Ascorbate guided conversion of hydrogen peroxide to hydroxyl radical on goethite

In this study, we demonstrate that the addition of ascorbate can lower the conversion percentage of H2O2 to O-2 from 71% to 11%, and thus increase the conversion percentage of H2O2 to (OH)-O-center dot from 11% to 82% on goethite within 3 h. This greatly enhanced production of (OH)-O-center dot 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 con-version of H2O2 to (OH)-O-center dot. Meanwhile, the decreased surface Fe(III) of goethite strongly inhibited the conversion of H2O2 to O-2. 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.

Automated summary

The addition of ascorbate reduces the conversion of H2O2 to O-2 and increases the conversion to (OH)-O-center dot on goethite. This is due to the efficient Fe(III)/Fe(II) redox cycle accelerated by ascorbate, resulting in abundant Fe(II) on the goethite surface favoring the conversion of H2O2 to (OH)-O-center dot. Meanwhile, decreased surface Fe(III) inhibits the conversion of H2O2 to O-2.