Review article

Evaluation of the selectivity of reverse osmotic membranes in separation of binary sodium chloride solutions








Manufacturers of reverse osmosis filter membranes provide their products with computer programs that allow for technological evaluation calculations for solutions with different concentrations of impurities. The description of the programs does not include the computer methods and algorithms which are necessary for calculating traffic flows. Consequently, it is not possible to evaluate the selectivity of the reversely osmotic stages of membranes. The development of computer algorithms and techniques that would evaluate the operation of reverse osmosis plants taking into account external and internal parameters is an important practical task. The article discusses reverse osmosis processes in installations with membrane filtration associated with the purification of water enriched with salt. The physical mechanisms of purification are considered, and it is shown that the difference between the working and osmotic pressures plays a leading role in this mechanism. Purification of water enriched with salt by a membrane is accompanied by diffusive flows of the salt component of the solution. The reverse osmosis process is simulated, in which salt water is fed under high pressure into a chamber with a membrane permeable only to water. The permeate outlet flow is low-pressure pure water, and the retentate flow is salt-enriched water. The initial parameters are set, namely, the pressure drop on the membrane, the mass fraction of salt at the inlet and the flow rate. An increase in the mixing rate reduces the concentration polarization on the inlet side of the membrane and increases the flow of water through the membrane.


Shabalin V. V. Saint Petersburg State University of Architecture and Civil Engineering St. Petersburg, Russia

Links to authors' articles: 

Journal Issue