Isotopic Evolution in Evaporation Process of Certain Volume Soil Water
Certain amount of oven-dried sand was doped with water having known isotopic composition. Using this method we prepared four groups soil water with different water contents. Evaporation process of certain volume soil water was simulated by the extraction in the vacuum pumping system. In the experiment, steam been evaporated from each sample was condensed and collected in four time segments and its hydrogen and oxygen isotopic compositions were determined. Based on the isotopic measured value of collected water and the law of mass conservation, isotopic evolution rules of steam and residual water were obtained in evaporation processes. In equilibrium evaporation process, the enrichment of hydrogen is about eight times of oxygens in the free water. Ian D.Clark had shown the steam and residual waters isotopic evolution rules in evaporation process of the limited volume free water. In the test, the steam isotope is corresponding depleted which is contrary to the water initial isotopic composition in soil water evaporation process. And the isotopic compositions of steam and residual water are all on the soil water evaporation line. In initial stage of evaporation process the steam losses heavy isotopes, but its isotopic composition changes toward the initial water with the increasing of the steam ratio. From comparison, it is obtained that the two isotopic evolution rules are similar in free water and soil water evaporation processes. For sand soil, van der waals force to water molecular has little influence to soil water evaporation under the equilibrium condition.
soil water evaporation hydrogen ozygen isotopes evolution rule free water vacuum pumping system
SUN Xiaoxu CHEN Jiansheng
School of Management, Hohai University, Jiangsu China, 210098
国际会议
2009 International Forum on Porous Flow and Applications(第十届全国渗流力学学术会议)
武汉
英文
930-934
2009-04-26（万方平台首次上网日期，不代表论文的发表时间）