Promoted growth of 1 T/2 H mixed-crystalline-phase Ca(II)-doped MoS2 nanoflower (100) crystallites: A study of efficient and selective adsorption of Pb(II)

Abstract

The aim of this study is to selectively remove Pb(II) in real water bodies. Therefore, based on the theory of selective adsorption-soft and hard acid-base theory, MoS2, which is capable of binding specifically to soft acid Pb(II), was selected as the substrate material. A simple one-step hydrothermal doping with an alkaline earth metal element (CaCl2) was used to greatly increase the proportion of the active phase (1 T phase), thus exposing more active sites for S adsorption. Subsequently, stable complexes were produced with partition coefficients (25.97 L g−1) as well as selectivity coefficients (236.09) approaching or exceeding those reported for materials in the literature. Qualitative constitutive relationships (QSAR) were used to analyze the correlation between the Pb(II) metal ion parameters and the adsorbent materials. Freundlich and pseudo-second-order kinetic models were well fitted, with high adsorption capacity and fast adsorption rates over a wide pH range (1−6), with a maximum adsorption capacity (123.5 mg g−1) reached within 40 min. Therefore, the material can be recycled 6 times with Na2-EDTA as the eluent and has excellent regeneration performance.