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Abstract The removal of heavy metal contaminants from water is important for public health, and recently many two-dimensional (2D) materials with high specific surface areas are being studied as promising new active components in water purification. In particular, 2D MoS2nanosheets have been used for the removal of various heavy metals, but usually in either in complex geometries and composites, or in the chemically exfoliated metallic 1T-MoS2phase. However, the interaction of heavy metals dissolved in water with unmodified semiconducting 2H-MoS2is not well studied. In this paper, we report a detailed fundamental investigation of how Pb2+ions interact with 2H-MoS2. We observe small solid clusters that form on the MoS2surfaces after exposing them to Pb(NO3)2aqueous solutions as shown by atomic force microscopy and transmission electron microscopy, and for liquid phase exfoliated MoS2we observe the nanosheets precipitating out of dispersion along with insoluble solid granules. We use a combination of x-ray photoelectron spectroscopy and x-ray diffraction to identify these solid clusters and granules as primarily PbSO4with some PbMoO4. We put forth an interaction mechanism that involves MoS2defects acting as initiation sites for the partial dissolution in aqueous oxygenated conditions which produces MoO42−and SO42−ions to form the solids with Pb2+. These results are an important contribution to our fundamental understanding of how MoS2interacts with metal ions and will influence further efforts to exploit MoS2for water remediation applications.
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Multi-pulse laser-induced bubble formation and nanoparticle aggregation using MoS2 nanoparticles
Abstract Understanding of how particles and light interact in a liquid environment is vital for optical and biological applications. MoS2has been shown to enhance nonlinear optical phenomena due to the presence of a direct excitonic resonance. Its use in biological applications is predicated on knowledge of how MoS2interacts with ultrafast (< 1 ps) pulses. In this experiment, the interaction between two femtosecond pulses and MoS2nanoparticles suspended in liquid is studied. We found that the laser pulses induce bubble formation on the surface of a nanoparticle and a nanoparticle aggregate then forms on the surface of the trapped bubble. The processes of formation of the bubble and the nanoparticle aggregation are intertwined.
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- Award ID(s):
- 1905043
- PAR ID:
- 10194234
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Reports
- Volume:
- 10
- Issue:
- 1
- ISSN:
- 2045-2322
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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