx on the titanium substrate. Spin coating and thermal decomposition were used to deposit the Sn-Sb-Ni precursor on the surface of the prepared Ti/TiHx electrode. Cyclic and linear scanning voltammetry, Raman spectroscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to reveal the electrode performance and morphology. Results show that the onset potential for the oxygen evolution reaction (OER) of Ti/TiHx /NATO is higher than for Ti/NATO. They also indicate that the service lifetime of the Ti/TiHx/NATO is twice as long as the Ti/NATO at a current density of 50 mA.cm(-2) at room temperature. Electrochemical ozone generation and degradation of the methylene blue were investigated to confirm selectivity and activity of the electrodes. After 5 min electrolysis, a current efficiency for ozone generation of 56% was obtained the electrode with TiHx while 38% was obtained on Ti/NATO under same conditions. The results also confirm that the Ti/TiH x /NATO has a higher kinetic rate constant and decolorization efficiency for removal of the methylene blue compare to the Ti/NATO. The rate constant for the pseudo-first ordered reaction of methylene blue degradation showed high values of 350 x 10(-3) min(-1) for Ti/NATO and 440 x 10(-3) min(-1) for Ti/TiHx/NATO. 

  • 2.
    Abdel-Magied, Ahmed F.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Nasser Abdelhamid, Hani
    Ashour, Radwa M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Zou, Xiaodong
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Hierarchical porous zeolitic imidazolate framework nanoparticles for efficient adsorption of rare-earth elements2019Inngår i: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, s. 175-184Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hierarchical porous zeolitic imidazolate frameworks nanoparticles (ZIF-8 NPs) were synthesized at room temperature via a template-free approach under dynamic conditions (stirring) using water as a solvent. The ZIF-8 NPs were evaluated as adsorbents for rare earth elements (La3+, Sm3+ and Dy3+). Adsorption equilibrium was reached after 7h and high adsorption capacities were obtained for dysprosium and samarium (430.4 and 281.1 mg g(-1), respectively) and moderate adsorption capacity for lanthanum (28.8 mg g(-1)) at a pH of 7.0. The high adsorption capacitiese, as well as the high stability of ZIF-8 NPs, make the hierarchical ZIF-8 materials as an efficient adsorbent for the recovery of La3+, Sm3+ and Dy3+ from aqueous solution.

  • 3.
    Acevedo Gomez, Yasna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    On Gas Contaminants, and Bipolar Plates in Proton Exchange Membrane Fuel Cells2019Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The proton exchange membrane (PEM) fuel cell is an electrochemical device that converts chemical energy into electrical energy through two electrocatalytic reactions. The most common catalyst used is platinum on carbon (Pt/C), which has shown the best performance in the fuel cell until now. However, the drawback of this catalyst is that it does not tolerate impurities, and both hydrogen and oxygen may carry small amounts of impurities depending on the production sources. The purpose of this thesis is to understand the effect of two impurities that are less investigated, i.e., ammonia, which may accompany the hydrogen rich reformates from renewable sources, and nitrogen dioxide, which may come from air pollution. The mechanism of contamination and an adequate recovery method for the respective contaminant are studied. Additionally, electroplated bipolar plates with Ni-Mo and Ni-Mo-P coatings were tested as alternatives to stainless steel and carbon materials.

    The results show that ammonia not only provokes changes in the polymer membrane but also in the oxygen reduction reaction (ORR), hydrogen oxidation reaction (HOR) and catalyst ionomer in both electrodes. The extent of performance recovery after the contamination depends on the concentration used and the exposure time. In contrast, nitrogen dioxide affects the catalyst in the electrode directly; the contamination is related to side reactions that are produced on the catalyst’s surface. However, NO2 is not attached strongly to the catalyst and it is possible to restore the performance by using clean air. The time the recovery process takes depends on the potential applied and the air flow.

    Finally, the evaluation of electroplated Ni-Mo and Ni-Mo-P on stainless steel by ex situ and in situ studies shows that these coatings reduce the internal contact resistance (ICR) and the corrosion rate of the stainless steel considerably. However, the in situ experiments show that phosphorus addition to the coating does not improve the fuel cell performance; thus, the Ni-Mo alloy is found to be a promising choice for electroplating stainless steel bipolar plates.

  • 4.
    Acevedo Gomez, Yasna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Effect of nitrogen dioxide impurities on PEM fuel cell performanceManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Air is the most practical and economical oxidant to feed to the cathode in a proton exchange membrane fuel cell (PEMFC). However, the air is accompanied by small amounts of impurities that affect the performance of the fuel cell. Among these, nitrogen dioxide is the impurity that has been least investigated, and its effect is not fully understood. In this study, a possible mechanism is proposed based on the contamination of the fuel cell at different concentrations and adsorption potentials, and by employing stripping cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results at different concentrations showed that the catalyst sites are blocked by the adsorption of NO2, and that there is a non-linear relationship between the concentration and degradation. The degradation is suggested to be related to the formation of intermediate species, as also shown by the pseudo-inductive impedance at the concentration of 100 and 200 ppm. Furthermore, the cyclic voltammetry showed that there is an oxidation to NO3- at 1.05 V, followed by the reduction of this specie to NO2- at 0.68 V, and a subsequent reduction of NO2- to N2O and/or NH2OH.

  • 5.
    Acevedo Gomez, Yasna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Performance recovery after contamination with nitrogen dioxide in a PEM fuel cellManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    While the market of fuel cell vehicles is increasing, these vehicles will still coexist with combustion engine vehicles on the roads and will be exposed to an environment with significant amounts of contaminants that will decrease the durability of the fuel cell. In order to investigate different recovery methods, a PEM fuel cell is in this study contaminated with 100 ppm of NO2 at the cathode side. The possibility to recover the cell performance is studied by using different airflow rates, different current densities, and by subjecting the cell to successive polarization curves. The results show that the successive polarization curves are the best choice for recovery; it took 35 min to reach full recovery of cell performance, compared to 4.5 hours of recovery with pure air at 0.5 A cm-2 and 110 ml min-1. However, the performance recovery at a current density of 0.2 A cm-2 and air flow 275 ml min-1 was done in 66 min, which is also a possible alternative. Additionally, two operation techniques are suggested and compared during 7 h of operation; air recovery and air depletion. The air recovery technique shows to be a better choice than the air depletion technique.

