Synthesis of magnetic mesoporous silica adsorbents by thiol-ene click chemistry with optimised lewis base properties through molecular imprinting for the rapid and effective capture of Pb(II)

The development of an environmentally friendly material for efficiently captures Pb(II) is crucial for human health and environmental preservation. In this investigation, we synthesized a magnetic mesoporous silica ion-imprinted polymer (IIP) using an efficient thiol-ene click reaction method. The maximum adsorption capacity reached 57.2 mg·g−1, with equilibrium achieved in just 14 min. Additionally, the IIP demonstrated high selectivity for Pb(II) in both simulated wastewaters and strongly acidic industrial wastewaters, with partition coefficients as high as 2444. The mechanism of Pb(II) capture by IIP was elucidated through a combination of density functional theory (DFT) and X-ray photoelectron spectroscopy (XPS). This selectivity is attributed to the strong attraction of imprinted sites originating from O atoms in the functional monomers. Furthermore, a strategy is proposed to regulate the Lewis alkalinity of imprinted sites using imprinted technology, based on the hard and soft acids and bases theory, offering a novel direction for the design of imprinted sites. It is noteworthy that IIPs can rapidly separate in the presence of a magnetic field and exhibit a tiny amount of Fe ion leakage in strongly acidic solutions, thereby presenting a wide range of practical applications.