Impact of Synthetic Clay as Filling Agents on the Dye Adsorption Capacity of Hydrogel

Abstract

Abstract-The focus of this study was to investigate whether the adsorption capacity of a Kappa-carrageenan based hydrogel towards cationic dyes (Basic red and Brilliant green) could be increased by using synthetic clays, cloisite (C) as filling agents. Hydrogel-cloisite composites were synthesized by using a free radical graft copolymerization technique. The hybrid nanocomposites were characterized using SEM and FT-IR spectroscopy. Adsorption experiments investigated the effects of the following parameters: adsorbent dosage, initial dye concentration, and contact time. The Langmuir-and Freundlich isotherm models were used to determine the hydrogel-cloisite nanocomposites adsorption affinity. The firstand second order kinetic models were used to determine the rate of adsorption of cationic dyes. It was found that using cloisite as filling agent for hydrogel resulted in improved adsorption capacity. The hydrogel-cloisite nanocomposite (H-C) displayed the best adsorption capacity for both dyes, with an equilibrium adsorption capacity of 64.14 mg/g for brilliant green (BG) dye and 58.73 mg/g for basic red (BR) dye. The nanocomposite saw a 20% improvement in adsorption capacity towards brilliant green dye and a 17% improvement towards basic red dye. Kappa-carrageenan hydrogel-clay composites can therefore be considered for the treatment of cationic dye containing wastewater.