Surface grafted silica adsorbent for efficient removal of Hg²⁺ ions from contaminated water

A mesoporous silica hybrid functionalized with aromatic 1,2-phenyl dithiol (PT@MS NPs) was prepared in two steps such as sol-gel co-condensation of VTMS and tetraethyl orthosilicate (TEOS) using Pluronic P123 as a structure directing surfactant, and surface grafting reaction of 1,2-phenyl dithiol with vinyl groups via click-reaction. Surface area, average pore size, and mesopore volume of the produced PT@MS NPs are approximately 546 m²/g, 2.8 nm, and 0.63 cm³/g, respectively. With an adsorption quantity of 252 mg/g and a removal capacity of nearly 95% from the initial metal ion (100 mg/L of Hg²⁺ ions) solutions, the PT@MS NPs material showed highly selective adsorption of mercury (Hg2+) from a mixture of other competitive metal (Zn²⁺, Ni²⁺, Pb²⁺, Cd²⁺, and Fe²⁺) ions. By treating the adsorbent with an acidic aqueous solution (0.1 M HCl), the produced adsorbent can be recycled and reused up to five times. As a result, the PT@MS NPs adsorbent might be used in wastewater treatment as a highly efficient and selective adsorbent for harmful Hg²⁺ ions.