Application of Response Surface Methodology for the Adsorptive Removal of Chromium Using Modified Cellulose

Abstract

In this study, a Modified Cellulose Polymer (MCP) was synthesized through selective oxidation in a cellulose polymer utilizing sodium periodate (NaIO₄), which introduces benzothiazole as a functional attachment without disrupting the cellulose backbone. Response surface methodology was employed for the adsorption of chromium on MCP, and the process parameters were optimized. Three critical process parameters, particle size (398-498 nm), pH (5-7), and adsorbent dose (20-30 mg/L), were optimized to obtain the optimal response of chromium adsorption using the statistical Box–Behnken design. The experimental data obtained were analyzed using analysis of variance (ANOVA) and fitted to a second-order polynomial equation using multiple regression analysis. Numerical optimization, utilizing the desirability function, was employed to determine the optimal conditions for maximum chromium ion removal. A two-level fractional factorial model and the Box-Behnken matrix were employed to optimize the batch adsorption parameters for the adsorption of chromium from aqueous solutions by modified cellulose. Under the optimized conditions of pH 6.04 ± 0.05, particle size 485.49 ± 2 nm, and adsorbent dose of 24.14 ± 0.5 mg/L, MCP demonstrated the maximum chromium adsorption capacity with a desirability score of 0.805. The batch adsorption experiments confirmed the efficacy of MCP in removing chromium from aqueous solutions, as evidenced by the close alignment between the predicted adsorption capacity (134.53 ± 1.8 mg/g) and the experimental result (132.52 ± 2,1 mg/g). These findings highlight the potential of MCP as an effective and environmentally friendly adsorbent for industrial water-treatment applications.