The extracellular polymeric substances (EPS) from activated sludge played significant roles in the removal of nanoparticles from wastewater. A series of batch experiments were carried out to determine the adsorption mechanism of three nano-Ag by activated sludge, as well as the contributions of EPS fractions including dissolved EPS (DEPS), loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS). The results demonstrated that the adsorption of nano-Ag by sludge biomass agreed with pseudo-second-order kinetic reaction model and Freundlich isotherm model. About 26.0-41.2% of nano-Ag was trapped by the bound EPS (BEPS) matrix of activated sludge (especially LB-EPS) and 42.5-52.6% of them was adsorbed onto the inner cells after the adsorption. Moreover, the interaction energy contributions of EPS fractions followed the order of E_DE > 0 > E_TB > E_LB, suggesting DEPS in wastewater went against the removal of nano-Ag due to steric repulsion while LB-EPS and TB-EPS were positive to nano-Ag adsorption by modifying biomass surface and providing extensive binding sites. Besides, EPS fractions played significant roles in the adsorption of nano-Ag with low initial concentrations but had limited effect at high concentrations. Overall, this study investigated the effect of EPS fractions on the adsorption behaviors of nano-Ag by activated sludge biomass, which is meaningful to understand the removal mechanism of nanoparticles in sewage and the potential role of EPS fractions.

来自活性污泥的胞外聚合物（EPS）在去除废水中的纳米颗粒方面发挥了重要作用。进行了一系列批次实验以确定活性污泥对三种纳米银的吸附机理，以及 EPS 组分的贡献，包括溶解的 EPS（DEPS）、松散结合的 EPS（LB-EPS）和紧密结合的 EPS（结核病-EPS）。结果表明，污泥生物质对纳米Ag的吸附符合准二级动力学反应模型和Freundlich等温线模型。约26.0-41.2%的纳米Ag被活性污泥（尤其是LB-EPS）的结合EPS（BEPS）基质捕获，其中42.5-52.6%的纳米Ag在吸附后被吸附到细胞内。此外，EPS分数的相互作用能量贡献遵循E的顺序_DE > 0 > E _TB > E _LB，表明废水中的DEPS由于空间排斥而不利于纳米Ag的去除，而LB-EPS和TB-EPS通过改变生物质表面并提供广泛的结合位点对纳米Ag的吸附是积极的. 此外，EPS组分在初始浓度低的纳米Ag吸附中起重要作用，但在高浓度时效果有限。总体而言，本研究探讨了EPS组分对活性污泥生物质吸附纳米银行为的影响，这对于了解污水中纳米颗粒的去除机制以及EPS组分的潜在作用具有重要意义。