The U.S. generates approximately two billion tons of mining waste annually, leading to inorganic heavy metal contaminates such as Ni, deposited into surrounding ecosystems at toxic levels. Phytoremediation offers a low-cost solution for environmental clean-up, particularly in impoverished areas, however current phytoremediation strategies generate unusable biomass due to the toxic metal contents. A novel solution for this unused waste lies in the area of energy storage, especially for supercapacitor applications. This work focuses on the cultivation of water hyacinths, a known metal hyperaccumulator, in various concentrations of Ni-doped water followed by synthesis of harvested biomass into high quality biocarbon. Biomass was subjected to thermal annealing at 500 °C for 1 h under Argon environment to cleave functional groups. Subsequent biochar was improved through thermochemical/catalytic activation at 800 °C for 1 h with KOH providing additional enhancement during biocarbon synthesis. Electrochemical results demonstrate a specific capacitance of 541 F g-1 making it suitable for use in the supercapacitor for electricity storage. Physical and electrochemical characterizations, including ICP, SEM, BET, ATR-FTIR, Raman, and XRD, cyclic voltammetry, chronopotentiometry, and EIS will be discussed. This work provides a value-added product and in-depth insights into naturally embedded catalyst, while simultaneously remediating contaminated mining sites.
