Li Chenru, Qian Kun, Liu Qinyao, Zhang Qianyi, Yao Chen, Song Wei, Wang Yihong
a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
Environ Technol. 2018 Apr;39(8):1007-1016. doi: 10.1080/09593330.2017.1317844. Epub 2017 Apr 27.
Benzimidazole is an important intermediate in industry and it is usually difficult to be degraded by many treatment technologies. Looking for a highly effective, environment-friendly degradation process for benzimidazole wastewater is of great significance to reduce pollution. Based on the structure of contaminants, the micro-electrolysis (ME) coupled with the Fenton technique was chosen to degrade the industrial benzimidazole wastewater. Special feeding was applied to maintain the suitable hydrogen peroxide (HO) concentration to produce the hydroxyl radicals (•OH) as much as possible and protect •OH from being quenched by excess HO according to the reaction mechanism. The results showed that this combined technique was highly efficient to decompose benzimidazole compounds. More chemical oxygen demand (COD) could be reduced when flow control was used, compared to the flow not being controlled. The COD removal rate could reach 85.2% at optimal parameters. Then the effluent of this process was combined with the existing biochemical system for further degradation. The studies of Ultraviolet Spectrophotometry, Fourier Transform Infrared Spectroscopy and Liquid Chromatography Mass Spectrometry showed that both 2-(a-Hydroxyethyl) benzimidazole and 2-Acetylbenzimidazole were decomposed to the isopropanolamine and aniline after the ME treatment; then the intermediates were oxidized into oxalic acid after the Fenton reaction.
苯并咪唑是一种重要的工业中间体，通常难以被多种处理技术降解。寻找一种高效、环保的苯并咪唑废水降解工艺对于减少污染具有重要意义。基于污染物的结构，选择微电解（ME）与芬顿技术联用对工业苯并咪唑废水进行降解。根据反应机理，采用特殊进料方式维持合适的过氧化氢（HO）浓度，以尽可能多地产生羟基自由基（•OH），并防止•OH被过量的HO淬灭。结果表明，该联合技术对分解苯并咪唑化合物具有高效性。与不控制流量相比，采用流量控制时可降低更多的化学需氧量（COD）。在最佳参数下，COD去除率可达85.2%。然后将该工艺的出水与现有的生化系统相结合进行进一步降解。紫外分光光度法、傅里叶变换红外光谱法和液相色谱-质谱联用研究表明，微电解处理后，2-（α-羟乙基）苯并咪唑和2-乙酰基苯并咪唑均分解为异丙醇胺和苯胺；芬顿反应后，中间体被氧化为草酸。
