Recycling of spend graphite anodes in Fenton-like catalysis for green economy and long-term sustainable wastewater purification

The sustainable recycling of spent graphite anodes from lithium-ion batteries is crucial for circular economy development. This study evaluates three types of decommissioned spent graphite, caused by metallic contamination, solid electrolyte interphase (SEI) film failure, and structural degradation, as well as regenerates them via four combined wet/thermal techniques. Among these, acid treatment followed by calcination (AW+CT) demonstrated the best overall performance, achieving the highest comprehensive score (95.68 %) for bisphenol A (BPA) removal across key metrics: catalytic activity ( k obs  = 0.12245 min −1 ), lithium recovery (99.92 %), energy efficiency (ΔEEO = 402.44 kWh·m −3 order −1 ), total metal ion safety (Δ l  = 4.1341 mg/L), and economic feasibility (0.000659 USD). Mechanistic analyses revealed that residual Mn(II) species and defect-engineered carbon structures (oxygen functionalities and lattice defects) synergistically enhanced Fe(III)/Fe(II) redox cycling, thereby promoting hydroxyl radical (•OH) generation. Compared to commercial graphite, the regenerated spent graphite exhibited superior stability in long-term continuous-flow column tests and reduced environmental burdens by 20 %, as confirmed by life cycle assessment. Overall, this work offers valuable insights into a unified framework that integrates material classification, mechanistic understanding, and life-cycle sustainability evaluation, enabling high-value reuse of spent graphite anodes in Fenton-like catalysis.