Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China; Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati, Cincinnati, OH, 45221-0012, USA.
Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Department of Water Engineering and Science, College of Civil Engineering, Hunan University, Changsha, 410082, China.
Water Res. 2018 Dec 1;146:288-297. doi: 10.1016/j.watres.2018.09.036. Epub 2018 Sep 26.
UV/monochloramine (NHCl) process has attracted some attention for the elimination of contaminants of emerging concern as a novel advanced oxidation process. However, there is still much uncertainty on the performance and mechanisms of UV/NHCl process because of its complexity and generation of various species of radicals, including NH, HO, Cl and other reactive chlorine species (RCS). The mechanism and influence factors of degradation of carbamazepine (CBZ) in the UV/NHCl process were investigated, and a synergistic effect was observed. Degradation of CBZ under all investigated conditions followed pseudo-first order kinetics. The corresponding rate constant increased along with the dosage of NHCl, and was affected significantly by the presence of bicarbonate and natural organic matter. The process has little pH-dependency, while the specific contribution of RCS and HO changed with solution pH, and RCS always act as a major contributor to the degradation of CBZ. Eleven byproducts of CBZ were identified and their respective evolution profiles were determined. The participation of UV in chloramination can reduce the formation of nitrogenous DBPs, but promote the formation of carbonaceous DBPs. Furthermore, when influent, sand filtered, and granular activated carbon filtered water was respectively used as background, degradation of CBZ was inhibited to different degree and more disinfection byproducts (DBPs) were generated, compared to deionized water. The electrical energy per order for degradation of CBZ in the UV/NHCl process was also calculated to obtain some preliminary cost information.
UV/单氯胺（NHCl）工艺作为一种新型的高级氧化工艺，因其能够去除新兴污染物而受到关注。然而，由于其复杂性以及生成 NH、HO、Cl 和其他活性氯物种（RCS）等各种自由基，UV/NHCl 工艺的性能和机制仍存在许多不确定性。本研究考察了 UV/NHCl 工艺中卡马西平（CBZ）的降解机制和影响因素，并观察到协同作用。在所有研究条件下，CBZ 的降解均遵循准一级动力学。相应的速率常数随着 NHCl 的剂量增加而增加，并且受碳酸氢盐和天然有机物的存在显著影响。该过程的 pH 值依赖性较小，而 RCS 和 HO 的具体贡献随溶液 pH 值而变化，且 RCS 始终是 CBZ 降解的主要贡献者。鉴定出 CBZ 的 11 种降解产物，并确定了它们各自的演化曲线。UV 参与氯胺化可以减少含氮 DBPs 的形成，但会促进碳质 DBPs 的形成。此外，与去离子水相比，当以进水、砂滤和颗粒活性炭过滤水分别作为背景时，CBZ 的降解受到不同程度的抑制，并且生成了更多的消毒副产物（DBPs）。还计算了 UV/NHCl 工艺中 CBZ 降解的单位能耗，以获得一些初步的成本信息。
