School of Sustainable Engineering and the Built Environment, Arizona State University, P.O. Box 875306, Tempe, AZ 85287-5306, USA.
Water Res. 2010 Jul;44(14):4105-14. doi: 10.1016/j.watres.2010.05.036. Epub 2010 Jun 1.
Sorption to activated sludge is a major removal mechanism for pollutants, including manufactured nanoparticles (NPs), in conventional activated sludge wastewater treatment plants. The objectives of this work were to (1) image sorption of fluorescent NPs to wastewater biomass; (2) quantify and compare biosorption of different types of NPs exposed to wastewater biomass; (3) quantify the effects of natural organic matter (NOM), extracellular polymeric substances (EPS), surfactants, and salt on NP biosorption; and (4) explore how different surface functionalities for fullerenes affect biosorption. Batch sorption isotherm experiments were conducted with activated sludge as sorbent and a total of eight types of NPs as sorbates. Epifluorescence images clearly show the biosorption of fluorescent silica NPs; the greater the concentration of NPs exposed to biomass, the greater the quantity of NPs that biosorb. Furthermore, biosorption removes different types of NPs from water to different extents. Upon exposure to 400 mg/L total suspended solids (TSS) of wastewater biomass, 97% of silver nanoparticles were removed, probably in part by aggregation and sedimentation, whereas biosorption was predominantly responsible for the removal of 88% of aqueous fullerenes, 39% of functionalized silver NPs, 23% of nanoscale titanium dioxide, and 13% of fullerol NPs. Of the NP types investigated, only aq-nC(60) showed a change in the degree of removal when the NP suspension was equilibrated with NOM or when EPS was extracted from the biomass. Further study of carbonaceous NPs showed that different surface functionalities affect biosorption. Thus, the production and transformations in NP surface properties will be key factors in determining their fate in the environment.
吸附到活性污泥是污染物的主要去除机制，包括制造的纳米颗粒（NPs），在传统的活性污泥废水处理厂。这项工作的目的是：（1）对废水生物量中荧光 NPs 的吸附进行成像；（2）量化和比较暴露于废水生物量的不同类型 NPs 的生物吸附；（3）量化天然有机物（NOM）、细胞外聚合物物质（EPS）、表面活性剂和盐对 NP 生物吸附的影响；（4）探索富勒烯的不同表面官能团如何影响生物吸附。用活性污泥作为吸附剂，用八种类型的 NPs 作为吸附物进行了批吸附等温线实验。荧光显微镜图像清楚地显示了荧光二氧化硅 NPs 的生物吸附；暴露于生物量的 NPs 浓度越高，生物吸附的 NPs 量就越大。此外，生物吸附将不同类型的 NPs 从水中去除到不同程度。在暴露于 400mg/L 总悬浮固体（TSS）的废水生物量的情况下，97%的银纳米颗粒被去除，这可能部分是由于聚集和沉淀，而生物吸附则主要负责去除 88%的水溶液富勒烯、39%的功能化银 NPs、23%的纳米二氧化钛和 13%的富勒醇 NPs。在所研究的 NP 类型中，只有 aq-nC(60)在 NP 悬浮液与 NOM 平衡或从生物量中提取 EPS 时，去除程度发生变化。对碳质 NPs 的进一步研究表明，不同的表面官能团会影响生物吸附。因此，NP 表面性质的产生和转化将是决定其在环境中命运的关键因素。
