| Vanadium is a kind of rare and high melting point metal, which can be dissolved in acid or alkali solution. In lixivium, vanadium is the form of vanadium radical which can be adsorbed and exchanged by the anion groups in the resin and be separated with impurities. The adsorption behavior and mechanism of D301 resin for vanadium (V) were studied. Main conclusions were obtained as following:Through the resin selection experiments, the D301 showed a better capability among the four kind resins of D201, D301, 717, 312. In the static adsorption experiment, based on vanadium solution, effects of pH, resin amount, temperature and time on adsorption behavior were investigated. The results indicated that best adsorption effect on vanadium could be obtained when pH was 2.0, since it's related with the condition of vanadium ions in solution.The equilibrium time of vanadium was about 13h. The adsorbtion amount of vanadium increased with the increasing of the adsorption time, and inceased with the inceasing of the temperature, higher temperature was beneficial for adsorption, and the process was endothermal.The static desorption experiments indicated that of all the three kinds of eluent, including NaOH, NaCl, NaOH+NaCl, the sequence followed by: NaOH+NaCl>NaOH>NaCl, according to the capability of desorption. And of the desorption capability of the combined solvent, when the concentration of NaCl was to a certainty, the increasing concentration of NaOH would get the better desorption effect.Effects of the temperature and flow rate on the dynamic adsorption had been axamined. The results showed that lowed flow rate and higher temperature were beneficial for the adsorbtion,and the suitable conditions were as follows: the flow rate should be lower than 2BV/h, the experiment is 40℃, The suitable conditions for the desorption were 5%NaOH+10%NaCl as the eluent and 2-3BV/h flow rate.Langmuir and Freundlich isotherms were both suitable for describing the adsorption process. The thermodynamic study showed that the adsorption of vanadium was spontaneous and the entropy was positive. The adsorption of vanadium was endothermal.A sencond-order adsorption-ion exchange kinetic equation was developed for the process, and the equation parameters were estimated, the results indicated that the adsorption of vanadium was controlled by the particle diffusion.The actual column static adsorption experiments indicated the similar result with the simulation column's about the absorption effect of D301 resin for vanadium. The impact on the adsorption breakthrough curve by different flux and different initial concentration was studied in the dynamic adsorption experiment, the result shows that low flux (2BV/h) and low concentration (0.0450mol/L) is conducive to the adsorption resin for vanadium. |
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