In this paper, a group of international researchers presents a novel equation for salt flux derived from the solution-friction theory. They apply this new equation to several datasets of seawater RO membranes, and propose an accurate method to compare the salt permeability of different membranes.
By characterizing membrane performance, membrane coupons were tested in controlled lab-scale setups using various operational settings and NaCl concentrations. The collected data (i.e., water flux and retention) could be compared and described using a comprehensive theoretical framework. From this theoretical framework, parameters, such as water and salt permeability, could be derived. These parameters can subsequently be used to compare membranes, temperatures, and salts.
With this tool, the group hopes to settle a debate and make a leap in reverse osmosis technology.
Biesheuvel, P.M., S.B. Rutten, I.I. Ryzhkov, S. Porada, and M. Elimelech. 2023. “Theory for Salt Transport in Charged Reverse Osmosis Membranes: Novel Analytical Equations for Desalination Performance and Experimental Validation.” Desalination 557 (116580): 116580. https://doi.org/10.1016/j.desal.2023.116580.