Fig. 4: Fundamental analysis of cation/anion separation performance for osmotic power generation.
From: Zeolite membrane with sub-nanofluidic channels for superior blue energy harvesting
a A graph of conductance versus KCl electrolyte concentration of ZC membrane. The dashed line in the graph shows the conductance behavior in the bulk solution of high concentrations. b the I-V curve showing osmotic Ios and Vos of ZC membrane in a 50-fold concentration gradient of KCl electrolyte. The horizontal and vertical lines in the graph represent the zero points of current and potential, respectively. The inserted image illustrates the configuration of the membrane testing. c Transference number t+ calculated based on measured Vos versus different concentration gradients of KCl electrolyte. The inserted image illustrates the mechanism of the cation/anion separation within the membrane. The pink-shaded area is intended solely to highlight the green line graph in the middle section and holds no scientific significance. d Osmotic power density and current density of the ZC membrane (effective area: ~0.03 mm2) tested by connecting the electrochemical cell to an external loader in a 50-fold concentration gradient of KCl electrolyte. e The green columns showing osmotic power density obtained in electrolytes of various cations under a 50-fold concentration gradient. The pink graph is the corresponding cation diffusion coefficient. f Selectivities of different cations obtained based on the osmotic power density according to the previous work6,14. The cation-anion selectivity of different cations relative to Cl− lead to varied osmotic power density which can be used to calculate the different cation-cation selectivity.
