有机质对河流沉积物吸附重金属的影响研究

Effects of Organic Matter on the Heavy Metal Adsorption Characteristics in Surface Sediment of River

研究了去除有机质前后河流沉积物(CK、QC)对重金属Cu^(2+)、Cd^(2+)、Zn^(2+)的吸附行为影响.结果表明,沉积物对Cu^(2+)、Cd^(2+)、Zn^(2+)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Cu^(2+)、Cd^(2+)、Zn^(2+)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Cu^(2+)、Cd^(2+)、Zn^(2+)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Cu^(2+)、Cd^(2+)、Zn^(2+)的吸附率下降;伪二级动力学方程可适合用来描述Cu^(2+)、Cd^(2+)、Zn^(2+)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Cu^(2+)>Zn^(2+)>Cd^(2+),去除有机质后沉积物对重金属的吸附能力降低.

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 Cu2＋ 〉Zn2＋ 〉Cd2＋ . Organic matter had strong effect on adsorption behaviors of metal in river sediments.