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通过共沉淀法制备了Fe-Cu-柱撑黏土(Fe-Cu-PILC)催化剂,并以单氯酚、二氯酚、三氯酚作为模式化合物,研究了氯酚中氯原子取代数目、取代位置对其降解动力学的影响,并探讨了氯离子的存在对反应的影响,也基于费米分布函数对其降解动力学进行非线性拟合.结果显示,这种基于费米函数的半经验模型适用于模拟氯酚氧化降解动力学反应(R2＞0.818).氯酚降解速率如下:3-氯酚(3-CP)＞3,5-二氯酚(3,5-DCP)＞2,3-二氯酚(2,3-DCP)＞3,4-二氯酚(3,4-DCP)＞2,5-二氯酚(2,5-DCP)＞4-氯酚(4-CP)＞2-氯酚(2-CP)＞2,4-二氯酚(2,4-DCP)＞2,4,6-三氯酚(2,4,6-TCP)＞2,6-二氯酚(2,6-DCP).氯酚降解过程明显受到苯环氯原子取代数目、取代位置的影响,且氯原子取代位置具有更重要的影响:氯原子取代数目相同时,间位氯越多,降解越快,邻、对位越多,降解越慢.这主要通过影响表观速率常数k和半衰期t*得以实现.3,5-DCP降解表观速率常数k高达18.17 h-1,半衰期为0.2h,而2,6-DCP表观速率常数仅为0.64 h-1,半衰期为5.88 h.氯离子的存在对氯酚降解动力学过程产生不同程度的抑制作用,其中2,6-DCP、2,4,6-TCP的抑制作用最为明显,这主要是由于氯离子的存在延长了其半衰期(分别由5.88 h、4.29 h延长至9.00 h、5.99 h),而对3,4-DCP、3,5-DCP则几乎没有抑制作用.表明氯离子抑制邻位氯代程度高的氯酚降解而不抑制间位氯代程度高的氯酚降解.研究结果为深入揭示氯酚降解机理提供了理论基础,也为提高含酚废水降解速率提供了技术参考.

Fe-Cu-pillared clay (Fe-Cu-PILC) catalyst was prepared by co-precipitation method.The effect of the substitution position and number of chlorine atoms and chloride ions on the degradation kinetics of chlorophenols (CPs) was studied using monochlorophenols,dichlorophenols and richlorophenol as the reaction mode compounds,Fe-Cu-PILC as the Fenton-like catalyst.The degradation kinetics was nonlinearly fitted based on the Fermi's equation.The results showed that a semi-empirical kinetic model based on Fermi's equation could be used to describe the oxidation process of CPs (R2＞0.818).CPs degradation rate followed the order of 3-chlorophenol (3-CP)＞3,5-dichlorophenol (3,5-DCP) ＞2,3-dichlorophenol (2,3-DCP) ＞ 3,4-dichlorophenol (3,4-DCP) ＞ 2,5-dichlorophenol (2,5-DCP) ＞ 4-chlorophenol (4-CP) ＞ 2-chlorophenol (2-CP) ＞ 2,4-dichlorophenol (2,4-DCP) ＞ 2,4,6-trichlorophenol (2,4,6-TCP) ＞ 2,6-dichlorophenol (2,6-DCP).The substitution position and number of chlorine atoms had strong effect on its degradation.The substitution position showed greater impact.For chlorophenols with the same number of chlorine atoms,the more meta-chloro substitution it had,the faster the oxidation was.On the contrary,the more ortho-chloro and para-chloro substitution it had,the slower the oxidation was.This was ascribed to the effect on the apparent rate constant (k) and half-life (t *).The apparent rate constant and half-life of 3,5-DCP and 2,6-DCP were 18.17 h-1 and 0.64 h-1,and 0.2 h and 5.88 h,respectively.In addition,in the presence of chloride ions,the degradation of 2,6-DCP and 2,4,6-TCP was strongly inhibited,in which their t* was extended from 5.88 h to 9.0 h and from 4.29 h to 5.99 h,respectively.But the degradation of 3,4-DCP and 3,5-DCP was not inhibited.This suggested that chloride ions inhibited the oxidation of the chlorophenols with more ortho-chloro substitution,but had no effect on the oxidation of the chlorophenols with more meta-chloro substitution.This study provided valuable information to assist in revealing the catalytic oxidation mechanism of chlorophenols,and improving the treatment efficiency of phenol-containing wastewater using catalytic wet peroxide oxidation (CWPO) technologies.