Preparation And Application Of Norfloxacin Molecularly Imprinted Polymer Microspheres Based On Self-stabilized Precipitation Polymerization

In recent years,the abuse of antibiotics results in serious water pollution.Traditional wastewater treatment methods are not efficient for the removal of antibiotics,so it is highly desired to develop high-performance adsorbent materials that can specifically adsorb antibiotics.Molecular imprinting polymer(MIP)is a new type of material that can specifically adsorb target molecules,which can meet the requirement for the separation and detection of antibiotics.Surface molecular imprinting polymers(SMIPs)are attracting intensive attention due to their advantages of rapid mass transport and high binding capacity.However,complicated surface modifications are required for the conventional support matrix,which greatly hindered the large-scale and application of SMIPs.In the present work,a series of low-cost polymer particles were facilely synthesized through self-stabilized precipitation polymerization(2SP)process,which is easily modified to serve as support matrices.The preparation of SMIPs based on these polymer particles,and their adsorption properties were investigated in detail,including adsorption kinetics,adsorption isotherms and adsorption selectivity.The main contents of this research are as follows:1.Monodisperse poly(maleic anhydride-alt-styrene)(PMS)particles with cross-linked strucuture and controlled size were prepared through 2SP process.Consequently,after being modified with 1,6-hexanediamine(HDA)and glycidyl methacrylate(GMA),a novel type of GMA functionalized PMS particles(PMS-GMA)were successfully obtained,which can serve as an ideal carrier for SMIP.In the presence of norfloxacin(NOR),using PMS-GMA as a carrier,NOR-imprinted SMIP microspheres(PMS@MIPs)were prepared through MAA and EGDMA copolymerizating.The influence of solvent,molar feed ratio of[NOR]/[MAA]/[EGDMA],core-shell ratio on the chemical composition and surface morphology of the resultant PMS@MIPs were investigated in detail to optimize the preparation condition.2.Due to the existence of the SMIP shell,the as-prepared PMS@MIPs can be used as a high-performance adsorbent for selective removal of NOR.The experimental results indicated that the adsorption of NOR on PMS@MIPs is very fast,the absorption completed in 60 minutes,and the maximum adsorption capacity is 149.3 mg/g.The NOR adsorption follows the Freundlich isotherm and the quasi-second-order kinetic model,and the adsorption capacity(86.7 mg/g)of NOR by PMS@MIPs is much higher than that of non-surface molecularly imprinted polymer particles(PMS@NIPs)(57.9 mg/g).Since the electrostatic attraction between the NOR and the adsorbent dominates during the adsorption process,PMS@MIPs has significant pH responsiveness,with a large adsorption capacity in the pH of 7-10.Additionally,PMS?MIPs exhibited high selectivity for NOR over other antibiotics.More importantly,the PMS@MIPs exhibited excellent reusability,and the adsorption capacity of the recycled MIP only reduced by 4.1%after four adsorption-desorption process.3.The anhydride functionalized hollow polymer microspheres(HPPs)were prepared via self-stable precipitation polymerization,which were further hydrolyzed to obtain carboxyl-functionalized HPPs.In the presence of NOR template molecules,dopamine self-polymerizes on the carboxyl-functionalized HPP surface to prepare NOR-imprinted surface molecularly imprinted polymers(HPP@MIPs).4.The effects of initial NOR concentration,contact time,and pH value on the adsorption of NOR on HPP@MIPs were investigated in detail.The adsorption kinetics data indicated fast adsorption rate(reach equilibrium within 60 minutes),and the maximum adsorption capacity is as high as 345.8 mg/g.Furthermore,HPP@MIPs also showed unique pH-responsiveness,and the optimal adsorption of NOR was attained at the pH of 7-10.In addition,HPP@MIPs exhibited much higher adsorption capacity for NOR over other antibiotics,indicating excellent selectivity for NOR.More importantly,the HPP@MIPs exhibited excellent reusability,and the adsorption capacity of the recycled HPP@MIPs only reduced by 2.1%after four adsorption-desorption cycles.