垃圾渗滤液水溶性有机物对土壤吸附重金属Cd^(2+)、Pb^(2+)的影响

Effect of sorption heavy metal Cd^(2+),Pb^(2+) onto soils with dissolved organic matter of landfill-leachate

采用序批次吸附试验,研究了不同填埋年限(0、4~5、12a)垃圾渗滤液中的DOM对土壤吸持重金属Cd2+、Pb2+的影响.结果表明,垃圾渗滤液中的DOM能促进土壤对重金属Cd2+、Pb2+的吸附.在有垃圾渗滤液DOM存在的条件下,Cd2+、Pb2+的吸附等温线可用Freundlich方程拟合(R2>0.94),土壤对Cd2+、Pb2+的吸附量比对照处理(无垃圾渗滤液DOM)分别高1.13~1.42倍和1.09~1.84倍,填埋年限长的垃圾渗滤液较之填埋年限短的渗滤液对土壤吸附Cd2+、Pb2+的影响强烈.在Cd2+、Pb2+初始浓度相同时,潮土较红壤具有更高的吸持能力,并且随体系pH的增高,其吸持量增加.

Batch adsorption experiments were carried out to investigate effect landfill sites（0,4 ～ 5,12y） on the sorption of Cd^2＋ , Pb^2＋ in the acidic and of dissolved organic matter（ DOM ） of landfill lcachate derived from different calcareous soil. The results showed that the snrption of Cd^2＋ ,Pb^2＋ in soils was enhanced in the presence of landfill-leaehate DOM . The Sorption isotherm of Cd^2＋ ,Pb^2＋ in soils in the presence of different landfill leaehate DOM could be described well by the Frcnudlich eqation （R2 〉 0.94）, and the Sorption of Cd^2＋ and Pb^2＋ in soils were 1.13 to 1.42 and 1.09 to 1.84 times higher than the control in absence of landfill leachate DOM, respectively. At the same initial concentration of Cd^2＋ and Pb^2＋, acidic soil demonstrated much less ability to retain the Cd^2＋ and Pb^2＋than calcareous soil due to much lower pH in the former, and landfill-leachate of longer landfill age enhanced sorption of Cd^2＋ ,Pb^2＋in soils in comparison with the shorter the landfill age of landfill-leachate. The results showed that in the presence of landfill leachate DOM, increase of Cd^2＋, Pb^2＋ sorption capacity in soils was obvious with an increase in pH.