Role of urea in the retention of DON in soil by clay minerals:Analysis based upon molecular weight  

作　　者：Leyun Wang Miao Li Xiang Liu 

机构地区：[1]School of Environment,Tsinghua University,Beijing 100084,China

出　　处：《Journal of Environmental Sciences》2025年第4期362-372,共11页环境科学学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(No.42107052);Beijing Natural Science Foundation(No.JQ21031).

摘　　要：As a widely used fertilizer,urea significantly promotes the leaching of dissolved organic nitrogen(DON)in soils and aggravates nitrogen contamination in groundwater.Clayminerals are considered the most important factor in retaining DON.However,the effect of urea on the retention of DON with different molecular weights by clay minerals is unknown.In this study,the retention of both low-molecular weight DON(LMWD)and high-molecular weight DON(HMWD)by clay minerals in the presence of urea was investigated.For this purpose,batch adsorption and soil column leaching experiments,characterization analysis(Fourier transform infrared spectroscopy X-ray diffraction,and X-ray photoelectron spectroscopy),and molecular dynamics simulations were carried out.Urea had a positive effect on the adsorption of LMWD,whereas a competitive effect existed for the adsorption of HMWD.The dominant interactions among DON,urea,and clay minerals included H-bonding,ligand exchange,and cation exchange.The urea was preferentially adsorbed on clay minerals and formed a complex,which provided more adsorption sites to LMWD and only a few to HMWD.The presence of urea increased the retention of LMWD and decreased the retention of HMWD in clay minerals.The retention capacity of LMWD increased by 6.9%–12.8%,while that of HMWD decreased by 6.7%–53.1%.These findings suggest that LMWD tended to be trapped in soils,while HMWD was prone to be leached into groundwater,which can be used to evaluate the leaching of DON from soil to groundwater.

关 键 词：UREA Dissolved organic nitrogen Clay mineral Molecular dynamics RETENTION 

分 类 号：X505[环境科学与工程—环境工程]