Ethylene glycol-functionalized commercial anion exchange membrane as an efficient adsorbent for the treatment of Congo red dye-contaminated wastewater

Water conservation and wastewater treatment have emerged as a worldwide challenge. Excessive concentrations of organic dyes in water can damage both humans and aquatic life. One of the most used azo dye, Congo red (CR), needs specific attention because of its high persistence in aquatic environments and potential for damage. This work aims to eradicate Congo red dye from wastewater utilizing a soluble polymer anion exchange membrane, i.e., ethylene glycol-functionalized benzyl dimethyl tetradecyl ammonium bromide (EG-BDTAB). The membrane’s structural, functional, and thermal properties were estimated using SEM, FTIR, and TGA. The thermal data were analyzed using the Coats Redfern technique to calculate the kinetic triplet: activation energy (E_a), g(α) function, and frequency factor (A). The experimental parameters (including the effect of solution pH, contact time, and initial concentration, on the elimination of CR dye by the utilization of an (EG-BDTAB) membrane in batch adsorption mode) were optimized through the response surface methodology that further helped to assess the inter-parameter interdependence and the maximal uptake capacity (q_e). Several kinetic models, including the pseudo-first-order, pseudo-second-order, liquid film diffusion, Bangham, Elovich, and Freundlich models, were employed on the experimental data. The adsorption of CR on the EG-BDTAB membrane closely matched the pseudo-second-order model (R² > 0.992). The adsorption of CR onto the (EG-BDTAB) was studied by using both linear and nonlinear isotherms models. The membrane was tested for its recyclability, and it showed a negligible loss in efficiency for three consecutive cycles.