The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, PR China.
Environ Pollut. 2013 Mar;174:38-49. doi: 10.1016/j.envpol.2012.11.016. Epub 2012 Dec 14.
The significance of biofilm on the transport and deposition behaviors of ZnO nanoparticles were examined under a series of environmentally relevant ionic strength at two fluid velocities of 4 m-d(-1) and 8 m-d(-1). Biofilm enhanced nanoparticles retention in porous media under all examined conditions. The greater deposition was also observed in extracellular polymeric substances (EPS) coated surfaces by employment of quartz microbalance with dissipation (QCM-D) system. Derjaguin-Landau-Verwey-Overbeek (DLVO) failed to interpret more ZnO nanoparticles deposition on biofilm (EPS) coated silica surfaces. Chemical interaction and physical morphology of biofilm contributed to this greater deposition (retention). Biofilm affected the spacial distribution of retained ZnO nanoparticles as well. Relatively steeper slope of retained profiles were observed in the presence of biofilm, corresponding to the greater deviation from colloid filtration theory (CFT). Pore space constriction via biofilm induced more nanoparticle trapped in the column inlet, leading to greater deviations (σln k(f)) from the CFT.
研究了在一系列具有实际意义的离子强度条件下，两种流速（4 m/d 和 8 m/d）下生物膜对 ZnO 纳米颗粒输运和沉积行为的影响。生物膜增强了纳米颗粒在多孔介质中的保留。通过石英晶体微天平（QCM-D）系统，在外源性聚合物（EPS）包覆的表面上观察到更大的沉积。DLVO 理论无法解释在生物膜（EPS）包覆的二氧化硅表面上 ZnO 纳米颗粒的更多沉积。生物膜的化学相互作用和物理形态导致了这种更大的沉积（保留）。生物膜也影响了保留的 ZnO 纳米颗粒的空间分布。在生物膜存在的情况下，保留曲线的斜率相对较陡，这与胶体过滤理论（CFT）的更大偏差相对应。生物膜引起的孔隙空间收缩导致更多的纳米颗粒被困在柱入口处，从而导致更大的偏离（σln k(f)）。
