3种固定剂联合修复铀尾矿污染土壤  

Remediation of uranium contaminated soil with three combinated stabilizers

作　　者：周书葵 田林玉 荣丽杉 刘迎九 肖江 李嘉丽 ZHOU Shukui;TIAN Linyu;RONG Lishan;LIU Yingjiu;XIAO Jiang;LI Jiali(School of Civil Engineering,University of South China,Hengyang 421001,Hunan,China)

机构地区：[1]南华大学土木工程学院,湖南衡阳421001

出　　处：《精细化工》2020年第10期2105-2111,共7页Fine Chemicals

基　　金：国家自然科学基金资助项目(51174117);湖南省教育厅科研平台项目(15K106);湖南省创新平台开放基金资助项目(17K078)。

摘　　要：采用纳米沸石、磷酸二氢钾、改性生物炭联合对铀尾矿库中的核素铀进行化学固定,并利用毒性浸出实验(TCLP)和Tessier逐级化学提取法,研究了固定前后铀的浸出特性与形态变化。TCLP结果表明,添加不同固定剂培养30d后,与对照组相比,土壤中铀的浸出量减少了42.13%~71.54%,且土壤pH与TCLP提取态铀含量存在显著的负相关关系。Tessier结果显示,施用不同固定剂后,土壤中可交换态和碳酸盐结合态铀质量分数分别降低7.38%~26.06%、1.43%~6.99%,而有机质结合态、铁锰氧化物结合态、残渣态铀比例分别增加2.56%~3.64%、2.71%~17.47%、4.07%~11.12%。在单一固定材料实验中,纳米沸石添加量为6%(以土壤质量计,下同)时稳定效果最佳,土壤可交换态铀比例降低15.68%。在复配材料固定实验中,以3种固定剂按质量比1∶1∶1,总添加量为6%时修复效果最好,土壤可交换态铀比例降低26.06%。由此可见,3种固定剂联合施用能有效降低土壤中铀的活性,为其他放射性污染土壤修复提供理论参考。The nuclide uranium in uranium tailings pond was chemically fixed by nanozeolite,potassium dihydrogen phosphate and modified biochar.And the leaching characteristics and morphological changes of uranium in soil before and after modification treatment were determined by toxicity characteristic leaching procedure(TCLP)and Tessier stepwise chemical extraction.TCLP results showed that after 30 days of solidification with different stabilizers,the amount of uranium leaching from soil decreased by 42.13%~71.54%compared with that of the control group.Moreover,there was a significant negative correlation between soil p H and TCLP-extracted uranium content.Tessier results showed that the mass fraction of exchangeable and carbonate-bound uranium in soil decreased by 7.38%~26.06%,1.43%~6.99%with different fixatives,while the organic-bound,Fe-Mn oxide-bound and residual uranium increased by 2.56%~3.64%,2.71%~17.47%,4.07%~11.12%respectively.In a single fixed material experiment,nano-zeolite with 6%(based on the mass of soil,the same below)exhibited the best stability effect on the soil,the proportion of exchangeable uranium in soil decreased by 15.68%.In the compound materials experiment,the best repair effect was obtained by adding three stabilizers with a mass ratio of 1∶1∶1 and a total dosage of 6%,the proportion of exchangeable uranium in soil decreased by 26.06%.Therefore,the combined application of three stabilizers can effectively reduce the activity of uranium in soil,which provides theoretical reference for the remediation of other radioactive contaminated soils.

关 键 词：纳米沸石 磷酸二氢钾 改性生物炭 铀尾矿库 化学固定 环境保护 

分 类 号：X53[环境科学与工程—环境工程]