Preparation of an organic–inorganic hybrid molecularly imprinted polymer for effective removal of albendazole sulfoxide enantiomers from aqueous medium

Abstract

An efficient adsorbent using an organic–inorganic hybrid molecularly imprinted polymer (MIP) based on poly(methacrylic acid)–silica, named MIP-poly(MAA)–SiO2, was prepared for removal of albendazole sulfoxide (ABZSO) enantiomers from contaminated water. Sorption behaviors of MIP-poly(MAA)–SiO2 and nonimprinted polymer (NIP) for ABZSO enantiomers including sorption kinetics, isotherms and effect of pH were investigated in detail. The pH 9.0 was te best for adsorption of ABZSO enantiomers and the time necessary to reaching equilibrium of adsorption was 20min. The kinetic data were analyzed using four models, but the adsorption kinetics were best described by the pseudo-second-order model with R2=0.999 for both materials, indicating that adsorption processes occur more effectively on external sites of MIP-poly(MAA)–SiO2 and NIP-poly(MAA)–SiO2, and at equilibrium the MIP adsorbed more than 70% and NIP no more than 50% of ABZSO enantiomers. These results agree with the Langmuir isotherm model, which assumes that the adsorption process occurs in a homogeneous way, in a monolayer surface. This model provided for both enantiomers employing MIP-poly(MAA)–SiO2 and NIP-poly(MAA)–SiO2 an adsorption capacity (Q) of around 140mgg−1and 35mgg−1, respectively. The constants related to the affinity, KL, for (R)-(+)-ABZSO and (S)-(–)-ABZSO were 0.0064 and 0.0063Lg−1 for MIP-poly(MAA)–SiO2 and 0.0166 and 0.0255Lg−1 for NIP-poly(MAA)–SiO2. This adsorbent material showed great potential in separation, sample preparation processes and removal pharmaceuticals from aqueous medium, besides being able to be used several times without significant losing its desorption amount.