Chemical Dissolution Pathways of MoS2 Nanosheets in Biological and Environmental Media

详细信息    查看全文

• 作者：Zhongying Wang ; Annette von dem Bussche ; Yang Qiu ; Thomas M. Valentin ; Kyle Gion ; Agnes B. Kane ; Robert H. Hurt
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：July 5, 2016
• 年：2016
• 卷：50
• 期：13
• 页码：7208-7217
• 全文大小：705K
• 年卷期：0
• ISSN：1520-5851

文摘

Material stability and dissolution in aqueous media are key issues to address in the development of a new nanomaterial intended for technological application. Dissolution phenomena affect biological and environmental persistence; fate, transport, and biokinetics; device and product stability; and toxicity pathways and mechanisms. This article shows that MoSb>2b> nanosheets are thermodynamically and kinetically unstable to Ob>2b>-oxidation under ambient conditions in a variety of aqueous media. The oxidation is accompanied by nanosheet degradation and release of soluble molybdenum and sulfur species, and generates protons that can colloidally destabilize the remaining sheets. The oxidation kinetics are pH-dependent, and a kinetic law is developed for use in biokinetic and environmental fate modeling. MoSb>2b> nanosheets fabricated by chemical exfoliation with n-butyl-lithium are a mixture of 1T (primary) and 2H (secondary) phases and oxidize rapidly with a typical half-life of 1–30 days. Ultrasonically exfoliated sheets are in pure 2H phase, and oxidize much more slowly. Cytotoxicity experiments on MoSb>2b> nanosheets and molybdate ion controls reveal the relative roles of the nanosheet and soluble fractions in the biological response. These results indicate that MoSb>2b> nanosheets will not show long-term persistence in living systems and oxic natural waters, with important implications for biomedical applications and environmental risk.