Insights into the interactions between triclosan (TCS) and extracellular polymeric substance (EPS) of activated sludge
Insights into the interactions between triclosan (TCS) and extracellular polymeric substance (EPS) of activated sludge
复制标题
深入了解三氯生 (TCS) 与活性污泥细胞外聚合物 (EPS) 之间的相互作用
DOI：
10.1016/j.jenvman.2018.11.059
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发表时间：
2019
影响因子：
8.7
通讯作者：
Sheng Guo ping
中科院分区：
文献类型：
--
作者：
Yan Zi run;Meng Hui shan;Yang Xue yuan;Zhu Yu ying;Li Xiu yan;Xu Juan;Sheng Guo ping
三氯生（TCS）污染物在水环境中转化为有毒二恶英的风险很高，已引起广泛关注。在污水处理过程中，活性污泥中积累了大量的TCS，但其作用机制尚不清楚。特别是，胞外聚合物（EPS），活性污泥的主要成分，在TCS去除的作用从来没有得到解决。采用荧光猝灭法研究了活性污泥中松散结合型EPS（LB-EPS）和紧密结合型EPS（TB-EPS）与TCS的结合特性。探讨了溶液pH、离子强度和温度等水环境条件对EPS与TCS相互作用的影响。可能的相互作用机制进行了讨论，以及相应的环境影响。结果表明，EPS与TCS的键合过程主要是由焓变驱动的放热过程。EPS中的蛋白质组分通过氢键和疏水作用控制EPS与TCS之间的相互作用。在弱碱性和较高离子强度条件下，可以提高粘结强度。在中性条件下，LB-EPS与TCS的结合能力比TB-EPS强，在结合过程中起着更重要的作用。本文的研究工作突出了EPS对TCS去除的重要贡献，有助于全面了解TCS在活性污泥系统中的迁移规律。
Triclosan (TCS) contaminant has aroused wide concerns due to the high risk of converting into toxic dioxin in aquatic environments. During the wastewater treatment process, considerable amounts of TCS are accumulated in activated sludge but the mechanisms are still unclear. Especially, roles of extracellular polymeric substances (EPS), the main components of activated sludge, in TCS removal have never been addressed. In this work, the binding properties of loosely-bound EPS (LB-EPS) and tightly-bound EPS (TB-EPS) of activated sludge to TCS are investigated by fluorescence quenching approach. The influences of aquatic conditions including solution pH, ionic strength and temperature on the interactions between EPS and TCS are explored. Possible interaction mechanisms are discussed as well as the corresponding environmental implication. Results indicate that binding processes of EPS to TCS are exothermic mainly driven by the enthalpy changes. The proteins components in EPS dominate the interactions between EPS and TCS by hydrogen bond and hydrophobic interaction. The binding strength could be improved under the condition of weak alkaline and relative high ionic strength. Generally, LB-EPS exhibit stronger binding ability to TCS than TB-EPS under neutral environment, playing more crucial roles in the binding process. This work highlights the important contributions of EPS to TCS removal, that is beneficial to comprehensively understand the migration of TCS in activated sludge system.