Fate of Zinc Oxide and Silver Nanoparticles in a Pilot Wastewater Treatment Plant and in Processed Biosolids
Fate of Zinc Oxide and Silver Nanoparticles in a Pilot Wastewater Treatment Plant and in Processed Biosolids
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DOI：
10.1021/es403646x
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发表时间：
2014-01-07
影响因子：
11.4
通讯作者：
Lowry, Gregory V.
中科院分区：
文献类型：
--
作者：
Ma, Rui;Levard, Clement;Lowry, Gregory V.
银纳米颗粒（Ag NPs）和氧化锌纳米颗粒（ZnO NPs）在废水处理和污泥处理过程中的化学转化必须进行表征，以准确评估这些纳米材料从土地应用生物固体带来的风险。在这里，X射线吸收光谱（XAS）和支持的表征方法被用来确定从试点污水处理厂（WWTP），已收到PVP涂覆的50纳米银纳米粒子和30纳米氧化锌纳米粒子，溶解的金属离子，或没有添加的金属污泥中的银和锌的化学形态。堆肥和石灰和热处理对金属形态在所产生的生物固体的影响也进行了研究。所有添加的Ag都转化为Ag 2S，而不管添加的Ag的形式（NP与离子）。Zn转化为三种含Zn物质，ZnS，Zn-3（PO 4）（2），和Zn相关的Fe氧/氢氧化物，也不管Zn的形式添加。锌的形态是相同的，在未经修改的控制污泥。Ag 2S在所有污泥处理中持续存在。Zn-3（PO 4）（2）存在于污泥和生物固体中，但ZnS和Zn与Fe（OH）2/Fe（OH）2的比值取决于生物固体的氧化还原状态和含水量。NP-剂量，离子-剂量，和控制生物固体之间的锌和银形态的有限差异表明，这些纳米颗粒被转化为类似的化学形式作为散装金属已经进入污水处理厂。
Chemical transformations of silver nanoparticles (Ag NPs) and zinc oxide nanoparticles (ZnO NPs) during wastewater treatment and sludge treatment must be characterized to accurately assess the risks that these nanomaterials pose from land application of biosolids. Here, X-ray absorption spectroscopy (XAS) and supporting characterization methods are used to determine the chemical speciation of Ag and Zn in sludge from a pilot wastewater treatment plant (WWTP) that had received PVP coated 50 nm Ag NPs and 30 nm ZnO NPs, dissolved metal ions, or no added metal. The effects of composting and lime and heat treatment on metal speciation in the resulting biosolids were also examined. All added Ag was converted to Ag2S, regardless of the form of Ag added (NP vs ionic). Zn was transformed to three Zn-containing species, ZnS, Zn-3(PO4)(2), and Zn associated Fe oxy/hydroxides, also regardless of the form of Zn added. Zn speciation was the same in the unamended control sludge. Ag2S persisted in all sludge treatments. Zn-3(PO4)(2) persisted in sludge and biosolids, but the ratio of ZnS and Zn associated with Fe oxy/hydroxide depended on the redox state and water content of the biosolids. Limited differences in Zn and Ag speciation among NP-dosed, ion-dosed, and control biosolids indicate that these nanoparticles are transformed to similar chemical forms as bulk metals already entering the WWTP.