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Photocatalytic degradation of lignin and lignin models, using titanium dioxide: the role of the hydroxyl radical

Chemosphere (Oxford), 2000, Vol.40 (1), p.115-124 [Tạp chí có phản biện]

1999 Elsevier Science Ltd ;2000 INIST-CNRS ;ISSN: 0045-6535 ;EISSN: 1879-1298 ;DOI: 10.1016/S0045-6535(99)00269-6 ;PMID: 10665453 ;CODEN: CMSHAF

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Nhan đề:
Photocatalytic degradation of lignin and lignin models, using titanium dioxide: the role of the hydroxyl radical
Tác giả: Machado, Antonio E.H. ; Furuyama, Aline M. ; Falone, Sandra Z. ; Ruggiero, Reinaldo ; Perez, Denilson da Silva ; Castellan, Alain
Chủ đề: Applied sciences ; biphenyl lignin model compounds ; bleaching ; Catalysis ; catalysts ; catalytic activity ; Cellulose - chemistry ; chemical reactions ; degradation ; electron transfer ; Exact sciences and technology ; free radicals ; hydrogen peroxide ; Hydroxyl Radical ; Hydroxyl radicals ; hydroxylation ; Indicators and Reagents ; irradiation ; Kinetics ; light ; lignin ; Lignin - chemistry ; Lignin degradation ; Paper, paperboard, non wovens ; phenolic compounds ; Photocatalysis ; Photolysis ; Polymer industry, paints, wood ; Pulp manufacturing ; simulation ; Titanium ; Titanium dioxide ; ultraviolet radiation ; wood pulp ; Wood. Paper. Non wovens
Là 1 phần của: Chemosphere (Oxford), 2000, Vol.40 (1), p.115-124
Mô tả: The role of hydroxyl radicals on the degradation of lignins during a cellulosic pulp bleaching process including a photocatalytic stage, was assessed using peroxyformic acid lignins EL1 and REL1 and two phenolic biphenyl lignin models 1 and 2 . The irradiations were performed in the absence of photocatalyst TiO 2 and H 2O 2 (condition a), in the presence of TiO 2 (condition b) and in the presence of H 2O 2 (condition c). The experiments were conducted in alkaline (pH ≈ 11) aqueous ethanol solutions with oxygen bubbling. The relative phenolic content of the irradiated solutions, which is indicative of the involvement of hydroxyl radicals, was determined by ionization absorption spectroscopy. The results obtained show that the catalyzed reaction involves both degradation of the phenolate groups by electron transfer and hydroxylation of the lignin aromatic structure. Benzyl alcohol structural elements in sodium borohydride reduced lignin REL1 and compound 2 were also found as good trapping agents for the hydroxyl radicals. The degradation of EL1 was studied by measuring its fluorescence emission by comparison to the fluorescence of compound 2 . The emission spectra indicate that some biphenyl phenolate anions in EL1 are reacting under UV/visible irradiation and some others, probably polyphenolic chromophores emitting less fluorescence, are formed.
Nơi xuất bản: Oxford: Elsevier Ltd
Ngôn ngữ: English
Số nhận dạng: ISSN: 0045-6535
EISSN: 1879-1298
DOI: 10.1016/S0045-6535(99)00269-6
PMID: 10665453
CODEN: CMSHAF
Nguồn: MEDLINE
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Photocatalytic degradation of lignin and lignin models, using titanium dioxide: the role of the hydroxyl radical

1999 Elsevier Science Ltd ;2000 INIST-CNRS ;ISSN: 0045-6535 ;EISSN: 1879-1298 ;DOI: 10.1016/S0045-6535(99)00269-6 ;PMID: 10665453 ;CODEN: CMSHAF

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