| The antibiotics, which are used extensively over the word, have now entered into the environment through various means. The antibiotic residues can cause serious damage to the human health and ecosystem balance. Adsorption method has been widely used to remove a variety of environmental pollutants, and the removal effect of the pollutants depends on the types and properties of adsorbents. However, most of adsorbents have no specificity and all the elements in water can be adsorbed by an adsorbent, which is unfavorable to the separation and analysis of the specific pollutants. So the research and development of new adsorbents with fast, selective and high efficient removal of antibiotic pollutants is the hotsport in the environment.So the molecularly imprinted polymers(MIPs) have been more and more used in removing environmental pollutants, because they can be used to selectively recognize and separate the special target analytes. There are many methods to prepare MIPs, and among which, surface imprinting technique is benefit to the elution and rebinding of template molecules by establishing the layer of MIPs on the surface of support matrices, in which the recognition sites can be utilized fully. Many materials can be used as supporter of MIPs, such as carbon nanotubes, Fe3O4 nanoparticles and SiO2 nanoparticles, etc. However, the surface modification or complex synthetic process is required in order to prepare these support materials. Moreover, the spherical MIPs can be easily synthetized by Pickering emulsion polymerization. And the type and stability of emulsion depend on the wettability of stabilizers. Various kinds of inorganic particles and synthetic functional polymers are often used as Pickering emulsion stabilizer. However, in order to prepare a stable Pickering emulsion, it is need to modify the surface of inorganic particles or add surfactants and salts into emulsion systems, and the functional polymers are often prepared by a complex, time consuming and economically wasteful synthetic process.In this paper, the biological materials with special morphology and function were selected from natural materials and used as the support matrices of MIPs or as the stabilizers of Pickering emulsion. And then the new MIPs were prepared by surface imprinting technique or Pickering emulsion polymerization technology in the imprinting system with a single functional monomer and crosslinking agent. The prepared MIPs can be use to effectively remove macrolide antibiotics in the environment. By various of characterization, the morphology, chemical composition, heat, magnetism and surface property of the prepared MIPs were studied. And the adsorption kinetics, adsorption equilibrium and selective adsorption abilities of MIPs were investigated by the batch mode adsorption experiments, and the recognition mechanism was also discussed.The main research results of this paper are as follows:1. The preparation of MIPs upon eggshells and eggshell membranes and study on the selective adsorption and separation of SP.(1) The imprinted membranes(ESM@MIPs) were prepared by surface imprinting technique using eggshell membranes(ESM), acetonitrile, spiramycin(SP), methacrylic acid(MAA), ethyleneglycol dimethacrylate(EGDMA) and 2,2’-Azobis(2-methylpropionitrile)(AIBN) as the support, solvent, template molecules, functional monomers, crosslinking agent and initiator, respectively. Then the ESM@MIPs were characterized by scanning electron microscope(SEM), infrared spectra(IR) and thermogravimetry(TG), and the results indicated that surface of ESM fibers was coated with a layer of MIPs, and ESM@MIPs with favorable thermal stability contained the special functional groups from ESM, MAA and EGDMA. The ESM@MIPs were used to adsorb SP in aqueous solutions. The results showed that elevated temperature was helpful to increase the adsorption quantity because of the endothermic adsorption process. The adsorption equilibrium data of SP on ESM@MIPs were well described by Langmuir isotherm, and the monolayer adsorption capacity of ESM@MIPs were 14.45 mg g-1(298K) and 19.01 mg g-1(308K). The pseudo-second-order kinetic model was more suited for fitting the adsorption kinetic data, and the spontaneous adsorption performance of ESM@MIPs was superior to ESM@NIPs. Selective adsorption experiments showed that ESM@MIPs had good selective identification for SP. Regeneration experiments were repeated five times, the adsorption capacity of ESM@MIPs for SP were slightly decreased, indicating the good regeneration performance.