To measure the performance of the membrane with the analogous Na2SO4 salt for the Li + /Na + selectivity calculations, 3 M Na2SO4 solution was employed as synthetic leachate in the anode compartment with 0.5 M NaOH as the receiving solution for NaOH production in the cathode compartment, as represented in Figure . Membranes were preconditioned by immersing them in deionised water for 24 h, followed by 2 h immersion in 0.5 M NaOH solution and rinsed in deionised water before use. Electrodialysis experiments were carried out by applying a current of 150 mA (ca.