Mixed-crystalline-phase molybdenum disulfide-based adsorbents with high selectivity for Pb(II) capture: Crystal surface growth modulation and selectivity mechanisms

It was a challenge to prepare an adsorbent with excellent selectivity for target heavy metals, especially when treating real wastewater contaminated with various heavy metals. In the present study, MoS2 with a specific binding capacity for Pb, was selected as the substrate material. And alkaline earth metal doped SM(Sr-MoS2) adsorbent was synthesized via a simple one-step hydrothermal method. The morphology and structure of SM were characterized and the results confirmed that Sr was successfully anchored to MoS2. In addition, it indicated that Sr played a role in expanding the MoS2 spacing, increasing the ratio of 1 T phrases, and modifying the crystal growth (such as the growth direction and growth rate). Therefore, it suggested that SM had a high selectivity factor (171.26) and partition coefficient Kd (31.34 L g-1). More importantly, SM maintained good adsorption performance (∼90 % removal) after six adsorption–desorption cycles, using NaOH or Na2-EDTA as desorbent. Therefore, this work provided a new idea for the preparation of selective adsorbents based on MoS2, which was expected to be used for the remediation of Pb2+-contaminated wastewater.