Adsorption and desorption properties of Li+ on PVC-H1.6Mn1.6O4 lithium ion-sieve membrane

A series of PVC-Li 1.6 Mn 1.6 O 4 precursor membranes were prepared by the solvent exchange method using spinel-type lithium manganese oxide powder (Li 1.6 Mn 1.6 O 4 ) as the precursor, poly(vinyl chloride) (PVC) as the binder, and N,N-dimethyl acetamide (DMAc) as solvent. The Li + of the precursor membrane was extracted by treated with HCl solution to obtain PVC-H 1.6 Mn 1.6 O 4 lithium ion-sieve membrane adsorbent. The preparation conditions were investigated by changing the concentration of PVC and Li 1.6 Mn 1.6 O 4 , and the thickness of liquid film . The structure, morphology and adsorption properties of PVC-H 1.6 Mn 1.6 O 4 lithium ion-sieve membrane were carried out by scanning electron microscope and atomic absorption spectrophotometer. The adsorption capacity depended on the preparation conditions. The membrane prepared with concentration of 10   wt% PVC and 15   wt% Li 1.6 Mn 1.6 O 4 in DMAc and liquid film thickness of 0.30   mm is optimum for the adsorption of Li + from aqueous solution. The thickness of membrane prepared under above conditions is about 0.1   mm. Repeated adsorption–desorption test indicates that the PVC-H 1.6 Mn 1.6 O 4 lithium ion-sieve membrane can be effectively regenerated with HCl solution and reused for Li + adsorption without significant loss in the adsorption capacity. Li + adsorption experiments confirm that the PVC-H 1.6 Mn 1.6 O 4 lithium ion-sieve membrane possesses high selectivity for Li + in the presence of Na + , K + , Ca 2+ and Mg 2+ . According to the coefficients, the isothermal data correlated with the Langmuir model better than the Freundlich model, and the adsorption process follows a pseudo-second-order kinetic model .