Fabrication of chitosan membrane modified by vanillin and gelatin for crystal violet dye adsorption

Crystal violet is a cationic dye that poses serious environmental risks when accumulated in aquatic ecosystems due to its high toxicity to living organisms. Therefore, effective treatment methods are required to remove this dye from wastewater. In this study, a chitosan (Cs)-based bioadsorbent membrane, cross-linked with vanillin (V) and modified with gelatin (G), was developed to adsorb crystal violet dye. The chitosan/vanillin membrane was mixed with gelatin at various concentrations of 0.5% (CsVG1), 0.75% (CsVG2), and 1% (CsVG3). The adsorption process was examined as a function of pH, contact time, initial dye concentration, and temperature. Porosity, swelling degree, water absorption, FTIR, and SEM were included in the membrane's physicochemical characterization. The results showed that the optimal parameters for dye adsorption were pH 6, contact time 80 min, and temperature 298 K, resulting in 88% dye removal. The adsorption kinetics followed a pseudo-second-order model, and the Freundlich model best described the adsorption isotherm. The thermodynamic analysis demonstrated that the adsorption process was spontaneous and exothermic. Thus, the CsVG membrane has the potential to serve as an effective alternative for removing crystal violet from textile industrial wastewater.