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A Mechanistic Understanding of Hydrogen Peroxide Decomposition by Vanadium Minerals for Diethyl Phthalate Degradation

Author:
Fang, Guodong, Deng, Yamei, Huang, Min, Dionysiou, Dionysios D., Liu, Cun, Zhou, Dongmei
Source:
Environmental science & technology 2018 v.52 no.4 pp. 2178-2185
ISSN:
1520-5851
Subject:
X-ray diffraction, X-ray photoelectron spectroscopy, aqueous solutions, diethyl phthalate, electron paramagnetic resonance spectroscopy, electron transfer, free radicals, hydrogen peroxide, hydroxyl radicals, minerals, oxidation, oxygen, pH, remediation, slurries, soil, vanadium
Abstract:
The interaction of naturally occurring minerals with H₂O₂ affects the remediation efficiency of polluted sites in in situ chemical oxidation (ISCO) treatments. However, interactions between vanadium(V) minerals and H₂O₂ have rarely been explored. In this study, H₂O₂ decomposition by various vanadium-containing minerals including V(III), V(IV), and V(V) oxides was examined, and the mechanism of hydroxyl radical (•OH) generation for contaminant degradation was studied. Vanadium minerals were found to catalyze H₂O₂ decomposition efficiently to produce •OH for diethyl phthalate (DEP) degradation in both aqueous solutions with a wide pH range and in soil slurry. Electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) analyses, and free radical quenching studies suggested that •OH was produced via single electron transfer from V(III)/V(IV) to H₂O₂ followed a Fenton-like pathway on the surface of V₂O₃ and VO₂ particles, whereas the oxygen vacancy (OV) was mainly responsible for •OH formation on the surface of V₂O₅ particles. This study provides new insight into the mechanism of interactions between vanadium minerals and H₂O₂ during H₂O₂-based ISCO.
Agid:
6008106