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Titolo:
Post-irradiation effect and reductive dechlorination of chlorophenols at oxygen-free TiO2/water interfaces in the presence of prominent hole scavengers
Autore:
Serpone, N; Texier, I; Emeline, AV; Pichat, P; Hidaka, H; Zhao, J;
Indirizzi:
Concordia Univ, Dept Chem & Biochem, Montreal, PQ H3G 1M8, Canada Concordia Univ Montreal PQ Canada H3G 1M8 m, Montreal, PQ H3G 1M8, Canada Ecole Cent Lyon, IFOS, Lab Photocatalyse Catalyse & Environm, CNRS,UMR, F-69131 Ecully, France Ecole Cent Lyon Ecully France F-69131 , CNRS,UMR, F-69131 Ecully, France St Petersburg State Univ, Dept Gen Phys 2, St Petersburg 198904, Russia StPetersburg State Univ St Petersburg Russia 198904 burg 198904, Russia Meisei Univ, Dept Chem, Ctr Global Environm Protect, Hino, Tokyo 1918506, Japan Meisei Univ Hino Tokyo Japan 1918506 Protect, Hino, Tokyo 1918506, Japan Chinese Acad Sci, Inst Chem, Ctr Mol Sci, Lab Photochem, Beijing 100080, Peoples R China Chinese Acad Sci Beijing Peoples R China 100080 100080, Peoples R China
Titolo Testata:
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
fascicolo: 3, volume: 136, anno: 2000,
pagine: 145 - 155
SICI:
1010-6030(20000929)136:3<145:PEARDO>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOCATALYTIC DEGRADATION; HETEROGENEOUS PHOTOCATALYSIS; CHLOROAROMATIC DERIVATIVES; CHLORINATED PHENOLS; AQUEOUS-SOLUTIONS; PULSE-RADIOLYSIS; TITANIUM-DIOXIDE; COLLOIDAL TIO2; ZINC-OXIDE; ELECTRONS;
Keywords:
2,4-dichlorophenol; pentachlorophenol; TiO2 particles; photolysis;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Serpone, N Concordia Univ, Dept Chem & Biochem, 1455 Maisonneuve Blvd W, Montreal, PQH3G 1M8, Canada Concordia Univ 1455 Maisonneuve Blvd W Montreal PQ Canada H3G 1M8
Citazione:
N. Serpone et al., "Post-irradiation effect and reductive dechlorination of chlorophenols at oxygen-free TiO2/water interfaces in the presence of prominent hole scavengers", J PHOTOCH A, 136(3), 2000, pp. 145-155

Abstract

Heterogeneous photocatalysis with TiO2 nanoparticles for the detoxification of waste-waters and other media is typically achieved by oxidative pathways involving ultimately photogenerated surface-trapped holes (i.e, surface-bound (OH)-O-. radicals). However, reductive pathways may coexist. The degradation of 2,4-dichlorophenol (2,4-DCP) and pentachlorophenol (PCP) was examined in irradiated O-2-free aqueous media in the presence of prominent hole scavengers such as polyethyleneimine (PEI), triethylamine (TEA), 2-propanol (IPA) and ethylenediaminetetraacetic acid (in the EDTA(4-) state) to assess the role of photogenerated electrons. The presence of these scavengers imparts a blue-violet color to the nanoparticles corresponding to a broad absorption band in the 400-850 nm region. A post-irradiation effect was observed when irradiation was terminated, which we ascribe to an electron transfer from radical species formed by hole scavenging to the TiO2 particles (reminiscent of the doubling current phenomena in semiconductor electrodes). The two chlorophenols degraded in oxygen-free media, a process inhibited byPEI, TEA and IPA. In the presence of EDTA, degradation of 2,4-dichorophenol occurred by dechlorination only after a 120-min induction period, a process attributed to the accumulated electrons on the particle surface. HPLC analyses revealed that the intermediate products were not those expected fromtypical oxidative pathways in aerated aqueous media. The degradative process is inferred to take place first by electron attachment to the halophenolto yield phenoxy related radicals and then by secondary reactions with water and/or with each other. (C) 2000 Elsevier Science S.A. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 24/09/20 alle ore 23:49:46