Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 21011, Tucson, AZ 85721, USA.
Bioresour Technol. 2012 Mar;108:300-4. doi: 10.1016/j.biortech.2011.12.113. Epub 2012 Jan 3.
This study investigated the fate of nano-CeO(2) during municipal wastewater treatment using a laboratory-scale activated sludge (A/S) system fed with primarily-treated municipal wastewater and nano-CeO(2) (55.0 mg Ce/L). Nano-CeO(2) was highly removed during A/S treatment (96.6% total Ce). Extensive removal of CeO(2) <200 nm was also attained and the concentration escaping treatment was only 0.11 mg Ce/L. Elimination occurred mainly by aggregation and settling of CeO(2) particles, promoted by circumneutral pH values and by nanoparticle interactions with organic and/or inorganic wastewater constituents. Biosorption also contributed to CeO(2) removal as shown by sludge analysis and batch adsorption studies. Batch bioassays demonstrated that nano-CeO(2) only exerted inhibition of O(2) uptake by A/S at concentrations exceeding those in the bioreactor feed (50% inhibition at 950 mg CeO(2)/L). These findings indicate that A/S treatment is expected to provide extensive removal of nano-CeO(2) in municipal wastewaters.
本研究采用实验室规模的活性污泥（A/S）系统，以主要经过处理的城市废水和纳米 CeO(2)（55.0 mg Ce/L）为处理对象，考察了纳米 CeO(2) 在城市废水中的归宿。A/S 处理对纳米 CeO(2)具有很高的去除率（总 Ce 的去除率为 96.6%）。也实现了对 CeO(2) <200nm 的大量去除，且逃避处理的浓度仅为 0.11 mg Ce/L。消除主要是通过 CeO(2)颗粒的聚集和沉淀来实现的，这是由中性 pH 值以及纳米颗粒与有机和/或无机废水成分的相互作用所促进的。通过污泥分析和批量吸附研究表明，生物吸附也有助于 CeO(2)的去除。批量生物测定表明，只有当纳米 CeO(2)的浓度超过生物反应器进料中的浓度时（在 950mg CeO(2)/L 时达到 50%的抑制），才会对 A/S 的氧气摄取产生抑制作用。这些发现表明，A/S 处理有望在城市废水中对纳米 CeO(2)进行广泛去除。
