Potocatalytic oxidative degradation of organic pollutant with molecular oxygen activated by a novel biomimetic catalyst ZnPz(dtn-COOH)4

Authors:  Zehui Zhang, Mingjian Zhang, Jia Deng, Kejian Deng, Bingguan Zhang, Kangle Lv, Jie Sun, Lianqing Chen

Abstract:
Zinc porphyrins and its analogs showing many excellent properties such as good potosensitivity, nontoxicity, high stability and facile preparation attract more and more attention of scientists. Here, a novel zinc porphyrazine, namely zinc(II) tetracarboxyl- tetra(1,4-dithiin) porphyrazine [abbreviated as ZnPz(dtn-COOH)₄] was successfully synthesized and its potocatalytic activity was studied. The ZnPz(dtnCOOH)₄ supported on an Amberlite CG-400 resin was used as a biomimetic catalyst for the activation of molecular oxygen under visible light to degrade a probe dye compound Rhodamine B (RhB) in aqueous solution. Interestingly, the mechanism for the oxidative degradation of RhB involves both ¹O₂ and HO^• (Type II and Type I mechanisms, respectively). More hydroxyl radicals were produced at pH 3, which was responded for the highest degradation ratio. The catalyst can be reused several times without losing its catalytic activity, with an average RhB degradation ratio around 80% for 12 h. The most probable mechanism of RhB degradation in this study was that N,N-diehyl-N-ethyl-rhodamine was the main intermediate, which was thencleavedto smallmoleculeby reactive oxidizing species. This studydemonstrated a promising approach for the activation of molecular oxygen by the newly developed biomimetic catalyst, in which the central metalto be unchangeable valence, for environmental remediation and oxidation catalysis.

Keywords:
Zinc porphyrazine with sulfur
Biomimetic catalyst
Activating molecular oxygen
Photodegradation
Rhodamine B

Published in: Applied Catalysis B: Environmental (Volumes 132–133, Pages 1-552, 27 March 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Potocatalytic oxidative degradation of organic pollutant with molecular oxygen activated by a novel biomimetic catalyst ZnPz(dtn-COOH)4

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