Preparation And Characterization Of β-cyclodextrin Nanocomposite Materials

With the rapid economic development in today’s society, the freshwater pollutionproblem caused by the chemicals is one of the major environmental problems, notonly affecting people’s daily lives but also endangering human health. Thus, methodsand materials of treating sewage become the main theme in environmental protectionfield. Compared with traditional materials, nano-material with large specific surfacearea, strong adsorption, etc., is one of the most cutting-edge field of nanoscienceresearch. At the same time, nanomaterial has also some limitations, such as it isdifficult to disperse and recycle. Functional composite nanomaterials meet thepeople’s needs, which have various qualitative composition, structure, and composite.Especially organic/inorganic nanocomposites, with multifunctional naturecombining organic, inorganic and nanomaterials，have been widespreadly concernedaround the world scientists, having potential applications in the field of watertreatment.Cyclodextrin is composed of hydrophilic outer edge and hydrophobic cavityconstituting the outer edge, not only for chelation with metal ion, but also formingnon-covalent-guest complex with the appropriate size of organic and inorganicmolecules. In addition, cyclodextrins have certain stereo options and recognitionability to remove and separate toxic pollutants from sewage, which play an importantrole in the environmental protection. But the outer edge allows cyclodextrin asolubility in water, which limits its practical application. In this thesis, we combineβ-cyclodextrin with organic and inorganic nanomaterials， preparing threecyclodextrin-modified composite nanomaterials and studing their properties andapplications. Details are as follows: 1. Polyvinylpyrrolidone (PVP)，β-CD and glutaraldehyde are combined throughelectrostatic spinning method, further forming water-insoluble composite nano-fibermaterial (β-CDXFM) by thermal-crosslinking. This nano-fiber membrane has goodhydrophilicity， which extends and curls freely in water without damaging. Inaddition, in this work we study the adsorption properties using methyl orange as anexample, and further evaluate and discuss the material by changing parameters of thereaction time, temperature and pH in the adsorption system. There are experimentaldata showing that under the best conditions the adsorption rate of methyl orange isabove95%, the maximum adsorption capacity is39.82mg. Therefore the materialhas a considerable adsorption capacity.2. Composite nanomaterial with both magnetic and adsorptive properties isprepared. Polyvinylpyrrolidone (PVP) is used as matrix，Fe3O4nanoparticles，β-CDand glutaraldehyde are used as functional materials. They are prepared by electrostaticspinning to form nanospheres capable of adsorption and recycling by magnet. Theprepared composite magnetic nanoparticles (β-CDX/Fe3O4@PVP) can disperse inwater uniformly via the ultrasound, which can be further characterized. In addition, inthis work we study the adsorption of methyl orange as an example, evaluating anddiscussing the material by changing the reaction time, temperature and pH in theadsorption system. Under the best conditions its adsorption rate of methyl orangecould reach over90%and the maximum adsorption capacity of47.62mg. Thistechnology provides a very promising material for the sewage treatment.3. We design and synthesize a β-cyclodextrin modified Fe3O4magneticnanoparticles. Firstly we prepare magnetic iron oxide nanoparticles，secondly attach alayer of SiO2out of nanoparticles, then modify β-CD on the surface of silica shell toobtain a certain adsorptive capacity of magnetic nanoparticles, which possesssuperparamagnetic of MNPs，electrochemical properties，cyclodextrin supramolecularrecognition and host-guest inclusion complexes. In addition, we test adsorptioncapacity of magnetic β-cyclodextrin nanoparticles (Fe3O4@SiO2/β-CD) inaqueous solution using methyl orange dye. Under the best conditions the adsorption rate of methyl orange could reach95%and the maximum adsorption capacity is39.82mg, which supports the application of cyclodextrin modified magneticnanoparticles in water pollution.