A Biodegradable Hybrid Adsorbent of Modified Chitosan and Activated Carbon for Pharmaceutical Pollutant Removal from Water

The steadily increasing pharmaceutical pollution in water resources has become a critical environmental issue where existing treatment systems fall short. In this project, a filtration system consisting of porous, coagulated chitosan-based adsorbent beads was developed to remove pharmaceutical pollutants from water. In order to achieve more effective adsorption levels, the surface areas of the chitosan beads were expanded through lyophilization. Furthermore, a hybrid adsorption system was created by physically combining the lyophilized chitosan beads with activated carbon powder. This configuration was selected to combine the established adsorption characteristics of chitosan and activated carbon within a single adsorbent system. However, because parallel experiments using the individual adsorbent components were not conducted, the specific contribution of each component and any additive or synergistic effect of the hybrid configuration could not be determined experimentally. The system was designed using chitosan and activated carbon with the aim of providing a potentially more sustainability-oriented adsorbent configuration. This way, the process reflects a potentially more sustainable adsorbent configuration. In order to evaluate the success of the newly created adsorbent system, two pharmaceuticals that are abundant in water sources, caffeine and naproxen, were used. The pharmaceuticals were used at a high initial concentration of 10 ppm and the system efficacy was tested using a fixed-bed column setup. Under the tested fixed-bed conditions, the initial absorbance measurements corresponded to estimated removal values of 90.3% for caffeine and 96.4% for naproxen. These values were obtained from single-run UV–Vis measurements using absorbance ratios without dedicated analyte-specific calibration curves and should therefore be interpreted as preliminary removal estimates. Ultimately, this system presents a potentially sustainable solution for treating environments with dense pharmaceutical loads, such as hospital wastewaters.