Title: The Impact of Peroxymonocarbonate (HCO4 -) on the Transformation of Organic Contaminants during Hydrogen Peroxide (H2O2) in situ Chemical Oxidation (ISCO).

Authors: Yang, Xuejing; Duan, Yanghua; Wang, Jinling; Wang, Hualin; Liu, Honglai; Sedlak, David L

Published In Environ Sci Technol Lett, (2019 Dec 10)

Abstract: Under the conditions employed when in situ chemical oxidation is used for contaminant remediation, high concentrations of H2O2 (e.g., up to ~10 M) are typically present. Using 13C NMR, we show that in carbonate-rich systems, these high concentrations of H2O2 result in a reaction with HCO3 - to produce peroxymonocarbonate (HCO4 -). After formation, HCO4 - reacts with phenol to produce di- and tri-hydroxyl phenols. HCO4 - 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 HCO4 - is a potentially important but previously unrecognized oxidative species generated during H2O2 in situ Chemical Oxidation (ISCO) that selectively reacts with electron-rich organic compounds. Under conditions in which HO· formation is inefficient (e.g., relatively high concentration of HCO3 -, low total Fe and Mn concentrations), the fraction of the phenolic compounds that are transformed by HCO4 - 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 HCO4 - as a means of accelerating rates of contaminant removal.

PubMed ID: 33163542

MeSH Terms: No MeSH terms associated with this publication