  • 6.
    Ahuja, Dipali
    et al.
    Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Svärd, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära. Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära. Univ Limerick, Synth & Solid State Pharmaceut Ctr, Bernal Inst, Dept Chem Sci, Castletroy, Co Limerick, Ireland..
    Investigation of solid-liquid phase diagrams of the sulfamethazine-salicylic acid co-crystal2019Inngår i: CrystEngComm, ISSN 1466-8033, E-ISSN 1466-8033, Vol. 21, nr 18, s. 2863-2874Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The influence of temperature and solvent on the solid-liquid phase diagram of the 1 : 1 sulfamethazinesalicylic acid co-crystal has been investigated. Ternary phase diagrams of this co-crystal system have been constructed in three solvents: methanol, acetonitrile and a 7 : 3 (v/v) dimethylsulfoxide-methanol mixture, at three temperatures. The system exhibits congruent dissolution in acetonitrile and the co-crystal solubility has been determined by a gravimetric technique. The Gibbs energy of co-crystal formation from the respective solid components has been estimated from solubility data, together with the corresponding enthalpic and entropic component terms. The Gibbs energy of formation ranges from -5.7 to -7.7 kJ mol -1, with the stability increasing with temperature. In methanol and the DMSO-methanol mixture, the co-crystal dissolves incongruently. It is shown that the solubility ratio of the pure components cannot be used to predict with confidence whether the co-crystal will dissolve congruently or incongruently. The size of the region where the co-crystal is the only stable solid phase is inversely related to the pure component solubility ratio of salicylic acid and sulfamethazine.

  • 7.
    Alemrajabi, M.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Forsberg, Kerstin
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Korkmaz, Kivanc
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Isolation of rare earth element phosphate precipitate in the nitrophosphate process for manufacturing of fertilizer2016Konferansepaper (Fagfellevurdert)
  • 8.
    Alemrajabi, Mahmood
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Recovery of Rare Earth Elements from an Apatite Concentrate2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Rare earth elements (REE) are a group of 17 elements including lanthanides, yttrium and scandium; which are found in a variety of classes of minerals worldwide. The criticality of the application, lack of high grade and economically feasible REE resources and a monopolistic supply situation has raised significant attention in recovery of these metals from low grade ores and waste materials. In this thesis, the recovery of REE from an apatite concentrate, containing 0.5 mass% of REE, within the nitrophosphate route of fertilizer production has been investigated. Most of the REE (≥ 95%) content can be recovered into a phosphate precipitate with almost 30 mass% REE. Different processes have been developed to convert the REE phosphate precipitate into a more soluble form to obtain a solution suitable for further REE purification and individual separation. It has been shown that after reprecipitation of the REE phosphate concentrate as REE sodium double sulphate and then transformation into a REE hydroxide concentrate, a solution containing 45g/L REE free of Ca, Fe and P can be obtained. The results suggest that the apatite waste after processing of iron ore have the potential to be a very important source for REE in Europe and that the economy is strongly supported by the simultaneous extraction of phosphorous.

    The potential of using hollow fiber supported liquid membrane (HFSLM) extraction in individual and group separation of REE has been investigated. A hollow fiber supported liquid membrane plant in pilot scale has been operated according to the three main configurations: standard hollow fiber supported liquid membrane technology (HFSLM); hollow fiber renewal liquid membrane technology (HFRSLM) and emulsion pertraction technology (EPT). The standard HFSLM operation is more selective than HFRSLM and EPT, while higher metal transport rate is observed in EPT followed by HFRSLM and HFSLM. The HFRLM configuration helps to maintain the performance of the liquid membrane.

  • 9.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Korkmaz, Kivanc
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Dephosphorization and impurity removal from a rare earth phosphate concentrate2017Konferansepaper (Fagfellevurdert)
  • 10.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Recovery of phosphorous and rare earth elements from an apatite concentrate2018Konferansepaper (Fagfellevurdert)
  • 11.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Korkmaz, Kivanc
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Processing of a rare earth phosphate concentrate obtained in the nitrophosphate process of fertilizer production2019Inngår i: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158Artikkel i tidsskrift (Fagfellevurdert)
  • 12.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Rasmuson, Åke C.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Korkmaz, Kivanc
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Recovery of rare earth elements from nitrophosphoric acid solutions2017Inngår i: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 169, s. 253-262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the present study, the recovery of rare earth elements (REEs) from an apatite concentrate in the nitrophosphate process of fertilizer production has been studied. The apatite concentrate has been recovered from iron ore tailings in Sweden by flotation. In the first step, the apatite is digested in concentrated nitric acid, after which Ca(NO3)2.4H2O is separated by cooling crystallization. The solution is then neutralized using ammonia whereby the REEs precipitate mainly as phosphates (REEPO4.nH2O) and together with calcium as REEn Cam (PO4)(3n + 2m) / 3. In this work, the degree of rare earth coprecipitation during seeded cooling crystallization of Ca(NO3)2.4H2O has been studied. The solubility of calcium nitrate tetrahydrate (Ca(NO3)2.4H2O) in acidic nitrophosphoric acid solutions in the temperature range of − 2 °C to 20 °C has been determined. For the neutralization step, it is shown that the calcium concentration and the final pH play an important role in determining the concentration of REEs in the precipitate. It is found that reaching maximum recovery of REE with minimum simultaneous precipitation of calcium requires careful control of the final pH to about 1.8. It is further observed that the precipitation yield of REEs and iron is favored by a longer residence time and higher temperature. Finally, the effect of seeding with synthesized REE phosphate crystals as well as a mixture of REE and Ca phosphates on the precipitation rate and the composition of the precipitate was studied.

  • 13.
    Alemrajabi, Mahmood
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Korkmaz, Kivanc
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Upgrading of a rare earth phosphate concentrate within the nitrophosphate process2018Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 198, s. 551-563Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the nitrophosphate process of fertilizer production, rare earth elements (REE) can be recovered as a REE phosphate concentrate. In this process, after digestion of apatite in concentrated nitric acid, Ca(NO3)2.4H2O is first separated by cooling crystallization and then the REE are precipitated in phosphate form by a partial neutralization step using ammonia. The obtained REE phosphate concentrate is contaminated by mainly calcium and iron, and the main solid phases are CaHPO4.2H2O, FePO4.2H2O and REEPO4.nH2O.

    In this study, a process to obtain a concentrate more enriched with REE with low concentration of calcium and iron and free of phosphorous is developed. In the developed process, enrichment and dephosphorization of the rare earth phosphate concentrate has been achieved by selective dissolution and re-precipitation of the REE as a sodium REE double sulfate salt. It is shown that by selective dissolution of the REE concentrate in nitric acid at a pH of 2.4, most of the calcium and phosphorus are dissolved, and a solid phase more enriched in REE is obtained. Thereafter, the REE phosphate concentrate is first dissolved in a mixture of sulfuric-phosphoric acid and then the REE are reprecipitated as NaREE(SO4)2.H2O by addition of a sodium salt. More than 95% of the Ca, Fe and P are removed and a REE concentrate containing almost 30 mass% total REE is obtained.

