title: Process design of high-concentration benzimidazole wastewater treatment based on the molecular structure of contaminants.
abstract: 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 (H2O2) concentration to produce the hydroxyl radicals (•OH) as much as possible and protect •OH from being quenched by excess H2O2according 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.
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Chenru
authors.initials: C
authors.lastname: Li
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Qian
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Qinyao
authors.initials: Q
authors.lastname: Liu
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Qianyi
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Chen
authors.initials: C
authors.lastname: Yao
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Song
authors.affiliation: a School of Chemistry and Chemical Engineering , Southeast University , Nanjing , People's Republic of China.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Wang
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D006861:Hydrogen Peroxide; D007220:Industrial Waste; D007501:Iron; D015394:Molecular Structure; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid; D062065:Wastewater; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D001562:Benzimidazoles; D006861:Hydrogen Peroxide; D007220:Industrial Waste; D007501:Iron; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Fenton; Pesticide wastewater; degradation pathway; micro-electrolysis; process designed