Development of an Efficient System for Blue Energy Production Based on Reverse Electrodialysis (RED) by Optimizing Electrolyte Composition: Experimental and Theoretical Simulations

SA Shah and Z Haider and M Shahbabaei and D Kim, ENERGY & FUELS, 36, 6353-6361 (2022).

DOI: 10.1021/acs.energyfuels.2c00763

Herein, the effect of electrolyte composition (single vs salt mixture) on the performance of reverse electrodialysis (RED) has been investigated using lab-made sulfonated poly(ether ether ketone) (sPEEK) cation exchange membrane (CE) membrane and Neosepta, a commercially available anion exchange (AE) membrane. The efficiency of the RED cell was monitored by measuring open-circuit voltage (OCV), power density (PD), and gross power density (PDgross). The effect of feed solution flow and concentration was analyzed by using several electrolytes (LiCl, NaCl, KCl, and NH4Cl) and mixed composition (NaKCl and NaNH4Cl). NaCl solution among single electrolytes exhibited the highest performance with a PD of 1.77 Wm(-2), which was improved further by intermixing with KCl and NH4Cl. For the case of binary mixtures, NaNH4Cl showed a PD of 2.51 Wm(-2), which is 42% higher compared to that of NaCl possibly due to the inferior stack resistance. A molecular dynamics (MD) simulation was performed to further investigate the adsorption-diffusion properties of CEM and AEM at the molecular scale. A positive correlation was observed between MD simulation and experimental measurements regarding the competitive adsorption of cations into the sPEEK membrane with the following trend NH4+ > K+ > Na+ > Li+, which is associated with the ionic radius and hydration energies of respective cations.

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