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

Methylmercury (MeHg) is a mercury species that is very toxic for humans, and its monitoring and sorption from environmental samples of water are a public health concern. In this work, a combination of theory and experiment was used to rationally synthesize an ion-imprinted polymer (IIP) with the aim of the extraction of MeHg from samples of water. Interactions among MeHg and possible reaction components in the pre-polymerization stage were studied by computational simulation using density functional theory. Accordingly, 2-mercaptobenzimidazole (MBI) and 2-mercaptobenzothiazole (MBT), acrylic acid (AA) and ethanol were predicted as excellent sulfhydryl ligands, a functional monomer and porogenic solvent, respectively. Characterization studies by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) revealed the obtention of porous materials with specific surface areas of 11 m g (IIP-MBI-AA) and 5.3 m g (IIP-MBT-AA). Under optimized conditions, the maximum adsorption capacities were 157 µg g (for IIP-MBI-AA) and 457 µg g (for IIP-MBT-AA). The IIP-MBT-AA was selected for further experiments and application, and the selectivity coefficients were MeHg/Hg (0.86), MeHg/Cd (260), MeHg/Pb (288) and MeHg/Zn (1510), highlighting the material's high affinity for MeHg. The IIP was successfully applied to the sorption of MeHg in river and tap water samples at environmentally relevant concentrations.