亚铁氰化锌对Co(Ⅱ)的吸附

    Co(Ⅱ) Sorption on Zinc Hexacyanoferrate

    • 摘要: 利用共沉淀法制备了亚铁氰化锌配合物(KZnFC),采用静态法研究了温度、pH值、吸附时间、Co2+初始浓度等因素对Co(Ⅱ)在KZnFC上吸附性能的影响,同时研究了KZnFC重复利用的可能性,从热力学和动力学方面对吸附过程进行了分析,并通过KZnFC吸附Co(Ⅱ)前后的透射电镜(TEM)、全谱等离子体直接光谱仪(ICP)和X射线衍射分析(XRD)对吸附机理进行了初步探讨。实验结果表明:pH值和Co2+初始浓度对吸附过程有显著影响;在25℃、pH=5.5、吸附平衡时间为300 min时KZnFC的平衡吸附量Qe=38.53 mg/g;KZnFC经过HCl和KCl溶液解吸后具有较好的重复利用性能。KZnFC对Co(Ⅱ)的吸附过程符合Langmuir吸附模型和假二级反应动力学模型。KZnFC吸附Co(Ⅱ)前后的ICP和XRD分析表明,该吸附过程是以样品中K+与溶液中的Co2+发生离子交换为主,吸附后样品晶格常数发生改变,影响了晶体的择优取向。

       

      Abstract: By batch sorption experiments, the effects of temperature, pH, contact time, initial Co2+ concentration on the sorption of Co(Ⅱ) on zinc ferrocyanide(KZnFC) prepared by co-precipitated method were investigated. The possibility of KZnFC reused was studied, too. The sorption process was analyzed by the thermodynamic and kinetic, and the sorption mechanism was characterized by TEM, ICP and XRD of KZnFC before and after Co(Ⅱ) sorption. The experimental results indicate that the sorption of Co(Ⅱ) on KZnFC is strongly dependent on pH and initial Co2+ concentration, the equilibrium sorption capacity Qe can be up to 38.53 mg/g at temperature 25℃, pH=5.5 and t=300 min. KZnFC has better reuse ability after desoption with HCl solution and KCl solution. The sorption process is more consistent with the Langmuir sorption model and second order reaction kinetics model. The ICP and XRD analysis of KZnFC before and after adsorbing Co(Ⅱ) indicate that the Co(Ⅱ) sorption is mainly due to the ion exchange between K+ in KZnFC and Co2+ in the solution. The lattice constants of the sample have changed after the sample absorbed Co(Ⅱ) and have effected the preferred orientation of crystals.

       

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