Novel hydrogel based on natural hybrid backbones: Optimized synthesis and effective adsorbent for the removal of dye from an aqueous solution

Abstract

Abstract In this study, we synthesized a novel hydrogel, GG/LBG-g-poly(AAm), utilizing a hybrid backbone composed of guar gum, locust bean gum, and acrylamide. The cross-linker N, N-Methylene-bis-acrylamide, and the initiator ammonium persulfate were employed in the synthesis process. Response surface methodology and a full factorial rotatable central composite design were used to optimize various reaction parameters to enhance the percentage swelling of the synthesized hydrogel. This optimization resulted in a notable increase in swelling capacity, reaching 1050%. The incorporation of acrylamide chains onto the guar-locust bean gum-based hybrid backbone, as well as crosslinking between different polymeric chains, was confirmed through various characterization techniques, including FTIR, TGA, XRD, FE-SEM, wettability studies, and zeta potential analysis. We investigated the hydrogel’s adsorption performance for malachite green (MG), varying pH, contact time, adsorbent dose, and dye concentration. Under ambient conditions, GG/LBG-g-poly(AAm) demonstrated a maximum adsorption capacity of 52.96 mg g− 1 and achieved a removal efficiency of 98%. The adsorption data best fit the Freundlich model (R2 = 0.99) and followed pseudo-second-order kinetics, indicating a consistent agreement. Positive values for ΔHo (61.23 KJ/mol) and ΔSo (239.80 J/mol. K) suggest an endothermic adsorption process with a strong affinity for dye molecules. Overall, the synthesized material exhibits significant potential for effectively removing toxic dyes from wastewater.