地表水-地下水相互作用下NH4-N的吸附/解吸行为及其对N迁移转化的影响  

Adsorption/Desorption Behavior of NH4-N under Surface Water-Groundwater Interaction and Its Impact on N Migration and Transformation

作　　者：张安广 梁莹 马瑞[1] Zhang Anguang;Liang Ying;Ma Rui(School of Environmental Studies,China University of Geosciences,Wuhan 430078,China)

机构地区：[1]中国地质大学环境学院,湖北武汉430078

出　　处：《地球科学》2024年第10期3761-3772,共12页Earth Science

基　　金：国家自然科学基金项目(No.42425207)。

摘　　要：铵吸附/解吸是控制氮转化的重要反应之一,但其在地表水-地下水相互作用影响下对氮迁移转化的影响机制尚不清晰.以江汉平原东部沙湖监测场为研究区,通过分析地下水位及其水化学指标长期监测数据,结合室内土柱实验和反应迁移数值模型解译,识别了地表水补给和地下水排泄两种模式下NH_(4)-N的迁移转化过程,探究了水动力驱动下N的迁移转化机制.研究表明,农业活动带来的高浓度NH_(4)-N会被表层沉积物颗粒吸附;地表水入渗会促进沉积物中NH_(4)-N的解吸附及后续的硝化作用,引起地下水中NO_(3)-N浓度上升;含NH_(4)-N的地下水排泄过程会促进沉积物对NH_(4)-N的吸附,使沉积物中NH_(4)-N吸附量升高.阳离子交换是影响NH_(4)-N迁移转化的关键机制,地表水-地下水相互作用引起的水文地球化学环境变化影响了NH_(4)-N的吸附/解吸及后续生物地球化学反应.The migration and transformation of NH_(4)-N are influenced by the interactions between surface water and groundwater.However,the mechanisms remain poorly understood.Continuous monitoring of the water level and its hydrochemical composition was conducted in the Shahu site.Column experiments and reactive transport modeling were applied to identify the migration and transformation of NH_(4)-N under conditions of both surface water recharge and groundwater discharge.In this study it indicates that most injected NH_(4)-N is adsorbed on shallow sediment.Infiltration of surface water enhances desorption of NH_(4)-N from sediment particle and subsequent nitrification reactions.In contrast,adsorption of NH_(4)-N on sediment is favored during discharge of NH_(4)-N containing groundwater.Simulating results emphasize the crucial role of cation exchange in NH_(4)-N mobility.Alterations in the hydrogeochemical environment during surface water-groundwater interactions impact the NH_(4)-N adsorption/desorption behaviors and associated biogeochemical reactions.

关 键 词：铵态氮 离子交换 反应迁移模型 地表水 地下水 江汉平原 水文地质学 

分 类 号：P641.3[天文地球—地质矿产勘探]