基于MICP法的巴氏生孢八叠球菌固化镉污染土的试验研究  

Experimental study on solidification of cadmium-contaminated soil by Sporosarcina pasteurii via MICP method

作　　者：王艳[1] 张李奕岚 唐晓武[2] 朱鹏[1] 陈冠年 阮方毅 WANG Yan;ZHANG Liyilan;TANG Xiaowu;ZHU Peng;CHEN Guannian;RUAN Fangyi(School of Civil Engineering and Geographical Environment,Ningbo University,Ningbo 315211,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]宁波大学土木工程与地理环境学院,宁波315211 [2]浙江大学建筑工程学院,杭州310058

出　　处：《工程科学学报》2025年第1期158-169,共12页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(42107174)。

摘　　要：以重金属污染土的治理为背景,通过毒性浸出、无侧限抗压强度、土柱淋滤试验并结合镉形态分析等其他微观测试方法,探讨了Ca^(2+)的添加、Cd^(2+)浓度、养护时间等因素对驯化巴氏生孢八叠球菌固化镉污染土特性的影响.结果表明:Ca^(2+)对固化土中Cd^(2+)浸出特性影响显著,不添加Ca^(2+)时,当尿素浓度为0.5 mol·L^(-1),固化土的Cd^(2+)浸出质量浓度(0.42~5.64 mg·L^(-1))最低;添加Ca^(2+)后,Cd^(2+)浸出浓度略有增大,胶结液中尿素和Ca^(2+)浓度均为0.5 mol·L^(-1)时,Cd^(2+)的固化效果较好.延长养护时间,固化后土体的抗压强度增加,Cd^(2+)浸出浓度降低且固化效果提高;增大Cd^(2+)浓度,固化后土体的抗压强度降低,Cd^(2+)浸出浓度提高;添加Ca^(2+)有助于增强镉污染土的固化效果,在养护时间为28 d时,当Cd^(2+)浓度为100 mg·kg^(-1)时,添加Ca^(2+)的试样强度达到312 kPa,相较于未添加Ca^(2+)试样强度(234 kPa)提升了33.3%;当Cd^(2+)浓度增大至1600 mg·kg^(-1)时,添加Ca^(2+)的试样强度达到269 kPa,相较于未添加Ca^(2+)试样强度提升了57.3%,试样的浸出浓度降低了15.4%;经淋滤后,添加Ca^(2+)的试样滤出液中Cd^(2+)浓度始终低于未添加Ca^(2+)试样.固化后土中弱酸可提取态镉向可还原态镉和残渣态镉转变,添加Ca^(2+)进一步降低弱酸可提取态镉所占比例,减小了Cd^(2+)的迁移能力.The immobilization of heavy metals using microbes presents an environmentally friendly approach,utilizing local indigenous microbes for remediating heavy metal-contaminated soils and improving soil environmental quality.Microbially induced carbonate precipitation(MICP),particularly through urea hydrolysis,is a typical biomineralization process in nature that has gained considerable attention.Sporosarcina pasteurii,a popular indigenous urease-producing bacterium,is especially effective in hydrolyzing urea.This study examines the effects of calcium ion(Ca^(2+))addition,cadmium ion(Cd^(2+))concentration,and curing time on the characteristics of cadmium-contaminated soil solidified by acclimatized Sporosarcina pasteurii.Various tests,including toxicity leaching,unconfined compressive strength,soil column leaching,cadmium speciation analysis,and microanalysis,were conducted to evaluate these effects.The results indicate that Ca^(2+)significantly affects the leaching behavior of Cd^(2+)in the contaminated soil after solidification.Without Ca^(2+),the lowest Cd^(2+)leaching concentration(0.42-5.64 mg·L^(-1))was observed at a urea concentration of 0.5 mol·L^(-1).When Ca^(2+)was added,the Cd^(2+)leaching concentration slightly increased,but optimal solidification efficiency was achieved when urea and Ca^(2+)concentrations were 0.5 mol·L^(-1).As curing time increased,the compressive strength of the solidified soil also improved,while Cd^(2+)leaching concentration decreased.The presence of Ca^(2+)further enhanced soil solidification over time.Higher Cd^(2+)concentrations led to reduced compressive strength and increased leaching concentration.However,the addition of Ca^(2+)enhanced the solidification effect on cadmium-contaminated soil.At a curing time of 28 d,for a Cd^(2+)concentration of 100 mg·kg^(-1),the unconfined compressive strength of samples with Ca^(2+)reached 312 kPa,a 33.3% increase compared to 234 kPa without Ca^(2+).For a Cd^(2+)concentration of 1600 mg·kg^(-1),the unconfined compressive strength with Ca^

关 键 词：微生物诱导碳酸盐沉淀 镉 污染土 巴氏生孢八叠球菌 固化 

分 类 号：X53[环境科学与工程—环境工程]