Comparative life cycle assessment of Fenton-like systems: Insights into the environmental benefits of reductant-driven strategies.

Reductant-driven Fenton-like advanced oxidation processes (AOPs) offer the potential to reduce transition metal and oxidant consumption, but the environmental implications of introducing reductants remain unclear. This study employs life cycle assessment (LCA) to evaluate the environmental impacts of reductant-driven Fenton-like systems as an alternative to conventional AOP. Five distinct Fenton-like systems were investigated, and their corresponding life cycle inventories compiled following systematic optimization of operating parameters. Results demonstrate that introducing reductant shifts environmental hotspots from oxidants to the added reductants. Commodity chemical reductants (hydroxylamine and ascorbic acid) significantly reduce energy consumption and environmental damage due to economies of scale. Their per unit Cumulative Energy Demand (CED) and environmental damage value are two orders of magnitude lower than those of specialty chemical reductants (10.31 and 8.93 MJ g-1 MXene and MoS2). Thus, novel catalysts, potentially associated with high energy consumption and toxic byproducts, require careful evaluation of their catalytic efficiency and unit environmental impact to determine overall environmental benefits. Scaling up chemical production, adopting regeneration strategy and transitioning to renewable energy sources represent key strategies for further environmental improvement. This study provides a quantitative framework for assessing the environmental performance of alternative Fenton-like systems, informing the design of more environmentally sustainable water purification technologies.