Yan Yingjie, Liao Qi-Nan, Ji Feng, Wang Wei, Yuan Shoujun, Hu Zhen-Hu
School of Civil Engineering, Hefei University of Technology, Hefei, 230009, China.
Chongqing Electric Power Design Institute, State Grid Chongqing Electric Power Company, Chongqing, 401121, China.
Environ Sci Pollut Res Int. 2017 Feb;24(6):5360-5369. doi: 10.1007/s11356-016-8245-1. Epub 2016 Dec 24.
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 (HO) and UV/titanium dioxide (TiO) advanced oxidation processes (AOPs) can decompose organic contaminants efficiently. In this study, the decomposition of 3,5-dinitrobenzamide in aqueous solution during UV/HO and UV/TiO oxidation 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 NO, Cl, SO, HCO, and CO inhibited the degradation of 3,5-dinitrobenzamide during the UV/HO and UV/TiO oxidation 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 CO, HO, and other inorganic anions. Ions such as NH, NO, and NO 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/HO and UV/TiO processes was proposed.
3,5-二硝基苯甲酰胺作为一种饲料添加剂，已被广泛用于控制家禽球虫病，添加的3,5-二硝基苯甲酰胺部分会排泄到废水和地表水中。以往的研究中尚未报道过从废水和地表水中去除3,5-二硝基苯甲酰胺的相关内容。紫外光/过氧化氢（HO）和紫外光/二氧化钛（TiO）高级氧化工艺（AOPs）产生的高活性羟基自由基能够有效分解有机污染物。在本研究中，对紫外光/HO和紫外光/TiO氧化过程中3,5-二硝基苯甲酰胺在水溶液中的分解情况进行了研究。3,5-二硝基苯甲酰胺的分解很好地符合基于辐照量的准一级动力学模型。两种氧化过程中的分解均受溶液pH值影响，在碱性条件下受到抑制。无机阴离子如NO、Cl、SO、HCO和CO在紫外光/HO和紫外光/TiO氧化过程中抑制了3,5-二硝基苯甲酰胺的降解。在两种氧化过程完全分解后，约50%的3,5-二硝基苯甲酰胺分解为有机中间体，其余部分矿化为CO、HO和其他无机阴离子。降解过程中有NH、NO和NO等离子释放到水溶液中。使用飞行时间质谱仪（LCMS-IT-TOF）鉴定了3,5-二硝基苯甲酰胺的主要分解产物。基于这些产物和离子释放情况，提出了3,5-二硝基苯甲酰胺在紫外光/HO和紫外光/TiO过程中可能的分解途径。
