Enhanced removal of methyl orange using modified anion exchange membrane adsorbent

In this study, anion exchange membranes are based on polyvinylchloride matrix as a net adsorbent, and then, the membrane surface modification was synthesized as a modified adsorbent to adsorption of methyl orange in batch tests. Regarding the elimination of methyl orange, the effects of solution pH, contact time, initial dye concentration, and adsorbent dosage were carried out. Scanning electron microscope, atomic force microscopy, and Fourier transform infrared spectroscopy have been used to characterize both net adsorbent and modified adsorbent. Three isotherm models were used to fit the experimental data. The results demonstrated that the Freundlich and Langmuir isotherms for net adsorbent and modified adsorbent were well matched to the adsorption isotherm data. The pseudo-second-order kinetic model provided better explanation of the adsorption kinetic data for both adsorbents. In order to determine the rate-limiting step, the pseudo-first-order, pseudo-second-order, and Elovich equations were used. The modified adsorbent exhibited a higher adsorption performance for the removal of methyl orange than net adsorbent and proved to be a potential approach for the adsorption of industrial dye. The measured maximum adsorption capacities for net adsorbent and MA at 25 °C and based on the nonlinear Langmuir isotherm were 90.67 mg/g and 1427.52 mg/g, respectively.