Chloride anion effect on the advanced oxidation processes of methidathion and dimethoate: Role of Cl2− radical

Abstract

Elsevier; IWA Publishing Caregnato, Paula; Rosso, Janina A.; Soler, Juan M.; et ál.. (2013). Chloride anion effect on the advanced oxidation process of methidathion and dimethoate: role of Cl2(center dot-) radical. Water Order of Authors: Monica Cristina Gonzalez, PhD.Abstract: The reaction of phosphor-containing pesticides such as methidathion (MT) and dimethoate (DM) with dichloride radical anions (Cl2.-) was investigated. The second order rate constants (1.3 ± -1 s-1, were determined for the reaction of Cl2.-with MT and DM, respectively. A reaction mechanism involving an initial charge transfer from the sulfide groups of the insecticides to Cl2.-is proposed and supported by the identified transient intermediates and stable reaction products. The formation of chlorinated by-products was determined. The unexpected consequences of an efficient Cl2.-reactivity towards MT and DM on the degradation capacity by Advanced Oxidation Procedures applied to polluted waters containing the insecticides and Cl-anions is discussed.

Transformation Reactions of Radicals from the Oxidation of Diphenhydramine: Pulse Radiolysis and Mass Spectrometric Studies

“…a broad peak band between 300–400 nm, is significantly different to that of the one obtained from our experiments (Figure ). The transient absorption spectra obtained in the present case (Figure ) is thus assigned to the exclusive reaction of • OH/SO 4 •− with DPH …”

Indirect Photochemistry in Sunlit Surface Waters: Photoinduced Production of Reactive Transient Species

“…The radical Cl 2 −. is both an oxidizing and a chlorinating agent,127, 210, 214, 215 but the chlorination yields are quite low (∼1 %) even with phenolic substrates that are activated to radical halogenation 214. This means that, on the one hand, Cl 2 −.…”

“…[213] Therefore, Cl 2 À C could be an important reactive transient in brackish to saline waters. The radical Cl 2 À C is both an oxidizing and a chlorinating agent, [127,210,214,215] but the chlorination yields are quite low (~1 %) even with phenolic substrates that are activated to radical halogenation. [214] This means that, on the one hand, Cl 2 À C may have limited ability to generate toxic and potentially persistent organochlorinated compounds.…”

Pesticides and Herbicides

“…The risk of Parkinson disease (PD) associated with exposure to pesticides and solvents was investigated using metaanalysis of data from cohort and case-control studies (Pezzoli and Cereda, 2013). The results support the hypothesis that exposure to pesticides or solvents is a risk factor for PD, although further prospective and high-quality case-control studies are required to substantiate a cause- Transferring of initial charge from the sulfide groups of the insecticides to Cl-2(center dot-) is proposed for the reaction mechanism and identified transient intermediates and reaction products supported the mechanism (Caregnato et al, 2013). Zinc oxide (ZnO) and titanium oxide (TiO2) were used as photocatalyst in photocatalyc degradation of sixteen substituted phenylurea herbicides (PUHs) in pure water by using artificial light.…”