  • 14.
    Alemrajabi, Mahmoud
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Recovery of REE from an apatite concentrate in the nitrophosphate process of fertilizer production.2015Konferansepaper (Fagfellevurdert)
  • 15.
    Andersson, Joakim
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Grönkvist, Stefan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Large-scale storage of hydrogen2019Inngår i: International journal of hydrogen energy, ISSN 0360-3199, E-ISSN 1879-3487, Vol. 44, nr 23, s. 11901-11919Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The large-scale storage of hydrogen plays a fundamental role in a potential future hydrogen economy. Although the storage of gaseous hydrogen in salt caverns already is used on a full industrial scale, the approach is not applicable in all regions due to varying geological conditions. Therefore, other storage methods are necessary. In this article, options for the large-scale storage of hydrogen are reviewed and compared based on fundamental thermodynamic and engineering aspects. The application of certain storage technologies, such as liquid hydrogen, methanol, ammonia, and dibenzyltoluene, is found to be advantageous in terms of storage density, cost of storage, and safety. The variable costs for these high-density storage technologies are largely associated with a high electricity demand for the storage process or with a high heat demand for the hydrogen release process. If hydrogen is produced via electrolysis and stored during times of low electricity prices in an industrial setting, these variable costs may be tolerable.

  • 16.
    Ashour, Radwa M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Funktionella material, FNM. Nuclear Materials Authority, Egypt.
    El-sayed, R.
    Abdel-Magied, A. F.
    Abdel-khalek, A. A.
    Ali, M. M.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Uheida, Abdusalam
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Funktionella material, FNM.
    Muhammed, Mamoun
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Funktionella material, FNM.
    Dutta, Joydeep
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Funktionella material, FNM.
    Selective separation of rare earth ions from aqueous solution using functionalized magnetite nanoparticles: kinetic and thermodynamic studies2017Inngår i: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 327, s. 286-296Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Separation of rare earth ions (RE3+) from aqueous solution is a tricky problem due to their physico-chemical similarities of properties. In this study, we investigate the influence of the functionalized ligands on the adsorption efficiency and selective adsorption of La3+, Nd3+, Gd3+ and Y3+ from aqueous solution using Magnetite (Fe3O4) nanoparticles (NPs) functionalized with citric acid (CA@Fe3O4 NPs) or L-cysteine (Cys@Fe3O4 NPs). The microstructure, thermal behavior and surface functionalization of the synthesized nanoparticles were studied. The general adsorption capacity of Cys@Fe3O4 NPs was found to be high (98 mg g−1) in comparison to CA@Fe3O4 NPs (52 mg g−1) at neutral pH 7.0. The adsorption kinetic studies revealed that the adsorption of RE3+ ions follows a pseudo second-order model and the adsorption equilibrium data fits well to the Langmuir isotherm. Thermodynamic studies imply that the adsorption process was endothermic and spontaneous in nature. Controlled desorption within 30 min of the adsorbed RE3+ ions from both Cys@Fe3O4 NPs and CA@Fe3O4 NPs was achieved with 0.5 M HNO3. Furthermore, Cys@Fe3O4 NPs exhibited a higher separation factor (SF) in the separation of Gd3+/La3+, Gd3+/Nd3+, Gd3+/Y3+ ions compared to CA@Fe3O4 NPs.

  • 17.
    Ashour, Radwa
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik. Nuclear Materials Authority, P.O. Box 530, 11381 El Maadi, Cairo, Egypt.
    Samouhos, Michail
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Polido Legaria, Elizabeth
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Svärd, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära.
    Högblom, Joakim
    AkzoNobel, Pulp and Performance Chemicals AB.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Palmlöf, Magnus
    Kessler, Vadim G.
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Seisenbaeva, Gulaim A.
    Swedish University of Agricultural Sciences, Department of Molecular Sciences, Uppsala BioCentre.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    DTPA-Functionalized Silica Nano- and Microparticles for Adsorption and Chromatographic Separation of Rare Earth Elements2018Inngår i: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 6, nr 5, s. 6889-6900Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Silica nanoparticles and porous microparticles have been successfully functionalized with a monolayer of DTPA-derived ligands. The ligand grafting is chemically robust and does not appreciably influence the morphology or the structure of the material. The produced particles exhibit quick kinetics and high capacity for REE adsorption. The feasibility of using the DTPA-functionalized microparticles for chromatographic separation of rare earth elements has been investigated for different sample concentrations, elution modes, eluent concentrations, eluent flow rates, and column temperatures. Good separation of the La(III), Ce(III), Pr(III), Nd(III), and Dy(III) ions was achieved using HNO3 as eluent using a linear concentration gradient from 0 to 0.15 M over 55 min. The long-term performance of the functionalized column has been verified, with very little deterioration recorded over more than 50 experiments. The results of this study demonstrate the potential for using DTPA-functionalized silica particles in a chromatographic process for separating these valuable elements from waste sources, as an environmentally preferable alternative to standard solvent-intensive processes.

  • 18.
    Atasoy, Merve
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Eyice, Ozge
    Queen Mary Univ London, Sch Biol & Chem Sci, London E1 4NS, England..
    Schnurer, Anna
    Swedish Univ Agr Sci, Dept Mol Sci, Bioctr, SE-75007 Uppsala, Sweden..
    Cetecioglu, Zeynep
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Volatile fatty acids production via mixed culture fermentation: Revealing the link between pH, inoculum type and bacterial composition2019Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 292, artikkel-id 121889Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of the study was to investigate the effects of operational parameters, inoculum type and bacterial community on mixed culture fermentation to produce one dominant acid type in the mixture of volatile fatty acids (VFA). The study was performed using three different inocula (large&small granular and slurry) with glucose under various initial pH. The VFA production efficiency reached to 0,97 (gCOD/gSCOD) by granular sludge. VFA composition was changed by initial pH: in neutral conditions, acetic acid; in acidic conditions, acetic and butyric acids, in alkali conditions butyric acid were dominated, respectively. The VFA production was positively affected by the high relative abundance of Firmicutes. On the contrary, a negative correlation was seen between VFA production and the relative abundance of Chloroflexi. The results revealed the physical sludge structure of inoculum was the key factor for production efficiency, whereas, pH was the most important parameter to affect VFA composition.

  • 19.
    Atasoy, Merve
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Owusu-Agyeman, Isaac
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Plaza, Elzbieta
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Cetecioglu, Zeynep
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Bio-based volatile fatty acid production and recovery from waste streams: Current status and future challenges2018Inngår i: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 268, s. 773-786Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Bio-based volatile fatty acid (VFA) production from waste-stream is getting attention due to increasing market demand and wide range usage area as well as its cost-effective and environmentally friendly approach. The aim of this paper is to give a comprehensive review of bio-based VFA production and recovery methods and to give an opinion on future research outlook. Effects of operation conditions including pH, temperature, retention time, type of substrate and mixed microbial cultures on VFA production and composition were reviewed. The recovery methods in terms of gas stripping with absorption, adsorption, solvent extraction, electrodialysis, reverse osmosis, nanofiltration, and membrane contractor of VFA were evaluated. Furthermore, strategies to enhance bio-based VFA production and recovery from waste streams, specifically, in-line VFA recovery and bioaugmentation, which are currently not used in common practice, are seen as some of the approaches to enhance bio-based VFA production.

