Novel Hing gum-based adsorbent with optimized synthesis parameters for cationic dye removal

Abstract

This research investigates the utilization of Hing gum-based hydrogel as an effective adsorbent for the removal of Malachite Green (MG) dye from aqueous solutions. The hydrogel was synthesized using Hing gum as the backbone, acrylamide as the monomer, ammonium persulfate (APS) as an initiator in free radical polymerization, and N, N'-Methylenebisacrylamide (MBA) as a crosslinking agent. Optimization of different reaction parameters was carried out using the Response surface methodology. A full factorial model was utilized to achieve the maximum swelling percentage, and key factors were identified through a Pareto chart. The optimized variables, including the initiator (2.19 ×10− 2 mol L− 1), monomer (8.65 × 10− 1 mol L− 1), and solvent (13 mL), resulted in a maximum percentage swelling of 760%. The significance of the model was confirmed using ANOVA statistics. Various properties were analyzed using Fourier transform infrared spectroscopy, X-ray diffraction, Field emission scanning electron microscopy, thermogravimetric analysis, Zeta Potential, and Brunauer-Emmett-Teller theory. The effectiveness of the prepared hydrogel in MG dye adsorption was evaluated by measuring contact time, pH impact, adsorbent dose, and temperature. The synthesized hydrogel exhibited high efficiency in removing MG dye from aqueous solutions, achieving a noteworthy adsorption rate of approximately 97% over 6 hours at room temperature. Adsorption calculations were described using kinetics and isotherm models. The results indicate that the pseudo-second-order kinetic model and Langmuir isotherm model provided the best fit for the absorption process of MG. The obtained results highlight the adsorbent high absorption capacity and demonstrate its potential as an eco-friendly and cost-effective solution for removing MG dye from water.