Synthesis of gum acacia-cl-acrylic acid-co-itaconic acid hydrogels for efficient removal of toxic dye rhodamine-B: A step for sustainable environment

In the present study, we prepared Gum Acacia-cl-Acrylic acid-co-itaconic acid (GA-cl-AA-co-IA) hydrogels by free radical crosslink polymerization method for the efficient removal of Rhodamine-B (RhB) dye. The hydrogels were further characterized by different characterization techniques: Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Atomic force microscopy (AFM), Brunuer-Emmett-Teller (BET) and field emission scanning electron microscopy (FE-SEM) to confirm synthesis. The synthesis parameters were optimized by swelling studies, which were performed by gravimetric analysis method. The maximum swelling ability of hydrogels synthesized at optimized concentrations was 2170 % in basic medium. GA-cl-AA-co-IA hydrogels showed a good adsorption ability for RhB dye. The impact of various adsorption parameters (adsorbent dose, initial adsorbate (dye) concentration, pH of medium, and temperature) on adsorption ability was also evaluated. Langmuir, Freundlich and temkin adsorption isotherm model and pseudo first, second order model and intra-particle diffusion kinetic models were used to study the nature of adsorption process and kinetics. The adsorption by the hydrogels were best explained by Langmuir isotherm and Pseudo second order kinetic model. The reusability studies of GA-cl-AA-co-IA hydrogel showed that hydrogels showed good adsorption abilities even after 6 consecutive adsorption desorption cycles.