Comparing activated carbon and graphene-based electrodes using electrosorption process to quantify environmental impact associated with thorium extraction via LCA framework

Thorium extraction from radioactive waste via various methods, including solvent extraction, ion exchange, adsorption, and electrosorption, raises significant concerns regarding radiological risks, human health, emissions, and other environmental impacts. To date, previous research estimated an optimal thorium recovery efficiency of 92% using electrosorption from a rare earth facility, though without a life cycle assessment (LCA) paradigm. To the best of our knowledge, this article quantified the environmental impact and emissions lifecycle of thorium extraction via the electrosorption process, employing activated carbon electrodes (ACE) and graphene-based electrodes (GBE) within a sustainable LCA framework. In this context, the inventory data for LCA were compiled from Ecoinvent database 3, sourcing input including raw material extraction, energy consumption, and chemical compounds. The comparative outcomes of midpoint analysis indicated that for each 1 kg of thorium extracted, the ACE system showed substantially higher environmental impacts than GBE, especially regarding human toxicity, freshwater ecotoxicity, and marine ecotoxicity, signifying a heightened release of toxins detrimental to ecosystems and human health. Also, the comparing results of endpoint indicators revealed that ACE showed a high impact over GBE in human health (0.0003-0.0001 DALY), ecosystems (7.14E-07-1.87E-07 species·yr), and resources (7.549-2.921 USD 2013), probably due to differences in chemical usage and emissions release during processing. In terms of output effectiveness and adverse environmental impacts, the GBE technique is more effective in removing thorium compared to ACE for the sustainable management of radioactive waste.