Porous alumina-supported lithium aluminum titanium phosphate membrane for lithium extraction using the electrodialysis process
Umma Habiba, Tawsif A. Siddique, I.M. Rizwanul Fattah, Shabin Mohammed, Edward Attenborough, Quan Lai, Zhouyou Wang
Abstract
Inorganic membranes that possess lithium ionic conductivity exhibit considerable potential as a viable option for the targeted extraction of lithium from brine sources. However, the practical implementation of ceramic anisotropic thin film membranes for lithium-ion extraction presents ongoing challenges due to the scarcity of suitable membrane materials and complex fabrication techniques. This research proposes an innovative approach to address this issue by employing a battery material, a lithium-ion conducting electrolyte, to produce a membrane that selectively permits the passage of lithium ions. A scalable approach was employed to fabricate an asymmetric lithium aluminum titanium phosphate (LATP) membrane by utilizing a citric acid-assisted sol–gel coating method on a porous alumina substrate and subsequent sintering. A continuous and compact LATP membrane with an approximate thickness of 14.32 ± 1.36 μm was successfully deposited onto the porous support through the dip coating technique. The lithium-ion permeation was checked using the electrodialysis system from a feed solution containing Li+ coexisting with Na+ and Mg2+. A high lithium flux of 215 mmol/h/m2 with a Li+/Mg2+ selectivity of 33 was produced when 2 V of voltage was applied to the 1.65 cm2 ionic conductor anisotropic membrane containing a mixed alkaline solution containing lithium chloride, sodium chloride, and magnesium chloride at the feed solution. These findings underscore the potential for producing lithium-selective membranes using electrolyte materials.