Sulfonated poly (ether ether ketone) composite cation exchange membrane for selective recovery of lithium by electrodialysis

Abstract

Lithium is in demand since decades due to high applicability in batteries for electronic devices, which is expected to increase by 8 to 11% every year and Lithium ion battery market is estimated to grow to € 180 billion by 2024. Land deposits and seawater are two major sources of lithium but availability in sea water is higher than land. So an efficient technology is required to recover the lithium from sea water. Electrodialysis (ED) may be an alternate approach to recover the lithium from sea by selective ion exchange membranes. Here, Lithium selective ion exchange membranes have been synthesized by modification of sulfonated poly (ether ether ketone) (SPEEK) with lithium selective nanomaterial. Synthesized membranes were characterized for their chemical, structural and morphological structures and uniform dispersion of lithium selective nanomaterials. Composite membrane shows better lithium exchange capacity with excellent lithium conductivity as compared to SPEEK membrane. The adsorption of lithium (15.2 mg/g) found to be five times higher than that of Mg while recovery of lithium was 64% using electrodialysis process by NC-4 composite membrane. Selectivity factor for composite membrane were 4.82, 3.0 and 2.17 for Li/Mg, Li/K and Li/Na, respectively. The selective composite membranes can be suitable for Li-ion recovery from sea brine/bittern on large scale.