Cu(Ⅱ)、Ca(Ⅱ)共存对IRC748树脂吸附四环素的影响与机制  

Effect of co-existing Cu( Ⅱ)/Ca( Ⅱ) on the adsorption of tetracycline onto IRC748 resin

作　　者：凌晨[1] 刘福强[1] 韦蒙蒙[1] 仇欢[1] 

机构地区：[1]污染控制与资源化国家重点实验室南京大学环境学院,南京210023

出　　处：《环境化学》2016年第5期884-892,共9页Environmental Chemistry

基　　金：国家自然科学基金(51078178;51378253)资助~~

摘　　要：通过静态pH影响、等温线和动力学实验,研究了Cu(Ⅱ)/Ca(Ⅱ)共存对亚氨基二乙酸树脂IRC748吸附四环素(TC)的影响规律.研究结果表明,广泛的pH(2—8)范围内,共存的Cu(Ⅱ)显著促进了IRC748对TC的吸附,而共存的Ca(Ⅱ)会抑制其吸附.TC对Cu(Ⅱ)/Ca(Ⅱ)的吸附影响较小.TC吸附在不同体系中均符合Frendlich模型,亲和力参数Kf随共存Cu(Ⅱ)浓度的增大而增大(约33%),随共存Ca(Ⅱ)浓度的增大而降低(约15%).不同体系中TC吸附动力学均较符合拟二级动力学方程,含Cu(Ⅱ)体系中TC与Cu(Ⅱ)的吸附进程一致.UV-Vis、FTIR、XPS和Cu(Ⅱ)预负载证明了液相中仅Cu(Ⅱ)与TC发生强烈络合,TC因[Cu-TC]络合物吸附(RouteⅠ)或Cu(Ⅱ)位点的桥联吸附作用(RouteⅡ)在IRC748上得到增强去除;Ca(Ⅱ)会与TC竞争相同的吸附位点(羧基)而降低TC的吸附.Effect of co-existing Cu（ Ⅱ）/Ca（ Ⅱ） on the adsorption of tetracycline（ TC） onto an iminodiacetic acid resin（ IRC-748） was investigated by equilibrium and kinetic studies. Under a wide range of p H（ 2—8）,the presence of Cu（ Ⅱ） markedly enhanced the adsorption of TC,while TC uptake was suppressed when Ca（ Ⅱ） was present. The adsorption of Cu（ Ⅱ）/Ca（ Ⅱ） was not influenced by TC. The adsorption isotherm of TC were well fitted by Freundlich model. With the increase of initial metal concentrations,Kfvalues of TC increased by 33% for Cu（ Ⅱ）-TC systems but decreased by 15% for Ca（ Ⅱ）-TC systems,comparing with TC alone. The kinetic data of TC adsorption in various systems were all well fitted by pseudo-second-order kinetic model. TC and Cu（ Ⅱ） adsorption occured synchronously in Cu（ Ⅱ）-TC systems. Furthermore,UV-Vis,FT-IR and XPS characterizations as well as Cu（ Ⅱ）/Ca（ Ⅱ） preloading tests demonstrated that only Cu（ Ⅱ）complexed with TC,and the enhancement of TC adsorption resulted from either the direct adsorption of [Cu-TC] complex or the bridge effect of Cu-sites in solid phase. Contrarily,Ca（ Ⅱ） and TC competed for the same carboxyl sites,leading to the decrease of TC uptake in Ca（ Ⅱ）-TC systems.

关 键 词：吸附 四环素 亚氨基二乙酸树脂 铜 钙. 

分 类 号：X703[环境科学与工程—环境工程] O647.3[理学—物理化学]