Photodegradation of the aminoazobenzene acid orange 52 by three advanced oxidation processes:: UV/H2O2 UV/TiO2 and VIS/TiO2 -: Comparative mechanistic and kinetic investigations
Photodegradation of the aminoazobenzene acid orange 52 by three advanced oxidation processes:: UV/H2O2 UV/TiO2 and VIS/TiO2 -: Comparative mechanistic and kinetic investigations
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DOI：
10.1016/s1010-6030(99)00199-9
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发表时间：
2000-01-03
影响因子：
4.3
通讯作者：
Kalt, A
中科院分区：
文献类型：
--
作者：
Galindo, C;Jacques, P;Kalt, A
本文报道了UV/H_2O_2、UV/TiO_2和VIS/TiO_2体系氧化氨基偶氮苯染料AO_(52)的结果。在前一种情况下，我们通过GC/MS、高效液相色谱和核磁共振氢谱对第一副产物的形成进行了研究。光谱学。我们得出的结论是，羟基自由基相对于磺酸基或含偶氮键的碳被加到了ipso位置的芳环上。无机自由基与N，N-二甲氨基的反应导致脱甲基化，增加了可能途径的多样性。紫外光/二氧化钛体系的降解与pH有关。在中性和碱性溶液中，羟基自由基是主要的氧化剂，而在酸性介质中，正空穴诱导的氧化与质子化染料分子的还原竞争。此外，AO52/Ti02晶片的FTIR光谱提供了对光产物性质的洞察。这一过程非常有效，因为只检测到最终的分解产物，即脂肪酸和无机盐。在使用可见光作为照射源的情况下，在晶片的情况下也获得了类似的结果，而在多相溶液中，染料似乎抗降解。(C)2000 Elsevier Science S.A.保留所有权利。
This paper presents the results obtained from the oxidation of the aminoazobenzene dye AO52 by the UV/H2O2, UV/TiO2 and VIS/TiO2 systems. In the former case, we investigated the formation of first by-products by means of GC/MS, HPLC and H-1 NMR. spectroscopy. We conclude that hydroxyl radicals are added to aromatic rings in the ipso position with respect to the sulfonate group or to the azo-linkage-bearing carbon. The reaction of the inorganic radical with the N,N-dimethylamino substituent, leading to demethylation, adds to the multiplicity of the possible pathways. Degradation by the UV/TiO2 system is pH dependent. Whereas hydroxyl radicals are the main oxidative agent in neutral and alkaline solutions, positive hole-induced oxidation competes with the reduction of the protonated dye molecules in acid media. Moreover, FTIR spectroscopy of AO52/TiO2 wafers provided an insight to the nature of the photoproducts. This process is very efficient since only ultimate breakdown products, i.e. aliphatic acids and inorganic salts, are detected. Similar results were obtained using visible light as the irradiation source in the case of wafers whereas in heterogeneous solutions, the dye seems to be resistant to degradation. (C)2000 Elsevier Science S.A. All rights reserved.