Microwave-assisted synthesis and characterization of Xanthan gum-grafted polyacrylamide hydrogel for the removal of acid red 8 dye from aqueous solutions.

This study focuses on creating a sustainable, biodegradable, and affordable hydrogel from xanthan gum grafted polyacrylamide using a microwave-assisted synthesis method. The hydrogel is designed to remove Acid red 8 dye (AR8) from aqueous solutions using adsorption technique. Characterization was done using FTIR, SEM, and TGA analyses. Factors affecting the adsorption of AR8 dye onto the hydrogel such as grafting percent, pH, hydrogel dosage, contact time and the dye's initial level in solution, temperature, as well as the reusability studies were investigated. The results indicated that at pH 1, the swelling ratio reached 1720% after 20 min. The maximum adsorption capacity of AR8 dye was 177 mg/g after 20 min, with no significant increase beyond 20 min. The percent of dye removal (%) increased from 84.7 to 88.6 with increasing the hydrogel dosage from 0.0063 to 0.05 g/L and there was no increase above 0.05 g/L. The percent of dye removal of AR8 increased with increasing the percentage of grafting due to rising the number of functional groups grafted on XG backbone. Also, q decreased as temperature increased from 20 to 60 °C.