Studies On Biomimetic Synthesis And Microwave-assisted Synthesis Of Calcium Carbonate Material

Calcium carbonate （CaCO₃） is the important mineral product in the biologicalmineralization, it has a very wide variety of biological and industrial applicationprospect. In current paper, we firstly summarize the importance of researching theinorganic materials calcium carbonate, the mineral crystallization theory andcommonly used method. Calcium carbonate with different morphologies andpolymorphies were obtained by employing the method of bionic mineralization andmicrowave assisted heating method, and these two kinds of methods were discussedand compared. The samples are characterized by X-ray powder diffractometry （XRD）analysis, scanning electron microscopy （SEM）, Fourier transform infraredspectrometer （FT-IR） and hot heavy differential thermal analysis （TG-DTA）,transmission electron microscopy （TEM）, and selected area electron diffraction（SAED）. The main research results obtained are as follows:1. Different morphologies and polymorphs of CaCO₃crystals were biomimeticsynthesized in the presence of the modifier of cationic polymer polyethyleneimine，which is rich in amido, with the gas diffusion method. The results show that themixture of hollow-sphere vaterite and calcite was obtained in low concentration ofpolyethyleneimine, the aggregations of calcite were obtained in high concentration andthe morphology of CaCO₃tends to regulation with the extension of mineralizationtime.2. The influence of diffident supersaturations and EG/H₂O ratios of the bulksolution on the nucleation and crystal growth of calcium carbonate was studied throughthe method of microwave-assisted heating in water/ethylene glycol mixed solvents.The result shows that EG molecules contribute to stabilizing the vaterite phase, whenthe ratio was92%, we obtained a novel morphology vaterite with pine-dendritic shape.the changes of solution supersaturation extraordinary influence the morphologies andpolymorphs of calcium carbonate, we obtained rhombohedron calcite, fiber strapping aragonite and pine-dendritic vaterite.3. The influence of sodium polystyrene sulfonate （PSSS） in EG/H₂O mixedsolvent using the microwave assisted method was studied. And we changed the PSSSconcentration, reaction time, EG/H₂O volume ratio and obtained spherical amorphouscalcium carbonate, lotus shape of slice layer accumulation，globular gathered flowersshape calcium carbonate. What’s more, the mechanism of crystal growth wasdiscussed.