Utilisation of Vigna mungo -based biochar for the adsorption of Ni 2+ , Cu 2+ and Pb 2+ ions and its re-utilisation in energy storage

Heavy metal-contaminated wastewater can lead to serious environmental and public health issues, requiring an environmentally friendly treatment process with resource recovery capability. In the present study, biochar prepared from Vigna mungo biomass was used as an adsorbent for the efficient removal of Ni2+, Cu2+ and Pb2+ ions from synthetic wastewater. Herein, we show an environmentally sustainable way to combine wastewater remediation and energy storage applications by transforming heavy metal-enriched biochar into a valuable electroactive material. The V. mungo- based biochar has been characterized using different advanced analytical methods. The maximum percentage removal of Ni2+, Cu2+and Pb2+ ions was found to be 86.8, 92, and 88.9%, respectively. The heavy metals-loaded V. mungo-based biochar was reutilised as an electrode material for supercapacitors. The maximum energy and power densities of heavy metals-loaded Vigna mungo-based biochar were evaluated to be 5.3 W/kg and 3020.4 Wh/kg, respectively.