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

Abstract

To gain insight into factors that control H2O2 persistence and ˙OH 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 to 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. 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.

Recent advances and prospects of catalytic advanced oxidation process in treating textile effluents

“…The effectiveness of FeO as a heterogeneous catalyst to degrade a wide range of pollutants is available in the literatures (Huang et al 2001, Baldrian et al 2006, Dantas et al 2006, Hanna et al 2008, Pham et al 2012. Heterogeneous FeO have been used as an efficient catalyst with a narrow band gap (2.0-2.3 eV).…”

Natural diatomites: Efficient green catalyst for Fenton-like oxidation of Orange II

“…The different activity of iron supported catalysts is influenced by the cation dispersion in the support, iron valence, surface area, point of zero charge, and the presence of different iron species, for example in clays, iron could be in the form of free iron oxides, structural iron in the clay lattice or complexed iron [27].…”

Fe/Nanoporous Carbon Catalysts Obtained from Molasses for the Limonene Oxidation Process

“…Hydrogen peroxide and Fe 3+ undergo a redox cycle in which ·OH radicals are produced. Taking into account the results presented for the 0.68Fe/NPC, 1.32Fe/NPC and 2.64Fe/NPC catalysts, and the analysis of the literature data [31][32][33][34][35][36], the paths for the transformation of hydrogen peroxide in the presence Fe/NPC catalysts presented in Fig. 12 can be proposed.…”