Destruction of Chlorinated Phenols by Dioxygen Activation under Aqueous Room Temperature and Pressure Conditions

Abstract

The complete destruction of separate mixtures of 1.1 mM 4-chlorophenol (aqueous) and 0.61 mM pentachlorophenol (aqueous slurry) take place in the presence of 0.5 g of iron particles in 10 mL of 0.32 mM ethylenediaminetetraacetic acid (EDTA) under ambient air under room temperature conditions. Under this reaction condition, the time required to reach complete disappearance to the detection limit of GC-FID for each compound was 4 h for 4-chlorophenol and 70 h for pentachlorophenol. Electrospray ionization mass spectral (ESI-MS) analysis of the 4-chlorophenol reaction mixture after its complete disappearance indicated non-chlorinated, primarily low molecular weight products; however, Clfrom 4-chlorophenol was not detected due to adsorption onto the iron or its corrosion products. Radical trap and control experiments suggest that the mechanism for destruction initiates with dioxygen activation, leading to the formation of reactive oxygen species (ROS) and ultimately ring opening of the phenolic compounds. This is the first example of an abiotic system capable of the complete destruction of an organic pollutant under room temperature and pressure conditions through dioxygen activation chemistry.

Degradation characteristics of humic acid over iron oxides/Fe0 core–shell nanoparticles with UVA/H2O2

“…Zero valent iron has been widely used in different environmental treatment processes [16,17] and the direct electron transfer from Fe 0 to H 2 O 2 during a Fenton reaction is a very slow process at neutral pH [18]. However, Fe 0 /Fe 3 O 4 composite showed highly catalytic activity for the decomposition of H 2 O 2 as a result of an electron transfer process from metal to magnetite [18,19].…”

Oxidation of organic contaminants in water by iron-induced oxygen activation: A short review

“…Several investigators have demonstrated the degradation of organic contaminants such as phenolic compounds, herbicides, pharmaceuticals and diagnostic agents, and dyes by the ZVI/O2 and the Fe(II)/O2 systems with or without additives [13,39,40,[45][46][47][48][49][50]. Table 2 summarizes those literature results reported in terms of the type of iron, the target compound, initial concentrations, conditions, and degradation efficiency.…”

“…The use of additives such as EDTA, TPP, POM, and NOM (iron-chelating agents or electron shuttles) greatly enhanced the degradation rate of organic contaminants [13,[39][40][41]46]. In particular, the addition of iron-chelating agents enables the ZVI/O2 system to work at neutral pH.…”

“…However, relatively recent studies have demonstrated • OH to be generated by activation of O2 [13][14][15]. Theoretically, the reduction of O2 by a three-electron transfer produces…”

Degradação de fármacos por processo foto-Fenton e ferro metálico

“…Em processos heterogêneos como Feº, a adsorção do contaminante na superfície das partículas do Feº é uma preocupação relatada por vários autores (NORADOUN et al, 2003;ZHOU et al, 2009 [Feº] 25 g L -1 sem pré-trat.…”