Department of Civil and Environmental Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
Environ Sci Technol. 2014 Jul 15;48(14):7924-32. doi: 10.1021/es501168p. Epub 2014 Jun 23.
The use of diverse engineered nanomaterials (ENMs) potentially leads to the release of multiple ENMs into the environment. However, previous efforts to understand the behavior and the risks associated with ENMs have focused on only one material at a time. In this study, the chemical interactions between two of the most highly used ENMs, nano-TiO2, and nano-ZnO, were examined in a natural water matrix. The fate of nano-ZnO in Lake Michigan water was investigated in the presence of nano-TiO2. Our experiments demonstrate that the combined effects of ZnO dissolution and Zn adsorption onto nano-TiO2 control the concentration of dissolved zinc. X-ray absorption spectroscopy was used to determine the speciation of Zn in the particulate fraction. The spectra show that Zn partitions between nano-ZnO and Zn2+ adsorbed on nano-TiO2. A simple kinetic model is presented to explain the experimental data. It integrates the processes of nano-ZnO dissolution with Zn adsorption onto nano-TiO2 and successfully predicts dissolved Zn concentration in solution. Overall, our results suggest that the fate and toxicity potential of soluble ENMs, such as nano-ZnO, are likely to be influenced by the presence of other stable ENMs, such as nano-TiO2.
多种工程纳米材料（ENMs）的使用可能导致多种 ENMs 释放到环境中。然而，以前为了理解与 ENMs 相关的行为和风险，我们的研究重点一直是一次只研究一种材料。在这项研究中，我们在天然水基质中研究了两种最常用的 ENMs，即纳米 TiO2 和纳米 ZnO 之间的化学相互作用。研究了纳米 ZnO 在密西根湖水中存在纳米 TiO2 时的命运。我们的实验表明，ZnO 溶解和 Zn 吸附到纳米 TiO2 上的联合作用控制着溶解锌的浓度。X 射线吸收光谱用于确定颗粒部分中 Zn 的形态。光谱表明 Zn 在纳米 ZnO 和吸附在纳米 TiO2 上的 Zn2+之间分配。提出了一个简单的动力学模型来解释实验数据。它将纳米 ZnO 溶解过程与 Zn 吸附到纳米 TiO2 上的过程整合在一起，并成功地预测了溶液中溶解 Zn 的浓度。总的来说，我们的研究结果表明，可溶性 ENMs（如纳米 ZnO）的命运和潜在毒性可能会受到其他稳定 ENMs（如纳米 TiO2）的存在的影响。
