Selective removal of perfluorooctane sulfonate from aqueous solution using chitosan-based molecularly imprinted polymer adsorbents

Perfluorooctane sulfonate (PFOS) pollution in aqueous environment is a problem of global concern. A novel chitosan-based molecularly imprinted polymer (MIP) was prepared by crosslinking with epichlorohydrin (ECH) in the presence of PFOS as the template. During the preparation of the MIP adsorbents, the template amount and crosslinking agents significantly affected the imprinting effect. The optimized MIP adsorbents had a sorption amount of 560 μmol g−1 for PFOS, while the sorption amount of the non-imprinted polymer (NIP) was only 258 μmol g−1. The sorption behaviors of the MIP adsorbents including sorption kinetics, isotherms, effect of pH, ionic strength and selective sorption were investigated in detail. Sorption experimental results showed that the MIP adsorbents had good selectivity for PFOS, while other anionic contaminants with different structure had little influence on the sorption of the target PFOS. It was found that the electrostatic interaction played an important role in recognizing the target compound in the sorption process. Additionally, the MIP adsorbents could be used at least five times without any loss in sorption capacity. The chitosan-based MIP adsorbents may find potential application in water or wastewater treatment for the selective removal of PFOS.