(2) Integrating with surface imprinting technique and template, the imprinted polymers(ES@MIPs-1) were synthesized with eggshell(ES), SP, MAA, EGDMA and AIBN as the support matrices, template molecules, functional monomers, crosslinking agent and initiator, respectively. Because the primary ingredients of eggshell(ES) were CaCO3, the imprinted polymers(ES@MIPs-2) were achieved after the ES matrices in ES@MIPs-1 were removed by acid. The ingredient, morphology and thermal stability were studied by FT-IR, SEM and TG, respectively. The results revealed that ES@MIPs-2 was hollow and porous particles, whose size was micron scale, and there are no ES ingredients in ES@MIPs-2, which had favorable thermal stability. The results of a series of adsorption experiment showed that the adsorption capacity of ES@MIPs-2 were superior to ES@MIPs-1, indicating that the removal of support matrices were benefit to increase the adsorption capacity of MIPs. Moreover, the adsorption of SP on ES@MIPs-2 was endothermic process. Langmuir isotherm was more suited for fitting the adsorption equilibrium data of SP on ES@MIPs-2, and the monolayer adsorption capacity of ES@MIPs-2 at 298 K and 308 K were 31.25 mg g-1 and 38.78 mg g-1, respectively. The adsorption kinetic data were well described by the pseudo-second-order kinetic model. Selective adsorption and regeneration experiments revealed the good selective identification and regeneration performance of ES@MIPs-2.2. The preparation of imprinted adsorbents by biological spores-based Pickering emulsion and study on the selective adsorption and separation of SP.(1) The spherical hydrophobic mushroom spores(MS) were adopted as stabilizers to prepared Pickering emulsion. The MS-MIPs were achieved after the surfaces of MS were modified by coating with a layer of MIPs which were prepared with surface imprinting technique, using the multiple activity groups on the surface of MS. And the water contact angles of MS and MS-MIPs were 141.8° and 98.24°, respectively. After that, the MS-MIPs were employed as stabilizers to prepare a stable Pickering emulsion, and the imprinted polymer microspheres(MS-IMIPs) were prepared by Pickering emulsion polymerization. Various characterization methods were adopted to research the surface structure and profile, thermostability and wettability of MS-IMIPs, and the results showed that some little balls were adhered on the surface of MS-IMIPs which were about 55 μm in diameter, and MS-IMIPs also possessed characteristics of good thermal stability and hydrophobicity for the water contact angle was measured to be 118.3°. The static adsorption experiments revealed that the adsorption process of SP on MS-IMIPs was endothermic. Langmuir isotherm and pseudo-second-order kinetic model were respectively more suited for fitting the adsorption equilibrium and adsorption kinetic data of SP on MS-IMIPs. The monolayer adsorption capacity of MS-IMIPs at 298 K and 308 K were 62.50 mg g-1 and 72.46 mg g-1, respectively. Moreover, the MS-IMIPs also possessed the good selective identification and rebinding ability and also can be utilized several times.(2) The ellipsoidal Ganoderma lucidums spores(GLS) were adopted as stabilizers to prepared Pickering emulsion. And the water contact angle of GLS was measured to be 31.45°, indicating a very hydrophilic material. The imprinted polymer microspheres were prepared via Pickering emulsion polymerization method by using GLS as the stabilizers, toluene as the solvent, SP as the template molecules, MAA as the functional monomers, EGDMA as the crosslinking agent and AIBN as the initiator. And then GLS-MIPs were achieved after the GLS particles had dropped off from the surface of the as-prepared imprinted polymers in the treatment process. The amount of GLS in the emulsion system had an effect on the stability of Pickering emulsion, which was also discussed. FTIR, SEM, TG and N2 adsorption-desorption were employed to characterize the morphology and property of GLS-MIPs, and the results showed: There were no GLS particles on the surface of GLS-MIPs, whose size was 60-70 μm, exhibiting favorable thermal stability, and the specific area and average pore diameter of GLS-MIPs were respectively 374. 8 m2 g-1 and 11.25 nm. The static adsorption experiments indicated that the adsorption capacity of SP on GLS-MIPs was affected by temperature and increased with the rising temperature, indicating an endothermic adsorption process. The adsorption equilibrium data of SP on GLS-MIPs can be fitted well by Langmuir isotherm, while the pseudo-second-order kinetic model was more suited for fitting and adsorption kinetic date. The monolayer adsorption capacity of GLS-MIPs were 32.57 mg g-1 and 43.48 mg g-1 at 298 K and 308 K, respectively. The adsorption dynamic characteristics of GLS-MIPs were better than those of GLS-NIPs, Moreover, GLS-MIPs also possessed the good selective identification and rebinding ability and also can be utilized several times.3. The preparation of imprinted adsorbents by eggshells/lotus leafs-based Pickering emulsion and study on the selective adsorption and separation of MALs.