Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore.
Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576, Singapore.
J Hazard Mater. 2014 Jan 15;264:370-9. doi: 10.1016/j.jhazmat.2013.11.015. Epub 2013 Nov 16.
To better understand the environmental behavior, fate, and exposure risks of engineered nanoparticles in aquatic systems, for the first time, combinatorial aqueous systems were established using three-level orthogonal array design (OAD), an OA27 (3(1)(3)) matrix, to assess the effects of six co-varying environmental factors (organic acid type, organic acid concentration, NP concentration, pH, salt content, and electrolyte type) on the aggregation of commercial zinc oxide nanoparticles (ZnO NPs, mean diameter ∼41nm). A separate set of OA27 (3(1)(3)) experiments including temperature was conducted for the dissolution of these NPs. The results showed that the organic acid concentration and the pH were the most significant factors (p<0.001) influencing aggregation and dissolution of ZnO NPs, respectively. The electrolyte type and the salt content were the next most important factors in both the aggregation and dissolution. Based on the kinetics study of the aggregation, a high rate of the NP aggregation resulted in decreased dissolution, such that observed in the presence of calcium chloride. Clear temperature-induced aggregation and reduced dissolution were further observed with increasing temperature. This approach demonstrates that the behavior of ZnO NP may vary substantially under combinatorial environmental conditions.
为了更好地理解工程纳米粒子在水生系统中的环境行为、归宿和暴露风险，首次采用三水平正交试验设计（OAD）和 OA27（3(1)(3)）矩阵建立组合水溶液体系，评估六种共变环境因素（有机酸类型、有机酸浓度、NP 浓度、pH 值、盐含量和电解质类型）对商业氧化锌纳米粒子（ZnO NPs，平均直径约为 41nm）聚集的影响。另外还进行了一组包括温度的 OA27（3(1)(3)）实验，以评估这些 NPs 的溶解情况。结果表明，有机酸浓度和 pH 值分别是影响 ZnO NPs 聚集和溶解的最重要因素（p<0.001）。电解质类型和盐含量是聚集和溶解的第二重要因素。基于聚集的动力学研究，NP 聚集的高速度导致溶解减少，如在氯化钙存在的情况下观察到的那样。随着温度的升高，还进一步观察到明显的温度诱导聚集和减少的溶解。这种方法表明，在组合环境条件下，ZnO NP 的行为可能会有很大的变化。
