微生物非脲解作用诱导碳酸钙沉积研究

Non-ureolytic Microbiologically-induced Calcium Carbonate Precipitation

利用嗜碱型芽孢杆菌的非脲解矿化作用,在含2种不同有机钙源的矿化培养基中实现了微生物诱导碳酸钙沉积.讨论了沉积过程中细菌生长特性及碳酸钙沉积动力学,并综合运用X射线衍射仪、热分析仪和扫描电子显微镜对沉积产物进行了研究,结果表明,降低初始钙离子浓度有利于提高有机钙源的转化率,而改变钙源种类对碳酸钙沉积动力学及碳酸钙晶型、形貌均有较大影响.在含乳酸钙和谷氨酸钙的矿化培养基中分别沉积得到了结晶不良的方解石和稳定性较差的球霰石,且后者的沉积产率更高,可达到近100%.证实了嗜碱菌的非脲解诱导碳酸钙沉积途径具备应用于混凝土防护和修复的潜质.

By using non-ureolytic bacteria of genus Bacillus, microbiologically-induced calcium carbonate precipitation was achieved in mineral medium containing two different kinds of organic calcium sources. The characteristics of bacterial growth and kinetics of calcium carbonate precipitation were discussed. Sediments were characterized by X-ray diffraction, thermal analysis and scanning electron microscopy. The results show that reducing the initial concentration of calcium ions is beneficial for improving the conversion ratio of organic calcium source, while altering the type of calcium source has a remarkable impact on both the kinetics of precipitation and the crystal form and morphology of calcium carbonate. Not well-crystallized calcite and unstable vaterite was formed from calcium lactate and calcium glutamate medium, respectively, and higher precipitation productivity was obtained in the latter case, which was nearly 100%. The potential application ofnon-ureolytic precipitation validated. bacterially-induced calcium carbonate in protection and remediation of concrete was