Temperature effect on lithium isotope separation by electrodialysis using La0.57Li0.29TiO3 electrolyte

•Electrodialysis with La0.57Li0.29TiO3 electrolyte concentrates 6Li isotopes.•The diffusion of Li+ in the lattice is the rate-determining process.•The apparent activation energy (Ea) of 6Li transfer is 4.54% lower than that of 7Li.•The difference in Ea follows the prediction considering the quantum effect.•The isotope enrichment coefficient of 6Li is higher at lower temperatures. The effect of temperature on lithium isotope separation by electrodialysis using La0.57Li0.29TiO3 (LLTO) electrolyte was investigated in the temperature range 298.15–323.15 K. The rates of mass 6 and 7 lithium isotopes (6Li and 7Li) moving through LLTO into pure water by electrodialysis were determined by inductively coupled mass spectrometry. An Arrhenius-type temperature dependence was observed for the rate of transfer of 6Li and 7Li into pure water by electrodialysis. The apparent activation energy of this lithium isotope transfer is the energy required for dissolution/elution of Li+ into/from LLTO or Li+ diffusion in LLTO crystals. The results of these experiments provided indication that the apparent activation energy of 6Li is approximately 5% lower than that of 7Li owing to the quantum effect. It was also shown that in electrodialysis using LLTO as the electrolyte, the isotope enrichment coefficient of 6Li may increase at lower temperature.