Ca^(2+)添加对微生物矿化固结Cd^(2+)的影响  

Effect of Ca^(2+)addition on microbial mineralization and consolidation of Cd^(2+)

作　　者：王晖 王敏 汤鼎 赵峰华 郦嘉颖 朱新园 赵兴青 WANG Hui;WANG Min;TANG Ding;ZHAO Fenghua;LI Jiaying;ZHU Xinyuan;ZHAO Xingqing(School of Environmental and Safety Engineering of Changzhou University,Changzhou,213164,China)

机构地区：[1]常州大学环境与安全工程学院,常州213164

出　　处：《环境化学》2021年第3期859-867,共9页Environmental Chemistry

基　　金：国家自然科学基金(41302025,41541016)资助.

摘　　要：微生物诱导碳酸盐沉淀(MICP)可将游离的重金属离子转化为稳定的矿化物,在修复土壤重金属污染方面具有广阔的应用前景.本研究从铜陵矿区周边土壤中筛选得到1株产脲酶且耐镉矿化菌株CZW-1,16S rDNA鉴定为芽孢杆菌(Bacillus sp.),并将其利用于添加外源Ca^(2+)的矿化固结Cd^(2+)实验中.通过扫描电镜(SEM)、傅立叶红外光谱(FT-IR)以及X射线衍射(XRD)对矿化产物进行表征和分析.结果表明,添加一定浓度的Ca^(2+)可促进细菌的生长,其最佳浓度为20 mmol·L^(-1).且Ca^(2+)的添加可提高细菌的最小抑制浓度和促进脲酶活性,提高对Cd^(2+)的矿化率,加钙前后的矿化率由68.93%提高到75.95%.通过对矿化物的定性分析,可知加钙前后的矿物沉淀由单一CdCO_(3)变为CdCO_(3)和CaCO_(3)的复合沉淀,其表面也由严密紧实变成填满了小颗粒CdCO_(3)的多孔状.Microbially induced carbonate precipitation(MICP)can transform free heavy metal ions into stable precipitation and has a broad application prospect in remediation of soil heavy metal pollution.In this study,a urease-producing and cadmium-tolerant strain CZW-1 was screened from heavy metal contaminated soil in Tongling mine area,and which was identified as Bacillus sp.by 16S rDNA sequences and used in Cd^(2+)mineralization experiments with and without the addition of Ca^(2+).The mineralization precipitation was characterized and analyzed by Scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR)and X-ray diffraction(XRD).The results showed that adding a certain concentration of Ca^(2+)could promote the growth of bacteria,and the optimal concentration was 20 mmol·L^(-1).Moreover,the addition of Ca^(2+)could improve the minimal inhibitory concentration(MIC)and the urease activity of the isolate,and increase the mineralization rates of Cd^(2+)from 68.93%to 75.95%without and with the addition of Ca^(2+).Through the qualitative analysis of the mineral precipitation,it was found that the mineral precipitation without and with the addition of Ca^(2+)changed from a single CdCO_(3)precipitation to a composite precipitation of CdCO3 and CaCO_(3),and the surface also changed from a tight and compact state to a porous state filled with small particles of CdCO_(3).

关 键 词：生物矿化 MICP 土壤修复 重金属镉 

分 类 号：X172[环境科学与工程—环境科学] X53