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中国农学通报

中国农学通报 ›› 2015, Vol. 31 ›› Issue (7): 189-195.doi: 10.11924/j.issn.1000-6850.2014-2214

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Cr（Ⅵ）在合成沸石上的吸附/脱附行为研究

宋卫军   

  1. 武夷学院
  • 收稿日期:2014-08-13 修回日期:2015-03-02 接受日期:2015-01-23 出版日期:2015-04-03 发布日期:2015-04-03
  • 通讯作者: 宋卫军
  • 基金资助:
    改性粉煤灰在微污染水源粗粒中的应用研究；纳米/SiO2凹凸棒石去除微污染水中腐殖酸的应用研究；

Study on Adsorption and Desorption of Cr (Ⅵ) in Synthetic Zeolite

  • Received:2014-08-13 Revised:2015-03-02 Accepted:2015-01-23 Online:2015-04-03 Published:2015-04-03

摘要： 为深入研究沸石对水溶液中Cr(Ⅵ)吸附和脱附机理，利用合成沸石对水溶液中的Cr(Ⅵ)进行了吸附和脱附实验。实验结果表明：pH值对合成沸石吸附Cr(Ⅵ)影响较大，Cr(Ⅵ)的吸附率随pH值与初始浓度的增加而减小，但吸附量却随初始质量浓度的增加而增加；Freundlich比Langmuir模型更适合描述其吸附行为，且其属于易吸附。在最优条件下，合成沸石在25.0、50.0和100.0 mg?L-l三种质量浓度下对Cr(Ⅵ)的平衡吸附量分别为3.58mg?g-l，6.76 mg?g-l和8.08 mg?g-l；准二级反应动力学模型比准一级能更好地描述合成沸石对Cr(Ⅵ)的吸附行为，准二级动力学拟合得到的吸附量与实测吸附量相差小于5.8%，吸附传质过程主要受液膜扩散和颗粒内扩散的共同控制其吸附速率。在蒸馏水中Cr(Ⅵ)的E%仅为2.57%，而添加NaOH后脱附率明显增加，同时Cr(Ⅵ)在合成沸石上的脱附符合准二级反应动力学。, 为深入研究沸石对水溶液中Cr(Ⅵ)吸附和脱附机理，利用合成沸石对水溶液中的Cr(Ⅵ)进行了吸附和脱附实验。实验结果表明：pH值对合成沸石吸附Cr(Ⅵ)影响较大，Cr(Ⅵ)的吸附率随pH值与初始浓度的增加而减小，但吸附量却随初始质量浓度的增加而增加；Freundlich比Langmuir模型更适合描述其吸附行为，且其属于易吸附。在最优条件下，合成沸石在25.0、50.0和100.0 mg?L-l三种质量浓度下对Cr(Ⅵ)的平衡吸附量分别为3.58mg?g-l，6.76 mg?g-l和8.08 mg?g-l；准二级反应动力学模型比准一级能更好地描述合成沸石对Cr(Ⅵ)的吸附行为，准二级动力学拟合得到的吸附量与实测吸附量相差小于5.8%，吸附传质过程主要受液膜扩散和颗粒内扩散的共同控制其吸附速率。在蒸馏水中Cr(Ⅵ)的E%仅为2.57%，而添加NaOH后脱附率明显增加，同时Cr(Ⅵ)在合成沸石上的脱附符合准二级反应动力学。

关键词: 研究进展, 研究进展

Abstract: The adsorption and desorption experiments of Cr(Ⅵ) from aqueous solution using the synthetic zeolite were conducted regarding the study on the adsorption and desorption mechanism of Cr(Ⅵ) from aqueous solutions. The results indicated that the solution pH showed great effect on synthetic zeolite adsorbing Cr(Ⅵ). And, the adsorption percentage of Cr(VI) increased with a decrease of solution pH and initial concentration. Nevertheless, the adsorption capacity increased with an increase of the initial concentration. The adsorption behavior showed more correspondents to Freundlich model than the Langmuir model. The adsorption capacity on the synthetic zeolite concentration reached 3.58, 6.76, 8.08 mg/g respectively under the initial concentration conditions of 25.0, 50.0, 100.0 mg/L. The pseudo second-order kinetic model was better than the pseudo first-order kinetic model to describe the behavior of the synthetic zeolite adsorbing Cr(Ⅵ), the adsorption capacity of pseudo second-order kinetic differed by less than 5.8%, the adsorption mass transfer process mainly was controlled by the proliferating in the fluid film and inside the grains. In distilled water the E% of Cr (Ⅵ) is only 2.57%. After the addition of NaOH, the desorption percentage increased significantly. The desorption of Cr (VI) in the synthetic zeolite was conformed to pseudo second-order kinetic.