Biomimetic Synthesis Of Calcium Carbonate Microcrystal And Research On Its Properties

Biomimetic synthesis is a process which is regulated by orgnic matric and then induced inorgnic crystals to nucleate and grow.According to its characteristic and confinement capability,template can be categorized into two major types:hard template and soft template.Among them,soft-template methods mainly included many kinds of ordered congeries that composed by amphiphathic molecules,such as micelles,microemulsion,LB films,self-assemble films,and so on,biomacromolecules and molecule additives were also included. Using templates to synthesize calcium carbonate is an immportant method which widely used in laboratory to simulate biomineralization and produce calcium carbonate with good performance. In this dissertation,functional calcium carbonate with specific morphologies and size can be synthesized using chitosan and plant veins as orgnic matic template and Mg2+ as molecule additives. Besides,the crystalline form and formation conditions of calcium carbonate have been further investigated and formation mechnism has been initially proposed.The brief information is followed.1.By method of gas difussion,calcium carbonate were prepared using chitosan solution as organic soft template and Mg2+ as molecule additives.The effects of crystalline morphology are studied under different Ca/Mg molar ratio and temperature.The result of experiment show that spherical calcium carbonate with porous structure was obtained.The microsphere with diameter 200μm has an average pore size of 128nm.Adsorption studies explain that this kind of material in adsorption of oil molecule have demonstrated excellent performance which is expected to become a new type of adsorbent materials to remove oil pollution.2.By casting method to make chitosan solution film,using gas method calcium carbonate were prepared on the chitosan film by the method of in situ synthesis.Some different experimental parameters,namely Ca2+/Mg2+ molar ratio and temperature were systematically investigated.The results indicate that at 10℃,using chitosan as hard template,the morphology of calcium carbonate has a series of changes with the increase of Ca2+/Mg2+ molar ratio.However,when the temperature is up to 25℃,the morphology of calcium carbonate with method of in situ synthesis is still unchanged which show uniform spherical structure.With the contact angle measuring instrument,calcium carbonate with method of in situ synthesis was proved to have good hydrophobic property.3. The plant veins has complex compositions and the main component is cellulose polysaccharides. In presence of Mg2+, biomorphic CaCO3 with different hierarchically ordered micro-and nanostructures was fabricated with natural willow leaf as hard template.The obtained crystals were charcaterized by scanning electronic microscopy(SEM), X-ray diffractometer(XRD),Fourier transform infrared spectroscopy(FT-IR) and the formation mechanism is initially speculated.The green synthesis method provides a new way to prepare calcium carbonate.