Adsorption and Desorption Behavior of Lithium Ion in Spherical PVC鈥揗nO2 Ion Sieve

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• 作者：Guoping Xiao ; Kefeng Tong ; Longsheng Zhou ; Jiali Xiao ; Shuying Sun ; Ping Li ; Jianguo Yu
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2012
• 出版时间：August 22, 2012
• 年：2012
• 卷：51
• 期：33
• 页码：10921-10929
• 全文大小：421K
• 年卷期：v.51,no.33(August 22, 2012)
• ISSN：1520-5045

文摘

A spherical PVC鈥揗nO₂ ion sieve of 2.0鈥?.5 mm diameter was prepared by the antisolvent method using synthesized Li₄Mn₅O₁₂ ultrafine powder as the precursor, poly(vinyl chloride) as the binder, and N-methyl-2-pyrrolidone as solvent. Batch experiments of the adsorption capacity (isotherm) and adsorption rate of Li⁺ on the spherical PVC鈥揗nO₂ ion sieve were studied. Spherical PVC鈥揗nO₂ had a high adsorption capacity for Li⁺, and the isotherm data were well fitted by the Langmuir model; the adsorption kinetics were well described by the Lagergren equation. Furthermore, a mathematical model was set up to calculate the film mass transfer coefficient (k_f) and pore diffusivity (D_p) of the adsorbent. Continuous flow experiments for study of Li⁺ adsorption breakthrough and the subsequent desorption (elution) in a PVC鈥揗nO₂ packed column were carried out employing six feed solutions of various pH values and concentrations of Li⁺, Na⁺, K⁺, and Mg²⁺ for simulating brine samples of various salt lakes and/or seawaters. After the adsorption treatment to concentrate the Li⁺ on PVC鈥揗nO₂, the column was regenerated by 1.0 mol/L HCl which supplied H⁺ to accomplish elution of the adsorbed Li⁺ by ion exchange. The experimental results demonstrate that PVC鈥揗nO₂ had high selectivity for Li⁺ and that its adsorption of Li⁺ from the feed were little affected by Na⁺, K⁺, and Mg²⁺ also present in the feed solution. Spherical PVC鈥揗nO₂ is an attractive medium for large scale lithium extraction from brine or seawater.