Papers by Author: Wen Kun Zhu

Abstract: Sugar is one of the key nutrients required to microorganism growth. In this paper , the effects of various sugars on the mineralization of calcium carbonate induced by Bacillus pasteurii . The precipitation amount, forms and structures of calcium carbonate were characterized. The results indicated that the induced calcium carbonate precipitation are mainly calcite as irregular aggregated bodies and rhombus blocks and aragonite appeared when the culture medium was added with dextran. The calcium carbonate precipitation reached a maximum of 2.32 g when glucose was added into the culture.

Abstract: Calcium carbonate with various structures and morphologies were prepared under double injection of the CaCl2 and Na2CO3 solutions with molar ratio of 1:1 at 30 °C, taking lignin as the induction agents. They were characterized by scanning electron microscopy, infrared spectroscopy thermal analysis and X-ray diffraction. The synthesis mechanism was also discussed. The results showed that calcium carbonate of different shape were obtained with the concentration of lignin at 10g/L, 20g/L and 30g/L, respectively, under 30°C while CaCl2 and Na2CO3 were kept at the same concentration of 0.5mol/L. The size of the particles was in a range between 3 and 5μm and the particles were calcites. Compared with the normal calcium carbonate, the compound has advanced thermal decomposition behavior. Fourier transform infrared spectroscopy (FT-IR) analysis revealed the presence of lignin and calcite. The electrostatic interaction of Ca2+ with lignin and the complementary of stereo-structure play important roles in the formation of Dumbbell Shaped Calcium Carbonate.