Alkynyl functionalized MoS2 mesoporous materials with superb adsorptivity for heavy metal ions

Abstract

Effective elimination of heavy metal ions from water is an arduous task for their toxic effects to aquatic ecosystem and human health. Herein, a novel alkynyl functionalized molybdenum disulfide (C-MoS2) is fabricated via mechanochemical method with well interlayered spacing, meso porosity, and high surface area (~211 m2g−1). Mineral MoS2 was first peeled mechanically and oxidized in situ to MoS2−xOx, and then reduced by ball milling with CaC2 to form the C-MoS2 composite. The as-obtained C-MoS2 shows extraordinary adsorptivity for heavy metal ions, viz. 1194 mg-Hg g−1 (Hg(NO3)2 solution, pH= 5, 303.15 K, equilibrium Hg(II) concentration Ce= 36.9 μg·g−1, ionic strength I= 17.2 mmolL−1), and 442.3 mg-Pbg−1 (Pb(NO3)2 solution, pH= 5, 303.15 K, equilibrium Pb(II) concentration Ce= 46.9μgg−1, I= 5.8 mmolL−1), respectively, along with excellent recyclability, representing one of the best sorbents till now. The adsorption isotherms of Hg(II) followed the Langmuir model and the adsorption kinetics followed the pseudo-second-order model. The adsorption is an endothermic and entropy driven spontaneous process. The excellent adsorption performance of C-MoS2 is attributed to its very high S-content, availability, and soft acid-base interaction with mercury and lead anions. The C-MoS2 is an advanced sorbent for Hg(II) and Pb(II) with excellent adsorption performance and recyclability.