Degradation of the biocide 4-chloro-3,5-dimethylphenol in aqueous medium with ozone in combination with ultraviolet irradiation: Operating conditions influence and mechanism
Degradation of the biocide 4-chloro-3,5-dimethylphenol in aqueous medium with ozone in combination with ultraviolet irradiation: Operating conditions influence and mechanism
复制标题
臭氧与紫外线照射相结合降解水介质中杀菌剂 4-氯-3,5-二甲基苯酚：操作条件影响和机制
DOI：
10.1016/j.chemosphere.2009.09.026
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发表时间：
2009-11-01
期刊：
影响因子：
8.8
通讯作者：
Li, Chaolin
中科院分区：
文献类型：
--
作者：
Song, Shuang;Liu, Zhiwu;Li, Chaolin
杀菌剂通常在城市污水处理过程中持续存在，并随后分布到水生环境中。为了探索高级氧化工艺快速去除杀菌剂的能力，我们研究了UV/O-3组合对4-氯-3,5-二甲基苯酚（PCMX）的总有机碳（TOC）的减少。确定了PCMX降解过程中的传质系数和光利用效率等重要参数。UV/O-3实验结果显示出明显的协同效应，导致在75分钟内几乎完全消除TOC。因此，研究了pH、臭氧用量、堆积温度和PCMX初始浓度对操作变量的影响。臭氧浓度从250 mg L-1降低到100 mg L-1时，PCMX的矿化效率随臭氧剂量的增加而增加，最高可达3.1 g h（-1）。根据温度对反应速率和臭氧溶解度的影响，最佳pH值为4.0，最佳体积温度为20℃。气相色谱/质谱法鉴定的主要芳香中间体为2,6-二甲基苯-1,4-二醇、2,6-二甲基苯-1,4-醌、2,6-双（羟甲基）苯-1,4-醌和2,6-二甲基苯-1,4-醛。用离子色谱法定量测定相关羧酸和无机阴离子。在确定反应产物的基础上，提出了水溶液中UV/O-3氧化PCMX的可能降解途径。2009爱思唯尔有限公司版权所有。
Biocides usually persist during municipal sewage treatment and are subsequently distributed into aquatic environments. To explore the capability of advanced oxidation processes for the rapid removal of biocides, we examined the total organic carbon (TOC) reduction of 4-chloro-3,5-dimethylphenol (PCMX) with a combination Of UV/O-3. Moreover, the related important parameters, including the mass transfer coefficient and light utilization efficiency, in PCMX degradation were determined. The UV/O-3 experimental results showed a pronounced synergistic effect, leading to the nearly complete elimination of TOC within 75 min. Thus, the effect of operating variables was investigated as a function of pH, ozone dosage, bulk temperature and the initial concentration of PCMX. The efficiency of PCMX mineralization increased with an increase in ozone dose up to 3.1 g h(-1), and a decrease in the initial concentration from 250 to 100 mg L-1. The optimal pH value was 4.0, and the preferred bulk temperature was 20 degrees C on the basis of the influence of temperature on reaction rate and ozone solubility. The major aromatic intermediates identified by gas chromatography/mass spectrometry were 2,6-dimethylbenzene-1,4-diol, 2,6-dimethyl benzo-1,4-quinone, 2,6-bis(hydroxymethyl)benzo-1,4-quinone, and 2,6-dimethylbenzo-1,4-aldehyde. Quantitative determination of related carboxylic acid and inorganic anions was done by ion chromatography. On the basis of the identified reaction products, a possible degradation pathway for the UV/O-3 oxidation of PCMX in aqueous media is proposed. (C) 2009 Elsevier Ltd. All rights reserved.