Facile fabrication of hydrogels for removal of crystal violet from wastewater

Abstract

Purification of dye-laden water endures to be immensely challenging owing to the occurrence of highly persistent and nonbiodegrade dyes, which pose a potential threat to humans, flora, fauna, and environment. The environmental problem was addressed by facile fabrication of poly [(2-acrylamido-2-methyl-1-propane sulfonic acid-co-acrylamide-co-acrylic acid)] hydrogels cross-linked via sodium borate (SB), graphene oxide (GO) or N,N-methylenebisacrylamide (MBA) for elimination of crystal violet (CV) from water. The capability of water uptake was recorded in terms of per cent (%) swelling, which exhibited the attainment of swelling equilibrium in 24 h with corresponding maximum per cent swelling of 2830 for HBR. The sorption capability of the hydrogels was investigated as a function of dosage, contact time, concentration, pH, and temperature. Relative to its other counter parts, the sodium borate cross-linked hydrogels demonstrated highest sorption capability, i.e. 44 mg.g −1 owing to the greater number of available sites. The sorption of CV onto the hydrogels followed pseudo-second-order kinetics and Freundlich isotherm models. The process of CV sorption onto the hydrogels was endothermic and spontaneous accompanied with entropy rise after sorption.