  • 20. Bai, Q.
    et al.
    Guo, Z.
    Li, H.
    Yang, Xiaohu
    KTH, Skolan för kemivetenskap (CHE).
    Jin, L.
    Yan, Jerry
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Experimental investigation on the solidification behavior of phase change materials in open-cell metal foams2017Inngår i: Energy Procedia, Elsevier Ltd , 2017, Vol. 142, s. 3703-3708Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This study presented an experimental investigation on solidification behavior of fluid saturated in highly porous open-cell copper foams. Particular attention has been made on the effect of pore parameters (pore density and porosity) on the solidification behavior. A purposely-designed apparatus was built for experimental observations. Results showed that the copper foam had a great effect on solidification and the full solidification time can be saved up to 50%, especially preventing the decrease in solidification rate during the later stage of phase change. The smaller the porosity is, the faster the solidification rate will be. Pore density was found to have little influence upon the solidification rate. In addition, the local natural convection does exist but it has a slight effect on solidification, leading to the slant of the solid-liquid interface.

  • 21. Barbarelli, S.
    et al.
    Castiglione, T.
    Zupone, G. L.
    Bova, S.
    Yan, Jinyue
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    CFD Investigation of the Open Center on the Performance of a Tidal Current Turbine2019Inngår i: Renewable Energy Integration with Mini/Microgrid, Elsevier, 2019, Vol. 159, s. 28-33Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In the present paper, a revision of the layout of an innovative open center self-balancing tidal turbine is presented. Initially, the design was characterized by a central deflector, responsible for the machine equilibrium, hosted in the central part of the machine; the presence of this device, however, affected the size of the opening. Moreover, the turbine was conceived as connected to a steel rope subject to tensile stress. These peculiarities brought some critical issues due to the excessive length of the rope and to the size of the deflector, which constrained the diameters ratio. The new design involves the possibility of reducing the anchoring line length by substituting the rope with a series of tubular elements connected by alternate heavy and light nodes. The heavy nodes can gather the anchoring line when the tides stops acting. Moreover, the light nodes are floating deflectors, which develop the same action of the central deflector, whose size, in this configuration, does not affect the equilibrium. In the new machine configuration, the main deflector is located out of the center so that it can counterbalance the torque exerted by the rotor during its rotation. Finally, by means of CFD simulations, some criteria for assessing the best diameter ratio are defined.

  • 22.
    Benavente Araoz, Fabian Andres
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lundblad, Anders
    Res Inst Sweden, RISE, Div Safety & Transport Elect, SE-50462 Boras, Sweden..
    Campana, Pietro Elia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Zhang, Yang
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Cabrera, Saul
    UMSA Univ Mayor San Andres, Carrera Ciencias Quim, Inst Invest Quim, La Paz, Bolivia..
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Photovoltaic/battery system sizing for rural electrification in Bolivia: Considering the suppressed demand effect2019Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, s. 519-528Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rural electrification programs usually do not consider the impact that the increment of demand has on the reliability of off-grid photovoltaic (PV)/battery systems. Based on meteorological data and electricity consumption profiles from the highlands of Bolivian Altiplano, this paper presents a modelling and simulation framework for analysing the performance and reliability of such systems. Reliability, as loss of power supply probability (LPSP), and cost were calculated using simulated PV power output and battery state of charge profiles. The effect of increasing the suppressed demand (SD) by 20% and 50% was studied to determine how reliable and resilient the system designs are. Simulations were performed for three rural application scenarios: a household, a school, and a health centre. Results for the household and school scenarios indicate that, to overcome the SD effect, it is more cost-effective to increase the PV power rather than to increase the battery capacity. However, with an increased PV-size, the battery ageing rate would be higher since the cycles are performed at high state of charge (SOC). For the health centre application, on the other hand, an increase in battery capacity prevents the risk of electricity blackouts while increasing the energy reliability of the system. These results provide important insights for the application design of off-grid PV-battery systems in rural electrification projects, enabling a more efficient and reliable source of electricity.

  • 23.
    Bergman, Susanna L
    et al.
    Princeton University, Science Division, Yale-NUS College, Singapore.
    Granestrand, Jonas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Tang, Yu
    University of Kansas.
    Suárez Paris, Rodrigo
    Scania CV.
    Nilsson, Marita
    Scania CV.
    Feng Tao, Franklin
    University of Kansas.
    Tang, Chunhua
    National University of Singapore.
    Pennycook, Stephen J
    National University of Singapore.
    Pettersson, Lars J
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Bernasek, Steven L
    Princeton University, Science Division, Yale-NUS College, Singapore.
    In-situ characterization by Near-Ambient Pressure XPS of the catalytically active phase of Pt/Al2O3 during NO and CO oxidation2018Inngår i: Applied Catalysis B: Environmental, ISSN 0926-3373, E-ISSN 1873-3883, Vol. 220, s. 506-511Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study concerns near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) studies of a Pt/Al2O3 diesel oxidation catalyst used in exhaust aftertreatment. We apply the technique to an industrial-grade porous catalyst, thus bridging both the pressure and materials gap, and probe the shift in binding energy of Pt 4d under different atmospheres. We observe that oxidizing atmospheres induce a shift in binding energy, corresponding to changes in Pt oxidation state, especially pronounced under an atmosphere of NO and O2. Such changes in Pt oxidation state have previously been linked to dynamic changes in NO oxidation activity.

  • 24.
    Bessman, Alexander
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Interactions between battery and power electronics in an electric vehicle drivetrain2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The electric machine and power electronics in electric and hybrid electric vehicles inevitably cause AC harmonics on the vehicle's DC-link. These harmonics can be partially filtered out by large capacitors, which today are overdimensioned in order to protect the vehicle's battery pack. This is done as a precaution, since it is not known whether ripple-current has any harmful effect on Li-ion  cells.

    We have measured and analyzed the ripple-current present in a hybrid electric bus, and found that a majority of the power was carried by frequencies in the range 100~Hz to 1~kHz. The single most energetic harmonic in this particular vehicle is believed to have been caused  by a misaligned resolver in the motor.

    We have also designed and built an advanced experimental set-up in order to study the effect of ripple-current on Li-ion cells in the lab. The set-up can cycle up to 16 cells simultaneously, with currents of up to 50~A including a superimposed AC signal with a frequency of up to 2~kHz. The cells' temperatures are controlled by means of a climate chamber. The set-up also includes a sophisticated safety system which automatically acts to prevent dangerous situations before they arise.

    Using this set-up we tested whether superimposing AC with a specific frequency improves the charging performance of Li-ion cells. Statistical analysis found no improvement over regular DC cycling, and a physics-based model explains the experimental findings.

    We have also investigated whether ripple-current accelerates the aging of Li-ion cells. Twelve cells were either calendar or cycle  aged for one year, with some cells being exposed to superimposed AC with a frequency of 1~Hz, 100~Hz, or 1~kHz. No effect was observed on any of capacity fade, power fade, or aging mechanism.

    Finally we also tested whether it is possible to heat Li-ion cells from low temperatures using only AC. We propose a method for AC heating of Li-ion cells, and open the discussion for generalizing the technique to larger battery packs.

