How permeable could a reverse osmosis membrane be if it was specifically developed for uncharged organic solute rejection?

Abstract

AbstractHere, we present both experimental data and modeling results of the removal of four different polar organic solutes by six different commercial nanofiltration (NF) and reverse osmosis (RO) membranes in a natural groundwater matrix. These results are significant for two reasons. First, three of the polar organic solutes are contaminants commonly found in both drinking water aquifers and municipal wastewaters and, hence, are particularly relevant to the protection of public health in drinking water production and potable reuse applications. Second, our membrane transport model can be used (1) to understand the fundamental mechanism governing uncharged, polar organic solute rejection and (2) to make forward predictions about how one might alter NF/RO membrane chemistry and structure to achieve a desired level of rejection. Perhaps a disappointing conclusion is that, for uncharged, polar organic solutes, the only obvious means of improving rejection is to reduce pore size, increase barrier layer thickness, and/or decrease barrier layer porosity, all of which reduce water permeability and energy efficiency. However disappointing this conclusion may be, we believe the fundamental insights that can be derived from this work are significant and important for the drinking water and water reuse scientific communities.