Determination of the Number of OH Radicals in EB-Irradiated Humid Gases Using Oxidation of CO

Abstract

Electron beam (EB) technology has an advantage for treating dilute environmental pollutants in gases due to high-density population of active species such as radicals and atoms. In general, OH radicals play an important role of initiating the decomposition and removal of such pollutants. It is quite important to understand the behavior of OH radical production for the development of efficient decomposition/removal processes and the comparison with other purification methods. The number of OH radicals produced in humid N 2 at doses of 2.0-10.0 kGy with dose rates of 0.17-2.55 kGy/s under 1-MeV EB irradiation was indirectly determined using an index of oxidation of CO to CO 2 , which has been used in atmospheric chemistry. An experiment under conditions where all OH radicals produced react with CO demonstrated that the concentration of CO 2 increased linearly with doses of 0-10 kGy, and the G(OH) was estimated as 4.90.

Theoretical Characterization of the Structure and Spectroscopy of HCNO2 Isomers and Applications

“…The main reaction products would result either from rearrangement of HCONO to CON­(H)O (hydrogen migration) and subsequent dissociation into HNO + CO or from further decomposition of HCO or HNO in the aforementioned reactions to give the observed H + CO + NO products. Moreover, HCNO 2 species are mentioned by Hakoda et al for the interpretation of their experimental results, where CO is used to titrate the hydroxyl radicals produced by β-irradiation of humid N 2 gas, forming the CO 2 product. These pentatomics are viewed to play a crucial role in the gas phase chemistry of the atmospherically significant HOCO radical, whose relevant chemistry has been studied both experimentally and theoretically (see refs and , for instance).…”

Analysis of hydroxyl radical formation in a gas‐liquid electrical discharge plasma reactor utilizing liquid and gaseous radical scavengers

“…Hydrogen peroxide (H 2 O 2 ) and OES were also used as indicators to determine the • OH scavenging power of primary alcohols such as methanol, ethanol, and propanol in such liquid phase discharges . Carbon monoxide (CO), was found to be an excellent gas phase • OH probe for pulsed corona discharges in humid argon and for electron beam irradiation experiments in humid nitrogen because its oxidation product is carbon dioxide (CO 2 ) . Those CO studies, as well as work with liquid phase probes, highlight the fact that accurate quantification of • OH by chemical probes requires careful measurement of reaction products since the reaction chemistry of probes can be complex …”

Potential energy profiles for the N+HOCO reaction and products of the chemically activated reactions N+HOCO and H+HOCO

“…Our interest in HOCO chemistry was sparked by our analysis of a study by Hakoda et al [4], in which CO was used to titrate OH radical formed upon b-irradiation of humid N 2 gas; the loss of CO and formation of CO 2 was used to determine the gross production of OH upon irradiation. One of us published [5] a kinetic model of b-irradiation of humid air, and used the results of Hakoda et al as a test of that model.…”