Synthesis of thiol-functionalized mesoporous silica nanoparticles for adsorption of Hg²⁺ from aqueous solution

Development of new adsorbents for efficient capturing of mercury (Hg(II)) ions from aqueous solution is of significant importance in environmental area. In this work, mesoporous silica nanoparticles with different morphologies (flower-like nanospheres with wrinkles, nanoparticles with concavities and sunken nanovesicles) were prepared and functionalized with 3-mercaptopropyltrimethoxysilane (MPTS). The as-prepared materials were characterized by different technics and applied for Hg²⁺ removal from aqueous solution. The sample with flower-like nanospheres morphology exhibited highest surface area and pore volume among the three silica samples, and the corresponding S-H groups functionalized nanospheres showed the highest adsorption capacity of 479 mg/g and fast adsorption rate for Hg²⁺. The isotherm and kinetics data fitted well with the Langmuir isotherm and the pseudo-second-order kinetics model, respectively. Furthermore, the above adsorbent could be easily regenerated and the regeneration efficiency could remain 94% up to three cycles of the regeneration.