Remediation of mine overburden and contaminated water with activated biochar derived from low-value biowaste

Abstract

Background: Mines can be regarded as the economic backbone of India with a contribution of 10-12 % towards the gross domestic production with industrial demand. It gives rise to environmental problems like soil, water and air pollution. The active mines generate lots of waste rock and wastewater that contaminate nearby soil and water bodies with heavy metals. Methods: The elimination of heavy metals by suitable amendments is emerging as a potential solution to such problems. Biochar, a carbon rich, stable, alkaline and porous product of thermo-chemical conversion of biomass has emerged as a promising adsorbent of heavy metals. Conversion of these biowastes into biochar is a sustainable approach as it fulfills multiple objectives of waste utilization, and pollution abatement. Significant findings: Due to its large surface area, biochar can restrain heavy metals while modified biochar has an increased potential for adsorption with an increased surface area. The review emphasizes the type of mines, overburden generation, their impact on soil and water, and the utility of different biowastes available to be mobilized into biochar for remediation of contaminated water and soil. It also bridges the gap in the current knowledge on the activation techniques of biochar with heavy metals remediation.