(1) The imprinted polymer microspheres(EM-MIPs) were prepared via Pickering emulsion polymerization method by using eggshell particles as the stabilizers, erythromycin(EM) as the template molecules, methyl methacrylate(MMA) as the functional monomers, EGDMA as the crosslinking agent and AIBN as the initiator. The EM-MIPs was characterized by FT-IR, SEM, TG and N2 adsorption-desorption, and the test results showed that EM-MIPs particles were approximately spherical with the size ranges from 60 μm to 90 μm as estimated from SEM, and the folds and eggshell particles were visible clearly on the surface of the EM-MIPs. The water contact angle of the EM-MIPs was determined to be 129.5° indicating that the microspheres were a hydrophobic material. The EM-MIPs also exhibited favorable thermal stability, and the specific area and average pore diameter of EM-MIPs were respectively 81.3 m2 g-1 and 13.70 nm. A series of static adsorption experiments were carried to study the adsorption behavior of EM-MIPs. The results revealed that the adsorption process of EM-MIPs for EM was endothermic; the adsorption equilibrium data of EM onto EM-MIPs can be fitted well by Langmuir isotherm, and the monolayer adsorption capacity of EM-MIPs were respectively 31.75 mg g-1, 43.10 mg g-1 and 66.23 mg g-1 at 288 K, 298 K and 308 K, which were better than those of EM-NIPs; while the pseudo-second-order kinetic model was more suited for fitting and adsorption kinetic date. Moreover, the selective identification and rebinding ability of EM-MIPs were superior to that of EM-NIPs.(2) In order to simplify the post-treatment process of MIPs and provide the magnetic separation by applied magnetic field, the hydrophilic Fe3O4 nanoparticles were introduced into Pickering emulsion system in a special way, because the magnetic eggshell particles were achieved immediately after the two particles were dispersed in water. A stable oil-in-water Pickering emulsion was formed by using magnetic eggshell particles as the stabilizers. And then the magnetic molecularly imprinted microspheres(MMIPs) were synthesized via Pickering emulsion polymerization method. The morphology, constitutes and magnetic performance of MMIPs were characterized by various methods, the results indicated that the diameter of MMIPs was 55-85μm, and there were many rill-like wrinkles on the unsmoothed surface of microspheres which looked like the walnuts; the MMIPs had the superparamagnetic property, and the saturation magnetization(Ms) values of MMIPs was 1.336 emu g-1, which can meet the need of fast separation with applied magnetic field. Furthermore, MMIPs were a slightly hydrophobic material because of the water contact angle value(θ=109.9°). The adsorption kinetic studies showed the adsorption rate and adsorption capacity of MMIPs increased with increasing of temperature, and the pseudo-second-order kinetic model can fit the experimental data well. The equilibrium adsorption experiments showed that the adsorption equilibrium data fitted the Langmuir isotherm model well, and the monolayer adsorption capacity of MMIPs was 47.393 mg g-1. The selective adsorption experiment showed that MMIPs had highly selective recognition properties for EM.(3) The water contact angle of the lotus leaf particles(LL) which had been extracted by ethanol was determined to be 113.9°, which were fit for use as the stabilizers of Pickering emulsion. After the LL and Fe3O4 nanoparticles were dispersed in water, the magnetic LL particles formed immediately. And then a stable Pickering emulsion was prepared by using magnetic LL particles as the stabilizers, toluene as the solvent, SP as the template molecules, MAA as the functional monomers, EGDMA as the crosslinking agent and AIBN as the initiator. After polymerization, the magnetic imprinted polymer microspheres(LL-MIPs) were synthesized. The analysis by a variety of characterization methods showed that the LL-MIPs were 6-16 μm hollow microspheres and a layer of LL particles were adhered to the surface of microsphere; and the specific area and average pore diameter of LL-MIPs were respectively 27.07 m2 g-1 and 15.56 nm; LL-MIPs also exhibited superparamagnetism and the saturation magnetization(Ms) values obtained at room temperature were 1.088 emu g-1, which can be separated by a magnetic field; the water contact angle of LL-MIPs was 109.9°, indicating a slightly hydrophobic material. The results of adsorption experiments showed that the adsorption process was endothermic and the adsorption capacity of LL-MIPs can increase with the rising of temperature; the adsorption equilibrium data of SP onto LL-MIPs can be fitted well by Langmuir isotherm, and the monolayer adsorption capacity of LL-MIPs were 42.74 mg g-1(298K) and 65.36 mg g-1(308K); while the pseudo-second-order kinetic model was more suited for fitting and adsorption kinetic date of LL-MIPs. Moreover, the selective identification and rebinding ability of LL-MIPs were better than that of LL-NIPs, and the regeneration experiments indicated the good regeneration performance of LL-MIPs, which can be reused many times. |
PDF Full Text Request