| As the second generation of supramolecular host compounds, cyclodextrin has a unique cavity structure of inner hydrophobic, outer hydrophilic, which makes it possible to form host-guest inclusion complexes with a wide range of compounds. Fe3O4 magnetic nanoparticles not only own the basic characteristics of nanomaterials but also have excellent magnetic properties. Magnetic nanocomposites which are fabricated by grafting the cyclodextrin and its derivates onto the magnetic nanoparticles contain the inclusion properties of cyclodextrin and allow for the exploitation of magnetic separation techniques of Fe3O4 magnetic nanoparticles. The nanocomposites show great application potentials. In the thesis, we focus on exploring the adsorption properties of these magnetic nanocomposites. The main contents are as follows:Chapter Ⅰ:This part summarized the history and development, structure and properties, preparation and applications of cyclodextrin. The characteristics, preparation tactics and modified methods of Fe3O4 magnetic nanoparticles were depicted briefly. The research progresses of cyclodextrin functionalized magnetic nanocomposites were reviewed in detail, especially the applications in the environmental field.Chapter Ⅱ:Carboxymethyl-β-cyclodextrin (CM-β-CD) was synthesized based on SN2 substitution reaction, and successfully modified onto the surface of the Fe3O4 magnetic nanoparticles (MNPs) in alkaline solution using coprecipitation method. The as-prepared CM-β-CD functionalized magnetic nanocomposites (CM-β-CD-MNPs) were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), particle size analysis, thermogravimetric analysis (TGA) and vibrating sample magnetometer (VSM). The mean diameter of CM-β-CD-MNPs was about 12 nm determinated by TEM. CM-β-CD was fabricated successfully to the surface of MNPs, which has been confirmed by FTIR、TGA and Zata potentials. In addition, the amount of CM-β-CD capped on the surface of MNPs was figured out to be 33mg/g approximately. The VSM data showed that the nanocomposites presented the superparamagnetic features, which were beneficial to their magnetic separation in solution.Chapter III:The adsorption properties of CM-β-CD-MNPs towards Rhodamine B (RhB), selected as a model molucle, were investigated. At 25℃ and pH=6, the adsorption attained the maximum. Futhermore, the adsorption equilibrium was reached within 1h and the adsorption kinetic coincided with the pseudo-second-order kinetic model. The maximum adsorption was calculated to be 135.1 mg/g according to the Langmuir isotherm adsorption equation, which was considered as monolayer adsorption. CM-β-CD-MNPs paly an important role in the treatment of waste water with dye as they combine the magnetic separation technology and the inclusion of cyclodextrin with pollutants.Chapter IV:CM-β-CDP-MNPs magnetic nanocomposites were prepared by anchoring cross-linked carboxymethyl-β-cyclodextrin (CM-(3-CDP) onto the surface of Fe3O4 superparamagnetic nanoparticles (MNPs). The characterizations of the nanocomposites were performed by TEM, DLS, FTIR, TGA, Zata potential and VSM. The mean diameter of CM-P-CDP-MNPs was 12 nm determinated by TEM. Compared to TEM data, the hydrodynamic mean diameter of CM-β-CDP-MNPs calculated by DLS was higher, resulting from the influences of solvent. CM-β-CDP-MNPs. was successfully synthesized, which has been confirmed by FTIR、TGA and Zata potentials. In addition, the amount of CM-β-CDP capped on the surface of MNPs was figured out to be 45mg/g approximately. The CM-(3-CDP-MNPs could be quickly separated from the solution under an external magnetic field according to the VSM data. These resuls provide the foundations for further applications of magnetic nanocomposites.Chapter V:The adsorption behaviors of CM-β-CDP-MNPs were studied by employing resorcin and bisphenol A as model phenolic compounds. The effect of pH on adsorption was also investigated. Based on the results, the maximum adsorption was reached at pH=5. The adsorption isotherms were fitted well to Langmuir adsorption model with the maximum adsorption capacity amounted to 114.91mg/g and 74.63mg/g for resorcin and bisphenol A, respectively. The adsorption kinetics indicated that the chemicals adsorption and intraparticle diffusion co-existed in the adsorption process. Briefly, the magnetic nanocomposites provide a versatile platform for magnetic separation and inclution.behaviors of cyclodextrin with potential applications in phenolic wastewater remediation.Chapter VI:Summarized the structures, properties and adsorption/ properties towards the model moleculars of the-two magnetic nanocomposites, and forecasted the possible research directions of magnetic rianocomposites in future. |
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