Facile preparation of MoS2@Kaolin composite by one-step hydrothermal method for efficient removal of Pb(II)

MoS2@Kaolin was prepared by facile one-step hydrothermal method for the efficient adsorption of Pb(II) from aqueous solution. XRD, TG, SEM, BET, XPS and FTIR were used to characterize the phase and structure of composite before and after the adsorption of Pb(II). The results showed that MoS2 nanosheets were successfully assembled on kaolinite surface to form MoS2@Kaolin, and the adsorption capacity of the MoS2@Kaolin is 1.74 and 16.95 times than that of single MoS2 and kaolinite, respectively. MoS2@Kaolin composite exhibited a fast adsorption rate for Pb(II) and an excellent adsorption efficiency for Pb(II) in a wide pH range (2-5.5). The adsorption process followed the Langmuir isotherm model and maximum adsorption capacity was 280.39 mg/g. The adsorption kinetics of MoS2@Kaolin composite to Pb(II) fitted well with the pseudo-second-order kinetics models, which showed that the adsorption process was controlled by chemical sorption. MoS2@Kaolin showed excellent regeneration and maintained high selectivity adsorption with co-existence metal ions. The adsorption mechanism was that the Pb(II) reacted with the S atoms on surface of MoS2@Kaolin under oxidation conditions provided by molybdenum disulfide to form the insoluble compound β-Pb3O2SO4 in aqueous solution. MoS2@Kaolin was an adsorbent for Pb(II) in aqueous solution with excellent adsorption properties and application potential.