KU Leuven, Department of Chemical Engineering, Process and Environmental Technology Lab, J. De Nayerlaan 5, B-2860 Sint-Katelijne-Waver, Belgium.
KU Leuven, Department of Chemical Engineering, Process Engineering for Sustainable Systems Section, Celestijnenlaan 200F, 3001 Leuven, Belgium; Tshwane University of Technology, Faculty of Engineering and the Built Environment, Private Bag X680, Pretoria 0001, South Africa.
Sci Total Environ. 2021 Aug 15;782:146781. doi: 10.1016/j.scitotenv.2021.146781. Epub 2021 Mar 27.
This study explores the efficiency and kinetics of the photoactivated periodate process for the degradation of 2,4-dichlorophenol (2,4-DCP) in water. The obtained results show that the degradation rate was considerably higher for UV/IO compared to UV irradiation alone. Pseudo first-order reaction rate kinetics were obtained for all process conditions. The pH did not have a significant impact on the decomposition of 2,4-DCP using photoactivated periodate. Therefore, the applied method can be used to treat (waste)water at various pH. By raising the initial concentration of periodate to 5 mM, the degradation rate increased, while it decreased again at a concentration of 8 mM. As the 2,4-DCP concentration increased, the removal rate decreased. The extent of degradation was observed to be proportional with the UV intensity. A mechanistic study revealed that iodine radicals dominated the degradation of 2,4-DCP by photoactivated periodate, whereas OH and O(P) only played a minor role. At pH 5.0, all chlorine atoms in 2,4-DCP were released as chloride ions in the UV/IO process, hence reaching a total dechlorination. Finally, the presence of inorganic salts, even at high levels, did not significantly impact the degradation. According to the results achieved in this study, the UV/IO system can be considered as a valuable alternative to treat effluents containing chlorinated organic compounds such as pulp and paper mill effluents and brine (waste)water.
本研究探讨了光活化过碘酸盐工艺在水中降解 2,4-二氯苯酚（2,4-DCP）的效率和动力学。结果表明，与单独的 UV 辐照相比，UV/IO 的降解速率要高得多。所有工艺条件下均获得了准一级反应动力学。pH 值对光活化过碘酸盐分解 2,4-DCP 没有显著影响。因此，该方法可用于处理各种 pH 值的（废水）。通过将过碘酸盐的初始浓度提高到 5 mM，降解速率增加，但在浓度为 8 mM 时又降低。随着 2,4-DCP 浓度的增加，去除率降低。降解程度与 UV 强度成正比。机理研究表明，碘自由基主导光活化过碘酸盐降解 2,4-DCP，而 OH 和 O(P) 仅起次要作用。在 pH 5.0 下，UV/IO 过程中 2,4-DCP 中的所有氯原子均以氯离子形式释放，从而实现完全脱氯。最后，即使存在无机盐，其浓度也不会对降解产生显著影响。根据本研究的结果，UV/IO 系统可以被视为处理含有氯化有机化合物的废水的一种有价值的替代方法，例如纸浆和造纸厂废水和盐水（废水）。
