| UV/SPS降解水中三氯生的效能及动力学 |
| 摘要点击 2723 全文点击 1089 投稿时间：2016-09-26 修订日期：2016-10-26 |
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| 中文关键词 三氯生 紫外 过硫酸钠 效能 动力学 中间产物 |
| 英文关键词 triclosan(TCS) UV sodium persulfate efficiency kinetics intermediates |
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| 中文摘要 |
| 采用短波紫外光激活过硫酸钠（UV/SPS）对水中三氯生（TCS）的去除进行了研究，考察了紫外光波长、紫外光强、过硫酸钠（SPS）投加量、pH值和腐殖酸（HA）等因素对TCS去除的影响，计算了自由基（·OH、SO4·-）与TCS的二级反应速率常数及其对TCS去除的贡献值，鉴定了反应中主导自由基，对比了UV254/SPS和UV254/H2O2对天然水体中TCS的去除效果，GC/MS分析了TCS降解的中间产物及可能的降解路径.结果表明UV/SPS能有效去除TCS，紫外光波长为254nm，光强为11.5μW·cm-2，SPS浓度为1 mmol·L-1时，100s后初始浓度为275 μg·L-1的TCS去除率可达98.15%，TCS降解过程符合拟一级反应动力学方程，其动力学常数K=0.0392 s-1.实验范围内TCS去除的速率常数随紫外光强（I）和SPS投加量的增加而增大，波长对TCS去除影响不显著，中性条件不利于TCS降解，HA对TCS去除具有抑制作用.·OH和SO4·-与TCS反应速率常数分别为7.62×109 L·mol-1·s-1、9.86×109 L·mol-1·s-1，UV254/SPS中主导自由基为SO4·-，其对TCS去除贡献率为97.63%.UV254/SPS工艺更能有效地去除TCS，其拟一级动力学常数K值是UV254/H2O2工艺的4.13倍.TCS降解过程中主要生成了2，4-二氯苯酚（2，4-DCP）、苯酚等中间产物. |
| 英文摘要 |
| UV activated sodium persulfate was employed to remove triclosan (TCS) in aqueous solution. The effects of several factors such as UV wavelength,UV254 intensity,sodium persulfate dosage,pH value,and HA on TCS degradation were investigated. The second-order rate constants of free radicals (·OH, SO4·-) 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 UV254/SPS and UV254/H2O2 was compared. Finally,the possible pathway and intermediate products of TCS degradation were analyzed with GC/MS. The results indicated that UV254 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-2,sodium persulfate dosage of 1mmol·L-1,and TCS initial concentration of 275 μg·L-1. TCS degradation followed the pseudo-first-order kinetic model and the pseudo-first-order rate constant was determined to be 0.0392 s-1. Pseudo-first-order rate constant for TCS degradation increased with the increase of UV254 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 SO4·- reacting with TCS were 7.62×109 L·mol-1·s-1 and 9.86×109 L·mol-1·s-1,respectively. SO4·- was the dominant free radical and its contribution rate to TCS removal was 97.63% in UV254/SPS system. The K value of UV254/SPS was 4.13 times higher than that of UV254/H2O2 process,which demonstrated that UV254/SPS process could remove TCS more effectively than UV254/H2O2. The main intermediate products found were 2,4-DCP and phenol in the degradation process of TCS in Milli-Q water by UV254/SPS. |
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