Development of Highly Water Stable Graphene Oxide-Based Composites for the Removal of Pharmaceuticals and Personal Care Products

In the present study, sorption of pharmaceuticals ((acetaminophen (ACP), carbamazepine (CBZ)) and personal care products (bisphenol A (BPA), caffeine (CAFF), triclosan (TCS)) using a graphene oxide (GO)-based composite adsorbent was extensively studied. Structural characterization indicated the incorporation of activated carbon and chitosan onto the GO. For both classes of pollutants, the adsorption kinetics followed a pseudo-second-order kinetic model. On the other hand, the Langmuir isotherm showed a better fit compared to the Freundlich isotherm. Maximum adsorption capacities of ACP, CBZ, BPA, CAFF, and TCS were found to be 13.7, 11.2, 13.2, 14.8, and 14.5 mg/g, respectively. Desorption of ACP, BPA, and CAFF was significantly higher in a polar solvent (70%-80%), whereas CBZ and TCS were able to desorb (60%) in a nonpolar solvent. DFT calculations indicated that the adsorption mechanism is majorly accompanied by size-related diffusion and also a minor contribution by synergetic combination of hydrophobic/hydrophilic, hydrogen bonding, electrostatic, and π- π interactions. Overall, the prepared composite material showed enhanced structural stability along with higher removal characteristics toward multiple emerging contaminants in water and wastewater.