Optimizing Copper Adsorption from Aqueous Solutions with Modified Rice Straw Using Response Surface Methodology

Heavy metal contamination poses an impulsive threat to human and aquatic life and ecosystem health. To ensure safe and sustainable water accessibility, biosorption with low-cost adsorbents is acknowledged as a promising approach for the remediation of noxious pollutants. The current study was oriented to appraise the performance of modified rice straw for copper adsorption in hand with the optimization of its operational parameters. RSM-based Box-Behnken design was employed to optimize the operational variables encircling temperature, pH, and adsorbent dose. The results elucidated that the generated model exhibited an R-squared of 0.98, reflecting its validity in describing the experimental data well. The optimized conditions for attaining maximum copper adsorption were marked to be a temperature of 37.71 oC, a solution pH of 5.7, and an adsorbent dose of 11.26 g L-1. Under these optimized conditions, the adsorption efficiency was marked to be 86.65 %. The experimental adsorption efficiency under these conditions was noted to be approximately 86.43 %, reflecting the suitability of the RSM-based Box-Behnken design. Conclusively, it can be inferred that acid modified rice straw offers a promising low cost adsorbent for remediation of heavy metals in accordance with the principles of green chemistry.