Mixed-crystalline-phase molybdenum disulfide-based adsorbents with high selectivity for Pb(II) capture: Crystal surface growth modulation and selectivity mechanisms
Ying Wang, Ying Cheng, Chong Peng, Liang Chen, Yuanfei Wang, Yun Li, Shuyi Yang, Tao E
Abstract
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, MoS 2 with a specific binding capacity for Pb, was selected as the substrate material. And alkaline earth metal doped SM(Sr-MoS 2 ) 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 MoS 2 . In addition, it indicated that Sr played a role in expanding the MoS 2 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 K d (31.34 L g - 1 ). More importantly, SM maintained good adsorption performance (∼90 % removal) after six adsorption–desorption cycles, using NaOH or Na 2 -EDTA as desorbent. Therefore, this work provided a new idea for the preparation of selective adsorbents based on MoS 2 , which was expected to be used for the remediation of Pb 2+ -contaminated wastewater.