Investigation of concentration polarization in a cross-flow nanofiltration membrane: Experiment and CFD modelling

Document Type : Research Paper


1 Department of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehranpars, Tehran, Iran

2 College of Petroleum and Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran


Numerous researches have been investigated on the mass transfer phenomena and hydrodynamics for the fluid in the vicinity of the membrane surface by the mathematical modelling and simulation. Due to complexities involved in solving transport phenomena within membranes, the application of CFD simulation study for determining the concentration polarization (CP) profile in the membrane channel is limited. In this study, a 2D CFD modelling and simulation of CP phenomena in nanofiltration of an aqueous solution of MgSO47H2O in a vertical spacer-filled flat sheet membrane module was presented. A response surface methodology (RSM) statistical analysis has been designed in order to fully capture effects of variations of the feed liquid flow and the transmembrane pressure (TMP) on the permeate flux and concentration. It was also shown that increasing TMP or the liquid flow rate led to enhancing the permeate flux while increasing the feed concentration decreased it. The simulated results were validated and compared with the available experimental data, showing a satisfactory agreement. Eventually, the mass transfer coefficient derived from CFD simulations and calculated from Sherwood empirical relationships were compared which showed 10% and 33% difference in lower and higher liquid flow rates, respectively.


  1. Abadikhah H., Zokaee Ashtiani F., Fouladitajar A., (2015). Nanofiltration of oily wastewater containing salt; experimental studies and optimization using response surface methodology, Desalin. Water Treat. 56:2783–2796.
  2. Mulder M., Basic principles of membrane technology, Kluwer Academic, 1991.
  3. Zeng K., Zhou J., Cui Z., Zhou Y., Shi C., Wang X., Zhou L., Ding X., Wang Z., Drioli E., (2018). Insight into fouling behavior of poly(vinylidene fluoride) (PVDF) hollow fiber membranes caused by dextran with different pore size distributions, Chinese J. Chem. Eng. 26: 268–277.
  4. Geraldes V., Afonso M.D., (2007). Prediction of the concentration polarization in the nanofiltration/reverse osmosis of dilute multi-ionic solutions, J. Memb. Sci. 300: 20–27.
  5. Prabhavathy C., De S., (2010). Estimation of transport parameters during ultrafiltration of pickling effluent from a tannery, Sep. Sci. Technol. 45:11–20.
  6. Mercier-bonin M., Daubert I., Le D., Maranges C., Fonade C., Lafforgue C., (2001). How unsteady filtration conditions can improve the process efficiency during cell cultures in membrane bioreactors, Sep. Purif. Technol. 22–23: 601–615.
  7. Liikanen R., Yli-Kuivila J., Laukkanen R., (2002). Efficiency of various chemical cleanings for nanofiltration membrane fouled by conventionally-treated surface water, J. Memb. Sci. 195:265–276.
  8. Asefi H., Alighardashi A., Fazeli M., Fouladitajar A., (2019). CFD modeling and simulation of concentration polarization reduction by gas sparging cross-flow nanofiltration, J. Environ. Chem. Eng.7 : 103275, 1-7.
  9. Asadi Tashvigh A., Zokaee Ashtiani F., Fouladitajar A., (2016). Genetic programming for modeling and optimization of gas sparging assisted microfiltration of oil-in-water emulsion, Desalin. Water Treat. 57 : 19160–19170.
  10. Cui Z.F., Wright K.I.T., (1996). Flux enhancements with gas sparging in downwards crossflow ultrafiltration: Performance and mechanism, J. Memb. Sci. 117 : 109–116.
  11. Jaffrin M.Y., (2008). Dynamic shear-enhanced membrane filtration: A review of rotating disks, rotating membranes and vibrating systems, J. Memb. Sci. 324 : 7–25.
  12. Sarkara B., Deb S., (2010). Electric field enhanced gel controlled cross-flow ultrafiltration under turbulent flow conditions, Sep. Purif. Technol. 74 :73–82.
  13. Ducom G., Puech F.P., Cabassud C., (2002). Air sparging with flat sheet nanofiltration: A link between wall shear stresses and flux enhancement, Desalination. 145 : 97–102.
  14. Ahmed S., Seraji M.T., Jahedi J., Hashib M.A., (2012) . Application of CFD for simulation of a baffled tubular membrane, Chem. Eng. Res. Des. 90:600–608.
