垃圾渗滤液中溶解性有机物对土壤重金属吸附

垃圾渗滤液主要组分为重金属和大量的溶解性有机物(DOM).选取我国北方具有代表性的褐土,通过不同pH(5~9)和温度(15,25和35℃)下的等温吸附试验,研究了垃圾渗滤液中DOM对Cu,Cd,Pb和Zn 4种重金属在土壤中吸附行为的影响.结果表明:DOM对Cu和Cd在土壤中的吸附促进作用较明显,对Pb有微弱的促进作用,对Zn的吸附影响不明显;改变pH,DOM对4种重金属在褐土中的吸附也表现出不同的影响,吸附平衡后土壤溶液pH变化差异明显;25℃下Cu在土壤中的吸附量高于15和35℃条件下;有DOM时,Cd,Zn和Pb在土壤中的吸附量随着温度的升高而增大.

Effect of Dissolved Organic Matter in Landfill Leachate on the Adsorption of Heavy Metals in Soils

Landfill leachate contains a lot of heavy metals and much dissolved organic matter (DOM).This study investigated the effect of leachate DOM on the adsorption of Cu,Cd,Pb and Zn in typical cinnamon soil in Northern China.The adsorption experiments were conducted under the conditions of isotherm at 15,25,35 ℃ and at various acidities (pH=5-9).The results revealed that leachate DOM significantly enhanced the adsorption of Cu and Cd on the soil,but slightly improved that of Pb.The influence on Zn was not observed.However,the effect of leachate DOM on the adsorption of the four metals tended to vary with the change of pH.After the adsorption equilibrium,various pH were detected in the soil solution.Among the studied temperatures (15,25 and 35 ℃),the maximum adsorption of Cu occurred at 25 ℃,while the adsorptions of Cd,Pb and Zn were elevated by the increase of the temperature.