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

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 (Kd) 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 (qm) 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.