South African Journal of Chemical Engineering | 2021
Influence of sawdust based biochar on gold tailings wastewater heavy metal contaminants removal
Abstract
Abstract In this study, the influence of saw dust based biochar on the removal of heavy metal ions contaminants in gold tailings wastewater was investigated. The target pollutants were cyanide (CN−), chromium (Cr3+), iron (Fe3+), zinc (Zn2+), nickel (Ni2+), lead (Pb2+), manganese (Mn2+) and copper (Cu2+). Their composition was determined before and after the adsorption process using biochar. The biochar loading was varied between 10\xa0mg/L, 30\xa0mg/L and 50\xa0mg/L and the retention times between 2 and 12\xa0h in a fixed bed column. The Pearson Coefficient analysis method indicated that the utilization of biochar significantly decreased heavy metal ions contaminants by more than 70% and there was a strong negative relationship between retention time and concentration of remaining metal ions at 95% confidence interval. Negative coefficients for effect of biochar loading and ions concentrations for CN−, Cr3+, Fe3+, Zn2+, Ni2+, Pb2+, Mn2+ and Cu2+ ions of 0.76, 0.74, 0.75, 0.83, 0.85, 0.87 and 0.87 respectively were observed. The magnitude of each coefficient indicated a significant reduction in the heavy metal ion. Saw dust based biochar can be successfully used to reduce heavy metal contaminants in tailings wastewater. However, more retention time and higher biochar loadings should be adopted to meet for the WHO disposal guidelines of CN−, Ni2+ and Pb2+..