性做久久久久久坡多野结衣-性做久久久久久久久浪潮-性欲影院-性影院-国产精品线路一线路二-国产精品兄妹在线观看麻豆

 文獻名： The effects of biofilm on the transport of stabilized zerovalent iron nanoparticles in saturated porous media

 

作者： Robert N. Lerner a, Qingye Lu a, b, Hongbo Zeng b, Yang Liu a,

a Department of Civil and Environmental Engineering, University of Alberta, Edmonton, AB, Canada T6G 2W2

b Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB, Canada T6G 2V4

 

摘要：The transport of stabilized zerovalent iron nanoparticles (nZVI) has recently been the topic of extensive research due to its proven potential as an in situ remediation tool. However, these studies have ignored the effects of biofilms—complex aggregations of bacterial cells and excreted extracellular polymeric substances present in nearly all aquatic systems—on the transport of these particles. This study examines the effects of Pseudomonas aeruginosa (PAO1) biofilm, at a cell concentration similar to that reported for saturated aquifers, on the transport of commercially available, poly (acrylic acid) stabilized nZVI (pnZVI) in 14 cm long columns packed with saturated glass beads at salt concentrations of 1 and 25 mM NaCl. Compared to retention on uncoated columns, in the presence of biofilm the retention of pnZVI increased at higher ionic strength, while ionic strength played no role in retention of these nanoparticles in the absence of biofilm. The Tufenkji–Elimelech correlation equation predicts lower retention of pnZVI on biofilm coated columns compared to uncoated columns due to a lower Hamaker constant, and DLVO energy considerations predict the most favorable attachment to uncoated porous media at higher ionic strength. A steric (polymer-mediated) model that considers the combined influence of steric effects of polymers and DLVO interactions is shown to adequay describe particle retention in columns.

 

關鍵詞：Zerovalent iron nanoparticles (nZVI); Fate and transport; DLVO theory; Tufenkji–Elimelech (T–E) correlation equation; Steric model