Adsorption of diclofenac sodium from aqueous solution using polyaniline as a potential sorbent. I. Kinetic studies

This study describes dynamic uptake of antibiotic drug diclofenac sodium from aqueous solution using polyaniline as sorbent. The sorbent polyaniline was prepared by oxidative polymerization of aniline and characterized by FTIR spectrum analysis and TGA. The optimum sorbent/sorbate mg/mL ratio and pH range for maximum drug uptake have been found to be 2.0 and 5.5 to 10.5, respectively. Out of various kinetic models applied, the pseudo second-order kinetic equation has been found to fit well on the kinetic uptake data. The pseudo second-order rate constants for adsorption have been found to be 0.982 x 10⁻², 7.24 x 10⁻², and 18.09 x 10⁻² min⁻¹ mg⁻¹ g for drug solutions with initial concentrations of 10, 20, and 30 mg L⁻¹, respectively. The overall sorption process has been found to be governed by intraparticle diffusion.The sorptive removal of drug from aqueous solution has also resulted in enhancement in bacterial growth of Escherichia coli.