Activation of peroxydisulfate by V-Fe concentrate ore for enhanced degradation of carbamazepine: Surface ≡V(III) and ≡V(IV) as electron donors promoted the regeneration of ≡Fe(II)

V-Fe concentrate ore was applied to activate peroxydisulfate (PDS) for carbamazepine (CBZ) degradation. The excellent performance of V-Fe concentrate ore was mainly ascribed to the quick electron transfer from surface equivalent to V(III) and equivalent to V (IV) to equivalent to Fe(III) for equivalent to Fe(II) regeneration, which was confirmed by XPS and XAS analyses. This accelerated equivalent to Fe(II) regeneration could thus lead to quick formation of HO center dot, SO4 center dot-, O-2(center dot-) and effective de-gradation of CBZ. The degradation rate of CBZ could be also expressed by a kinetic model, i.e.,-d[CBZ]/dt = (0.83 mM(-0.55) min(-1)(g/L)(-0.65)) [CBZ](0.29)[PDS](1.26)[V-Fe](0.65). Combined with the measured intermediates and the results of DFT calculation, CBZ degradation pathway was proposed systematically. Moreover, this catalyst displayed excellent recyclability and general applicability for a broad substrate scope. This study suggests low valent vanadium makes crucial contributions to the high activity of V-Fe-based catalysts, and improves the understanding of electron transfer mechanism between V and Fe in PDS activation process.

Automated summary

By utilizing V-Fe concentrate ore to activate peroxydisulfate for carbamazepine degradation, this study revealed the essential role of low valent vanadium in the high activity of V-Fe-based catalysts. Through experiments and modeling, the degradation process and mechanism were inferred, demonstrating the catalyst's excellent recyclability and broad applicability.