摘要
为定量分析施加外源硅治理土壤镉污染过程中硅对含镉土壤水分运动的影响并揭示其机理,本研究设置三个镉添加水平(0,2.5,5 mg/kg),三个硅添加水平(0,200,400 kg/hm^(2))共九组处理,通过压力膜仪分别测量各处理土壤的水分特征曲线并对土样进行pH值、zeta电位及扫描电镜分析,选取Brooks-Core(BC)模型、van Genuchten(VG)模型及Dual-Porosity(DP)模型对结果进行拟合。结果表明:①与对照组相比,镉添加对土壤水分特征曲线没有影响,单独施硅以及含镉土壤施硅会使曲线偏移,分别导致整体土壤含水率增加以及710~1200 kPa高吸力段的土壤含水率下降;②相比于对照组,镉添加对土壤孔隙分布没有影响,施硅能够增加含镉土壤与不含镉土壤大当量孔径孔隙占比,提高土壤低吸力段持水能力,同时施硅对小当量孔径孔隙没有影响;③施硅能够显著增加土壤zeta电位绝对值,分散土壤胶体颗粒,不利于土壤微团粒的形成,但施硅后形成的硅酸凝胶可促进微团粒的胶结从而增加土壤大孔隙占比,提高低吸力范围内的土壤持水性;含镉土壤施硅后形成的硅-镉配合物可能导致范德华力减弱,从而降低了高吸力范围内的土壤持水性;④相比于BC模型与DP模型,VG模型能更好地描述硅、镉对土壤水分特征曲线的影响,且施硅对含镉土壤水分特征曲线的影响可通过影响水分特征曲线的饱和含水率和残余含水率进行定量表达。
Exogenous silicon is widely applied to soils to alleviate the soil cadmium contamination.The effect of silicon on the translocation and transformation of cadmium in plants and soils has been thoroughly studied,but the influence of silicon on soil water movement has rarely been reported.Hence,an experiment is conducted to investigate the influence and mechanism of silicon(0,200,400 kg/hm^(2)),cadmium(0,2.5 and 5 mg/kg)and their reactions on the soil water characteristic curve(SWCC).The group of soil with no addition of silicon and cad⁃mium(0 kg/hm2,0 mg/kg)is denoted as CK for comparison.The SWCCs of soils are measured by pressure plate extractor,and pH,zeta po⁃tential.Field Emission Scanning Electron Microscopy(FESEM)are performed for the soil samples.After that,three models including Brooks-Core(BC)model,Van Genuchten(VG)model,and Dual-porosity(DP)model are used to fit the experiment data.The results show that①in comparison with the CK,cadmium has no influence on the SWCCs,the right-skewed SWCCs of soils with silicon application indicate that more water is held in soils,whereas the left-skewed SWCCs of cadmium-contaminated soils with silicon application indicate a reduction in the water holding capacity of soils within the suction range of 710~1200 kPa.②Compared to CK,cadmium has no influence on the soil pore distribution.Silicon application in both no cadmium-contaminated and cadmium-contaminated soils increase the proportion of soil macropores(equivalent pore size of 0.00214~0.00250 mm),whereas there is no influence on the small pores(equivalent pore size of 0.00049~0.00214 mm).③The images of FESEM illustrate that there is no difference between the CK and the cadmium-contaminated soils,whereas the soil particles are more clustered after silicon application in comparison with CK.④Silicon application can significantly in⁃crease the pH value and the absolute value of soil zeta potential.The high absolute value of soil zeta potential is of benefit to disperse the soil colloidal particles,which goes a
作者
汪跃
高晶晶
谭霄
谭博
李龙国
刘超
WANG Yue;GAO Jing-jing;TAN Xiao;TAN Bo;LI Long-guo;LIU Chao(Sichuan Provincial Water Resources Department,Chengdu 610017,Sichuan Province,China;State Key Laboratory of Hydraulics and Mountain River Engineering,Chengdu 610065,Sichuan Province,China;College of Water Resources and Hydropower,Sichuan University,Chengdu 610065,Sichuan Province,China)
出处
《中国农村水利水电》
北大核心
2023年第9期103-109,共7页
China Rural Water and Hydropower
基金
四川省科技厅重点研发项目(2019YFN0153)
国家自然科学基金(51909175)。
关键词
水分特征曲线
镉
外源硅
ZETA电位
PH值
water characteristic curve
cadmium
exogenous silicon
zeta potential
pH value
