Impact of Peroxymonocarbonate on the Transformation of Organic Contaminants during Hydrogen Peroxide in Situ Chemical Oxidation
Year: 2019
Type: article
Abstract: Under the conditions employed when in situ chemical oxidation is used for contaminant remediation, high concentrations of H 2 O 2 (e.g., up to ∼10 M) are typically present. Using 13 C NMR, we show that in carbonate-rich systems, these high concentrations of H 2 O 2 result in a reaction with HCO 3 – to produce peroxymonocarbonate (HCO 4 – ). After formation, HCO 4 – reacts with phenol to produce di- and trihydroxyl phenols. HCO 4 – reacts with substituted phenols in a manner consistent with its electrophilic character. Exchanging an electron-donating substituent in the para position of a phenolic compound with an electron-withdrawing group decreased the reaction rate. Results of this study indicate that HCO 4 – is a potentially important but previously unrecognized oxidative species generated during H 2 O 2 in situ chemical oxidation that selectively reacts with electron-rich organic compounds. Under conditions in which HO· formation is inefficient (e.g., relatively high concentration of HCO 3 –, low total Fe and Mn concentrations), the fraction of the phenolic compounds that is transformed by HCO 4 – could be similar to or greater than the fraction transformed by HO·. It may be possible to adjust treatment conditions to enhance the formation of HCO 4 – as a means of accelerating rates of contaminant removal.
Language: English
Subfield: Water Science and Technology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2989174088