摘要
利用微生物诱导碳酸盐沉淀修复重金属污染场地是一种具有较大潜力和应用前景的修复技术。然而,由于在生物矿化应用于西北地区污染场地时黄土中富含的碳酸盐、各种矿物以及周围环境酸碱度(pH值)对重金属赋存形态影响甚剧,其中的内在影响机制仍有待更进一步的探究。通过一维土柱试验考虑不同Cu(II)浓度(500、2000 mg/kg和4000 mg/kg)来制备污染黄土试件,后通过注入不同体积(50m L和100m L)的细菌胶结液对其进行修复,以Tessier顺序提取、土壤pH值测量和X射线衍射(X-ray diffraction,XRD)分析不同深度土样的修复效率。结果表明,注入细菌胶结液可将可交换态的Cu转变为生物毒性更低的赋存形态(比如碳酸盐结合态Cu),然而当Cu(II)浓度较低(500 mg/kg)时,未见类似的Cu赋存形态转变。因为土柱不同深度土样Cu赋存形态的转化与周围环境pH值紧密相关,且pH值与注入细菌胶结液的体积呈正比关系,碱性环境进一步促进了Cu和黄土中矿物的配位吸附,但是当碱性环境进一步提高时,修复效率因铜氨络合物的生成而显著降低。这些发现强调了将微生物诱导碳酸盐沉淀(microbially induced carbonate precipitation,MICP)技术应用于铜污染场地复原治理的潜力。
The remediation of heavy metal contaminated sites using microbially induced carbonate precipitation is a promising technology.However,the carbonate,various minerals,and pH of the topsoil-rich surrounding environment strongly influence the heavy metal fugacity pattern during biomineralization in contaminated sites in Northwest China.The intrinsic influencing mechanism requires further investigation.In present study,contaminated loess specimens underwent one-dimensional soil column experiments with varying Cu(II)concentrations(500 mg/kg,2000 mg/kg,and 4000 mg/kg).Subsequently,they were remediated by injecting different volumes(50 mL and 100 mL)of bacterial colloid.The remediation efficiency of soil samples at different depths was analyzed using Tessier sequential extraction,soil pH measurements,and X-ray diffraction(XRD).The results indicated that injecting bacterial cements converted exchangeable Cu into a less biotoxic form(e.g.,carbonate-bound Cu).However,no similar transformation of Cu was observed at lower Cu(II)levels(500 mg/kg).The transformation of Cu forms in soil samples at various depths of the soil column correlated strongly with the pH of the surrounding environment.The pH,in turn,was positively associated with the volume of the injected bacterial colloid.The alkaline environment further enhanced the coordination adsorption of Cu and minerals in the loess.Nevertheless,with further alkalization,the remediation efficiency decreased significantly due to the formation of Cu-ammonia complexes.These results underscore the potential of utilizing microbially induced carbonate precipitation(MICP)technology for remediating Cu-contaminated sites.
作者
谢毅鑫
郑文杰
薛中飞
王琳
XIE Yi-xin;CHENG Wen-chieh;XUE Zhong-fei;WANG Lin(School of Civil Engineering,Xi’an University of Architecture and Technology,Xi’an,Shaanxi 710055,China;Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering,Xi’an University of Architecture and Technology,Xi’an,Shaanxi 710055,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第S01期443-450,共8页
Rock and Soil Mechanics
基金
中共中组部“国家海外高层次人才引进计划”青年项目(2019)
关键词
生物矿化
铜污染黄土
细菌胶结液
配位吸附
铜氨络合物
biomineralization
copper-contaminated loess
bacterial cementation solution
coordination adsorption
copper-ammonia complex
作者简介
第一作者:谢毅鑫,男,1998年生,博士研究生,主要从事环境岩土工程方面的研究。E-mail:xieyixin@xauat.edu.cn;通讯作者:郑文杰,男,1980年生,博士,教授,主要从事特殊土力学与工程防灾方面的研究。E-mail:w-c.cheng@xauat.edu.cn
