为深入分析土-膨润土混合物对重金属离子的吸附特性,文章开展典型尾矿库中Cu2+在土-膨润土混合物中的吸附试验,探讨土-膨润土混合物对Cu2+的吸附特征.结果表明:增大膨润土掺量,土-膨润土混合物对Cu2+最大吸附量和去除率均提升;同一膨润土掺量下,初始Cu2+质量浓度越高,去除率越低.吸附等温模型分析表明:3种模型均适用于试验的吸附特征,基于Langmuir模型的最大吸附量在膨润土掺量增加至20％时,Cu2+最大吸附量Qm增加了29.99％,表明膨润土的掺入可显著提升混合物吸附能力;基于Freundli-ch模型的吸附常数KF随膨润土掺量增大而增大,表明膨润土掺量越大,吸附能力越强;基于D-R模型,当膨润土掺量为0～20％时,混合物吸附特性主要由离子交换吸附所控制,并通过X射线衍射(X-ray diffraction,XRD)、扫描电子显微镜(scanning electron microscope,SEM)等分析,表明土-膨润土的吸附机理主要表现为离子交换吸附.
Experimental study on adsorption characteristics of heavy metal Cu2+by soil-bentonite mixture
In order to further analyze the adsorption characteristics of heavy metal ions by soil-bentonite mixture,the adsorption test of Cu2+in soil-bentonite mixture in typical tailings pond was carried out to explore the adsorption characteristics of Cu2+by soil-bentonite mixture.The results show that with the increase of bentonite content,the maximum adsorption capacity and removal rate of Cu2+by soil-bentonite mixture are increased.Under the same bentonite content,the higher the initial mass con-centration of Cu2+,the lower the removal rate.The adsorption isothermal model analysis shows that the three models are suitable for the adsorption characteristics of the test.The maximum adsorption capacity Qm based on the Langmuir model increases by 29.99％when the bentonite content increases to 20％,indicating that the addition of bentonite can significantly improve the adsorption capacity of the mixture.The adsorption constant KF based on Freundlich model increases with the increase of bentonite content,indicating that the adsorption capacity is stronger with the increase of bentonite content.According to the D-R model,when the bentonite content is 0-20％,the adsorption character-istics of the mixture are mainly controlled by ion exchange adsorption.X-ray diffraction(XRD)and scanning electron microscope(SEM)analyses show that the adsorption mechanism of soil-bentonite is mainly ion exchange adsorption.
soil-bentoniteCu2+adsorptionadsorption isotherm model
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