Limbach Ludwig K, Bereiter Robert, Müller Elisabeth, Krebs Rolf, Galli René, Stark Wendelin J
Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, CH-8093 Zurich, Switzerland.
Environ Sci Technol. 2008 Aug 1;42(15):5828-33. doi: 10.1021/es800091f.
The rapidly increasing production of engineered nanoparticles has created a demand for particle removal from industrial and communal wastewater streams. Efficient removal is particularly important in view of increasing long-term persistence and evidence for considerable ecotoxicity of specific nanoparticles. The present work investigates the use of a model wastewater treatment plant for removal of oxide nanoparticles. While a majority of the nanoparticles could be captured through adhesion to clearing sludge, a significant fraction of the engineered nanoparticles escaped the wastewater plant's clearing system, and up to 6 wt % of the model compound cerium oxide was found in the exit stream of the model plant. Our study demonstrates a significant influence of surface charge and the addition of dispersion stabilizing surfactants as routinely used in the preparation of nanoparticle derived products. A detailed investigation on the agglomeration of oxide nanoparticles in wastewater streams revealed a high stabilization of the particles against clearance (adsorption on the bacteria from the sludge). This unexpected finding suggests a need to investigate nanoparticle clearance in more detail and demonstrates the complex interactions between dissolved species and the nanoparticles within the continuously changing environment of the clearing sludge.
工程纳米颗粒产量的迅速增长，引发了从工业和生活污水流中去除颗粒的需求。鉴于特定纳米颗粒的长期持久性不断增加以及有证据表明其具有相当大的生态毒性，高效去除尤为重要。本研究调查了使用模型污水处理厂去除氧化物纳米颗粒的情况。虽然大部分纳米颗粒可通过附着在澄清污泥上被捕获，但仍有相当一部分工程纳米颗粒逃过了污水处理厂的澄清系统，在模型工厂的流出物中发现高达6 wt%的模型化合物氧化铈。我们的研究表明，表面电荷以及在制备纳米颗粒衍生产品时常规使用的分散稳定表面活性剂的添加具有重大影响。对废水中氧化物纳米颗粒团聚的详细研究表明，颗粒对清除（吸附在污泥中的细菌上）具有高度稳定性。这一意外发现表明有必要更详细地研究纳米颗粒的清除情况，并证明了在澄清污泥不断变化的环境中，溶解物质与纳米颗粒之间的复杂相互作用。
