Synthesis and application of restricted access material-ion imprinted poly (allylthiourea) for selective separation of Cd2+ and humic acid exclusion

A new restricted access cadmium ion-imprinted poly(allythiourea) was synthesized and evaluated as sorbent for Cd2+ preconcentration with simultaneous exclusion of humic acid (HA). Restricted access medium-ion imprinted polymer was assessed by using the co-monomer 2-hydroxyethyl methacrylate (HEMA) as well as by surface coating with bovine serum albumin (BSA). A set of techniques were used for sorbent characterization including, Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), CHNS/O elemental analysis, Thermogravimetric Analysis (TGA), N-2 physisorption to obtain textural data, swelling effect analysis (SE) and wettability. HP modified with HEMA and HP modified with HEMA-BSA, compared with IIP showed better performance in binding Cd2+ and simultaneous HA exclusion. However, based on relative selectivity coefficient (k'), the selective sorption of Cd2+ and efficient HA exclusion was achieved by using HP-HEMA. The obtained results demonstrate that coating of BSA onto IIP surface is unnecessary for preparing restricted material medium-ion imprinted polymer as well as decreases the selectivity of imprinted polymer. Therefore, the insertion of HEMA in the synthesis of TIP has been the best strategy to obtain a highly selective ion imprinted polymer with restricted access very promising for practical application in the interference-free determination of Cd2+ in natural waters.