Journal ArticleDOI
Cobalt-mediated activation of peroxymonosulfate and sulfate radical attack on phenolic compounds. implications of chloride ions.
TLDR
The sulfate radical pathway of the room-temperature degradation of two phenolic compounds in water is reported, and it provides strong evidence on the interaction of chloride ions with sulfate radicals leading to halogenation of organics in water.Abstract:
The sulfate radical pathway of the room-temperature degradation of two phenolic compounds in water is reported in this study. The sulfate radicals were produced by the cobalt-mediated decomposition of peroxymonosulfate (Oxone) in an aqueous homogeneous system. The major intermediates formed from the transformation of 2,4-dichlorophenol were 2,4,6-trichlorophenol, 2,3,5,6-tetrachloro-1,4-benzenediol, 1,1,3,3-tetrachloroacetone, pentachloroacetone, and carbon tetrachloride. Those resulting from the transformation of phenol in the presence of chloride ion were 2-chlorophenol, 4-chlorophenol, 2,4-dichlorophenol, 2,6-dichlorophenol, 1,1,3,3-tetrachloroacetone, and pentachloroacetone. In the absence of chloride ion, phenol transformed into 2,5-cyclohexadiene-1,4-dione (quinone), 1,2-benzenediol (catechol), and 1,4-benzenediol (hydroquinone). Several parameters were varied, and their impact on the transformation of the organic compounds is also discussed. The parameters varied were the initial concentration of the organic substrate, the dose of Oxone used, the cobalt counteranion, and in particular the impact of chloride ions and the quenching agent utilized for terminating the reaction. This is one of the very few studies dealing with intermediates formed via sulfate radical attack on phenolic compounds. It is also the first studythat explores the sulfate radical mechanism of oxidation, when sulfate radicals are generated via the Co/Oxone reagent. Furthermore, it provides strong evidence on the interaction of chloride ions with sulfate radicals leading to halogenation of organics in water.read more
Citations
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Journal ArticleDOI
Decontamination and disinfection of water by solar photocatalysis: Recent overview and trends
TL;DR: In this article, the authors reviewed the use of sunlight to produce the OH radicals by TiO2 photocatalysis and photo-Fenton process and summarized most of the research carried out related to solar photocatalytic degradation of water contaminants and how it could significantly contribute to the treatment of persistent toxic compounds.
Journal ArticleDOI
Generation of sulfate radical through heterogeneous catalysis for organic contaminants removal: Current development, challenges and prospects
TL;DR: In this paper, the authors provide a state-of-the-art review on the development in heterogeneous catalysts including single metal, mixed metal, and nonmetal carbon catalysts for organic contaminants removal, with particular focus on peroxymonosulfate (PMS) activation.
Journal ArticleDOI
Persulfate-Based Advanced Oxidation: Critical Assessment of Opportunities and Roadblocks.
TL;DR: This Critical Review comparatively examines the activation mechanisms of peroxymonosulfate and peroxydisulfates and the formation pathways of oxidizing species and the impacts of water parameters and constituents such as pH, background organic matter, halide, phosphate, and carbonate on persulfate-driven chemistry.
Journal ArticleDOI
Identification of Sulfate and Hydroxyl Radicals in Thermally Activated Persulfate
Chenju Liang,Hsin-Wey Su +1 more
TL;DR: In this article, a chemical probe method was developed to identify the active radical species, and differences between the reactivity of the probe compounds and the potential radical species were observed, and the usage of various probes, including tert-butyl alcohol, phenol, and nitrobenzene, for simultaneously identifying SO4−•/HO• was investigated.
Journal ArticleDOI
Influence of pH on the formation of sulfate and hydroxyl radicals in the UV/peroxymonosulfate system.
TL;DR: The formation of HO(•) and SO(4)(•-) in the UV/PMS system was confirmed mainly from the cooperation of the photolysis of PMS, the decay of peroxomonosulfate radical (SO(5)(•-)) and the conversion of SO(3)(•) to HO( •) by simulation and experimental results.
References
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Characterization of the Ni(III) intermediate in the reaction of (1,4,8,11-tetraazacyclotetradecane)nickel(II) perchlorate with KHSO5: implications to the mechanism of oxidative DNA modification.
TL;DR: The results indicate that the Ni(III) center is coordinately saturated under excess chloride conditions but is still able to interact with DNA substrates, which suggests alternative mechanistic pathways for DNA modification by reaction of [Ni(cyclam)]2+ with KHSO5 and possibly other Ni(II) complexes as well.