Modeling for reverse permeation process in forwad osmosis and its experimental vertification

The effective operation of forward osmosis systems requires that the reverse flux of draw solute from the draw solution into the feed solution be minimized. To better understand the effect of reverse draw solute permeation in forward osmosis membrane separation process, a model which describes the reverse permeation of draw solution in different operation modes was developed based on previous studies of concentration polarization. A set of sequencing batch experiments were conducted to validate the model predictions with a highly soluble salt (NaCl) as a draw solution. Reverse draw solute permeation and water flux at different initial osmotic pressures were measured, and strong agreement between the model predictions and experimental results was observed.