    In conclusion, ripple-current has negligible effect on Li-ion cells, except for heating them slightly.

  • 25.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rudi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elektroteknisk teori och konstruktion.
    Software documentation for current-rippleequipment2018Rapport (Annet (populærvitenskap, debatt, mm))
  • 26.
    Bessman, Alexander
    et al.
    KTH.
    Soares, Rúdi
    KTH.
    Wallmark, Oskar
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Svens, Pontus
    KTH.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Aging effects of AC harmonics on lithium-ion cellsManuskript (preprint) (Annet vitenskapelig)
  • 27.
    Bessman, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Soares, Rúdi
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Wallmark, Oskar
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Elkraftteknik.
    Svens, Pontus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Aging effects of AC harmonics on lithium-ion cells2019Inngår i: Journal of Energy Storage, E-ISSN 2352-152X, Vol. 21, s. 741-749Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With the vehicle industry poised to take the step into the era of electric vehicles, concerns have been raised that AC harmonics arising from switching of power electronics and harmonics in electric machinery may damage the battery. In light of this, we have studied the effect of several different frequencies on the aging of 28 Ah commercial NMC/graphite prismatic lithium-ion battery cells. The tested frequencies are 1 Hz, 100 Hz, and 1 kHz, all with a peak amplitude of 21 A. Both the effect on cycled cells and calendar aged cells is tested. The cycled cells are cycled at a rate of 1C:1C, i.e., 28 A during both charging and discharging, with the exception of a period of constant voltage at the end of every charge. After running for one year, the cycled cells have completed approximately 2000 cycles. The cells are characterized periodically to follow how their capacities and power capabilities evolve. After completion of the test about 80% of the initial capacity remained and no increase in resistance was observed. No negative effect on either capacity fade or power fade is observed in this study, and no difference in aging mechanism is detected when using non-invasive electrochemical methods of post mortem investigation.

  • 28.
    Bian, Xiaolei
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Liu, Longcheng
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Yan, Jinying
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    A model for state-of-health estimation of lithium ion batteries based on charging profiles2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 177, s. 57-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using an equivalent circuit model to characterize the constant-current part of a charging/discharging profile, a model is developed to estimate the state-of-health of lithium ion batteries. The model is an incremental capacity analysis-based model, which applies a capacity model to define the dependence of the state of charge on the open circuit voltage as the battery ages. It can be learning-free, with the parameters subject to certain constraints, and is able to give efficient and reliable estimates of the state-of-health for various lithium ion batteries at any aging status. When applied to a fresh LiFePO 4 cell, the state-of-health estimated by this model (learning-unrequired or learning-required)shows a close correspondence to the available measured data, with an absolute difference of 0.31% or 0.12% at most, even for significant temperature fluctuation. In addition, NASA battery datasets are employed to demonstrate the versatility and applicability of the model to different chemistries and cell designs.

  • 29. Bohlin, M.
    et al.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Application of controlled cooling and seeding in batch crystallization1992Inngår i: The Canadian Journal of Chemical Engineering, Vol. 70, nr 1, s. 120-126Artikkel i tidsskrift (Fagfellevurdert)
  • 30. Bohlin, M.
    et al.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Importance of Macromixing in Batch Cooling Crystallization1996Inngår i: AIChE Journal, Vol. 42, nr 3, s. 691-699Artikkel i tidsskrift (Fagfellevurdert)
  • 31. Bohlin, M.
    et al.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Modeling of growth rate dispersion in batch cooling crystallization1992Inngår i: AIChE Journal, Vol. 38, nr 12, s. 1853-1863Artikkel i tidsskrift (Fagfellevurdert)
  • 32. Bouzek, K.
    et al.
    Cornell, Ann M.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rodrigo, M. A.
    Preface on the special issue 2nd workshop on electrochemical engineering: new bridges for a new knowledge on electrochemical engineering2018Inngår i: Journal of Applied Electrochemistry, ISSN 0021-891X, E-ISSN 1572-8838, Vol. 48, nr 12, s. 1305-1306Artikkel i tidsskrift (Fagfellevurdert)
  • 33.
    Bäbler, Matthäus
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Liberzon, A.
    Saha, D.
    Holzner, M.
    Soos, M.
    Lüthi, B.
    Kinzelbach, W.
    Breakup of individual colloidal aggregates in turbulent flow investigated by 3D particle tracking velocimetry2018Inngår i: Multiphase Flow Phenomena and Applications: Memorial Volume in Honor of Gad Hetsroni, World Scientific Publishing Co. Pte. Ltd. , 2018, s. 83-96Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbulence where their breakup is recorded by three-dimensional particle tracking velocimetry (3D-PTV). The aggregates have an open structure with fractal dimension around 2.2, and their size varies from 0.9 to 3.1 mm which is large compared to the Kolmogorov length scale η = 0.15 mm. 3D-PTV allows for the simultaneous measurement of aggregate trajectories and the full velocity gradient tensor along their pathlines which enables us to access the Lagrangian stress history of individual breakup events. The analysis suggests that aggregates are mostly broken due to accumulation of drag stress over a time interval of order Kolmogorov time scale, O(τη). This finding is explained by the fact that the aggregates are large, which gives their motion inertia and which increases the time for stress propagation inside the aggregate.

  • 34.
    Campana, Pietro Elia
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Wästhage, Louise
    Mälardalen Univ, Sch Business Soc & Engn, Future Energy Ctr, S-72123 Vasteras, Sweden..
    Nookuea, Worrada
    Mälardalen Univ, Sch Business Soc & Engn, Future Energy Ctr, S-72123 Vasteras, Sweden..
    Tan, Yuting
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Yan, Jinyue
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Optimization and assessment of floating and floating-tracking PV systems integrated in on- and off-grid hybrid energy systems2019Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 177, s. 782-795Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Considering the targets of Thailand in terms of renewable energy exploitation and decarbonization of the shrimp farming sector, this work evaluates several scenarios for optimal integration of hybrid renewable energy systems into a representative shrimp farm. In particular, floating and floating-tracking PV systems are considered as alternatives for the exploitation of solar energy to meet the shrimp farm electricity demand. By developing a dynamic techno-economic simulation and optimization model, the following renewable energy systems have been evaluated: PV and wind based hybrid energy systems, off-grid and on-grid PV based hybrid energy systems, ground mounted and floating PV based hybrid energy systems, and floating and floating-tracking PV based hybrid energy systems. From a water-energy nexus viewpoint, floating PV systems have shown significant impacts on the reduction of evaporation losses, even if the energy savings for water pumping are moderate due to the low hydraulic head. Nevertheless, the study on the synergies between water for food and power production has highlighted that the integration of floating PV represents a key solution for reducing the environmental impacts of shrimp farming. For the selected location, the results have shown that PV systems represent the best renewable solution to be integrated into a hybrid energy system due to the abundance of solar energy resources as compared to the moderate wind resources. The integration of PV systems in off-grid configurations allows to reach high renewable reliabilities up to 40% by reducing the levelized cost of electricity. Higher renewable reliabilities can only be achieved by integrating energy storage solutions but leading to higher levelized cost of electricity. Although the floating-tracking PV systems show higher investment costs as compared to the reference floating PV systems, both solutions show similar competiveness for reliabilities up to 45% due to the higher electricity production of the floating-tracking PV systems. The higher electricity production from the floating-tracking PV systems leads to a better competitiveness for reliabilities higher than 90% due to lower capacity requirements for the storage systems.

