In this study, LUS-1, as a mesoporous silica material, was functionalized using sulfur-containing ligand (Bis [3-(triethoxysilyl) propyl] tetrasulfide, TESPT) and used for mercury removal from the aqueous solution. Different characterizations such as N2 adsorption-desorption (BET), TGA, XRD, FT-IR, and SEM were used to verify the nanocomposite synthesis. In addition, the effects of several independent parameters like pH, the contact time of reaction, and adsorbent dose on the removal efficiency of mercury from aqueous in a batch system were studied using response surface methodology (RSM). Based on the results and after both theoretical and experimental studies, the optimum conditions using the LUS-1-TESPT were contact time of reaction of 23.16 min, sorbent dose of 51.12 mg, and pH of 4.5. The kinetic and isotherm models for the adsorption process showed a maximum adsorption capacity of adsorbent which was 136.73 mg g-1 with 99% removal of Hg(II) via the Langmuir model. Meanwhile, the sorbent's reusability and efficiency verified that the sorbent could be used five times after recovery with 99% efficiency.
Keywords: Adsorption equilibrium; Heavy metal; LUS-1-TESPT; Mercury ions; Mesoporous material; RSM optimization.