State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University , Shanghai 200092, China.
Environ Sci Technol. 2017 Jul 5;51(13):7467-7475. doi: 10.1021/acs.est.7b00956. Epub 2017 Jun 16.
A clear understanding of the factors governing the deposition and release behaviors of engineered nanoparticles (NPs), such as TiO NPs, is necessary for predicting their transport and fate in both natural and engineered aquatic environments. In this study, impacts of specific chemistries on TiO NP deposition, as a function of TiO NP concentration and ionic strength/valence, were investigated using self-assembled monolayers (SAMs) with five different ending chemical functionalities (-CH, -OH, -COOH, -NH, and -CONH). The fastest deposition and maximum deposition mass were observed on -NH, followed by -COOH, -CONH, -CH, and -OH, showing that contact angle and zeta potential of surfaces were not good indicators for predicting the deposition. Specific interactions, for instance, between -COOH and -CONH and TiO, significantly affected their deposition. Deposition rate increased linearly with TiO NP concentration; however, specific deposition rate was dependent on the type of SAMs. The increase of monovalent (Na) and divalent (Ca) led to different changes in deposition rates for the SAMs due to different functionalities. Results also showed that favorable SAM (e.g., -NH) had lowered release of NPs compared to unfavorable surface (e.g., -OH). The obtained deposition and release behaviors will support more accurate prediction of the environmental fate of nanoparticles.
要预测工程纳米粒子(如 TiO2 NPs)在自然和工程水生环境中的迁移和归宿,必须清楚了解影响其沉积和释放行为的因素。本研究采用具有五种不同末端化学官能团(-CH、-OH、-COOH、-NH 和 -CONH)的自组装单分子层(SAMs),研究了特定化学性质对 TiO2 NP 沉积的影响,这取决于 TiO2 NP 浓度和离子强度/价态。在 -NH 上观察到最快的沉积和最大的沉积质量,其次是 -COOH、-CONH、-CH 和 -OH,这表明表面的接触角和动电位不是预测沉积的良好指标。特定相互作用,例如 -COOH 和 -CONH 与 TiO2 之间的相互作用,显著影响了它们的沉积。沉积速率随 TiO2 NP 浓度线性增加;然而,特定的沉积速率取决于 SAMs 的类型。单价(Na)和二价(Ca)的增加由于不同的官能团而导致 SAMs 的沉积速率发生不同的变化。结果还表明,有利的 SAM(例如,-NH)与不利的表面(例如,-OH)相比,纳米颗粒的释放量较低。所获得的沉积和释放行为将支持更准确地预测纳米颗粒的环境归宿。