Sustainable energy recovery from salt-lake brines through a novel selective reverse electrodialysis process

Abstract

The salinity gradient energy (SGE) in salt-lake brines can be exploited as a sustainable energy source through reverse electrodialysis (RED). However, the composition of brines is notably intricate. In order to avoid the adverse effects of multivalent cations on RED in brines, we introduced a novel selective reverse electrodialysis (SRED) here. The results demonstrate that when increasing the salinity ratio between high and low concentration feeds (HCFs, LCFs) from 20 to 60, the SRED maximal maximum power density (Pd,max) improves from 0.069 to 0.109 W/m2. The feed salinity has less obvious effect on SRED. Moreover, the role of Mg2+ on the adverse effects is regulated. The maximal Pd,max of SRED is 1.13 ∼ 1.23 times higher than that of the conventional RED at the Mg2+ concentrations of 4861.00 ∼ 14583.00 ppm in HCFs and 40.51 ∼ 121.53 ppm in LCFs. This suggests that SRED is a feasible and efficient strategy for capturing SGE in salt-lake brines.