Comediating Adsorption and Electron Transfer via Dual-Active Site Catalyst Construction for Improving the Treatment of Extraction Wastewater.

Abstract

Solvent extraction is widely applied, while extraction wastewater treatment remains a hugechallengebecause of the stability of extractants.Heterogeneous Fenton-like catalysis is a promising method, but the short half-life of hydroxyl radicals (•OH)generated by hydrogen peroxide (H2O2)activation results in unsatisfactory •OH utilization and organics removal.Herein, an efficient strategy for treating extraction wastewater based on comediating adsorption and electron transfer by fluorine and nitrogen co-doped carbon (FNC) catalyst with dual-active site was developed. Specially, N sites adsorb organics andFsites activateH2O2, shortening the migration distanceof •OH. Theoretical calculation and di(2-ethylhexyl) phosphoric acid (D2EHPA)extraction wastewater degradation experimentshowed that F sitewith electron acquisition can transfer electrons provided by electron-rich D2EHPA enriched at N sites toH2O2,facilitating the continuous generation of •OH through lowering the energy barrier for H2O2activation.As a result, 96.49% D2EHPA in simulated wastewaterand 90.26% total organic carbonin realextraction wastewaterwere removed. Moreover, FNC catalystexhibited excellent reusability and ionic adaptability, and can be extended to the removal of various extractants. The proposed dual-active site catalyst providesan effective strategyforFenton-likereactiontotreatrefractory extraction wastewater, promotingsustainable development of solvent extraction industry.