微生物-石膏固化铅污染土胶结速率与污染物控制研究  

Cementation rate and pollutant control of lead-contaminated soil solidified by microorganisms and gypsum

作　　者：雍琪军 邵光辉[1,2] 戴浩然 黄容聘 狄志强 YONC Qjun;SHAO Cauanghui;DAI Haoran;HUANG Rongpin;DI Zhigiang(College of Civil Engineering,Nanjing Forestry University,Nanjing 210049,China;Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Nanjing Forestry University,Nanjing 210049,China;Jiangsu Chenghui Engineering Technology Co.,Ltd.,Nanjing 210037,China)

机构地区：[1]南京林业大学土木工程学院,江苏南京210049 [2]南京林业大学江苏省水土保持与生态修复重点实验室,江苏南京210049 [3]江苏诚晖工程技术有限公司,江苏南京210037

出　　处：《应用化工》2024年第6期1284-1289,共6页Applied Chemical Industry

基　　金：国家自然科学基金(51578293)。

摘　　要：通过微生物-石膏单次搅拌法处理铅污染粉土,以铅污染浓度、钙盐浓度、钙盐种类以及搅拌时长等作为控制参量,探究固化铅污染粉土的工程特性和污染物浸出特性的影响与控制规律。结果表明,以石膏作为钙盐,经微生物固化和稳定化处理后,铅污染粉土的无侧限抗压强度能够由不足40 kPa提高到120 kPa以上;在搅拌时长由30 min增加到120 min后,试样强度提高了30%;铅污染浓度为200 mg/kg的粉土的铅离子浸出值能控制在TCLP限值5 mg/L以下,铅元素的迁移水平显著下降。铅污染粉土中生成的碳酸钙形貌为无定形团聚体和玫瑰状方解石共生结晶体,附着少量碳酸铅结晶。采用石膏钙源能够有效延缓微生物固化铅污染粉土的胶结速率,可为实际工程的原位搅拌工艺应用提供时间条件,同时提升微生物矿化作用对污染土体的胶结效果。The microbial-gypsum single stirring method was used to treat lead-contaminated silt.Lead pollution concentration,calcium salt concentration,calcium salt type and stirring time were adopted as control parameters to investigate the engineering characteristics and pollutant leaching characteristics of solidified lead-contaminated silt.The results show that the unconfined compressive strength of lead-contaminated silt can be increased from less than 40 kPa to more than 120 kPa by using gypsum as calcium salt and being solidified and stabilized by microorganisms.When the stirring time increased from^(3)0 min to 120 min,the strength of the sample increased by 30%.After solidification and stabilization treatment,the lead ion leaching value of the 200 mg/kg lead contaminated soil can be controlled below the TCLP limit of 5 mg/L,and the migration level of lead elements is significant reduced.The morphology of calcium carbonate formed in lead-contaminated silt is amorphous aggregates,symbiotic crystals of rosette calcite,with a small amount of lead carbonate crystals attached.The use of gypsum calcium source can effectively delay the cementation rate of lead-contaminated silt,which could provide time conditions for the application of in-situ mixing technology in engineering applications.Meanwhile,the cementation effect of microbial mineralization on contaminated soil was improved.

关 键 词：铅污染粉土 石膏 搅拌时长 铅离子浸出值 污染物控制 

分 类 号：TQ09[化学工程] TU44[建筑科学—岩土工程]