Department of Civil and Environmental Engineering, Pratt School of Engineering, Duke University , Durham, North Carolina 27708, United States.
Environ Sci Technol. 2013 Mar 5;47(5):2246-53. doi: 10.1021/es304501n. Epub 2013 Feb 13.
Column experiments were conducted to investigate the transport of aqueous C60 (aqu-nC60), fullerol, silver nanoparticles (NPs) coated with polyvinylpyrrolidone (Ag-PVP) and stabilized by citrate (Ag-CIT) in biofilm-laden porous media. Gram-negative Pseudomonas aeruginosa (PA) and Gram-positive Bacillus cereus (BC) biofilm-laden glass beads were selected to represent the bacterial interfaces NPs might encounter in the natural aquatic environment. The biomass distribution, extracellular polymeric substances (EPS) components, electrokinetic property, and hydrophobicity of these interfaces were characterized, and the hydrophobicity was found to correlate with the quantity of proteins in EPS. The retention of NPs on glass beads coated with bovine serum albumin (BSA) and alginate were also studied. Except for Ag-PVP, the affinity of NPs for porous medium, indicated by attachment efficiency α, increased in the presence of biofilms, BSA and alginate. For hydrophobic aqu-nC60, the larger the proteins/polysaccharides ratio, the larger the α, suggesting the hydrophobic interaction determines the attachment of aqu-nC60 to the collector surface. Uncharged PVP stabilized Ag-PVP by steric repulsion, and the attachment to glass beads was not enhanced by biofilm. The presence of divalent ion Ca(2+) significantly hydrophobized biofilm, BSA, and alginate-coated glass beads and further retarded the mobility of aqu-nC60, fullerol, and Ag-CIT; while Ag-PVP was again sterically stabilized.
采用柱实验研究了水相 C60（aqu-nC60）、富勒醇、聚维酮（PVP）包裹的银纳米颗粒（Ag-PVP）和柠檬酸稳定的银纳米颗粒（Ag-CIT）在生物膜负载多孔介质中的传输。选择革兰氏阴性铜绿假单胞菌（PA）和革兰氏阳性蜡状芽孢杆菌（BC）生物膜负载玻璃珠来代表 NPs 在自然水环境中可能遇到的细菌界面。对这些界面的生物量分布、细胞外聚合物（EPS）成分、电动特性和疏水性进行了表征，发现疏水性与 EPS 中蛋白质的含量相关。还研究了 NPs 在涂覆牛血清白蛋白（BSA）和藻酸盐的玻璃珠上的保留情况。除了 Ag-PVP，NPs 对多孔介质的亲和力，用附着效率α表示，在生物膜、BSA 和藻酸盐存在下增加。对于疏水性的 aqu-nC60，蛋白质/多糖的比例越大，α越大，表明疏水性相互作用决定了 aqu-nC60 与集流器表面的附着。不带电的 PVP 通过空间排斥稳定 Ag-PVP，生物膜不会增强其对玻璃珠的附着。二价离子 Ca(2+) 的存在显著疏水化了生物膜、BSA 和藻酸盐涂覆的玻璃珠，进一步减缓了 aqu-nC60、富勒醇和 Ag-CIT 的迁移；而 Ag-PVP 再次受到空间稳定。
