Insights into thermodynamic mechanisms driving bisphenol A (BPA) binding to extracellular polymeric substances (EPS) of activated sludge
Insights into thermodynamic mechanisms driving bisphenol A (BPA) binding to extracellular polymeric substances (EPS) of activated sludge
复制标题
深入了解驱动双酚 A (BPA) 与活性污泥胞外聚合物 (EPS) 结合的热力学机制
DOI：
10.1016/j.scitotenv.2019.04.413
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发表时间：
2019
影响因子：
9.8
通讯作者：
Zhang Wei
中科院分区：
文献类型：
--
作者：
Yan Zi run;Zhu Yu ying;Meng Hui shan;Wang Si yuan;Gan Li hong;Li Xiu yan;Xu Juan;Zhang Wei
废水中的双酚A（BPA）具有引起生物女性化的高风险。在废水处理过程中，活性污泥中会积累大量BPA。然而，BPA与活性污泥相互作用的机制仍不清楚。特别是，作为活性污泥主要成分的细胞外聚合物（EPS）在去除BPA方面的作用从未受到关注。本研究结合荧光光谱和动态光散射探讨了污泥 EPS 和 BPA 之间的结合相互作用。通过等温滴定量热法说明了驱动 BPA 与 EPS 结合行为的热力学机制。结果表明，BPA 和 EPS 之间的结合相互作用是自发的。 BPA主要通过疏水缔合与EPS的蛋白质结合。 EPS的随机卷曲结构与BPA结合后转变为相对致密的核心。中性 pH 值、高离子强度和高温促进结合过程，有利于稳定污泥 EPS 中的 BPA。这项研究为活性污泥系统中污泥 EPS 在 BPA 迁移和去除中的作用提供了新的见解。
Bisphenol A (BPA) in wastewater has high risks of causing biological feminization. During the wastewater treatment process, large amounts of BPA are accumulated in activated sludge. However, the mechanisms of BPA interacted with activated sludge are still unclear. Especially, the roles of extracellular polymeric substances (EPS), which are major components of activated sludge, in the removal of BPA have never been concerned. In this study, the binding interactions between sludge EPS and BPA are explored combining fluorescence spectroscopy and dynamic light scattering. The thermodynamic mechanisms driving the binding behavior of BPA to EPS are illustrated by isothermal titration calorimetry. The results indicate that the binding interaction between BPA and EPS is spontaneous. BPA mainly binds with the proteins of EPS by hydrophobic association. The random-coiled structure of EPS transforms into relatively condensed cores after binding with BPA. A neutral pH, high ionic strength, and high temperature promote the binding process, facilitating to stabilize BPA in sludge EPS. This study provides new insights into the roles of sludge EPS in the migration and removal of BPA in activated sludge system.