Economic and Environmental Sustainability of Biogenic Synthesis of Indium-Graphitic Material from Electronic Waste

Due to the escalating concern over the increasing generation of electronic waste (e-waste), legislative measures, and the inherent value of critical metals contained within e-waste, recycling has emerged as a potentially viable business opportunity. Previously, phytoextraction for sustainable resource recovery of critical metals was proposed, and the metal-incorporated biomass was translated into a carbon-rich precursor for graphitic material synthesis. Experimental findings suggest that the phytoextraction process has lower chemical consumption and reduced energy requirements than pyrometallurgical and hydrometallurgical methods. To assess, quantify, and compare the sustainability of this combined phytoextraction and graphitization methodology, technoeconomic analysis and life cycle assessment were conducted. The financial viability and environmental implications of this process were studied in two scenarios. In the first scenario, indium recovery from an LCD screen slurry followed by pyrolysis for indium-graphitic material synthesis was evaluated. The second scenario, derived from the first, incorporated modifications that reduced the median costs by 28%. Both scenarios achieved a 38.8% reduction in median global warming potential per kilogram of graphite compared with industrial graphite synthesis. Overall, the results demonstrate that biomass-based resource recovery and graphite synthesis can provide sustainable alternatives while recovering critical metals and synthesizing value-added products.