离子特异性效应对紫色土孔隙状况的影响机制研究  

Study on the Mechanism of Ion Specificity Effect on the Pore Condition of Purple Soil

作　　者：宋孝帅 丁武泉[1] 刘新敏[3] 李廷真 SONG Xiaoshuai;DING Wuquan;LIU Xinmin;LI Tingzhen(Chongqing Key Laboratory of Environmental Materials&Remediation Technologies/School of Chemical and Environmental Engineering,Chongqing University of Arts and Sciences,Chongqing 402160,P.R.China;Chongqing Key Laboratory of Geological Environment Monitoring and Disaster Early-warning in Three Gorges Reservoir Area/School of Environmental and Chemical Engineering,Chongqing Three Gorges University,Chongqing 404100,P.R.China;School of Resources and Environment,Southwest University,Chongqing 400716,P.R.China)

机构地区：[1]重庆文理学院化学与环境工程学院/环境材料与修复技术重庆市重点实验室,重庆402160 [2]重庆三峡学院环境与化学工程学院/三峡库区地质环境监测与灾害预警重庆市重点实验室,重庆404100 [3]西南大学资源环境学院,重庆400716

出　　处：《生态环境学报》2023年第2期292-298,共7页Ecology and Environmental Sciences

基　　金：重庆市自然科学基金项目(CSTB2022NSCQ-MSX1670,cstc2018jcyjAX0354);重庆市教委科学技术研究重点项目(KJZD-K201901305);三峡库区地质环境监测与灾害预警重庆市重点实验室开放基金项目(MP2020B0601)。

摘　　要：土壤孔隙对土壤水分和养分迁移及水土保持有着关键作用,不同离子条件下土壤颗粒相互作用控制着土壤团聚体稳定性,而土壤团聚体形成和结构对土壤孔隙状况起重要影响。紫色土是三峡库区代表性土壤之一,探究离子特异性效应下颗粒的相互作用对紫色土孔隙状况的影响,对三峡库区水土生态环境安全具有重要意义。采用工业CT扫描技术和联合测定法分别对不同类型离子条件下的土壤孔隙状况和颗粒表面电荷性质进行测定,并分析其形成土壤孔隙特征差异原因。结果表明,(1)当浓度为0.01 mol·L^(−1)时,Cs^(+)体系下土壤孔隙的数量分别是Li^(+)、Na^(+)和K^(+)体系下的2.90、2.23和1.44倍,其中,Li^(+)、Na^(+)、K^(+)和Cs^(+)体系下>1 mm孔隙数量分别占0.33%、1.06%、1.57%和1.88%;同时,Cs^(+)体系下土壤最大孔隙的直径分别是Li^(+)、Na^(+)、K^(+)体系下的1.97、1.81、1.30倍。(2)当浓度为0.01 mol·L^(−1)时,Li^(+)、Na^(+)、K^(+)、Cs^(+)体系土体中>1 mm土壤孔隙体积占所有孔隙比例分别为22.7%、40.1%、56.5%、59.9%,并且,Cs^(+)体系下土体中>1 mm土壤孔隙体积分别为Li^(+)、Na^(+)、K^(+)体系的13.70、5.22、2.70倍;同时,土壤孔隙度在Li^(+)、Na^(+)、K^(+)、Cs^(+)体系下分别为1.36%、2.06%、2.84%、7.22%。(3)在测定孔隙相同离子浓度条件下,Li^(+)、Na^(+)、K^(+)、Cs^(+)体系中紫色土颗粒表面电位分别为−210.34、−198.63、−186.29、−175.57 mV,绝对值表现为Li^(+)>Na^(+)>K^(+)>Cs^(+),进一步计算发现,在相同颗粒间距离3 nm时,Li^(+)、Na^(+)、K^(+)、Cs^(+)体系下颗粒间净作用力分别为4.68、3.90、2.32、−0.15 atm,同样表现为Li^(+)>Na^(+)>K^(+)>Cs^(+)。该研究表明Li^(+)、Na^(+)、K^(+)、Cs^(+)通过改变紫色土表面电荷性质,进而引起土壤颗粒间相互作用力发生变化,最终影响土壤的孔隙状况。Soil pore space plays a key role in soil water and nutrient migration and soil conservation.The interaction of soil particle under different ionic conditions controls the stability of soil aggregate,while the formation and structure of soil aggregate play an important role in soil pore conditions.Purple soil is one of the representative soils in the Three Gorges Reservoir area,and it is important to investigate the influence of particle interactions under ion-specific effects on the pore condition of purple soil for the ecological and environmental security of soil and water in the Three Gorges Reservoir area.Therefore,in this study,industrial CT scanning technique and combined measurement method were used to determine soil pore conditions and particle surface charge properties under different types of ionic conditions,and to analyze the reasons for their differences in forming soil pore characteristics.The results showed that(1)the number of soil pores in the Cs^(+)system was 2.90,2.23 and 1.44 times higher than that in the Li^(+),Na^(+)and K^(+)systems at the concentration of 0.01 mol·L^(−1),respectively,where the number of>1 mm pores accounted for 0.33%,1.06%,1.57%and 1.88%in the Li^(+),Na^(+),K^(+)and Cs^(+)systems,respectively.Meanwhile,the maximum pore diameter of the soil in Cs^(+)system was 1.97,1.81 and 1.30 times higher than that in Li^(+),Na^(+)and K^(+)systems,respectively.(2)When the concentration was 0.01 mol·L^(−1),the proportion of soil pore volume>1 mm in the soil of Li^(+),Na^(+),K^(+),Cs^(+)system to all pores was 22.7%,40.1%,56.5%,59.9%,respectively.Moreover,the pore volume of soil>1 mm in the Cs^(+)system was 13.70,5.22,and 2.70 times higher than that in the Li^(+),Na^(+),and K^(+)systems,respectively;meanwhile,the soil porosity was 1.36%,2.06%,2.84%,and 7.22%in the Li^(+),Na^(+),and K^(+),and Cs^(+)systems,respectively.(3)Under the same ion concentration conditions of the measured pores,the surface potentials of purple soil particles in Li^(+),Na^(+),K^(+),Cs^(+)systems were−210.34,�

关 键 词：土壤孔隙 相互作用力 CT扫描 离子特异性效应 联合测定法 紫色土 

分 类 号：S153[农业科学—土壤学] X144[农业科学—农业基础科学]