Rational Design of an Ion-Imprinted Polymer for Aqueous Methylmercury Sorption

Area of Science:

• Environmental Chemistry
• Materials Science
• Analytical Chemistry

Background:

• Methylmercury (MeHg+) poses significant human health risks.
• Effective monitoring and removal of MeHg+ from water are critical public health concerns.

Purpose of the Study:

• To rationally synthesize an ion-imprinted polymer (IIP) for selective methylmercury (MeHg+) extraction from water samples.
• To investigate the interactions between MeHg+ and potential synthesis components using computational methods.

Main Methods:

• Density functional theory (DFT) simulations for pre-polymerization interaction studies.
• Synthesis of ion-imprinted polymers (IIPs) using predicted optimal components: 2-mercaptobenzothiazole (MBT) or 2-mercaptobenzimidazole (MBI) as ligands, acrylic acid (AA) as functional monomer, and ethanol as porogenic solvent.
• Characterization using scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis.
• Adsorption capacity and selectivity studies against various metal ions.

Main Results:

• DFT predicted MBT and MBI as effective ligands for MeHg+.
• Synthesized porous polymers (IIP-MBI-AA and IIP-MBT-AA) with specific surface areas up to 11 m²g⁻¹.
• Maximum adsorption capacities of 157 µgg⁻¹ (IIP-MBI-AA) and 457 µgg⁻¹ (IIP-MBT-AA) were achieved.
• IIP-MBT-AA demonstrated high selectivity for MeHg+ over other metal ions (e.g., selectivity coefficients up to 1510 for MeHg+/Zn²+).
• Successful application of the IIP for MeHg+ sorption from real river and tap water samples.

Conclusions:

• A computationally guided synthesis approach led to the development of a highly selective ion-imprinted polymer for methylmercury.
• The synthesized IIP-MBT-AA exhibits excellent adsorption capacity and selectivity, making it suitable for environmental water analysis.
• This material offers a promising tool for monitoring and mitigating methylmercury contamination in water resources.