Design And Synthesis Of Novel Norfloxacin Molecular Imprinting Polymer And Its Study On Adsorption Behavior

Norfloxacin(NOR) is a synthetic fluoroquinolone antibacterial drug that is widely used in prevention and control of animal diseases in aquaculture. However,norfloxacin and other antibacterial drugs can residue in animals and then deliver to human body, which is hazardous to people. Meanwhile, only a fraction of antimicrobials were absorbed by organisms and most of them were discharge into the environment, which caused the pollution to the surface water and soil. So, public concern about the effective measures to detect the norfloxacin in environment has increased.Molecular imprinting technology(MIT) is well know for the formation of polymers with memory of the functional groups of a target template. Molecular imprinted polymer(MIP) is widely used as novel sorbent in detection and prevention due to its simple prearation, stable physical and chemical properties, high selectivity and so on. But the screening of molecular imprinring system generally with large workload and long period. In recent years, the molecular simulation technique was used in the optimization of molecular imprinting system and the recognition mechanism.In this paper, by combining the method of the molecular imprinting technique and molecular simulation technique, we designed and prepared three kinds of MIPs which used NOR as template molecules to adsorb NOR specifically. And we studied performance of many aspects of them. Three main contents were presented as the following items:(1) The molecular dynamics(MD) simulation was used to simulate the imprinted prepolymerization systems and we ensured the best quantitative relation among template molecules, functional monomers and crosslinkers by the radial distribution function analysis. Then, we prepared a series of MIPs through bulk polymerization. To investigate morphology, we found NOR-MIPs had larger pore volumes and specific surface areas through several characterization methods. As shown by the results, NOR-MIPs prepared with norfloxacin(NOR) as a template,methacrylic acid(MAA) as a functional monomer, ethylene glycol dimethacrylate(EGDMA) as a crossliner at a mole ratio of 1:8:40 showed the highest adsorption capacity(29.35 mg/g) and the shortest equilibrium time(120 min). Furthermore, the selective recognition ability and regeneration of NOR-MIPs were excellent.(2) In this study, silica was used as carrier, N-isopropylacrylamide(NIPAM) and N,N-methylenebisacrylamide(MBA) were used as temperature-sensitive monomer and hydrophilic crosslinker respectively. We synthesized temperature responsive molecularly imprinted polymers(TMIPs) by using NOR as template molecules. We could control the adsorption capacity of TMIPs by changing the external temperature.The morphology structure, adsorption properties, selectivity and regeneration were studied by several characterization methods and adsorption experiments. The results showed pseudo-second-order kinetic model was the most suitable for the adsorption capacity of TMIPs toward NOR and the maximum adsoption capacity was 46.8 mg/g under the temperature of 35 ℃. In the evaluation of thermosensitive property of TMIPs, they showed good performance in temperature responsive with high selectivity and regeneration.(3) In this study, we prepared the temperature responsive molecularly imprinted polymers(T-MMIPs) by using magnetic Fe3O4 nanoparticle as carrier. To investigate morphology and composition of T-MMIPs, we used several characterization methods such as transmission electronmicroscope(TEM), Fourier transform infrared spectrometry(FTIR), vibrating sample magnetometer(VSM), thermogravimetic(TGA) and so on. It was showed that T-MMIPs not only had temperature sensitivity but also with superparamagnetism. So, they could separate quickly with the help of external magnetic field. The adsorption kinetic of T-MMIPs at 35 ℃ fitted the pseudo-second-order model well. The experiment data for T-MMIPs fitted Langmuir isotherm and the binding capacity to NOR of T-MMIPs at 35 ℃ was 52.85 mg/g.Furthermore, the selectivity and release analysis of T-MMIPs were also investigated in our work and the performance were showed good.