Preparation and Recognition Character of Trichloroacetic Acid Anion Surface Imprinted Material

Micron sized silica gel particles were surface modified with coupling agent γ- aminopropyltrimethoxysilane (AMPS), and the modified particles AMPS-SiO2 bonded with amino groups were obtained. In aqueous solution, trichloroacetic acid (TCAA) anions combined with cationic monomer acryloxyethyltrimethyl ammonium chloride (DAC) by right of electrostatic interaction. A redox initiating system was constructed by the amino groups on AMPS SiO2 and ammonium persulphate in the solution, and free radicals were produced on the surfaces of silica gel particles. These free radicals initiated the crosslinking copolymerization of the monomer DAC and the crosslinker N,N′-methylene bisacrylamide (MBA) to be synchronously carried out with the surface imprinting of TCAA. After removing the template ions, TCAA anion surface imprinted material IIP-PDAC/SiO2 was obtained. The molecular structure of monochloroacetic acid (MCAA) is very similar to that of TCAA, so MCAA anion was selected as contrast ion. Both static and dynamic combination experiments and the competing sorption experiment were performed to study the binding properties and ion recognition character of IIP-PDAC/SiO2 for TCAA anion. Results show that IIP-PDAC/SiO2 has fine recognition selectivity and binding affinity for TCAA anion, and its selectivity coefficient for TCAA anion with respect to MCAA anion is 3.612.