【摘要】 钙离子利用率是微生物诱导碳酸钙沉积矿化技术中一项重要指标和参数,待矿化钙离子能否参与到矿化反应和如何被利用是这项技术的关键。本文借助紫外线吸光度法、电导率法和EDTA滴定法等技术手段,分析了待胶结菌液浓度和脲酶活性的时变规律,阐述了不同胶结配比对矿化反应过程中钙离子利用率的影响。结果表明:在胶结过程中,细菌的浓度和脲酶活性会逐渐降低;在合理浓度范围内,钙离子利用率随菌液浓度以及胶结液浓度的增大而提高,最高可达99.73%。进而通过X射线衍射、扫描电镜检测来揭示矿化产物的形成机理,分析得出:球霰状碳酸钙晶体是钙离子在有机质的调控下依托细菌表面的成核位点富集矿化而成,矿化产物中碳酸钙晶体尺寸大小和形态受菌液和胶结液配比浓度的影响。本研究对于微生物诱导矿化反应生成碳酸钙在工程材料领域的应用具有一定的参考价值。更多还原

【Abstract】 The utilization of calcium ions is an important index and parameter in microbially induced calcium carbonate deposition. The key to this technology is whether it can participate in the mineralization reaction. In this study, UV absorbance, conductivity measurement and EDTA titration were used to analyze the time-varying law of bacterium concentration and urease activity, and also the effects of different cementing ratios on the utilization of calcium ion in the mineralization process were discussed.The results showed that, the concentration and urease activity of the bacteria gradually decreased during the cementing process. Within a proper concentration range, calcium ion utilization increased with the increase of bacteria concentration and cementation concentration, and the highest value was 99.73%. The formation mechanism of mineralization products was revealed by X-ray diffraction and scanning electron microscopy. The analysis showed that the sphere-like calcium carbonate crystals are formed by the enrichment and mineralization of calcium ions at the nucleation sites on the surface of the bacteria under the control of organic matter. The size and morphology of the calcium carbonate crystals are affected by the concentration ratio of the bacterial liquid and the cement liquid. This research has particular reference value for the application of calcium carbonate in mineralization induced by microorganisms and its application in engineering materials.更多还原