Permeation of Interacting Solutes In Forward Osmosis

Osmotically driven membrane processes are an emerging set of technologies that show promise in water and wastewater treatment, desalination, and power generation.  The majority of research in the field has focused on predicting and enhancing water permeation through membranes, however, the effective operation of these systems requires that the reverse flux of draw solute from the draw solution into the feed solution be minimized. In this study, a model is developed that describes the reverse permeation of draw solution across an asymmetric membrane in forward osmosis operation.  This model accounts for solute-solute interactions that can arise between solutes within both the active layer and support layer of the asymmetric membrane.  Experiments were carried out to validate the model predictions.  Using independently determined membrane transport coefficients, strong agreement between the model predictions and experimental results was observed.