Zhang Cheng-Cheng, Guo Jin-Song, Chen You-Peng, Ji Fang-Ying, Wang Jing, Yan Peng, Bai Yun
a Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE , Chongqing University , Chongqing , People's Republic of China.
b Chongqing Institute of Green and Intelligent Technology , Chinese Academy of Sciences , Chongqing , People's Republic of China.
Environ Technol. 2019 May;40(12):1525-1533. doi: 10.1080/09593330.2018.1426635. Epub 2018 Jan 24.
The removal of antibiotics in biological wastewater treatment plants (WWTPs) has attracted an ever-increasing interest. Extracellular polymeric substances (EPS) play a crucial role in antibiotics' bio-adsorption using activated sludge, but the interaction mechanism between antibiotics and EPS remains unclear. In this study, the thermodynamics of interactions between EPS and antibiotics (acetaminophen (ACT) and sulfamethazine (SMZ)) were investigated via isothermal titration calorimetry (ITC). The results show that the extracellular proteins strongly combined with ACT and SMZ, and the binding process depended on entropy driven by the hydrophobic interaction as the main driving force. Environmental conditions have a significant impact on the adsorption performance. Therefore, binding of antibiotics and EPS at different pH and ionic strength were investigated to determine the optimal pH and ionic strength. At the near-neutral condition of pH 6.8, the binding reaction of EPS and antibiotics was the most favorable and the conformational change was the maximal. Ionic strength has an obvious effect on the interaction between EPS and antibiotics. The results of this study provided a better understanding of the interaction between antibiotics and EPS in the WWTPs.
生物污水处理厂（WWTPs）中抗生素的去除已引起越来越多的关注。胞外聚合物（EPS）在利用活性污泥进行抗生素生物吸附过程中起着关键作用，但抗生素与EPS之间的相互作用机制仍不清楚。在本研究中，通过等温滴定量热法（ITC）研究了EPS与抗生素（对乙酰氨基酚（ACT）和磺胺二甲嘧啶（SMZ））之间相互作用的热力学。结果表明，胞外蛋白质与ACT和SMZ强烈结合，且结合过程取决于以疏水相互作用为主要驱动力的熵。环境条件对吸附性能有显著影响。因此，研究了不同pH和离子强度下抗生素与EPS的结合情况，以确定最佳pH和离子强度。在pH 6.8的近中性条件下，EPS与抗生素的结合反应最有利，构象变化最大。离子强度对EPS与抗生素之间的相互作用有明显影响。本研究结果有助于更好地理解污水处理厂中抗生素与EPS之间的相互作用。
