Removal of lindane from aqueous solution by glycidyl methacrylate based chelating macroporous copolymer: kinetics and mechanism

Abstract

Lindane belongs to the persistent organic pollutants (POPs) group, which can cause carcinogenic, endocrine, and neurological problems in an organism. The widespread presence of lindane in the environment demands efficient methods of its removal. In the present work, we investigated the removal of lindane from an aqueous solution using a synthesized macroporous copolymer surface modified with different functional groups through two-step post-functionalization. The modified copolymer was characterized by Fourier transform infrared spectroscopy (FTIR-ATR), scanning electron microscopy (SEM), and mercury intrusion porosimetry. For the kinetics of lindane sorption, pseudo-first-order, pseudo-second-order, Elovich, Avrami, and fractional power models were used via linear and non-linear regression analyses. The quality of the fitting of each model to experimental data was assessed based on seven error functions: coefficient of determination (R2), Marquardt’s percent standard deviation (MPSD), Chi-square statistic test (χ2), hybrid fractional error function (HYBRID), the sum of the errors squared (SSE), sum of the absolute errors (EABS), and average relative error (ARE). The investigation of error estimation methods showed that the pseudo-second-order model best fits the experimental kinetics data for both regression analyses. The mechanism of lindane sorption was investigated by subjecting the data to the liquid film diffusion model, intraparticle diffusion model, Bangham, and Boyd models. The results showed that intraparticle diffusion was not the sole rate-controlling step; film-diffusion also affected the sorption process.