Zou Wei, Liu Zhenzhen, Li Rui, Jin Caixia, Zhang Xingli, Jiang Kai
School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, International Joint Laboratory on Key Techniques in Water Treatment, Henan Normal University, Xinxiang 453007, China.
School of Environment, Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, International Joint Laboratory on Key Techniques in Water Treatment, Henan Normal University, Xinxiang 453007, China.
J Hazard Mater. 2021 Aug 15;416:126043. doi: 10.1016/j.jhazmat.2021.126043. Epub 2021 May 7.
The transformation of Ag is strongly correlated with its risks in aquatic environment. Considering the wide application of molybdenum disulfide (MoS) and the inevitable release into the environment, the effects of MoS on Ag transformation and toxicity are of great concerns. This study revealed the pH-dependent reduction of Ag (0.5 mM) to Ag nanoparticles (AgNPs) by MoS (50 mg/L) and solar irradiation obviously accelerates the AgNPs formation (2.638 mg/L per day, pH=7.0) compared with dark condition (0.637 mg/L per day), ascribing to the electrons capture from electron-hole pairs of MoS by Ag. Ionic strengths and natural organic matter decreased the AgNPs yield. Metallic 1 T phase of MoS primarily participated in AgNPs formation and was oxidized to soluble ions (MoO) due to the oxygen generation in valance band. The above processes also occurred between Ag and MoS at environmentally relevant concentrations. Further, photoinduced transformation of Ag by MoS (10-100 μg/L) significantly lowered its toxicity to freshwater algae. The AgNPs formation on MoS reduced the bioavailability of Ag to algae, which was the mechanism for attenuated Ag toxicity. The provided data are helpful for better understanding the roles of MoS on the environmental fates and risks of metal ions under natural conditions.
银的转化与其在水生环境中的风险密切相关。鉴于二硫化钼（MoS）的广泛应用以及其不可避免地释放到环境中，MoS对银转化和毒性的影响备受关注。本研究揭示了MoS（50mg/L）在光照下能将0.5mM的银还原为银纳米颗粒（AgNPs），且与黑暗条件相比（每天0.637mg/L），光照明显加速了AgNPs的形成（每天2.638mg/L，pH = 7.0），这归因于银从MoS的电子 - 空穴对中捕获电子。离子强度和天然有机物降低了AgNPs的产量。MoS的金属1T相主要参与AgNPs的形成，并由于价带中的析氧而被氧化为可溶性离子（MoO）。在环境相关浓度下，银和MoS之间也发生了上述过程。此外，MoS（10 - 100μg/L）光诱导的银转化显著降低了其对淡水藻类的毒性。MoS上AgNPs的形成降低了银对藻类的生物可利用性，这是银毒性减弱的机制。所提供的数据有助于更好地理解MoS在自然条件下对金属离子环境归宿和风险的作用。
