Construction Si–O–Mo bond via etching method: enhancing selective adsorption capacity of MoS2/montmorillonite to Pb2+

The inert substrate surface of MoS 2 leads to unsatisfactory adsorption performance. Herein, an inert substrate surface activation strategy is proposed, and the resulted MoS 2 /montmorillonite (MMT) prepared via the hydrothermal method is immersed with NaF (F–Mt). The intercalation of Na  +  contributes to inducing the transformation of MoS 2 from 2H phase to 1 T phase, thereby providing a large number of S vacancies and exposing available Mo 4+ . Meanwhile, the surface of MMT is activated due to the fact that partially [Si 4 O 10 ] 4- are etched by F - , which facilitates forming Si–O–Mo bonds to promote the charge transfer. The improved charge transfer rate can make S 2- in MoS 2 accumulate more negative charges, greatly enhancing the adsorption capacity to Pb 2+ . Moreover, the natural negative potential on the surface of MMT solves the problem of easy stacking for nanosheets , improving the availability of active sites on the edge, which are also benefit from the etching effect on MoS 2 nanosheets with NaF. The maximum adsorption capacity achieves 97.09 mg/g. Additionally, density functional theory (DFT) calculations confirm the resulted S vacancies in MoS 2 are in favor of removing Pb 2+ , which is also contributed by the electrostatic and chemical adsorption with MMT. Therefore, it suggests that F–Mt is an excellent adsorbent for Pb 2+ .