纳米四氧化三铁对微生物诱导碳酸钙沉淀的作用效果与机理研究  

Study on the Effect and the Mechanism of Nano-Fe_(3)O_(4)on Microbially Induced Calcium Carbonate Precipitation

作　　者：李爽 黄明[1] 崔明娟 胡鑫杭 许凯 姜启武 LI Shuang;HUANG Ming;CUI Mingjuan;HU Xinhang;XU Kai;JIANG Qiwu(College of Civil Engineering,Fuzhou University,Fuzhou 350108,China)

机构地区：[1]福州大学土木工程学院,福州350108

出　　处：《材料导报》2024年第20期76-83,共8页Materials Reports

基　　金：国家自然科学基金(41972276,52108307,52378392);福建省自然科学基金(2020J06013);福建省“雏鹰计划”青年拔尖人才项目(00387088);福州大学“旗山学者”项目(XRC-22015)。

摘　　要：微生物诱导碳酸钙沉淀(MICP)是环境岩土工程领域一项新型的土体加固技术。微生物的生长及活性会受到外部磁场的影响,改变MICP中碳酸钙的晶型晶貌及沉淀方式,从而对碳酸钙的胶结性能产生影响。采用纳米四氧化三铁(Nano-Fe_(3)O_(4)),设计了Nano-Fe_(3)O_(4)作用下的微生物诱导碳酸钙沉淀的水溶液及MICP砂土固化试验,对比分析了Nano-Fe_(3)O_(4)含量对微生物诱导生成的碳酸钙晶体含量(CCC)、类型、比例以及MICP固化砂土力学强度等参数的影响规律,并结合扫描电镜(SEM)试验分析了溶液环境及砂柱中碳酸钙的微观形貌特征,系统归纳了Nano-Fe_(3)O_(4)对MICP的作用效果及机制。结果表明:(1)Nano-Fe_(3)O_(4)能够有效改善细菌的新陈代谢性能,显著提高细菌OD_(600)及脲酶活性;(2)溶液环境中,MICP产生的碳酸钙晶体类型以球霰石为主,含少量方解石,且Nano-Fe_(3)O_(4)含量增加能够促进球霰石的生成及增大MICP沉淀物中稳定相碳酸钙所占的比例;(3)Nano-Fe_(3)O_(4)可以显著提高MICP固化砂土的无侧限抗压强度和CCC;(4)SEM分析结果表明,溶液环境中,碳酸钙晶体以球型堆积为主,MICP固化砂柱中碳酸钙晶型随Nano-Fe_(3)O_(4)含量的增加逐渐呈菱柱状堆积。Microbially induced carbonate precipitation(MICP)is a promising technique in geoenvironmental engineering.The metabolic activity of bacteria is sensitive to external magnetic fields,which will affect the CaCO_(3)crystal morphology.Therefore,nano-Fe_(3)O_(4)was utilized to investigate the influence of magnetic materials on MICP.Both MICP in solution environment and MICP on a quartz sand surface were investigated with different nano-Fe_(3)O_(4)content.The calcium carbonate content(CCC),crystal types and unconfined compressive strength were analyzed by scanning electron microscope(SEM)and uniaxial compression test.Furthermore,a series of tests were conducted to reveal the mechanism of the effect of nano-Fe_(3)O_(4)on MICP.The results showed that the optical density at 600 nm of bacteria(OD_(600))and bacterial activity increased with an increase in nano-Fe_(3)O_(4)content.In the solution environment,the crystal type of CaCO_(3)was primarily vaterite,with little calcite,and it was confirmed by TG-DTA testing that nano-Fe_(3)O_(4)could facilitate the formation of vaterite.Additionally,the unconfined compressive strength(UCS)and calcium carbonate content of MICP-treated sand increased with an increase in nano-Fe_(3)O_(4)content.Interestingly,CaCO_(3)presented in the form of spheres in the solution environment,while it was in the form of rhomboid imbricate on the surface of quartz sand particles.

关 键 词：微生物诱导碳酸钙沉淀(MICP) 纳米四氧化三铁 晶体类型与形貌 细菌脲酶活性 溶液环境 MICP固化砂土 

分 类 号：TU526[建筑科学—建筑技术科学]