水环境中共存重金属对不同固相物质吸附镉和铜的影响

 利用采集的固相物质（生物膜、 悬浮颗粒物和沉积物）模拟水环境中多种固相物质共存吸附体系, 研究共存金属对固相物质吸附镉和铜的影响.  结果表明, 各固相物质对镉的吸附均受共存金属（铜和铅）的抑制作用. 当悬浮颗粒物吸附镉时, 铜和铅的浓度增大, 对镉吸附的抑制程度增强； 当生物膜和沉积物吸附镉时, 铅浓度的增加使得铅抑制镉的吸附作用增强, 不同浓度的铜对镉吸附作用的抑制程度差别较小. 共存铅对铜吸附有抑制作用, 当铅浓度增加时, 3种固相物质吸附铜所受的抑制作用均增强, 而共存镉对铜的吸附影响较小. 即在重金属总浓度较低时, 重金属间的相互影响较小； 随着重金属总浓度的增加, 重金属间的相互影响增强. 共存金属浓度变化对悬浮颗粒物吸附铜和镉受到的抑制程度影响较大, 共存金属浓度越大, 共存金属对悬浮颗粒物吸附镉和铜的抑制作用越强.

Influence of Co-existing Heavy Metals on the Adsorption of Cadmium and Copper onto Different Types of Solid Materials in Aquatic System

The influence of co-existing heavy metals on the adsorption of cadmium and copper onto solid phases was investigated by simulating aquatic multi-phase system comprising three types of solid phases,including biofilms,suspended particulate materials and sediments,in the absence and presence of co-existing heavy metals.The results indicate that co-existing metals(copper and lead) reduced the adsorption of cadmium to all solid phases remarkably.Under the conditions of the adsorption of cadmium onto suspended particulate materials,the reduction effects increased as the initial concentration of copper and lead increased.Under the conditions of the adsorption of cadmium to biofilm and sediments,increasing lead initial concentration enhanced the reduction effects on cadmium adsorption,but increasing copper initial concentration had little influence on the reduction effects.The co-existing lead reduced the adsorption of copper to solid materials and these reduction effects increased with the increase of lead concentration for all the solid materials,while the co-existing cadmium had only a little effect on copper adsorption.Overall,the competitive adsorption between heavy metals was insignificant at low concentrations,and enhanced with the increasing of the concentration of co-existing heavy metals.The concentration of co-existing metals influenced the reduction of the adsorption of copper and cadmium to suspended particulate materials.The greater the concentrations of co-existing heavy metals were,the stronger the reduction of the adsorption of cadmium and copper to suspended particulate materials was.