Porous Nanomaterials for Heavy Metal Removal

Lee, Lin Zhi; Zaini, Muhammad Abbas Ahmad; Hui, Tang

doi:10.1007/978-3-319-68255-6_27

Cited by 18 publications

(15 citation statements)

References 35 publications

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“…We have identified peaks that likely correspond to Pb-S bonding [22], PbMoO 4 [42,43], and PbSO 4 [44]. These results suggest that there is chemisorption of the Pb onto the MoS 2 surface by forming a Pb-S bond, as well as a reductive reaction between Pb and MoS 2 , which is reported to form MoO 4 2− and SO 4 2− [11,45], to form the new PbMoO 4 and PbSO 4 compounds.…”

Section: Chemical and Elemental Analysismentioning

confidence: 71%

“…First, point defects in the basal plane of MoS 2 have a higher electron density of states [31], and thus higher reactivity. Second, MoS 2 has been shown to gradually dissolve in water in the presence of oxygen as described this reaction pathway [45]: 4 , respectively. We speculate that the increased reactivity at point defects and edges increases the rate of formation of MoO 4 2− and SO 4 − ions, and also that the small clusters or particles observed in AFM and TEM imaging are preferentially located at defects and are composed of PbMoO 4 and PbSO 4 .…”

Section: Mechanisms Of Interactions Between Pb 2+ and Mosmentioning

confidence: 99%

“…Second, MoS 2 has been shown to gradually dissolve in water in the presence of oxygen as described this reaction pathway [45]: 4 , respectively. We speculate that the increased reactivity at point defects and edges increases the rate of formation of MoO 4 2− and SO 4 − ions, and also that the small clusters or particles observed in AFM and TEM imaging are preferentially located at defects and are composed of PbMoO 4 and PbSO 4 . The XPS peaks corresponding to PbSO 4 are stronger than those for PbMoO 4 , suggesting there is more of that material being formed, consistent with the relative amounts of the MoO 4 2− and SO 4 2− ions being generated in equation (1).…”

Section: Mechanisms Of Interactions Between Pb 2+ and Mosmentioning

confidence: 99%

“…In particular, Pb is a very dangerous contaminant in water because it causes serious health effects even at very low concentrations [2,3]. Recently, nanomaterials [4] including various inorganic and organic [5] structures have been used for the removal of heavy metals from water. Two-dimensional (2D) materials and especially molybdenum disulfide (MoS 2 ) in various forms have increasingly been studied for the removal of heavy metals [6][7][8][9][10][11] due to their high specific surface areas.…”

Section: Introductionmentioning

confidence: 99%

“…Overall, we have found evidence that the interaction between Pb 2+ ions and MoS 2 is a combination of reaction to form new compounds, complexation or adsorption, and intercalation. The underlying mechanism is due to the oxidation and dissolution of MoS 2 at defect sites to produce MoO 4 2− and SO 4 2− ions. These results will be important to all researchers working in the area of 2D materials for environmental remediation because they indicate that there may be multiple mechanisms of interaction between the contaminants and sorbents based on 2D materials.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of Pb²⁺ ions in water with two-dimensional molybdenum disulfide

Gilliam

Debnath

et al. 2020

J. Phys. Mater.

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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 MoS 2 nanosheets 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-MoS 2 phase. However, the interaction of heavy metals dissolved in water with unmodified semiconducting 2H-MoS 2 is not well studied. In this paper, we report a detailed fundamental investigation of how Pb 2+ ions interact with 2H-MoS 2 . We observe small solid clusters that form on the MoS 2 surfaces after exposing them to Pb(NO 3 ) 2 aqueous solutions as shown by atomic force microscopy and transmission electron microscopy, and for liquid phase exfoliated MoS 2 we 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 PbSO 4 with some PbMoO 4 . We put forth an interaction mechanism that involves MoS 2 defects acting as initiation sites for the partial dissolution in aqueous oxygenated conditions which produces MoO 4 2− and SO 4 2− ions to form the solids with Pb 2+ . These results are an important contribution to our fundamental understanding of how MoS 2 interacts with metal ions and will influence further efforts to exploit MoS 2 for water remediation applications.

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