Ascorbate guided conversion of hydrogen peroxide to hydroxyl radical on goethite

Abstract In this study, we demonstrate that the addition of ascorbate can lower the conversion percentage of H2O2 to O2 from 71% to 11%, and thus increase the conversion percentage of H2O2 to OH from 11% to 82% on goethite within 3 h. This greatly enhanced production of OH could be attributed to the efficient Fe(III)/Fe(II) redox cycle accelerated by ascorbate, which produced abundant Fe(II) confined on the goethite surface, favoring the conversion of H2O2 to OH. Meanwhile, the decreased surface Fe(III) of goethite strongly inhibited the conversion of H2O2 to O2. These findings can clarify the quantitative influence of ascorbate on the H2O2 decomposition process over the iron mineral surface, and thus deepen the understanding of heterogeneous Fenton reaction mechanism during organic containment treatment.