Sulfate radical-induced degradation of 2,4,6-trichlorophenol: A de novo formation of chlorinated compounds

An effective heterogeneous iron-based catalyst to activate peroxymonosulfate for organic contaminants removal

“…Among these various AOPs, activated peroxymonosulfate (PMS) oxidation has been regarded as an interesting treatment method because PMS is more easily activated compared with hydrogen peroxide, which is one of the most commonly used oxidants in AOPs [7,8]. Although some research has demonstrated that heat and UV irradiation can be used to activate PMS to generate powerful radicals, these techniques are restricted in practical application owing to their high energy input [9,10].…”

Transformations of chloro and nitro groups during the peroxymonosulfate-based oxidation of 4-chloro-2-nitrophenol

“…It indicates that only parts of 4C2NP were decomposed to inorganic nitrate and chloride. It was known that Cl À released from the aromatic ring would be involved in the de novo formation of chlorinated compounds, resulting in the decrease of released Cl À (Xu et al, 2013). It should be noted that a mass balance of nitrogen was not reached if considering nitrate as the sole product of nitro group (Fig.…”

“…According to the previous investigations (Vione et al, 2002;Anipsitakis et al, 2006;Xu et al, 2013), the released chloride and nitrate are supposed to be involved in the re-chlorination and re-nitration. To manifest the involvement of these two inorganic ions, amounts of Cl À and NO 3 À were deliberately added into the Co/PMS/4C2NP systems.…”

“…4) based on the identified intermediates (Figs. S6-S25) and the previous data available (Xu et al, 2013). Firstly, sulfate radicals were combined with the parent compound by addition, followed by elimination of sulfate ion, leading to formation of the carbon-centered radicals through one electron transfer (Anipsitakis et al, 2006).…”

“…Advanced oxidation processes (AOPs), based on very strongly oxidizing free radicals such as hydroxyl and sulfate radicals, have proven to be effective in destroying these aqueous pollutants (Titus et al, 2004;Shen et al, 2008). Despite the success of chlorophenols removal by a Co(II)-mediated activation of peroxymonosulfate (PMS) (Benitez et al, 2000;Anipsitakis et al, 2006;Saritha et al, 2009), our recent study indicated a de novo formation mechanism of organohalogens coupled with dechlorination and mineralization of 2,4,6-trichlorophenol (Xu et al, 2013). The chloro groups are firstly converted into chloride ions via dechlorination, which are partly re-oxidized to reactive chlorine species (RCS, i.e.…”