Investigation of Fouling of Membranes of a Reverse Osmosis Unit by Silica

Sadeddin Kherfan

doi:10.4236/oalib.1100485

Home > Journals > Biomedical & Life Sciences | Business & Economics > OALibJ

Open Access Library Journal > Vol.1 No.3, June 2014

Investigation of Fouling of Membranes of a Reverse Osmosis Unit by Silica ()

Sadeddin Kherfan

Faculty of Chemical & Petroleum Engineering, Baath University, Homs, Syria.

DOI: 10.4236/oalib.1100485 PDF 1,036 Downloads 1,855 Views

Abstract

A reverse osmosis unit to treat ground water in Saboura/Syria has been in operation for several years. It suffered frequently from severe fouling of membranes. This led to frequent stoppages and losses of flow. Operators of the unit reported the formation of white solid scales on the membranes. It is well known that membranes treating ground water suffer from precipitates such as CaCO₃, CaSO₄, Fe, Al, Silica compounds, colloidal matters, bacteria and others. In this study analysis of the solid scales on the membranes showed that silica is the main scaling component. So experiments were carried out to investigate the effect of silica concentration in ground water and other variables such as pressure, pH, metal cations and type of membrane on fouling. The results obtained showed that silica has a direct effect on fouling of membranes. This is influenced by many parameters. Increasing pressure leads to increase in flow rates of water through the membranes. Reduction of pH causes less scaling of silica on the membranes. Cations present in water such as calcium and magnesium help in forming polymeric silicates which cause fouling.

Keywords

Reverse Osmosis, Fouling, Silica, Pretreatment, Membrane

Share and Cite:

Kherfan, S. (2014) Investigation of Fouling of Membranes of a Reverse Osmosis Unit by Silica. Open Access Library Journal, 1, 1-7. doi: 10.4236/oalib.1100485.

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Lisitsin, D., Hasson, D. and Semiat, R. (2005) Critical Flux Detection in a Silica Scaling RO System. Desalination, 186, 311-318. http://dx.doi.org/10.1016/j.desal.2005.06.007
[2]	Den, W. and Wang, C.-J. (2008) Removal of Silica from Brackish Water by Electrocoagulation Pretreatment to Prevent Fouling of Reverse Osmosis Membranes. Separation and Purification Technology, 59, 318-325. http://dx.doi.org/10.1016/j.seppur.2007.07.025
[3]	Ning, R.Y., