温度梯度作用下非饱和黏土中热湿运移及重金属离子时空分布  

Heat and moisture transport and spatiotemporal distribution of heavy metal ions in unsaturated clay under temperature gradient

作　　者：贺勇[1,2] 李旺强 邹艳红 娄伟[3] 张召 张可能 HE Yong;LI Wangqiang;ZOU Yanhong;LOU Wei;ZHANG Zhao;ZHANG Keneng(Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring(Central South University),Ministry of Education,Changsha 410083,China;School of Geosciences and Info-Physics,Central South University,Changsha 410083,China;Hunan HIKEE Environmental Technology CO.,LTD.,Changsha 410221,China)

机构地区：[1]中南大学有色金属成矿预测与地质环境监测教育部重点实验室,长沙410083 [2]中南大学地球科学与信息物理学院,长沙410083 [3]湖南省和清环境科技有限公司,长沙410221

出　　处：《环境工程学报》2024年第8期2246-2254,共9页Chinese Journal of Environmental Engineering

基　　金：国家重点研发计划资助项目(2019YFC1805905);国家自然科学基金资助项目(42372333,42072318,41807253);中南大学创新驱动计划资助项目(2023CXQD044)。

摘　　要：以某重金属污染场地粉质黏土为研究对象,采用自主研制的一维非饱和土热-水-化耦合试验系统开展温度梯度作用下非饱和黏土中热湿运移及重金属离子迁移试验。试验结果表明:试样两端施加一定温度差后,土体中水分由高温侧向低温侧运移,土体内部水分场重新分布。土样的初始含水率对土体水分场分布的影响最为显著,当初始含水率为12%时,离子运移效果显著,土体高温侧含水率降低了79.3%,低温侧升高了40.5%。同时,随着土样两端温度梯度的增大或土样干密度的降低,水分运移效果越显著。在温度梯度作用下,非饱和黏土中重金属离子随液态水一同迁移,其中,高温端重金属离子浓度减少量为28.4%~54.7%,低温端浓度增加量为19.5%~37.6%。此外,重金属离子的迁移效果也与离子种类和离子初始浓度相关。Silty clay layer from a typical heavy metal contaminated site was selected,and a self-developed onedimensional unsaturated thermal-hydro-chemical coupled test system was employed to investigate heat and moisture transport and migration behaviors of heavy metal ions in unsaturated silty clay under a temperature gradient.Experimental results demonstrated that moisture inside the soil migrated from the high-temperature side to the low temperature one after an application of temperature gradient,leading to a redistribution of the moisture field.The water field distribution inside soil was significantly influenced by initial water content,and the migration of heavy metal ions was remarkable at the initial water content of 12%,accompanied with a 79.3% decrease of water content at the high-temperature side and a 40.5% decrease at the low-temperature side.Simultaneously,the transport of water became more and more obviously with the increases of the temperature gradient or the soil dry density.Heavy metal ions migrated together with liquid water under the action of temperature gradient,corresponding to a 28.4%~54.7% decrease in heavy metal concentration at the hightemperature side and a 19.5%~37.6%increase at the low-temperature side.Besides,the migration of heavy metals was also related to the ion type and the initial concentration.

关 键 词：非饱和黏土 重金属污染 温度梯度 重金属离子 热湿运移 

分 类 号：X53[环境科学与工程—环境工程]