Preparation of Spherical PVC-MnO2 Ion-Sieve and Its Lithium Adsorption Property

Ultrafine powder Li4Mn5O12 prepared by our lab has a high adsorption capacity and selectivity for Li+ in brine (containing Li+, Na+, K+ and Me2+). However, in the practical application, the ultrafine powder should be formed into the granular adsorbent materials in order to be packed in column with a lower pressure drop of fluid flowing. In this paper, the spherical PVC-Li4Mn5O12 ion-sieve with particle diameter 2.0 similar to 3.5 mm was prepared, where using Li4Mn5O12 ultrafine powder as ion-sieve precursor, poly vinyl chloride (PVC) as binder. And it was treated with HCl solution to obtain spherical PVC-MnO2 ion-sieve. The prepared spherical ion-sieve was characterized by Scanning Electron Microscopy (SEM) and X ray Diffraction (XRD). The adsorption/desorption behavior for lithium ion was evaluated by the experimental measurements in the batch and fixed bed adsorbers packed with the spherical PVC-MnO2 ion-sieve. It was found that the prepared spherical ion-sieve well maintained the excellent adsorption behavior of the ultrafine powder with a high Li+ adsorption capacity of 5.28 mmol.g(-1), and also it has a high Li+ selectivity when recovering Li+ from the solution containing Li+, Na+, K+, Mg2+. With the developed PVC granulation process, the prepared spherical PVC-MnO2 ion-sieve (H type of PVC-Li4Mn5O12) makes the ion-sieve adsorption potential application in industry for lithium recovery from brine or seawater.