Evaluation of the Adsorption Efficiency of Biopolymer Hydrogel Nanocomposite/Nanoclay in Wastewater Dye Removal

Abstract

A new type of hybrid biopolymer nanocomposite hydrogel was created using sodium alginate and carrageenan combined with N-isopropyl acrylamide and bentonite nanoclay. The hydrogel was synthesised through free radical polymerisation. The purpose was to test its ability to remove the dye crystal violet (CV) from an aqueous solution. The structure and morphology of the synthesised nanocomposite hydrogel were analysed using Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. Key parameters affecting the efficiency of crystal violet removal were explored, including pH, initial dye concentration, contact time, and amount of adsorbent. Optimal values for each parameter were identified. The removal mechanism was highly pH-dependent, with the dye removal rate increasing when more nanoclay was added in an acidic environment. Using an initial dye concentration of 30 mg/L and 0.05 g of the nanocomposite hydrogel, the equilibrium adsorption time was 3 hours. The adsorption matched the Langmuir isotherm model and followed pseudo-second order kinetics. Overall, the nanocomposite hydrogel was an effective adsorbent for eliminating crystal violet dye from water.