  • 35.
    Campana, Pietro Elia
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser.
    Zhang, J.
    Univ Maryland, Dept Geog Sci, College Pk, MD 20742 USA..
    Yao, T.
    Sci Syst & Applicat Inc SSAI, Lanham, MD 20706 USA.;NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA..
    Andersson, S.
    Swedish Meteorol & Hydrol Inst, SE-60176 Norrkoping, Sweden..
    Landelius, T.
    Swedish Meteorol & Hydrol Inst, SE-60176 Norrkoping, Sweden..
    Melton, F.
    NASA ARC CREST, Moffett Field, CA 94035 USA.;Calif State Univ Monterey Bay, Sch Nat Sci, Seaside, CA 93955 USA..
    Yan, Jerry
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Energiprocesser. Malardalen Univ, Future Energy Ctr, Sch Business Soc & Engn, SE-72123 Vasteras, Sweden.;KTH Royal Inst Technol, Dept Chem Engn, SE-10044 Stockholm, Sweden..
    Managing agricultural drought in Sweden using a novel spatially-explicit model from the perspective of water-food-energy nexus2018Inngår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 197, s. 1382-1393Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using a multi-disciplinary approach, this paper integrated spatial analysis with agricultural and energy system modelling to assess the impacts of drought on crop water demand, water availability, crop yield, and electricity requirements for irrigation. This was done by a novel spatially-explicit and integrated water-food-energy nexus model, using the spatial climatic data generated by the mesoscale MESAN and STRANG models. In this study, the model was applied to quantify the effects of drought on the Swedish irrigation sector in 2013, a typical drought year, for a specific crop. The results show that drought can severely affect the crop yield if irrigation is not applied, with a peak yield reduction of 18 t/ha, about 50 % loss as compared to the potential yield in irrigated conditions. Accordingly, the water and energy requirements for irrigation to halt the negative drought effects and maintain high yields are significant, with the peaks up to 350 mm and 700 kWh per hectare. The developed model can be used to provide near real-time guidelines for a comprehensive drought management system. The model also has significant potentials for applications in precision agriculture, especially using high-resolution satellite data.

  • 36.
    Carlson, Annika
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Eriksson, Björn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Olsson, Joel
    Lund University.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Jannasch, Patric
    Lund University.
    Lindström, Rakel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Fuel cell evaluation of anion exchange membranes based on PPO with different cation placementManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Four different poly(phenylene oxide)-based anion exchange membranes were investigated for electrochemical performance, conductivity and water transport properties in an operating fuel cell. The polymers have a 1- or 5-carbon alkyl spacer between the backbone and a trimethylalkylammonium or piperidinium cationic group, and two different levels of ion-exchange capacity. These structural variations result in different water uptake, hydration number (λ, number of H2O molecules per cation) and conductivity. It is shown that the use of a 5-carbon alkyl spacer does not improve performance unless coupled with a large increase in ion-exchange capacity for the membranes with trimethylalkylammonium cations. Introduction of a piperidinium cation results in lower performance regardless of high ion-exchange capacity. The polymer with a 1-carbon alkyl spacer shows higher and more stable performance than expected from previous ex-situ evaluation, which is attributed to a lower λ value and lower dependence on humidification. The overall water flux under load is in the direction from anode to cathode and high flux improves the performance primarily at unsaturated cell conditions and higher current densities. In summary the results showed that the membrane properties: high conductivity, a higher water transport from anode to cathode and a lower dependency on hydration promote the higher electrochemical performance. Further, no loss of functional groups or crosslinking is detected even after stressing the membranes extensively. Therefore, with further electrode development and fine-tuning of the operating conditions these membranes are promising for electrochemical applications.

  • 37.
    Carlson, Annika
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Shapturenka, Pavel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Eriksson, Björn
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lindbergh, Göran
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Lagergren, Carina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Wreland Lindström, Rakel
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Electrode parameters and operating conditions influencing the performance of anion exchange membrane fuel cells2018Inngår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 277, s. 151-160Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A deeper understanding of porous electrode preparation and performance losses is necessary to advance the anion exchange membrane fuel cell (AEMFC) technology. This study has investigated the performance losses at 50 °C for varied: Tokuyama AS-4 ionomer content in the catalyst layer, Pt/C loading and catalyst layer thickness at the anode and cathode, relative humidity, and anode catalyst. The prepared gas diffusion electrodes in the interval of ionomer-to-Pt/C weight ratio of 0.4–0.8 or 29–44 wt% ionomer content show the highest performance. Varying the loading and catalyst layer thickness simultaneously shows that both the cathode and the anode influence the cell performance. The effects of the two electrodes are shown to vary with current density and this is assumed to be due to non-uniform current distribution throughout the electrodes. Further, lowering the relative humidity at the anode and cathode separately shows small performance losses for both electrodes that could be related to lowered ionomer conductivity. Continued studies are needed to optimize, and understand limitations of, each of the two electrodes to obtain improved cell performance.

  • 38.
    Cetecioglu, Zeynep
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Dolfing, Jan
    Newcastle Univ, Sch Engn, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England..
    Taylor, Jessica
    Univ Warwick, Sch Life Sci, Coventry CV4 7AL, W Midlands, England..
    Purdy, Kevin J.
    Univ Warwick, Sch Life Sci, Coventry CV4 7AL, W Midlands, England..
    Eyice, Ozge
    Queen Mary Univ London, Sch Biol & Chem Sci, London E1 4NS, England..
    COD/sulfate ratio does not affect the methane yield and microbial diversity in anaerobic digesters2019Inngår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 155, nr A Z, 1986, APPLIED AND ENVIRONMENTAL MICROBIOLOGY, V51, P572 rdy KJ, 2003, FEMS MICROBIOLOGY ECOLOGY, V44, P361, s. 444-454Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Anaerobic digestion of organic matter is the major route of biomethane production. However, in the presence of sulfate, sulfate-reducing bacteria (SRB) typically outcompete methanogens, which may reduce or even preclude methane production from sulfate-containing wastewaters. Although sulfate reduction and methanogenesis can occur simultaneously, our limited understanding of the microbiology of anaerobic digesters treating sulfate-containing wastewaters constrains improvements in the production of methane from these systems. This study tested the effects of carbon sources and chemical oxygen demand-to-sulfate ratio (COD/SO42-) on the diversity and interactions of SRB and methanogens in an anaerobic digester treating a high-sulfate waste stream. Overall, the data showed that sulfate removal and methane generation occurred in varying efficiencies and the carbon source had limited effect on the methane yield. Importantly, the results demonstrated that methanogenic and SRB diversities were only affected by the carbon source and not by the COD/SO42- ratio. 

