摘要
文章利用FeS纳米颗粒对人工配制的高、中、低3种水平的镉铅铬复合污染土壤进行修复,并对氧气和FeS纳米颗粒投加量等关键因素对土壤修复过程的影响进行了探究。结果表明:氧气对稳定化过程影响不大;对于低浓度污染土壤,土壤中Cr(Ⅵ)含量和浸出液中Cd、Pb、Cr(Ⅵ)、总Cr浓度一般可达标,可不进行处理;对于中浓度污染土壤,当FeS与(Cd+Pb+Cr(Ⅵ))的摩尔比为2∶1时,可将土壤中Cr(Ⅵ)含量可降低至标准值以下,但浸出液中的Pb无法得到较好的稳定化,按PO_(4)^(3-)与Pb的摩尔比为8∶1复合投加磷酸盐后,浸出液中Cd、Pb、Cr(Ⅵ)、总Cr浓度均可降至标准值以下;对于高浓度污染土壤,当FeS与(Cd+Pb+Cr(Ⅵ))的摩尔比在2∶1及以下时,FeS对土壤中的Cr(Ⅵ)的还原效果存在波动,达标存在难度,与磷酸盐复合投加可有效稳定高浓度污染土壤浸出液中的Cd、Pb、Cr(Ⅵ)和总Cr。经FeS NPs和磷酸盐稳定化处理后,土壤中生成了Pb_(3)(PO4)_(2)、CdS、PbS、Cr(OH)_(3)、[Cr,Fe](OH)_(3)和Fe_(3)(PO4)_(2)等沉淀物,3种重金属形态由可交换态等形态向稳定性较高的残渣态转化,释放迁移到环境的可能性减小,对环境的风险降低。修复后的土壤pH呈弱碱性,利于土壤中Cr(Ⅲ)、Cd和Pb的长期稳定;有机质含量和阳离子交换容量升高;氧化还原电位降低,体系保持还原环境,可有效防止Cr(Ⅵ)的再次氧化。
FeS nanoparticles were used to remediate artificially prepared high,medium and low levels of Cd-Pb-Cr(Ⅵ)contaminated soil,and the effects of key factors such as oxygen and FeS nanoparticles dosage on soil remediation process were investigated.The results showed that oxygen had little effect on the stabilization process.For low concentration con⁃taminated soil,without being treated,the content of Cr(Ⅵ)in soil and the concentrations of Cd,Pb,Cr(Ⅵ)and total Cr in the leachate could generally meet the standard;for medium concentration contaminated soil,when the molar ratio of FeS to(Cd+Pb+Cr(Ⅵ))was 2∶1,Cr(Ⅵ)in soil could reach the standard while the leaching Pb could not be effectively stabilized.After adding phosphate at PO_(4)^(3-)∶Pb=8∶1,the concentration of Cd,Pb,Cr(Ⅵ)and total Cr in the leachate can be reduced to below the standard value;for high concentration contaminated soil,when the molar ratio of FeS to(Cd+Pb+Cr(Ⅵ))was 2∶1 or less than 2:1,the reduction effect of FeS to Cr(Ⅵ)in soil fluctuated and the Cr(Ⅵ)in soil was difficult to reach the standard,while compound addition of FeS and phosphate could effectively stabilize the Cd,Pb,Cr(Ⅵ)and total Cr in the leachate.As for the soil treated by FeS NPs and phosphate,the sediments of Pb_(3)(PO_(4))_(2),CdS,PbS,Cr(OH)_(3),[Cr,Fe](OH)_(3) and Fe_(3)(PO_(4))_(2) were formed in the soil,and three heavy metals’chemical forms changed from exchangeable form to residue form with high stability,the possibility of releasing and migrating to the environment is reduced,and the same to the risk to the environment.The soil pH was weak alkaline,which was beneficial to the long-term stability of Cr(Ⅲ),Cd and Pb in soil;the content of organic matter and cation exchange capacity of soil increased;the redox potential of soil decreased,to maintain the redox environment,which could effectively prevent the reoxidation of Cr(Ⅵ).
作者
王婉玉
彭聃
佘健
刘元元
瞿宏璟
WANG Wanyu;PENG Dan;SHE Jian;LIU Yuanyuan;QU Hongjing(Central-Southern Safety&Environment Technology Institute Co.,Ltd.,Wuhan 430071,China;Key Laboratory of the Three Gorges Reservoir Region’s Eco-environment of Ministry of Education,Chongqing University,Chongqing 400044,China)
出处
《环境科学与技术》
CAS
CSCD
北大核心
2021年第9期144-153,共10页
Environmental Science & Technology
基金
中南工程咨询设计集团有限公司科研项目:FeS纳米颗粒修复镉-铅-铬重金属污染土壤的应用技术研究。
关键词
镉铅铬
FeS纳米颗粒
磷酸盐
土壤修复
复合污染
Cd-Pb-Cr(Ⅵ)
FeS nanoparticles
phosphate
soil stabilization
multiple contamination
作者简介
王婉玉(1991-),女,工程师,硕士,主要从事土壤及地下水污染状况调查及修复,(电子信箱)312061807@qq.com;通讯作者:彭聃,高级工程师,(电子信箱)78876355@qq.com。
