Oxidative Degradation of Organic Compounds Using Zero-Valent Iron in the Presence of Natural Organic Matter Serving as an Electron Shuttle

School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 790-784, Korea.
Environmental Science and Technology (Impact Factor: 5.33). 03/2009; 43(3):878-83. DOI: 10.1021/es801705f
Source: PubMed


This study aims to understand the oxidative degradation of organic compounds utilizing zerovalent iron (ZVI) which is further promoted by the presence of natural organic matters (NOMs) (as humic acid (HA) or fulvic acid (FA)) working as electron shuttle mediators. The main target substrate used was 4-chlorophenol. Both HA and FA can mediate the electron transfer from the ZVI surface to O2, while enhancing the production of Fe2+ and H2O2 that subsequently initiates the OH radical-mediated oxidation of organic compoundsthrough Fenton reaction. The electron transfer-mediating role of NOMs was supported by the observation that higher concentrations of H2O2 and ferrous ion were generated in the presence of NOM. The NOM-induced enhancement in oxidation was observed with NOM concentrations ranging 0.1-10 ppm. Since the reactive sites responsible for the electron transfer action are likely to be the quinone moieties of NOMs, benzoquinone that was tested as a proxy of NOM also enhanced the oxidative degradation of 4-chlorophenol in the ZVI suspension. The NOM-mediated oxidation reaction on ZVI was completely inhibited in the presence of methanol, an OH radical scavenger, and in the absence of dissolved oxygen.

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Available from: Wonyong Choi, Feb 01, 2015
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    • "These reactions are mostly reductive and proceed with several types of reducing species generated during iron corrosion (Reddy, 2010; Kang and Choi, 2008). The mechanism involved in ZVI catalyzed reactions is similar to that found for iron mineral catalysis reactions (Kang and Choi, 2008). As mentioned before, the classic Fenton reaction has some limitations. "
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    ABSTRACT: Magnetite, a naturally occurring mineral of iron oxide, and zero-valent iron (ZVI) were used to catalyze hydrogen peroxide and initiate a dark Fenton-like reaction of diesel-contaminated loamy sand in a batch system at circumneutral pH. The effects of hydrogen peroxide concentration and catalyst content on the removal efficiency of total petroleum hydrocarbons (TPHs) were studied. A central composite rotatable design was applied and the derived equation for magnetite and ZVI were linear and quadratic, respectively. In both equations, the factor of hydrogen peroxide concentration was more significant than catalyst content. At optimum conditions (4.27 wt% of catalyst content and 2.17 mol/L of hydrogen peroxide), 57% and 67% of TPH removal were achieved by magnetite and ZVI, respectively. The obtained results suggest the potential of ZVI and magnetite to catalyze a heterogeneous Fenton-like reaction at circumneutral pH. It seems that using ZVI, rather than magnetite, as a catalyst may result in slightly more TPH mineralization; however, since magnetite is a naturally occurring mineral, it may be able to compete economically with ZVI.
    Soil and Sediment Contamination 08/2015; 24:609-623. DOI:10.1080/15320383.2015.996633 · 1.04 Impact Factor
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    • "In this " ocean " of iron oxides, Fe II and H/H 2 are more or less abundant and may act as reducing agents (chemical reaction). Evidently, the papers cited [21] [22] [30] [31] [32] [33] [34] are not clear enough in their explanation to convince many authors of current publications dealing with contaminant removal in Fe 0 /H 2 O systems [35] [36] [37]. Moreover, despite the generalized access to modern scientific search engines (e.g. "
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    Fresenius Environmental Bulletin 09/2014; 23(10). · 0.38 Impact Factor
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    • "The versatility of nanoscale zerovalent iron (nZVI) has been regarded as one of the most promising permeable barrier materials used for the in-situ remediation of wastewater in environmental engineering due to its large surface area, extremely small particle size and high in-situ reactivity [6]. Therefore, more attentions have extensively focused on NZVI for the rapid removal of organic contaminants [7] [8] [9] [10] [11] [12] and variant valence metals such as chromium [13] [14] [15] [16], arsenic [17] [18] [19] [20] [21], selenium [22] [23] [24] [25], technetium [26] [27] [28] [29], and uranium [30] [31] [32] [33] [34] [35]. It is demonstrated that these metals with high valence can be reduced to low valence metals by Fe 2+ ions, then these metals can also be removed by iron corrosion products [36] [37] [38]. "
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