Performance analysis of pressure-retarded osmosis power using biomimetic aquaporin membrane

Salinity gradient power is a system which sustainably generates electricity for 24 hrs, if the system is constructed at a certain place where both seawater and river water are consistently pumped. Since power is critically determined by the water flux and the salt rejection, a membrane of water-semipermeable aquaporin protein in cell membranes was studied for pressure-retarded osmosis. NaCl was used as a salt, and NaNO₃ was used as a candidate to check the ion selectivity. The water flux of biomimetic aquaporin membranes was negligible at a concentration below 2 M. Also, there is no remarkable dependence of water flux and ion selectivity on concentrations higher than 3 M. Therefore, the biomimetic aquaporin membrane could not be applied into pressure-retarded osmosis; however, if a membrane could overcome the current limitations, the properties shown by natural cells could be accomplished.