Optimized synthesis of molecularly imprinted polymers coated magnetic UIO-66 MOFs for simultaneous specific removal and determination of multi types of macrolide antibiotics in water

Abstract

Macrolide antibiotics (MALs) are widely used in various fields and are resistant to degrade in the water environment, thus constituting potential hazards to human health. In this work, a new composite, molecularly imprinted polymers coated magnetic metal-organic frameworks with carboxyl modification (M-UIO-66@MIPs) was selected and characterized, for the simultaneous specific adsorption and determination of five MALs from aqueous solution. It was found that UIO-66-COOH with ligand defects showed better pre-polymerization effect than other matrix materials. The synthesis conditions for the imprinting polymer were optimized via response surface methodology. The characteristics of related materials were studied, and a series of adsorption experiments were carried out. The results showed that the adsorption equilibriums of M-UIO-66@MIPs were reached within 1 h, with the total adsorption capacity for the five MALs was 99.05 mg g−1. The pseudo-second-order kinetic model and Freundlich isotherm model could best fit the adsorption process, and the adsorption thermodynamics was controlled by the change of entropy. Adsorption mechanisms were deduced as hydrogen bonding interaction and electrostatic interaction. In addition, M-UIO-66@MIPs has good selectivity and reusability. Furthermore, a new detection method for the five MALs was developed, using the prepared material as the adsorbent for magnetic solid-phase extraction, coupled with high-performance liquid chromatography. Under the optimal extraction condition, the limits of detection for five MALs were 3.1–44.6 μg L−1, and the recoveries were 92.9–108.7 % in the determination of real water samples. Therefore, the M-UIO-66@MIPs could be the efficient adsorbent for simultaneous selective removal and sensitive determination of multi-residual MALs.