Properties and mechanism of Li~+ adsorption based on D751 resin

In order to investigate Li ion adsorption behaviors based on D751 resin,several parameters such as static and dynamic experiments have been studied.Kinetics and thermodynamics behaviors of ion exchange were studied to analyze the adsorption process,and the adsorption mechanism was investigated by Fourier transform infrared(FTIR)spectroscopy.It demonstrates that ion exchange occurred between Li+and H+on functionalized—COOH groups,and nitrogen atom on functional groups was also involved in the coordination.Results indicate that the adsorption isotherm fitted Langmuir monolayer adsorption characteristics.The adsorption of Li+on D751 resin was an endothermic process and would be faster with higher temperature and larger pH value.Static experiments show that the adsorption rate could be well described by second-order kinetics equation,film diffusion was the rate-determining step,and adsorption equilibrium was achieved within 1 hour.It would be beneficial for absorption with higher rotating speed and lower flow speed in dynamic experiment.Meanwhile the resin displayed good regeneration performance which can be used in extraction and enrichment of lithium.