Removal of cefalexin using yeast surface-imprinted polymer prepared by atom transfer radical polymerization.

The first use of yeast as a support in the molecular imprinting field combined with atom transfer radical polymerization was described. Then, the as-prepared molecularly imprinted polymers were characterized by Fourier transmission infrared spectrometry, scanning electron microscope, thermogravimetric analysis, and elemental analysis. The obtained imprinted polymers demonstrated elliptical-shaped particles with the thickness of imprinting layer of 0.63 µm. The batch mode experiments were adopted to investigate the adsorption equilibrium, kinetics, and selectivity. The kinetic properties of imprinted polymers were well described by the pseudo-second-order kinetic equation, indicating the chemical process was the rate-limiting step for the adsorption of cefalexin (CFX). The equilibrium data were well fitted by the Freundlich isotherm, and the multimolecular layers adsorption capacity of imprinted polymers was 34.07 mg g(-1) at 298 K. The selectivity analysis suggested that the imprinted polymers exhibited excellent selective recognition for CFX in the presence of other compounds with related structure. Finally, the analytical method based on the imprinted polymers extraction coupled with high-performance liquid chromatograph was successfully used for CFX analysis in spiked pork and water samples.

Selective recognition of 4-nitrophenol from aqueous solution by molecularly imprinted polymers with functionalized tetratitanate whisker composites as support.

Three kinds of molecularly imprinted polymers (MIPs) were obtained with surface molecular imprinting technique on functionalized potassium tetratitanate whisker (F-PTW). The results of adsorption experiments indicated that MIP prepared using PTW modified with N-(2-aminoethyl)-3-(trimethoxysilyl)propylamine (AAPTS) (F-PTW A) as support [MIP(1)] was superior to the other two polymers, then MIP(1) was selected to analyze the 4-nitrophenol (4-NP) adsorption process from aqueous solution in this study. AAPTS offered hydrophilic exterior that allowed to self-assemble with the template 4-NP through intermolecular interaction rather than based on the interactions between the functional monomers and template. Equilibrium adsorption data were analyzed by the Langmuir and Freundlich isotherm models at various temperatures. Kinetic properties were successfully investigated by pseudo-first-order model, pseudo-second-order model, intraparticle diffusion equation, initial adsorption rate, half-adsorption time. A diffusion-controlled process as the essential adsorption rate-controlling step was also proposed. The performance of such imprinted polymer was further demonstrated by high-performance liquid chromatography, and the results showed that the selectivity of MIP(1) exhibited higher affinity for template 4-NP over competitive phenolic compounds than that of non-imprinted polymer NIP(1). MIP(1) could be reused four times without significant loss in the adsorption capacity.

Preparation of thermal-responsive magnetic molecularly imprinted polymers for selective removal of antibiotics from aqueous solution.

A novel thermal-responsive magnetic molecularly imprinted polymers (TMMIPs), maghemite/silica/poly (N-isopropylacrylamide-co-acrylamide-co-ethylene glycol dimethacrylate) (γ-Fe(2)O(3)/SiO(2)/P (NIPAm-co-AAm-co-EGDMA)), were developed as a potential effective adsorbent for selectively remove sulfamethazine (SMZ) exist in aquatic environments, which has been recognized as a warranting considerable issue. Free radical polymerization of NIPAm, AAm and EGDMA was performed in dimethyl sulfoxide/water (DMSO/H(2)O) (v/v=9/1) with 2,2'-azobisisobutyronitrile (AIBN) as initiator to coat γ-Fe(2)O(3)/SiO(2)/3-(methacryloxyl) propyl trimethoxysilane (MPS) microspheres through the capture of oligomers with the aid of vinyl groups on their surfaces. The unique aspect of TMMIPs was that they combined molecular recognition, magnetic separation and thermo-responsiveness. The got material was characterized by SEM, TEM, FT-IR and VSM. Batch mode adsorption studies were carried out to investigate the specific adsorption equilibrium, kinetics, and selective recognition ability of TMMIPs. Reversible recognition and release of template molecule were realized by changing environmental temperatures. Several other antibiotics were selected as model analytes to evaluate the selective recognition performance of TMMIPs. The TMMIPs have good temperature response, selectivity and reusability, making them possible in applying for antibiotics separation and controlled release.