Microwave-Assisted Synthesis of Guar-Gum and Carboxymethyl Cellulose-Based Hydrogel for Efficient Removal of Crystal Violet and Brilliant Green Dyes

This study reports the microwave synthesis of Guar gum (GG) and Carboxymethyl cellulose (CMC) based hydrogel covalently crosslinked using epichlorohydrin (epi), aiming to remove hazardous dyes like Crystal Violet (CV) and Brilliant Green (BG). The optimized parameters were the reaction time (40 s), solvent (12 ml), pH (11), the ratio of reactants (GG: CMC, 1 : 2), and crosslinker concentration (0.8 ml) resulting in the highest percentage of swelling (4215 %). The synthesized hydrogel was characterized by different techniques like FTIR, TGA, FESEM/EDX, and XRD. The adsorption ability of the synthesized hydrogel was assessed for the removal of toxic dyes. Different kinetic and isotherm models were used to evaluate the type of adsorption that occurred on hydrogel materials. The CV and BG were both removed in 96.78 and 94.01 % of the adsorption process, respectively. The pseudo-second-order kinetic model is the best-fitted model for the adsorption of dyes on the synthesized hydrogel. Adsorption was determined to be homogeneous and physical adsorption, and it was revealed through adsorption isotherm studies that the Langmuir model was the best-fitted model. The adsorption process for both dyes is spontaneous, as further confirmed by the negative values of the change in Gibbs free energy from 298 to 318 K. The synthesized hydrogel material was discovered to be a promising adsorbent to remove these toxic dyes from wastewater and can be used as an eco-friendly and sustainable material for wastewater remediation