Experimental Evidence for Hyperfiltration of Saline Water through Compacted Clay Aquitard in the Hebei Plain  

作　　者：Ying Wang Zongyu Chen Baoqian Duan Jingli Shao 

机构地区：[1]School of Water resources and Environment, China University of Geosciences [2]Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Sciences

出　　处：《Journal of Earth Science》2014年第6期1076-1082,共7页地球科学学刊（英文版）

基　　金：financially supported by the National Basic Research Program of China (No. 2010CB428803);the National Natural Science Foundation of China (Nos. 41272252, 41472225)

摘　　要：It becomes an increasing concern that groundwater quality in exploited deep confined aquifer may deteriorate due to brackish water leakage from its overlying saline aquifer in Hebei Plain. However, the monitoring data show that the TDS does not significantly change in the exploited aquifer. Some physics or chemistry processes must have taken place in aquitards during brackish leakage. The semi-permeable membrane function of clay aquitard during the process of hyperfiltration（reverse osmosis） should be one of the most important processes. To confirm and test this hyperfiltration mechanism, a series of experiments were performed in which Na Cl solutions were hydraulically forced through different clay sampled from aquitard. The solution 7 g/L in NaC l was forced through at 20 °C by a fluid pressure of 0.5 kN. The results show that hyperfiltration indeed happens in caly aquitard. Semi-permeability is quantified by the reflection coefficient σ. The mean rejection coefficients（σ） for clay samples #1, #2 and #3 were estimated to be 0.063, 0.164 and 0.040, respectively. This behavior of clay was well explained with the theory of the diffuse double layer. The hyperfiltration effect is to the great extent responsible for the chemical process in the aquitard.It becomes an increasing concern that groundwater quality in exploited deep confined aquifer may deteriorate due to brackish water leakage from its overlying saline aquifer in Hebei Plain. However, the monitoring data show that the TDS does not significantly change in the exploited aquifer. Some physics or chemistry processes must have taken place in aquitards during brackish leakage. The semi-permeable membrane function of clay aquitard during the process of hyperfiltration（reverse osmosis） should be one of the most important processes. To confirm and test this hyperfiltration mechanism, a series of experiments were performed in which Na Cl solutions were hydraulically forced through different clay sampled from aquitard. The solution 7 g/L in NaC l was forced through at 20 °C by a fluid pressure of 0.5 kN. The results show that hyperfiltration indeed happens in caly aquitard. Semi-permeability is quantified by the reflection coefficient σ. The mean rejection coefficients（σ） for clay samples #1, #2 and #3 were estimated to be 0.063, 0.164 and 0.040, respectively. This behavior of clay was well explained with the theory of the diffuse double layer. The hyperfiltration effect is to the great extent responsible for the chemical process in the aquitard.

关 键 词：clay membrane reverse osmosis HYPERFILTRATION AQUIFER SALT Hebei Plain 

分 类 号：P641[天文地球—地质矿产勘探]