有机质对河流沉积物吸附重金属的影响研究

摘要

The experiments were conducted to study the effect of organic matter on adsorption behaviors of heavy metal sediments. Results showed that the adsorption capacity of Cu2+,Cd2+and Zn2+ in sediment increased with increasing initial heavy metal concentrations. The adsorption capacity of Cu2+,Cd2+and Zn2+decreased due to their organic matter removal from the sediments which decreased by 36.60%,16.58% and 25.52% respectively. The adsorption process of heavy metal could be well described by Freundlich equation and Langmuir equation in different organic content sediment(P<0.01). The removal of organic matter showed the strong influence on the metal adsorption. The pseudo-second-order kinetics equation showed the best fit to the adsorption process,which was dominated with the chemical adsorption. The heavy metals adsorption capacity of river sediment were Cu 2+>Zn2+>Cd2+. Organic matter had strong effect on adsorption behaviors of metal in river sediments.%研究了去除有机质前后河流沉积物(CK、QC)对重金属Cu2+、Cd2+、Zn2+的吸附行为影响.结果表明,沉积物对Cu2+、Cd2+、Zn2+的吸附量均随着加入重金属浓度的增加而增加;去除有机质后,河流沉积物对Cu2+、Cd2+、Zn2+的理论最大吸附量较原河流沉积物理论最大吸附量分别降低了36.60%、16.58%和25.52%;沉积物对Cu2+、Cd2+、Zn2+的吸附过程适用Langmuir方程和Freundlich方程描述(P<0.001);有机质的去除,可导致沉积物对Cu2+、Cd2+、Zn2+的吸附率下降;伪二级动力学方程可适合用来描述Cu2+、Cd2+、Zn2+在沉积物上的吸附过程(P<0.01),表明以化学吸附为主.原沉积物CK对重金属离子的吸附能力为Cu2+>Zn2+>Cd2+,去除有机质后沉积物对重金属的吸附能力降低.