Multifunctional carbon-modified MoS2 with expanded interlayer spacing and multiple exposed sulfur active sites for high-capacity Hg(ii) adsorption

Abstract

A novel multifunctional carbon-modified MoS₂ material (C-W-D-MoS₂-x) was synthesized through a solvothermal method, exhibiting expanded interlayer spacing, a large surface area (∼47.03 m² g⁻¹), and abundant exposed sulfur (S) active sites that enabled efficient adsorption of Hg²⁺ from wastewater. Among the prepared variants, C-W-D-MoS₂-0.03 showed the highest adsorption performance, achieving an exceptional distribution coefficient (K_d) of 2.0 × 10⁵ mL g⁻¹. The adsorption kinetics were best described by the pseudo-second-order model, while the adsorption isotherms were well-fitted to the Langmuir model, with a maximum adsorption capacity (q_m) of 1974.0 mg g⁻¹. This remarkable adsorption capability of C-W-D-MoS₂-0.03 can be attributed to the synergistic effect of carbon functional groups and the high density of S active sites. Furthermore, an alumina inorganic membrane functionalized with C-W-D-MoS₂-0.03 was successfully assembled into a device, demonstrating a dynamic removal process that reduced 50 mg L⁻¹ of Hg²⁺ to below 0.1 mg L⁻¹.