  15. Schock A.M. G., (1987) Mass transfer and pressure loss in spiral wound modules, Desalination. 64 : 339 – 352.
  16. B. hallstrom Vassilis gekas, (1987). Mass transffer in the membrane concentration polarization layer under turbulent cross flow, J. Memb. Sci. 30 : 153.
  17. Li M., Bui T., Chao S., (2016) Three-dimensional CFD analysis of hydrodynamics and concentration polarization in an industrial RO feed channel, Desalination. 397 :194–204.
  18. Fouladitajar A., Zokaee Ashtiani F., Rezaei H., Haghmoradi A., Kargari A., (2014). Gas sparging to enhance permeate flux and reduce fouling resistances in cross flow microfiltration, J. Ind. Eng. Chem. 20 : 624–632.
  19. Shakaib M., Hasani S.M.F., Mahmood M., (2009) . CFD modeling for flow and mass transfer in spacer-obstructed membrane feed channels, J. Memb. Sci. 326 :270–284.
  20. Monfared M.A., Kasiri N., Salahi A., Mohammadi T., (2012). CFD simulation of baffles arrangement for gelatin-water ultrafiltration in rectangular channel, Desalination. 284 : 288–296.
  21. Ahmed S., Taif Seraji M., Jahedi J., Hashib M.A., (2011). CFD simulation of turbulence promoters in a tubular membrane channel, Desalination. 276 : 191–198.
  22. Wardeh S., Morvan H., (2008). CFD simulations of flow and concentration polarization in spacer-filled channels for application to water desalination, Chem. Eng. Res. Des. 86 : 1107–1116.
  23. Sutzkover I., Hasson D., Semiat R., (2009). Simple technique for measuring the concentration polarization level in a reverse osmosis system, 131 : 117–127.
  24. Geraldes V., Afonso M.D., (2006). Generalized mass-transfer correction factor for nanofiltration and reverse osmosis, AIChE J. 52 : 3353–3362.
  25. Fernandez-Sempere J., Ruiz-Bevia F., Garcia-Algado P., Salcedo-Diaz R., (2010). Experimental study of concentration polarization in a crossflow reverse osmosis system using Digital Holographic Interferometry, Desalination. 257: 36–45.
  26. Subramani A., Kim S., V Hoek E.M., (2006). Pressure, flow, and concentration profiles in open and spacer-filled membrane channels, J. Memb. Sci. 277 : 7–17.
  27. Geraldes V., Semiao V., De Pinho M.N., (2004). Concentration polarisation and flow structure within nanofiltration spiral-wound modules with ladder-type spacers, Comput. Struct. 82 : 1561–1568.
  28. Salcedo-D?az R., Garc?a-Algado P., Garc?a-Rodr?guez M., Fern?ndez-Sempere J., Ruiz-Bevi? F., (2014). Visualization and modeling of the polarization layer in crossflow reverse osmosis in a slit-type channel, J. Memb. Sci. 456 : 21–30.
  29. Ahmad A.L., Lau K.K., (2006). Impact of different spacer filaments geometries on 2D unsteady hydrodynamics and concentration polarization in spiral wound membrane channel, J. Memb. Sci. 286 : 77–92.
  30. Kim S., V Hoek E.M., (2005). Modeling concentration polarization in reverse osmosis processes, Desalination. 186 : 111–128.
  31. Baker R.W.,( 2004). Membrane Technology and Applications, John Wiley & Sons, Ltd, Chichester, UK.
  32. Khayet M., Seman M.N.A., N. Hilal, (2010). Response surface modeling and optimization of composite nanofiltration modified membranes, J. Memb. Sci. 349.
  33. Khayet C.C. M., Essalhi M., (2011). Artificial neural network modeling and response surface methodology of desalination by reverse osmosis, J. Memb. Sci. 368 : 13.
  34. Li R.G. Q.Y., Bellara S.R. , Cui Z.F. , Pepper D.S., (1998). Enhancement of ultrafiltration by gas sparging with flat sheet membrane modules, Sep. Purif. Technol. 14: 5.
  35. Ishii M., Thermo-fluid dynamic theory of two-phase flow, Eyrolles, Paris, 1975
  36. Issa R.I., (1986). Solution of the Implicit Discretized Fluid Flow Equations by Operator Splitting, J. Comput. Phys. 62 : 40–65.
  37. Cavaco Mor?o A.I., Brites Alves A.M., Geraldes V., (2008). Concentration polarization in a reverse osmosis/nanofiltration plate-and-frame membrane module, J. Memb. Sci. 325: 580–591.
  38. Karode S.K., Kumar A., (2001). Flow visualization through spacer filled channels by computational fluid dynamics I. Pressure drop and shear rate calculations for flat sheet geometry, J. Memb. Sci. 193 : 69–84.
  39. Zare M., Fouladitajar A.,(2013). CFD modeling and simulation of concentration polarization in microfiltration of oil–water emulsions; Application of an Eulerian multiphase model, Desalination. 324:11.