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Identification of sulfate and hydroxyl radicals in thermally activated persulfate / Chenju Liang in Industrial & engineering chemistry research, Vol. 48 N° 11 (Juin 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5558–5562 Titre : Identification of sulfate and hydroxyl radicals in thermally activated persulfate Type de document : texte imprimé Auteurs : Chenju Liang, Auteur ; Hsin-Wey Su, Auteur Année de publication : 2009 Article en page(s) : pp. 5558–5562 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Thermal  activation  Persulfate  degradation  Chemical  probe  method Résumé : Thermal activation can induce persulfate (S2O82−) degradation to form sulfate radicals (SO4−•) that can undergo radical interconversion to form hydroxyl radicals (HO•) under alkaline conditions. The radicals SO4−•/HO• can be present either individually or simultaneously in the persulfate oxidation system. To identify the active radical species, a chemical probe method was developed. An excess of probe compounds was added to the system, and differences between the reactivity of the probes and the potential radical species were observed. The usage of various probes, including tert-butyl alcohol, phenol, and nitrobenzene (NB), for simultaneously identifying SO4−•/HO• was investigated. NB can only react with radicals: it cannot react with persulfate. The reaction rate of NB with HO• is 3000−3900 times greater than that of NB with SO4−•, which is a good candidate for use as a probe for differentiating between SO4−•/HO• reactivity. Furthermore, the effects of pH on the formation of SO4−•/HO• were demonstrated by the degradation kinetics of NB at varying pH values. The results indicated that SO4−• is the predominant radical at pH <7; both SO4−• and HO• are present at pH 9; HO• is the predominant radical at a more basic pH (i.e., pH 12). The use of chemical probe NB is a suitable compound for differentiating HO•/SO4−• reactivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002848 [article] Identification of sulfate and hydroxyl radicals in thermally activated persulfate [texte imprimé] / Chenju Liang, Auteur ; Hsin-Wey Su, Auteur . - 2009 . - pp. 5558–5562. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 11 (Juin 2009) . - pp. 5558–5562 Mots-clés : Thermal  activation  Persulfate  degradation  Chemical  probe  method Résumé : Thermal activation can induce persulfate (S2O82−) degradation to form sulfate radicals (SO4−•) that can undergo radical interconversion to form hydroxyl radicals (HO•) under alkaline conditions. The radicals SO4−•/HO• can be present either individually or simultaneously in the persulfate oxidation system. To identify the active radical species, a chemical probe method was developed. An excess of probe compounds was added to the system, and differences between the reactivity of the probes and the potential radical species were observed. The usage of various probes, including tert-butyl alcohol, phenol, and nitrobenzene (NB), for simultaneously identifying SO4−•/HO• was investigated. NB can only react with radicals: it cannot react with persulfate. The reaction rate of NB with HO• is 3000−3900 times greater than that of NB with SO4−•, which is a good candidate for use as a probe for differentiating between SO4−•/HO• reactivity. Furthermore, the effects of pH on the formation of SO4−•/HO• were demonstrated by the degradation kinetics of NB at varying pH values. The results indicated that SO4−• is the predominant radical at pH <7; both SO4−• and HO• are present at pH 9; HO• is the predominant radical at a more basic pH (i.e., pH 12). The use of chemical probe NB is a suitable compound for differentiating HO•/SO4−• reactivity. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie9002848