Kinetics and efficiency of H2O2 activation by iron-containing minerals and aquifer materials

WATER RESEARCH

卷:46

Article

Anh Le-Tuan Pham¹  Doyle, Fiona M.²  Sedlak, David L.¹ 

[1] Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA

[2] Univ Calif Berkeley, Dept Mat Sci & Engn, Berkeley, CA 94720 USA

关键词: Fenton reaction;    Advanced oxidation process;    Groundwater treatment;    Iron oxides;    Hydrogen peroxide;    Dissolved silica;   

DOI  :  10.1016/j.watres.2012.09.020

来源: Elsevier

【 摘 要 】

To gain insight into factors that control H2O2 persistence and (OH)-O-center dot yield in H2O2-based in situ chemical oxidation systems, the decomposition of H2O2 and transformation of phenol were investigated in the presence of iron-containing minerals and aquifer materials. Under conditions expected during remediation of soil and groundwater, the stoichiometric efficiency, defined as the amount of phenol transformed per mole of H2O2 decomposed, varied from 0.005 to 0.28%. Among the iron-containing minerals, iron oxides were 2-10 times less efficient in transforming phenol than iron-containing clays and synthetic iron-containing catalysts. In both iron-containing mineral and aquifer materials systems, the stoichiometric efficiency was inversely correlated with the rate of H2O2 decomposition. In aquifer materials systems, the stoichiometric efficiency was also inversely correlated with the Mn content, consistent with the fact that the decomposition of H2O2 on manganese oxides does not produce (OH)-O-center dot. Removal of iron and manganese oxide coatings from the surface of aquifer materials by extraction with citrate-bicarbonate-dithionite slowed the rate of H2O2 decomposition on aquifer materials and increased the stoichiometric efficiency. In addition, the presence of 2 mM of dissolved SiO2 slowed the rate of H2O2 decomposition on aquifer materials by over 80% without affecting the stoichiometric efficiency. (C) 2012 Elsevier Ltd. All rights reserved.

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