Efficient decolorization/degradation of aqueous azo dyes using buffered H₂O₂ oxidation catalyzed by a dosage below ppm level of chloroperoxidase

详细信息	查看全文 | 推荐本文 |

• 作者：Juan Zhang^a ; ^{zhangjuan291282@stu.snnu.edu.cn} ; Mingyue Feng^a ; ^{moonwindyfeng@yahoo.cn} ; Yucheng Jiang^a ; ^b ; ^{jyc@snnu.edu.cn} ; Mancheng Hu^a ; ^b ; ^{hmch@snnu.edu.cn} ; Shuni Li^a ; ^b ; ^{lishuni@snnu.edu.cn} ; Quanguo Zhai^a ; ^b ; ^{zhaiqg@snnu.edu.cn}
• 关键词：Orange G ; Sunset Yellow ; Decolorization/degradation ; H2O2 ; Chloroperoxidase ; Products determination
• 刊名：Chemical Engineering Journal
• 出版年：2012
• 期刊代码：16_13858947
• 类别：ce
• 出版时间：15 May, 2012
• 卷：191
• 期：Complete
• 页码：236-242
• 文件大小：930 K

摘要

The decolorization/degradation of aqueous azo dyes generated by textile photography industries are a main issue in wastewater treatment. Despite many significant efforts and numerous systems have been exploited, the problem is still unsolved due to intrinsically low activity or use of non-convenient chemical reagents. Biodegradation appears to be one of the most efficient ways, however, the initial step of biotransformation usually involves a reductive cleavage of the azo bond, which under anaerobic conditions leads to the formation of aromatic amines known to be carcinogenic. This study shows that applying an oxidative process of H₂O₂ catalyzed by chloroperoxidase (CPO) for decolorization/degradation of aqueous azo dyes (Orange G and Sunset Yellow) in buffer solution is a very efficient system. The effect of initial pH, dosage of enzyme, H₂O₂ concentration, reaction temperature and time, and suitable initial dye concentration on the decolorization efficiency were investigated in detail and optimized accordingly. At optimum reaction condition, the decolorization efficiency of Orange G reached 98.72%in 5 min, and 77.25%in 10 min for Sunset Yellow. The dosage of CPO was below ppm level. This enzymatic reaction is an ideal potential alternative for application on decolorization/degradation of aqueous azo dyes.

Furthermore, the elucidation of degradation pathways is of special interest considering healthy and environmental priorities. In this work, LC-MS was used to determine the structures of intermediates arising from Orange G by CPO-H₂O₂ oxidation. Eight transformation products were identified and two types of cleavage were proposed for the degradation pathway.