Preparation\nand Adsorption Properties of a Three-Dimensional\nSuperhydrophilic Mercury-Ion-Imprinted Polymer with Dual Recognition\nSite Based on MoS<sub>2</sub>/SBA-15

Water pollution resulting from Hg(II)\nions has garnered\nsignificant\nglobal concern for public health. The flexibility and simplicity of\ndesign, cost savings, and ease of operation with adaptive designs\nprovide adsorption with a considerable advantage over other processes.\nHowever, MoS<sub>2</sub> is hydrophobic in nature, which limits its\nefficiency in the removal of Hg(II) ions from water. Therefore, the\nincorporation of hydrophilic SBA-15 as supporting material, combined\nwith a nanoflower-like layered MoS<sub>2</sub> and its highly reactive\nexposed edges, produces hydrophilic properties that effectively eliminate\nHg(II) from water . A mercury-ion-imprinted polymer (Hg(II)-IIP) was\nsynthesized on the MoS<sub>2</sub>/SBA-15 surface using <i>N</i>-allylthiourea (ATU) as a functional monomer to enhance material\nselectivity and create dual recognition sites. Characterization investigation\nusing scanning electron microscopy (SEM), X-ray diffraction (XRD),\nFourier transform infrared (FTIR), X-ray photoelectron spectroscopy\n(XPS), and water contact angle showed the successful synthesis of\nHg(II)-IIP, excellent hydrophilicity, and close interaction between\nMoS<sub>2</sub> and SBA-15. The maximum adsorption capacity of Hg(II)-IIP\nfor Hg(II) under optimized adsorption conditions was 567.78 mg·g<sup>–1</sup> in 90 min, which was 6 times greater than that of\nthe IIP solely based only on SBA-15, and followed by pseudo-second-order\nand aligned more closely fits with the Langmuir adsorption isotherm.\nFurthermore, the adsorption capacity of the synthesized Hg(II)-IIP\nwas greater than that of three other common monomers IIP. Hg(II)-IIP\npossesses a strong ability to regenerate, while also showing better\nselectivity for Hg(II) in the presence of other interfering ions,\nindicating its robust anti-interference capability in the multivariate\nmixed solution. The analysis of the actual sample indicated that Hg(II)-IIP\nattained recoveries between 97.92 and 100.28% in water samples. Theoretical\ncalculations using density functional theory (DFT) and frontier molecular\norbital (FMO) indicated that the binding energy of the sulfur atom\nforming a tetra-ligand with Hg(II) on ATU was 0.6511 eV greater than\nthat of a diligand. The energy gap was determined to be 0.1550 eV,\nsupporting the preference for S–Hg tetra-ligand adsorption.