Interfacial interactions in aqueous systems of poly(ε-caprolactone)-co-poly(2-hydroxyethyl methacrylate) hydrogel with dye molecules in synthetic wastewaters

Abstract

The use of dyes is widespread in the textile business, having various detrimental effects on humans and ecosystems. When dying, both cationic and anionic dyes are used. A lot of studies have been conducted in order to find an effective eco-friendly solution to resolve this issue. In this study, we recommend the use of an amphoteric and amphiphilic hydrogel consisting of ε-caprolactone and 2-hydroxyethyl methacrylate which are both biodegradable and cost-effective. The synthesis of this material was confirmed by FTIR, XRD, and SEM. The parameters under which the composite was adsorptively examined were the effects of pH, temperature, and contact time. It was found that the kinetics followed the pseudo fractal-like first order kinetic model for Μethylene Blue, while for Remazol Brilliant Blue R, both the pseudo fractal-like first order and the pseudo-second order models describe the data equally well. Thermodynamic analysis indicated that the adsorption process of both dyes was endothermic and spontaneous. Reuse experiments showed that their removal efficiency was retained at high levels, while stability studies revealed that the hydrogel retains its structural integrity, even at extreme pH values. Finally, the poly(ε-caprolactone)-co-poly(2-hydroxyethyl methacrylate) approach appears to be a viable strategy for removing dye residues from wastewater that is both successful and ecologically acceptable.