微生物在石英砂中诱导方解石沉积的实验研究

Studies on the Experiment of Microbiologically-induced Calcite Precipitation in Silica

利用巴斯德芽孢杆菌和培养基来处理石英砂,与不含菌的对照样品相比,其固化效果比较明显。通过X-射线衍射分析处理后的样品,发现其中有方解石晶体生成。通过扫描电子显微镜可观察到石英砂颗粒的缝隙之间紧密地填充有大量的方解石晶体,由于方解石晶体本身具有胶结作用,从而使得石英砂颗粒能够胶结在一起。放大至10000倍可看到这些晶体表面附着有杆状菌体。能谱分析的结果也证明巴斯德芽孢杆菌在石英砂中诱导沉积出了方解石晶体。通过测算得出在本试验条件下(500 mL含活菌5×109个的巴斯德芽孢杆菌菌液用urea-CaC l2重悬后与50 g石英砂混合装入60 mL注射器中,urea-CaC l2以重力作用流过注射器)方解石的产量平均为2.178 g。

This research used Bacillus pasteurii and medium to treat silica, compared to the control without bacteria, the effect of cementation was obvious. By analysis of XRD on the specimen after treatment, it was found that there was calcite produced in it. By analysis of SEM, it was observed that calcite filled into the gaps of silica grains. Due to the cementation effect of calcite, it can solidify silica grains. Magnifying to 10000, it was observed that rod-like bacteria clung to the surface of calcite. While the result of EDS demonstrated that Bacillus pasteurii induces calcite precipitation in silica. This experiment put into the injector the mixture of 50 g silica and 500 mL urea-CaCl2 resuspension Bacillus pasteurii bacteria solution with 5 × 109 bacteria. Urea-CaCl2 flew through the injector by the action of gravity. By measuring, the yield of calcite in silica under this experimental condition is 2. 178 g averagely.