Eco‐Friendly CMC/TKP Hydrogel: Design and Optimization for Dye Removal from Aqueous Solutions

Abstract Toxic dyes in wastewater represent serious environmental and health hazards, necessitating the development of efficient and sustainable remediation strategies. Conventional dye removal techniques are often limited by high costs and low efficiency, underscoring the need for eco‐friendly and cost‐effective alternatives. In this study, a cross‐linked three‐dimensional (3D) hydrogel composed of carboxymethyl cellulose and tamarind kernel powder (TKP) was synthesized and optimized, achieving a maximum swelling capacity of 1508%. The hydrogel's structural, morphological, and thermal properties were characterized via FTIR, XRD, FESEM, and TGA analyses. Its adsorption performance was evaluated using methylene blue (cationic dye) and rose Bengal (anionic dye) under varying parameters, including initial dye concentration, pH, temperature, ionic strength, and adsorbent dosage. The hydrogel exhibited maximum adsorption capacities of 353.0 mg/g for RB and 404.8 mg/g for MB. Adsorption followed pseudo‐second‐order kinetics and fitted well with the Langmuir isotherm model, suggesting monolayer adsorption. Thermodynamic parameters revealed the adsorption process to be spontaneous and exothermic, with Gibbs free energy changes of −4.492 kJ/mol for RB and −4.478 kJ/mol for MB. Additionally, the hydrogel demonstrated good reusability, supporting its potential for practical wastewater treatment applications.