纳米碳对黄绵土水分运动及溶质迁移特征的影响

Effects of Nano-carbon on Water Movement and Solute Transport in Loessial Soil

以黄绵土为研究对象,均匀添加不同含量纳米碳(质量含量分别为0,0.001,0.005,0.01,0.05g/g),采用室内土柱试验分别测定土壤累积入渗量曲线、溶质穿透曲线及水分特征曲线,初步研究了纳米碳含量对黄绵土水分运动及溶质迁移过程的影响。结果表明:(1)纳米碳的存在对土壤水分入渗过程产生阻碍作用,入渗率随着纳米碳含量增加而减小,Philip方程能较好地描述添加纳米碳的黄绵土入渗过程;(2)纳米碳可以提高土壤的持水能力,随着纳米碳含量增加,土壤饱和含水量增加,相同土壤水吸力下的土壤含水量增大,van Genuchten模型可较好拟合含有纳米碳的黄绵土水分特征曲线,进气吸力随纳米碳含量增加而减小,形状参数(n)随之减小;(3)纳米碳可以有效提高土壤吸持溶质能力,随纳米碳含量增加,初始穿透时间提前,完全穿透时间延长,弥散度增大;土柱被置换液完全穿透后,土样中Cl-平均含量随纳米碳含量增加而变大。

Improvement of the water and nutrient retention of in a Loessial soil is very important for soil water and fertilizer efficient utilization.Based on a disturbed one-dimensional soil column experiment,different nano carbon contents（0,0.001,0.005,0.01,0.05g/g in gravity）,were evenly mixed well with the Loessial soil,in order to determine the effect of nano carbon contents on soil cumulative infiltration capacity curve,solute breakthrough curve as well as the moisture characteristic curve.The main results showed as follows：（1）Nano carbon inhibited soil water infiltration process,the infiltration rate was reduced with the increase of nano carbon contents,Philip equation could describe the water infiltration process well of Loessial soil that mixed with different nano carbon contents.（2）Nano carbon could improve the water capacity,and with the increases of nano carbon contents,the soil saturated water content increased,meanwhile,the soil water content under the same soil water suction increased;van Genuchten model also could fit with the moisture characteristic curve of Loessial soil with different nano carbon contents,and the inlet suction decreased with the increase of nano carbon content,but the shape parameter（n）decreased.（3）Nano carbon could effectively improve the capacity of soil retention of solution.With the increase of nano carbon contents,both the the initial transport time and fully transport time were prolonged,dispersivity increased accordingly.After solute transport experiment,the concentration of Cl-in the soil samples were measured and the results showed an increasing Cl^-concentration with the increase of nano carbon contents.