Environmental Implications of Hydroxyl Radicals (^•OH)

Abstract

The hydroxyl radical ((•)OH) is one of the most powerful oxidizing agents, able to react unselectively and instantaneously with the surrounding chemicals, including organic pollutants and inhibitors. The (•)OH radicals are omnipresent in the environment (natural waters, atmosphere, interstellar space, etc.), including biological systems where (•)OH has an important role in immunity metabolism. We provide an extensive view on the role of hydroxyl radical in different environmental compartments and in laboratory systems, with the aim of drawing more attention to this emerging issue. Further research on processes related to the hydroxyl radical chemistry in the environmental compartments is highly demanded. A comprehensive understanding of the sources and sinks of (•)OH radicals including their implications in the natural waters and in the atmosphere is of crucial importance, including the way irradiated chromophoric dissolved organic matter in surface waters yields (•)OH through the H2O2-independent pathway, and the assessment of the relative importance of gas-phase vs aqueous-phase reactions of (•)OH with many atmospheric components. Moreover, considering the fact that people spend so much more time in dwellings than outside, the impact of the reactivity of indoor hydroxyl radicals on health and well-being is another emerging research topic of great concern.

Reaction rates and kinetic isotope effects of H2 + OH → H2O + H

“…It contributes to fundamental processes in atmospheric chemistry, astrochemistry, and combustion. [1][2][3] The reaction being surface catalyzed was shown to be one of the main routes of H 2 O formation in the interstellar medium.…”

Mixing state of oxalic acid containing particles in the rural area of Pearl River Delta, China: implications for the formation mechanism of oxalic acid

“…The modeling studies from Ervens et al (2014) suggest that oxalic acid production from glyoxal and glyoxylic acid in the aqueous phase significantly depends on q OH availability (Ervens et al, 2014). The main sources of aqueous-phase q OH in cloud droplets include direct uptake from the gas phase (Jacob, 1986), ozone photolysis by UV and visible light at the air-water interface (Anglada et al, 2014) and also aqueous-phase chemical reactions (Gligorovski et al, 2015). For the last kind of source, q OH radicals could be generated through Fenton or Fenton-like reactions and photolysis of H 2 O 2 , NO − 3 , NO − 2 and chromophoric dissolved organic matter (CDOM) (Badali et al, 2015;Ervens, 2015;Herrmann et al, 2015;Tong et al, 2016).…”

Synthesis, thermal behaviour and some properties of CuII complexes with N,O-donor Schiff bases

“…degradation products ð6Þ In the blank solution, a decrease in the concentration of MB is also observed. The discoloration can be explained by formation of •OH radical during homolysis of hydrogen peroxides induced by light as well as heat [66,67]. In comparison with the solutions containing the complexes addition, this process is slower; a significant change in the concentration of MB (\2%) can be seen only after an hour.…”