Role of Antioxidant Moieties in the Quenching of a Purine Radical by Dissolved Organic Matter

• DOI: 10.1021/acs.est.1c04576
• Publication Date: 2021-11-08T16:53:27Z
• Authors: Shuangshuang Cheng; Yujie Zhao; Yanheng Pan; Jinpeng Yu; Yu Lei; Xin Lei; Gangfeng Ouyang; Xin Yang
• Keywords: Hydroxyl radical

Dissolved organic matter (DOM) has been known to inhibit the degradation of trace contaminants (TrOCs) in advanced oxidation processes but quantitative understanding is lacking. Adenine (ADN) was selected as a model TrOC due wide occurrence purine groups TrOCs and well-documented transient spectra its intermediate radicals. ADN presence DOM during UV/peroxydisulfate treatment quantified using steady-state photochemical experiments, time-resolved spectroscopy, kinetic modeling. The inhibitory effects were found include competing for photons, scavenging SO4•– HO•, also converting radicals (ADN(-H)•) back into ADN. Half ADN(-H)• reduced about 0.2 mgC L–1 DOM. quenching rate constants by 10 tested isolates range (0.39–1.18) × 107 MC–1 s–1. They showed positive linear relationship with total antioxidant capacity laser flash photolysis results low-molecular-weight analogues redox-active moieties further supported dominant role ADN(-H)•. diverse roles should be considered predicting abatement processes.