MICP反应引入NBPT对碳酸钙沉积的影响

Study on the effect of MICP with NBPT on calcium carbonate deposition

在进行前期探究试验并取得一定成果的基础上,进一步将正丁基硫代磷酰三胺(NBPT)应用于微生物诱导碳酸钙沉积(MICP)固化砂柱试验,结合无侧限抗压强度试验、生成物含量检测、扫描电镜试验、能谱分析及X射线衍射试验等监测手段,对反应生成物进行深入研究,分析NBPT对MICP反应生成碳酸钙的影响作用效果.结果表明:NBPT参与MICP反应对诱导产生的碳酸钙晶体形貌及大小具有调控作用.NBPT摩尔分数不高于0.1%时碳酸钙晶体主要为方解石,摩尔分数在0.1%~1%之间时碳酸钙晶体为方解石与球霰石,而摩尔分数高于1%时碳酸钙晶体几乎全部为球霰石.此外,NBPT还可与碳酸钙晶体形成共聚体从而进一步提高MICP反应的胶结效果.

Previous tests on introducing N-(N-butyl)thiophosphoric triamide(NBPT)to microbially induced carbonate precipitation(MICP)process achieved a certain positive result.Further study about applying NBPT to sand column tests with MICP method was carried out.Some test methods such as the unconfined compressive strength test,product content detection,scanning electron microscope,energy spectrum analysis and X-ray diffraction test were conducted.An in-depth study on the reaction products was conducted and the effect of NBPT on the formation of calcium carbonate by MICP reaction was analyzed.The results show that the participation of NBPT in MICP reaction has a regulatory effect on the morphology and size of CaCO3 crystals.When the concentration of NBPT is not higher than 0.1%,the formation of calcite micrograins is controlled.When the concentration is between 0.1%and 1%,the products coexist with calcite and vaterite.When the concentration is higher than 1%,almost all crystals are vaterite.In addition,NBPT is involved in the formation of organic precipitates that form copolymeries with calcium carbonate crystals,which contributed to the bonding effect of MICP reactions.