VUV Activated Fe(VI)\nby Promoting the Generation of\nIntermediate Valent Iron and Hydroxyl Radicals

In this study, vacuum ultraviolet (VUV) was first proposed\nto activate\nferrate (Fe(VI)) for degrading micropollutants (e.g., carbamazepine\n(CBZ)). Results indicated that VUV/Fe(VI) could significantly facilitate\nthe CBZ degradation, and the removal efficiencies of VUV/Fe(VI) were\n30.9–83.4% higher than those of Fe(VI) at pH = 7.0–9.0.\nCorrespondingly, the degradation rate constants of VUV/Fe(VI) were\n2.3–36.0-fold faster than those of Fe(VI). Free radical quenching\nand probe experiments revealed that the dominant active species of\nVUV/Fe(VI) were <sup>•</sup>OH and Fe(V)/Fe(IV), whose contribution\nratios were 43.3 to 48.6% and 48.2 to 46.6%, respectively, at pH =\n7.0–9.0. VUV combined with Fe(VI) not only effectively mitigated\nthe weak oxidizing ability of Fe(VI) under alkaline conditions (especially\npH = 9.0) but also attenuated the deteriorating effect of background\nconstituents on Fe(VI). In different real waters (tap water, river\nwater, WWTPs effluent), VUV/Fe(VI) retained a remarkably enhanced\neffect on CBZ degradation compared to Fe(VI). Moreover, VUV/Fe(VI)\nexhibited outstanding performance in the debasement of CBZ and sulfamethoxazole\n(SMX), as well as six other micropollutants, displaying broad-spectrum\ncapability in degrading micropollutants. Overall, this study developed\na novel oxidation process that was efficient and energy-saving for\nthe rapid removal of micropollutants.