Efficient Removal of Heavy Metals from Mining-Impacted Water and Soil Using Rice Husk Biosorbent

Abstract

This study investigates the efficacy of rice husk a readily available agricultural by-product as a biosorbent for the removal of heavy metals from contaminated water and soil samples collected across industrial coal mining areas in the Korba district. Experiments were conducted during premonsoon, monsoon, and post-monsoon seasons, with comprehensive analysis on seven key heavy metals: antimony, molybdenum, copper, lead, cadmium, mercury, and iron. Treatment with rice husk achieved significant reduction rates for all metals, ranging from 40% (molybdenum) to 90% (lead), with final concentrations consistently below WHO guidelines for safe drinking water and soil. Particularly notable was the reduction of initially elevated lead and cadmium levels by approximately 90% and 85% respectively, as well as the effective removal of mercury and iron, even at sites subject to intensive mining activities. Pearson correlation analysis revealed strong positive associations among all heavy metals, suggesting shared sources of contamination and the necessity for integrated remediation strategies. The biosorption method utilizing rice husk proved to be low-cost, sustainable, and environmentally friendly making it a practical solution for heavy metal removal in mining-impacted environments and demonstrating strong potential for application in similar ecological contexts across India and beyond.