The influence of feedwater pH on membrane charge ionization and ion rejection by reverse osmosis: An experimental and theoretical study

Modeling mass transport of ions across the polyamide active layer a reverse osmosis (RO) membrane requires comprehensive understanding structure and chemistry. For instance, charge ionization thus salt greatly depend on feedwater pH composition, but these relations are not yet well understood. To address this gap in understanding, one dimensional model is developed that couples all using extended Donnan steric partitioning pore model. The includes as interaction with H+ OH?-ions. dependence ion rejection permeate described function pH. Finally, predictions quantitatively compared experimental data by adjusting few fitting parameters Nelder-Mead algorithm. Contrary to other RO studies, we show only weakly charged, small still plays key role determine performance. These findings reveal local functional groups, how affects overall