Removal of naproxen from wastewater using chitosan-aerogel-activated carbon biocomposites: Theory, equilibrium, kinetics, thermodynamics, and process optimization.

Abstract

This study investigated the performance of chitosan-aerogel-activated carbon (CHT:AEO:AC) biocomposite as an adsorbent for the removal of naproxen from wastewater. Naproxen removal in % was 99, 33, 62, and 90 using 300 mg of raw AC, raw CHT, CHT:AEO, and CHT:AEO:AC, respectively. Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Temkin isotherm models were used to obtain adsorption isotherms. Chi-squared (χ2 ) and correlation coefficients (R2 ) values showed that the parameters of the Freundlich, Temkin, and D-R models were more suitable for naproxen adsorption than the Langmuir model for raw CHT, CHT:AEO, and CHT:AEO:AC, whereas the Langmuir model fitted well for raw AC. The adsorption of naproxen onto biocomposites was defined by pseudo-second-order kinetic model, and adsorption rate constants were 0.245, 0.036, 0.075, and 0.147 mg g-1 min-1 for raw AC, raw CHT, CHT:AEO, and CHT:AEO:AC, respectively. The impact of optimum process conditions on naproxen adsorption was explored using response surface methodology. The optimum independent variables were 288.94 mg, 29.64°C, and 372.5 min, leading to a rate of naproxen removal onto CHT:AEO:AC of 90.29%. PRACTITIONER POINTS: Naproxen adsorption from wastewater using chitosan-aerogel-activated carbon biocomposite (CHT:AEO:AC) was investigated. The effects of the amount of biocomposite, temperature, and time on the adsorption were investigated. Optimization of the process conditions was carried out using the response surface methodology.