  • 39.
    Cetecioglu, Zeynep
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Ince, Bahar
    Anaerobic sulfamethoxazole degradation is driven by homoacetogenesis coupled with hydrogenotrophic methanogenesis2016Inngår i: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 90Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, microbial community dynamics were assessed in two lab-scale anaerobic sequencing batch reactors (ASBRs). One of the reactors was fed by synthetic pharmaceutical industry wastewater with sulfamethoxazole (SMX) as the test reactor and the other without sulfamethoxazole as the control reactor. DNA based DGGE results indicated that Clostiridum sp. became dominant in the SMX reactor while the inoculum was dominated with Firmicutes (61%) and Methanomicrobiales (28%). However their abundances in active community decreased through the last phase. Also the abundance of hydro-genotrophs was high in each phase, while acetoclastic methanogens disappeared in the last phase. Q-PCR analysis revealed that there is a significant reduction in the bacterial community approximately 84%, while methanogens increased to 97% through the operation. Additionally an increase in the expression level of bacterial and methanogenic 16S rRNA (60% and 20%, respectively) was detected. Significant correlation between microbial community and the reactor operation data was found. The study demonstrated that the microbial community maintains the system stability under high antibiotic concentration and long-term operation by homoacetogenesis coupled with hydrogenotrophic methanogenesis.

  • 40.
    Chen, Song
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Abdel-Magied, Ahmed F.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Fu, Le
    Uppsala Universitet, Department of Engineering Sciences.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Incorporation of strontium and europium in crystals of α-calcium isosaccharinate2019Inngår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 364, s. 309-316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The final repository for short-lived, low and intermediate level radioactive waste in Sweden is built to act as a passive repository. Already within a few years after closure water will penetrate the repository and conditions of high alkalinity (pH 10.5―13.5) and low temperature (< 7 °C) will prevail. The mobility of radionuclides in the repository is dependent on the radionuclides distribution between solid and liquid phases. In the present work the incorporation of strontium (II) and europium (III) in α-calcium isosaccharinate (ISA) under alkaline conditions (pH ~10) at 5 °C and 50 °C have been studied. The results show that strontium and europium are incorporated into α-Ca(ISA)2 when crystallized both at 5 °C and 50 °C. Europium is incorporated to a greater extent than strontium. The highest incorporation of europium and strontium at 5 °C rendered the phase compositions Ca0.986Eu0.014(ISA)2 (2.4% of Eu(ISA)3 by mass) and Ca0.98Sr0.02(ISA)2 (2.2% of Sr(ISA)2 by mass). XPS spectra show that both trivalent and divalent Eu coexist in the Eu incorporated samples. Strontium ions were found to retard the elongated growth of the Ca(ISA)2crystals. The incorporation of Sr2+ and Eu3+ into the solid phase of Ca(ISA)2 is expected to contribute to a decreased mobility of these ions in the repository.

  • 41.
    Chen, Song
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Wang, Shihuai
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Li, Hu
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap..
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Eu3+ doped monetite and its use as fluorescent agent for dental restorations2018Inngår i: Ceramics International, ISSN 0272-8842, E-ISSN 1873-3956, Vol. 44, nr 9, s. 10510-10516Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is essential but challenging to distinguish the dental restorations from the surrounding teeth when removing filling materials from cavity. In this study, Eu3+ doped monetite was proposed as a fluorescent agent for dental restorations to meet this challenge. Eu3+ doped monetite with enhanced fluorescent property was obtained via a precipitation method. The presence of Eu3+ could prevent the phase transformation of brushite to monetite. However, all the brushite particles transformed to monetite at 300 °C and to tricalcium phosphate at 800 °C. The emission intensity increased with the addition of Eu3+ and reached the maximum when 12 mol% Eu3+ was added into the aqueous solution. With either 254 nm or 393 nm excitation, Eu3+ doped monetite showed the strongest fluorescence emission peaking at 616 nm and other two moderate bands peaking at 699 nm and 593 nm. The excitation spectra at the emission wavelength of 616 nm showed strong absorption peaks at 254 nm and 393 nm. We further investigate the fluorescence properties of Eu3+ doped monetite in one type of dental restorations. Glass ionomer cement with Eu3+ doped monetite exhibited clear fluoresce with origin color under UV irradiation at 254 nm, showing that Eu3+doped monetite is a promising fluorescent agent for dental restorations.

  • 42.
    Chernyshev, Alexander
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Impact of organic cement additives on the mobility of radionuclides in a radioactive waste repository2017Konferansepaper (Fagfellevurdert)
  • 43.
    Chernyshev, Alexander N.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Jonsson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Characterization and degradation of a polyaryl ether based superplasticizer for use in concrete barriers in deep geological repositories2018Inngår i: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 95, s. 172-181Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Superplasticizers are important additives used in concrete barriers in geological waste repositories. Superplasticizers have been a major concern in the long-term assessments of safe geological disposal for radioactive waste since superplasticizers and their degradation products can act as complexing ligands and thereby increase the mobility of radionuclides. In this work a new type of superplasticizer, based on a polyaryl ether polymer, has been characterized. It was found that the superplasticizer combines the structural features of polycarboxylate ether based superplasticizers and sulfonated naphthalene-formaldehyde based superplasticizers and that it contains organophosphatecharged groups. A novel method for evaluating the rate of degradation of the superplasticizer under alkaline conditions was elaborated and the degradation products and rate constant of the process was determined. The results demonstrate that degradation occurs rapidly compared to the typical lifetime of a repository.

  • 44.
    Cornell, Ann
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Tillämpad elektrokemi.
    Rodrigo, Manuel
    Univ Castilla La Mancha, Dept Chem Engn, Ciudad Real, Spain..
    Bouzek, Karel
    Univ Chem & Technol Prague, Prague, Czech Republic..
    Special Issue: 11th European Symposium in Electrochemical Engineering (ESEE 11) Foreword2018Inngår i: Journal of Applied Electrochemistry, ISSN 0021-891X, E-ISSN 1572-8838, Vol. 48, nr 6, s. 559-560Artikkel i tidsskrift (Fagfellevurdert)
  • 45. Croker, D. M.
    et al.
    Davey, R. J.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik. Univ Limerick, Mat & Surface Sci Inst, Dept Chem & Environm Sci.
    Seaton, C. C.
    Nucleation in the p-toluenesulfonamide/triphenylphosphine oxide co-crystal system2013Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, nr 8, s. 3754-3762Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nucleation has been studied in pure co-crystal and mixed co-crystal phase regions of the ternary phase diagram (TPD) in acetonitrile at 20 C using cooling crystallization experiments. Direct nucleation of each of the co-crystal phases in this system was independently observed in regions of the TPD where each is stable. In mixed regions, regions where either a co-crystal and a coformer, or both co-crystals, are stable, the phase that initially nucleated was a function of the mass composition in that region. The relative amount of each phase nucleating could be controlled by adjusting the relative mass fraction of each component. The kinetic return to equilibrium was also observed as the systems were held over time, with the selected mass fractions always returning to the equilibrium dictated by the TPD after 24 h

