Fly Ash-based Adsorption for Hexavalent Chromium Removal in Aqueous Systems: A Promising Eco-Friendly Technique

Abstract

Heavy-metal pollution has been and continues to be significantly influenced by excessive Cr(VI) emissions; recently, there has been a lot of interest in the emergence of a low-cost, secure, and effective technology for removing of Chromium from wastewater. Fly ash has been used in the present study for Hexavalent chromium adsorption. Characterized for their elemental composition, functional groups, and surface morphology, the impacting aspects of the adsorbent were explored. In this study, the chromium adsorption parameters were optimized and the prediction models were strengthened using the response surface methodology (RSM) and box behnken design (BBD). High regression coefficient (R2>0.98), insignificant lack of fit (0.52), high F-value, and low P-value (0.05) were all indicators of the quadratic model's good agreement with the predicted values. Adsorbent dose of 200 mg/100 ml, initial Cr (VI) concentration of 20 mg/L, contact time of 90 min, and pH of 1.0 were the optimal adsorption conditions. The cost-effectiveness, ease of modification, and high efficiency of fly ash make it a promising candidate for large-scale applications in addressing chromium pollution in wastewater.