电压对微生物诱导生成碳酸钙沉淀的影响

Effect of Voltage on Microbial Induced Calcium Carbonate Precipitation

微生物诱导碳酸钙沉淀(microbial induced calcium carbonate precipitation,MICP)是一种新型环保固化方法,但碳酸钙的生成量直接影响MICP技术的固化效果,为了在一定界限内提高碳酸钙的生成量,利用MICP技术,研究了不同电压梯度下,脲酶活性的变化规律,在此基础上进一步研究了不同电压梯度、不同通电时间、不同通电方式条件下微生物诱导生成碳酸钙的沉积规律。试验所用微生物为巴氏芽孢杆菌,营养液为三种钙源(氯化钙、硝酸钙、醋酸钙)与尿素1∶1等体积混合,菌液与营养液体积比为1∶15,溶液环境的pH为7.3。结果表明:最佳通电电压为1.2 V;最适通电时间为20 min;最佳的通电方式为全程通电;氯化钙为最佳钙源。故电压对巴氏芽孢杆菌的生物活性起促进作用,提高了其脲酶活性,最终提高了碳酸钙的产量。

Microbial induced calcium carbonate precipitation(MICP)is a new type of environmental friendly remediation method.However,the amount of calcium carbonate affects directly the remediation effect of MICP technology.To increase the amount of calcium carbonate precipitation within a certain limit,the variation of urease activity under different voltage gradients was studied in MICP technology.The deposition laws of microbiologically induced calcium carbonate formation under different voltage gradients,different energization times,and different energization modes were studied.The microorganism used in the experiment was Bacillus bacillus,and the nutrient solution was mixed with three types of calcium sources(calcium chloride,calcium nitrate,and calcium acetate)and urea in an equal volume of 1∶1.The volume ratio of the bacterial liquid to the nutrient solution was 1∶15,and the pH was 7.3.The results show that the optimal energization voltage was 1.2 V and the optimum energization time was 20 min.The best energization mode was the energization throughout the whole process.Calcium chloride was the best calcium source.Therefore,voltage could promote the biological activity of Bacillus.bacillus,increase its urease activity,and increase ultimately the formation of calcium carbonate.