  • 46. Croker, D. M.
    et al.
    Kelly, D. M.
    Horgan, D. E.
    Hodnett, B. K.
    Lawrence, S. E.
    Moynihan, H. A.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Demonstrating the Influence of Solvent Choice and Crystallization Conditions on Phenacetin Crystal Habit and Particle Size Distribution2015Inngår i: Organic Process Research and Development, Vol. 19, nr 12, s. 1826-1836Artikkel i tidsskrift (Fagfellevurdert)
  • 47.
    Croker, Denise
    et al.
    Chemical and Environmental Science, University of Limerick, Ireland.
    Foreman, Michael
    University of Cork, Ireland.
    Hogan, Bridget
    University of Cork, Ireland.
    Maguire, Nuala
    University of Cork, Ireland.
    Curtis, Elcoate
    University of Cork, Ireland.
    Hodnett, Kieran
    Chemical and Environmental Science, University of Limerick, Ireland.
    Maguire, Anita
    University of Cork, Ireland.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära. Univ Limerick, Ireland.
    Lawrence, Simon
    University of Cork, Ireland.
    Understanding the p-toluenesulfonamide / triphenylphosphine oxide crystal chemistry: a new 1:1 cocrystal and ternary phase diagram2012Inngår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 2, s. 869-875Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A novel 1:1 cocrystal between p-toluenesulfonamide and triphenylphosphine oxide has been prepared and structurally characterized. This 1:1 cocrystal was observed to form during solid state grinding experiments, with subsequent formation of a known 3:2 cocrystal in the presence of excess sulfonamide. Both cocrystals are stable in the solid state. The ternary phase diagram for the two coformers was constructed in two different solvents: acetonitrile and dichloromethane. Examination of these diagrams clarified solution crystallization of both the newly discovered 1:1 cocrystal and the previously reported 3:2 cocrystal, and identified regions of stability for each cocrystal in each solvent. The choice of solvent was found to have a significant effect on the position of the solid state regions within a cocrystal system.

  • 48.
    Dahlin, Sandra
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Lantto, Cornelia
    Luleå University of Technology, Knightec AB.
    Englund, Johanna
    Chalmers University of Technology.
    Westerberg, Björn
    Scania CV.
    Regali, Francesco
    Scania CV.
    Skoglundh, Magnus
    Chalmers University of Technology.
    Pettersson, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Chemical aging of Cu-SSZ-13 SCR catalysts for heavy-duty vehicles –Influence of sulfur dioxide2018Inngår i: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 320, s. 72-83Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Selective catalytic reduction of nitrogen oxides is an efficient technique for emission abatement in heavy-dutyvehicles. Cu-SSZ-13 SCR catalysts are more active than vanadium-based catalysts at low temperatures, but aremore sensitive to deactivation by sulfur. Consequently, there is a need to study poisoning by sulfur for thiscatalyst material. This experimental investigation focuses on the effect of sulfur on the low-temperature per-formance of Cu-SSZ-13 SCR catalysts. The effect of sulfur exposure temperature, and the influence of the NO 2 /NO x ratio, are considered and two different regeneration temperatures are compared. In addition, catalystsamples from an engine-aged catalyst are evaluated. The SO 2 exposure temperature is shown to have an im-portant impact on the deactivation of the Cu-SSZ-13 catalyst. The lowest sulfur exposure temperature (220 °C)results in the most severe deactivation, while the highest temperature during sulfur exposure (400 °C) results inthe lowest degree of deactivation. This was found to be related to the amount of sulfur on the catalyst.Additionally, SO 2 exposure was shown to decrease the N 2 O selectivity. The engine-aged catalyst has a decreasedperformance in terms of both decreased activity and increased N 2 O selectivity. For this catalyst, impurities fromfuel and engine-oil can play a role in the deactivation. Different deactivation mechanisms are seen for the lab-and engine-aged catalysts.

  • 49. Dahlquist, Erik
    et al.
    Mirmoshtaghi, Guilnaz
    Larsson, Eva K.
    Thorin, Eva
    Yan, Jinyue
    Engvall, Klas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Processteknologi.
    Liliedahl, Truls
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Dong, C.
    Hu, X.
    Lu, Q.
    Modelling and simulation of biomass conversion processes2015Inngår i: 2013 8TH EUROSIM CONGRESS ON MODELLING AND SIMULATION (EUROSIM), 2015, s. 506-512Konferansepaper (Fagfellevurdert)
    Abstract [en]

    By utilizing biomass gasification, the energy content of the biomass can be utilized to produce gas to be used for cogeneration of heat and power as well as other energy carriers such as fuels for vehicles. The concept is suitable for application to existing CHP plants as well as for utilizing spent liqour in small scale pulp and paper mills. The introduction would enable flexible energy utilization, use of problematic fuels as well as protects the environment by e.g. avoiding the release of toxic substances. In this paper, the possibilities to develop this concept is discussed. In this paper we compare different gasification processes with respect to what gas quality we get, and how the gasification can be modelled using different modelling approaches, and how these can be combined. Results from simulations are compared to experimental results from pilot plant operations in different scales and with different processes like CFB and BFB Technologies, athmospheric and pressurized, and using steam, air and oxygen as oxidizing media.

  • 50.
    Diesen, Veronica
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemi.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Jonsson, Mats
    KTH, Skolan för kemivetenskap (CHE), Kemi, Tillämpad fysikalisk kemi.
    Effects of cellulose degradation products on the mobility of Eu(III) in repositories for low and intermediate level radioactive waste2017Inngår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 340, s. 384-389Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The deep repository for low and intermediate level radioactive waste SFR in Sweden will contain large amounts of cellulosic waste materials contaminated with radionuclides. Over time the repository will be filled with water and alkaline conditions will prevail. In the present study degradation of cellulosic materials and the ability of cellulosic degradation products to solubilize and thereby mobilise Eu(III) under repository conditions has been investigated. Further, the possible immobilization of Eu(III) by sorption onto cement in the presence of degradation products has been investigated. The cellulosic material has been degraded under anaerobic and aerobic conditions in alkaline media (pH: 12.5) at ambient temperature. The degradation was followed by measuring the total organic carbon (TOC) content in the aqueous phase as a function of time. After 173 days of degradation the TOC content is highest in the anaerobic artificial cement pore water (1547 mg/L). The degradation products are capable of solubilising Eu(III) and the total europium concentration in the aqueous phase was 900 μmol/L after 498 h contact time under anaerobic conditions. Further it is shown that Eu(III) is adsorbed to the hydrated cement to a low extent (<9 μmol Eu/g of cement) in the presence of degradation products.

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