摘要
为明确垃圾渗滤液对冻融黏土热物理性质的影响规律,开展了不同温度、不同污染物质种类及浓度影响下粉质黏土的热物理性质测定,并分析了其影响机理。结果表明:对单一土壤而言,正温条件下有机污染物(COD_(cr))与镉(Cd)单一污染土壤导热系数与污染物浓度成正比,氨氮单一污染土壤的导热系数与其浓度成反比;负温条件下COD_(cr)与Cd单一污染土壤导热系数与污染物浓度成反比,氨氮在负温下析出的溶质固体会使土壤的导热系数随其浓度的增大而增大。对复合污染土壤而言,其导热系数均与COD_(cr)或氨氮的浓度成反比。在COD_(cr)浓度相同的条件下,正温时复合污染土壤的导热系数随Cd浓度的增加而减小,负温时由于有机污染物与Cd结合形成结晶盐导致其导热系数与浓度成正比。而氨氮与Cd复合污染土壤的导热系数在氨氮浓度相同的条件下在正温时与Cd浓度呈正比,负温时则与Cd浓度呈反比。此外,不论是单一污染土壤还是复合污染土壤,其容积热容量均小于未污染土,同时随污染物质浓度的增加而略有增加,并与温度成正比。在复合污染土壤中COD_(cr)和氨氮浓度的变化是影响土壤容积热容量的主导因素。该研究结果为定量研究、评价和预测垃圾渗滤液中主要污染物在冻土中的扩散、迁移等提供了科学依据。
To elucidate the regulatory influence of leachate on the thermal-physical properties of frozen-thawed clay,this research conducts thermal-physical property measurements on silty clay under different temperatures,types,and concentrations of pollutants,and analyzes their underlying mechanisms.The research findings indicate the following:for a single soil type,under positive temperature conditions,the thermal conductivity of soils contaminated with or-ganic pollutants(COD.r)and cadmium(Cd)increases proportionally with pollutant concentration,while for soils contaminated with ammonia nitrogen,the thermal conductivity decreases inversely with its concentration.Under neg-ative temperature conditions,the thermal conductivity of soils contaminated with CODer and Cd decreases inversely with pollutant concentration,whereas the presence of solid solutes precipitated by ammonia nitrogen at negative tem-peratures increases the soils thermal conductivity with increasing concentration.Regarding composite polluted soils,their thermal conductivities are inversely proportional to the concentrations of CODer or ammonia nitrogen.Under conditions of equal CODer concentration,the thermal conductivity of composite polluted soils decreases with increas-ing Cd concentration under positive temperatures,whereas under negative temperatures,the formation of crystalline salts due to the combination of organic pollutants and Cd results in a direct proportionality between thermal conduc-tivity and concentration.Meanwhile,the thermal conductivity of composite polluted soils containing both ammonia ni-trogen and Cd is directly proportional to the Cd concentration under positive temperatures when the ammonia nitro-gen concentration is constant,and inversely proportional under negative temperatures.Additionally,both single pollu-ted soils and composite polluted soils exhibit lower volumetric heat capacities than unpolluted soils,with a slight in-crease as pollutant concentration rises,directly proportional to temperature.In composite polluted soils,variations in CODer and ammonia nitrogen concentrations are identified as the predominant factors affecting soil volumetric heat capacity.These research findings provide a scientific basis for quantitatively studying,evaluating,and predicting the diffusion and migration of major pollutants in leachate within frozen soil.
作者
郭钰
李师翁
张淑娟
李双洋
姜琪
GUO Yu;LI Shiweng;ZHANG Shujuan;LI Shuangyang;JIANG Qi(School of Environmental and Municipal Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)
出处
《兰州交通大学学报》
CAS
2024年第3期86-93,115,共9页
Journal of Lanzhou Jiaotong University
基金
国家自然科学基金(31760110)。
关键词
垃圾渗滤液
粉质黏土
导热系数
容积热容量
landfill leachate
silty clay
thermal conductivity
volumetric heat capacity
