Heterogeneous Fe(III)/Fe(II) circulation in FeVO4 by coupling with dithionite towards long-lasting peroxymonosulfate activation: Pivotal role of vanadium as electron shuttles

Coupling dithionite (DNT) with FeVO4 induced PMS activation (FeVO4/PMS/DNT) effectuates fast heterogeneous Fe(III) reduction to generate multitudinous reactive oxygen species (ROS) for fast degradation of carbamazepine (2.5 mg/L, >90 % degradation efficiency within 300 s) in batch mode. The Fe(III)/Fe(II) circulation propelled by DNT and reduced V species experiences two stages. DNT induces SO2 center dot- generation, which is a highly active species with strong reducibility for Fe and V reduction. The reduced V species donate electrons to equivalent to Fe(III) via Fe-O-V bond rather than directly react with PMS, implying introducing polyvalent V to modulate Fe-based materials intensifies DNT utilization and alleviates ROS quenching effects. Moreover, FeVO4 crystalline form regains after reaction, and FeVO4/PMS/DNT system has an excellent reutilization and strong resistance to natural waters. Our discovery sheds new light on acceleration of heterogenous Fe(III)/Fe(II) circulation to promote Fenton-like oxidation, it may be a long-lasting strategy for water remediation.