Versatile MoS2 hollow nanoroses for a quick-witted removal of Hg (II), Pb (II) and Ag (I) from water and the mechanism: Affinity or Electrochemistry?

Ultra‐Rapid Removal of Pb(II) Ions by a Nano‐MoS2 Decorated Graphene Aided by the Unique Combination of Affinity and Electrochemistry

“…The relatively higher d ‐value than Gr [ 57–61 ] is attributed to the attachment of nano‐MoS 2 on the prGO sheets. Further, the peaks at 36.7°, 43.6°, 50.9°, and 59.6°, corresponding to the (100), (006), (105), and (110) planes of MoS 2 , [ 16,54,57,62 ] confirm the formation of MoS 2 . The chemical composition of prGO‐MoS 2 was determined using the X‐ray photoelectron spectroscopy (XPS) analysis data.…”

“…The product obtained was systematically studied for its adsorption properties toward toxic metal ions. Interestingly, unlike that of our MoS 2 ‐HNR, [ 16 ] the prGO‐MoS 2 exhibited different adsorption properties with higher selectivity and ultrafast removal toward Pb (II) from contaminated water with very high efficiency as high as log reduction value (LRV) of 4 at a V/m ratio of ≈1.4 mL mg −1 . The adsorption was ultrafast that it took ≤3 min to reach ≤0.8642 ppb from an initial concentration of 10 000 ppb.…”

“…[ 4 ] The low concentration limit of Pb (II) in water makes the removal of Pb (II) a challenging problem. [ 5 ] Among the techniques employed to remove excess metal ions from wastewater: ion exchange, [ 6 ] biological treatment, [ 7,8 ] membrane filtration, [ 9,10 ] co‐precipitation, [ 11 ] cloud point extraction, [ 12 ] flocculation, [ 13 ] reverse osmosis, [ 14 ] and adsorption, [ 15,16 ] the adsorption‐based removal methodology is one of the most promising and widely applied methods to remove pollutants from the environment due to its cost‐effectiveness, simple operation, and environmental friendliness. [ 17 ] However, the efficiency of adsorption in the removal of toxic metal ions such as Pb (II) depends on the selectivity of the materials used toward the particular ions because of the presence of other pollutants and common metal ions in relatively higher concentrations in water and the very low (safe) level of Pb (II) that need to be achieved.…”

“…[ 17 ] However, the efficiency of adsorption in the removal of toxic metal ions such as Pb (II) depends on the selectivity of the materials used toward the particular ions because of the presence of other pollutants and common metal ions in relatively higher concentrations in water and the very low (safe) level of Pb (II) that need to be achieved. [ 16 ] For past decades, various adsorbents have been explored to remove heavy metal ions, which included activated carbon [ 18,19 ] from various sources and methods, zeolites, [ 20,21 ] clays, [ 22,23 ] and polymers [ 24,25 ] which exhibited lower removal efficiency for Pb (II) due to the weak binding affinity toward Pb (II) and lack of selectivity.…”

“…Pb (II) removal from contaminated water by adsorption has been reported with materials such as 3D‐Gr/MnO 2 , [ 44 ] Fe 3 O 4 /SiO 2 /GO, [ 43 ] lignosulfonate‐GO‐polyaniline, [ 45 ] MoS 2 nanosheets, [ 37 ] 2D‐MoS 2 , [ 38 ] Zn‐metal organic framework, [ 46 ] multiwalled carbon nanotubes with and without amino groups, [ 47 ] Mg/Fe layered double hydroxide with Fe 3 O 4 carbon spheres, [ 48 ] and MoS 2 ‐HNR. [ 16 ] The highest efficiency reported is by the MoS 2 ‐HNR with an adsorption efficiency of 1267 mg g −1[ 16 ] followed by the 2D MoS 2 , [ 38 ] and 3D Gr/MnO 2 , [ 44 ] with adsorption efficiencies of 740.0 and 643.6 mg g −1 , respectively. The MoS 2 ‐HNR decreased the [Pb (II)] to 1.011 from 10 000 ppb in ≤30 min, while other adsorbent materials required ≥150 min to decrease the [Pb (II)] to the safe level (≤10 ppb) in water.…”