Kinetic acceleration of phosphate remediation in dilute aquatic environments via photovoltaic-driven solid-state electrolyte electrocoagulation

The kinetic limitations of reclaiming low-level orthophosphate (PO 4 3− ) in low-conductivity natural water bodies impede the in-depth remediation of anthropogenic eutrophication. Conventional adsorption and electrocoagulation (EC) methods are hindered by excessive chemical reagent consumption, high electrical energy demand, and substantial metal electrode consumption. Here, we present a solid-state electrolyte electrocoagulation (SEE) system that employs an interfacial coupling strategy to integrate dynamic ion enrichment with in situ anodic coagulation. By concentrating PO 4 3− at the solid-state electrolyte interface, the system overcomes inherent mass-transport constraints and enhances ion conductivity in dilute media. This localized concentration gradient accelerates apparent reaction kinetics, achieving a removal rate of 0.197 mg/L·min, minimizing energy consumption to 0.0325 kWh/g P and iron consumption to 3.829 g/g P. Consequently, SEE enables efficient, one-step purification below strict regulatory thresholds ( ≤ 0.02 mg/L, China’s Class I Surface Water Environmental Quality Standard). Validated as a photovoltaic-integrated, boat-mounted unit, this approach offers a robust decentralized solution for natural waters, with techno-economic and life cycle assessments confirming its economic viability and low environmental footprint.