Efficiency of a molecularly imprinted polymer for selective removal of phenols and phenoxyacids from contaminated waters

The efficiency and the reuse of a bisphenol-A molecularly imprinted polymer (BPA-MIP) were evaluated for the selective removal of several phenolic compounds and phenoxyacid herbicides from environmental water samples. The proper sorption and selective recognition ability of the MIP were studied in aqueous solution by the batch equilibrium technique. Furthermore, removal of the analytes studied by the MIP was carried out from river, tap and ground waters, and different factors, such as the sample volume, the solution pH or the analyte concentration in the sample, were studied. Results obtained indicated a rapid sorption of analytes by the MIP, being the sorption dependent on the concentration of analyte in the solution. The MIP showed an excellent affinity toward phenolic compounds and phenoxyacid herbicides, and removal efficiencies of over 70 % were achieved in aqueous solution. Removal efficiency was not affected by the pH or by the water type, although it was affected by the volume of water especially for nitrophenols when amounts in solution were ≥1 mg. Removal efficiencies recorded by the MIP for the highest volume of water assayed were around 20 % higher than those obtained with traditional sorbents for chlorophenols and bisphenols, and similar removal efficiencies were obtained for phenoxyacid herbicides. The use of the MIP provided a selective, simple, reliable and viable solution for removing these compounds from water, and it could be re-used at least 20 times without losing any removal efficiency.

Keywords
Molecularly imprinted polymers; Phenols; Phenoxyacids; Selective removal; Water treatment