In this review, several factors have been collected from previous studies on emerging pharmaceutical pollutant adsorption to explain and describe the mechanisms and determine the reactions involved: X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), and the Boehm titration are the most used characterization techniques to determine activated carbons’ surface functional groups. Some studies have confirmed that the specific surface area and the pore structure are not more important than the functional groups present in the adsorbent surface to explain the amount of adsorption obtained and to describe correctly the interaction between the adsorbent-adsorbate. After the analysis of several studies, we concluded that to have good adsorption, it is necessary to choose the right treatment with the right activating agent to obtain the appropriate functions that will enhance the adsorption process. In addition, the functions that can react with the pharmaceutical pollutants are the oxygenated functions such as hydroxyl function, carboxylic function, and carbonyl function.