Activated carbon embedded chitosan/polyvinyl alcohol biocomposites for adsorption of nonsteroidal anti-inflammatory drug-naproxen from wastewater

The feasibility of using activated carbon/chitosan-poly (vinyl alcohol) biocomposites (AC/CHTPVA) as an adsorbent for removal of naproxen from a factory wastewater in Tuzla, Istanbul/Turkey was studied in the presented study. The biocomposites were synthesized with different AC: CHT-PVA ratios of 1.0; 2.0 and 3.0 (w/w). The adsorbent materials were characterized by FT-IR, SEM and TGA analysis. When AC was embedded into CHT-PVA matrix, the naproxen removal performance increased from 41.01% to 97.03%. The optimal pH for maximum adsorption was found as 7.0. Equilibrium isotherms for the naproxen adsorption onto AC/CHT-PVA biocomposite were measured experimentally. The Langmuir model was fitted to the equilibrium data better than The Freundlich, Temkin and Dubinin-Raduskevich isotherm models. The mono layer adsorption capacity of AC/ CHT-PVA:3.0 for naproxen was found to be 12.24 mg/g at 298 K. According to the kinetics results, the equilibrium time of AC/CHT-PVA biocomposites was found 100 min and it was indicated that the adsorption follows the pseudo second-order kinetic model. The process was favorable and spontaneous. The thermodynamic parameters, ΔG°, ΔS° and ΔH° were calculated and the enthalpy of adsorption (ΔH°) was found positive for all biocomposites supported the endothermic nature of adsorption reactions.