[目的]藻类对重金属吸附和吸收是重金属进入食物链的重要渠道之一.研究活体微藻对水体中Cd2+的吸附性能和吸附机理,旨在为Cd2+等重金属离子进入水体后的去向及去除提供理论依据.[方法]选取地表水普遍存在的4种微藻:钝顶螺旋藻(Spirulina platensis)、铜绿微囊藻(Microcystis aeruginosa)、四尾栅藻(Scenedesmus quadricauda)和小球衣藻(Chlamydomonas microsphaera)作为试验材料,通过室内模拟实验,利用Langmuir、Freundlich 和Dubinin-Radushkevich (D-R)3种等温吸附模型,研究4种活体微藻对Cd2+的吸附规律及吸附参数.[结果]4种微藻对水体Cd2+吸附均可以用Langmuir、Freundlich和D-R模型描述,其中用Langmuir模型拟合钝顶螺旋藻、Freundlich模型拟合小球衣藻、D-R模型拟合铜绿微囊藻和四尾栅藻的吸附效果最佳.四尾栅藻对Cd2+的吸附量最高,而钝顶螺旋藻对Cd2+的吸附量最低,但与Cd2+的亲和力最强,4种微藻吸附Cd2+主要是以离子代换为主的化学吸附.[结论]微藻对Cd2+均有较强的吸附能力,会引起以微藻为食的水生动物Cd2+富集;微藻也是去除水体Cd2+的潜在吸附剂原料.%[Objective] It is one way of heavy metals into the food chain by algae adsorption.In order to study the fates of Cd2+ in water,the adsorption mechanisms of Cd2+ by living microalgae was studied.[Methods] Four microalgae species,including Spirulina platensis,Microcystis aeruginosa,Scenedesmus quadricauda and Chlamydomonas microsphaera,which are commonly found in surface water,were selected as experiment materials.After simulation experiments,Langmuir,Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of Cd2+ by four organisms.[Results] The results indicated that biosorption isotherm was better fitted by the Langmuir model comparing with the other models in explaining the biosorption of Cd2+ by Spirulina platensis.Freundlich was the best one to describe Chlamydomonas mierosphaera,and D-R was the best isotherm when describing the biosorption of Cd2+ by Microcystis aeruginosa and Seenedesmus quadricauda.The adsorption capacity of Scenedesmus quadricauda was the largest,whereas Spirulina platensis was the lowest with the strongest absorbability.It also showed that the biosorption of Cd2+ by the four microalgae was taken place by chemisorption.[Conclusion] There exists large adsorption capacity of living microalgae to Cd2+,which may induce the enrichment of Cd2+ in aquatic animals by eating them.On the other hand,living microalgae can be used as a kind of adsorbent material to remove Cd2+ from wastewater.
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