Abstract
Pharmaceuticals and personal care products (PPCPs) residues in water and wastewater have a thoughtful impact on man, animal and environment. In this paper, we studied the removal of dextromethorphan (Dex) and guaifenesin (Gua) as an example of hazardous PPCPs from an aqueous solution using activated charcoal (AC). The effect of adsorption time, sothent mass, solution pH, and temperature were optimized The adsorption kinetics was investigated at different temperatures, applying pseudo-first-order and the pseudosecond-order kinetic models. The results showed that the adsorption kinetic follows the pseudo-second-order model with the very good agreement. Also, the adsorption mechanism was studied for Dex and Gua via infra-particle diffusion and the liquid-film diffusion models; the results show partial agreement with both models particularly at 20 degrees C, with acceptable linear regression coefficients. The adsorption isotherm of Dex and Gua fit well with a good agreement with Langmuir model. In addition, the thermodynamic parameters including free energy, enthalpy, and entropy have been calculated and discussed. AC showed relatively good removal efficiency especially at low concentration.