Combination of zero-valent copper and ferric ion promoted the activation of hydrogen peroxide: Deep insight into interaction mechanism and reactive species

Abstract

Zero-valent copper (ZVC) activated hydrogen peroxide (H2O2) was widely used to degrade various organic pollutants due to its excellent degradation performance. However, under acidic condition, the low efficiency inhibited the pollutants degradation efficiency. In this study, the supplement of ferric ion (Fe(III)) markedly improved the orange G degradation in the ZVC/H2O2 system. Various reactive species such as hydroxyl radical (•OH) and Fe(Ⅳ) were identified, besides the contribution rate of the reactive species could be adjusted by changing the reaction parameters. During the degradation of orange G, ZVC furnished Cu(I) by hydrogen erosion and the reaction with O2 and H2O2, and then ZVC and Cu(I) boosted Fe(III)/Fe(II) circulation, part of Fe(II) and Cu(I) activated H2O2 to generate •OH, another part of Fe(II) reacted with H2O2 to generate Fe(Ⅳ), resulting in orange G removal. Common coexisting substances in natural water bodies such as nitrate ion and sulfate ion hardly influence the removal of orange G, while Cl- notably enhanced the removal of orange G, and humic acid markedly suppressed the decoloration of orange G. Orange G removal by the ZVC/Fe(III)/H2O2 system showed outstanding performance in actual water samples. In addition, the total dissolved copper complied with the II-level environmental quality criteria after alkali precipitation. All the above facts bespoke the ZVC/Fe(III)/H2O2 system had substantial application prospects.