Li Qing-Song, Li Xue-Yan, Yao Ning-Bo, Luo Jing-Yu, Li Guo-Xin, Chen Guo-Yuan, Gao Nai-Yun
Water Resources and Environmental Institute, Xiamen University of Technology, Xiamen 361024, China.
School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China.
Huan Jing Ke Xue. 2017 Apr 8;38(4):1467-1476. doi: 10.13227/j.hjkx.201609211.
UV activated sodium persulfate was employed to remove triclosan (TCS) in aqueous solution. The effects of several factors such as UV wavelength,UV intensity,sodium persulfate dosage,pH value,and HA on TCS degradation were investigated. The second-order rate constants of free radicals (·OH, SO) reacting with TCS and their contributions to TCS removal were determined,respectively. The dominant free radical was also identified. Furthermore, the TCS degradation efficiency in natural water by UV/SPS and UV/HO was compared. Finally,the possible pathway and intermediate products of TCS degradation were analyzed with GC/MS. The results indicated that UV activated sodium persulfate could effectively remove TCS. The removal rate of TCS could reach 98.15% within 100s under the conditions of UV wavelength of 254 nm,UV intensity of 11.5μW·cm,sodium persulfate dosage of 1mmol·L,and TCS initial concentration of 275 μg·L. TCS degradation followed the pseudo-first-order kinetic model and the pseudo-first-order rate constant was determined to be 0.0392 s. Pseudo-first-order rate constant for TCS degradation increased with the increase of UV intensity(I)and sodium persulfate dosage within experiment ranges. The effect of UV wavelength on TCS removal was not notable. Neutral condition was detrimental to TCS degradation. TCS removal was inhibited in the presence of HA. The reaction rate constants for·OH and SO reacting with TCS were 7.62×10 L·mol·s and 9.86×10 L·mol·s,respectively. SO was the dominant free radical and its contribution rate to TCS removal was 97.63 in UV/SPS system The value of UV/SPS was 4.13 times higher than that of UV/HO process,which demonstrated that UV/SPS process could remove TCS more effectively than UV/HO. The main intermediate products found were 2,4-DCP and phenol in the degradation process of TCS in Milli-Q water by UV/SPS.
采用紫外光活化过硫酸钠去除水溶液中的三氯生（TCS）。研究了紫外波长、紫外强度、过硫酸钠用量、pH值和腐殖酸（HA）等几个因素对TCS降解的影响。分别测定了自由基（·OH、SO）与TCS反应的二级速率常数及其对TCS去除的贡献。还确定了主要自由基。此外，比较了紫外光/过硫酸钠（UV/SPS）和紫外光/过氧化氢（UV/H₂O₂）对天然水中TCS的降解效率。最后，用气相色谱/质谱联用仪（GC/MS）分析了TCS降解的可能途径和中间产物。结果表明，紫外光活化过硫酸钠能有效去除TCS。在紫外波长为254nm、紫外强度为11.5μW·cm⁻²、过硫酸钠用量为1mmol·L⁻¹、TCS初始浓度为275μg·L⁻¹的条件下，100s内TCS的去除率可达98.15%。TCS降解遵循准一级动力学模型，准一级速率常数为0.0392s⁻¹。在实验范围内，TCS降解的准一级速率常数随紫外强度（I）和过硫酸钠用量的增加而增大。紫外波长对TCS去除的影响不显著。中性条件不利于TCS降解。HA的存在会抑制TCS的去除。·OH和SO与TCS反应的速率常数分别为7.62×10⁹L·mol⁻¹·s⁻¹和9.86×10⁹L·mol⁻¹·s⁻¹。SO是主要自由基，在UV/SPS体系中其对TCS去除的贡献率为97.63%。UV/SPS的去除效果是UV/H₂O₂工艺的4.13倍，这表明UV/SPS工艺比UV/H₂O₂更能有效地去除TCS。在超纯水（Milli-Q水）中，UV/SPS降解TCS的过程中发现的主要中间产物是2,4-二氯苯酚（2,4-DCP）和苯酚。
