title: Decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2and UV/TiO2oxidation processes.
abstract: 3,5-Dinitrobenzamide has been widely used as a feed additive to control coccidiosis in poultry, and part of the added 3,5-dinitrobenzamide is excreted into wastewater and surface water. The removal of 3,5-dinitrobenzamide from wastewater and surface water has not been reported in previous studies. Highly reactive hydroxyl radicals from UV/hydrogen peroxide (H2O2) and UV/titanium dioxide (TiO2) advanced oxidation processes (AOPs) can decompose organic contaminants efficiently. In this study, the decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/H2O2and UV/TiO2oxidation processes was investigated. The decomposition of 3,5-dinitrobenzamide fits well with a fluence-based pseudo-first-order kinetics model. The decomposition in both two oxidation processes was affected by solution pH, and was inhibited under alkaline conditions. Inorganic anions such as NO3-, Cl-, SO42-, HCO3-, and CO32-inhibited the degradation of 3,5-dinitrobenzamide during the UV/H2O2and UV/TiO2oxidation processes. After complete decomposition in both oxidation processes, approximately 50% of 3,5-dinitrobenzamide was decomposed into organic intermediates, and the rest was mineralized to CO2, H2O, and other inorganic anions. Ions such as NH4+, NO3-, and NO2-were released into aqueous solution during the degradation. The primary decomposition products of 3,5-dinitrobenzamide were identified using time-of-flight mass spectrometry (LCMS-IT-TOF). Based on these products and ions release, a possible decomposition pathway of 3,5-dinitrobenzamide in both UV/H2O2and UV/TiO2processes was proposed.
authors.affiliation: School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Yan
authors.affiliation: Chongqing Electric Power Design Institute, State Grid Chongqing Electric Power Company, Chongqing, 401121, China.
authors.forename: Qi-Nan
authors.initials: QN
authors.lastname: Liao
authors.affiliation: Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China. jifengji@sina.com.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Ji
authors.affiliation: School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: Shoujun
authors.initials: S
authors.lastname: Yuan
authors.affiliation: School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China. zhhu@hfut.edu.cn.
authors.forename: Zhen-Hu
authors.initials: ZH
authors.lastname: Hu
mesh_terms: D001549:Benzamides; D006861:Hydrogen Peroxide; D017665:Hydroxyl Radical; D007700:Kinetics; D010084:Oxidation-Reduction; D014025:Titanium; D014466:Ultraviolet Rays; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical; D018508:Water Purification / Q000379:methods*
chemical_list: D001549:Benzamides; D006861:Hydrogen Peroxide; D017665:Hydroxyl Radical; D014025:Titanium; D062065:Wastewater; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; C008599:nitromide
keywords: 3,5-Dinitrobenzamide; Decomposition; Pathway; UV/H2O2 oxidation; UV/TiO2 oxidation