| Summary: | 碩士 === 國立中興大學 === 環境工程學系所 === 106 === The applications of two-dimensional transition metal dichalcogenides, including molybdenum disulfide (MoS2), have been developing rapidly, due to their unique optoelectronics properties. With different synthesis methods, the semiconducting 2H- and the metallic 1T-MoS2 can be synthesized. However, the environmental implications of these materials remain largely unknown. In this study, we study the short-term and long-term stability of MoS2 nanosheets concurrently with the presence of dissolved organic matter (DOM, e.g., Suwannee River natural organic matter (NOM) and Aldrich humic acid (HA)) under dark or sunlight-irradiated conditions in the aquatic environment. The results indicate that HA quickly binds with MoS2 nanosheets through Mo-C bonding onto MoS2 nanosheets surface. The oxidative deterioration and the phase transformation, 1T to 2H, of MoS2 nanosheets are retarded in the presence of NOM. In the dissolution experiments, MoS2 nanosheets with DOM species have less total mobilized concentration of Mo (TMC of Mo) under dark condition. By contrast, MoS2 nanosheets have enhanced TMC of Mo by adding HA under sunlight irradiation. Overall, the results suggest that the chemical stability and reactivity of MoS2 nanosheets depend on the dispersing media and the types of concurrent DOM in the environment; HA could react with MoS2 directly, while, NOM may protect MoS2 from oxidation and phase transformation.
|
|---|
