Xi’an Research Institute of China Coal Technology & Engineering Group Corp,; Shaanxi Key Laboratory of Coalmine Water Hazard Control; School of Environmental & Municipal Engineering,Xi’an University of Architecture and Technology; Shaanxi Key Laboratory of Geotechnical and Underground Space Engineering

Loess region is an important coal producing region in China.The paleosol are widely developed in vadose zone in the loess areas.A large amount of coal gangue will be produced in the process of coal mining and washing,among which the coal gangue stacked in the open dump will release a large number of pollutants under the long term leaching effect,causing pollution to the underground water around the mining area.The leachate produced in coal gaugue dump will flow through the paleosol before it arrives to aquifer.Thus,in order to understand the accurate environmental effect of the coal gaugue leachate on the aquifer,the antifouling property of the paleosol needs to be assessed.Hydraulic conductivity tests and batch adsorption tests were conducted to evaluate the antifouling property of paleosol for Mn2+，Zn2+，Cu2+ and SO2-4 in coal gaugue leachate.The results of hydraulic conductivity tests show that the hydraulic conductivity of paleosol ranges between 0.852×10-9 and 1.01×10-9 m/s,which is lower than the values obtained using distilled water as permeation solution.The decreases in the hydraulic conductivity should be attributed to pore plugging resulting from the production of precipitates.The batch adsorption test demonstrate that paleosol can adsorb Mn2+，Zn2+and Cu2+ and the adsorption processes are well described by Freundlich model.The adsorption of heavy metals on the paleosol is mainly through ion exchange reaction.The adsorption capacity of paleosol for SO2-4 is so small that can be ignored.This may be attributed to the negative surface of the paleosol,which produces a repulsion between the paleosol surface and the SO2-4 ions.POLLUTE V7 was used to simulate and predict the time of typical pollutants in coal gangue leachate to penetrate the paleosol.The model results show that the paleosol with 1.0 m thickness can protect aquifer for 10 years from polluting.In general,the paleosol used in the present study is an effective barrier to limit the flow of coal gaugue leachate.Therefore,the potential effect of the paleosol layer should be considered when conducting the groundwater environmental impact assessment and pollution control of coal gangue dump in the loess area.

国家自然科学基金资助项目(41907264，42007179);天地科技股份有限公司科技创新创业资金专项资助项目(2018-TD-MS073)

董兴玲，董书宁，王皓，等.古土壤层对煤矸石淋滤液中典型污染物的防污性能[J].煤炭学报,2021,46(6):1957-1965.
DONG Xingling,DONG Shuning,WANG Hao,et al.Antifouling property of the paleosol layer to the contaminants in the coal gaugue leachate[J].Journal of China Coal Society,2021,46(6):1957-1965.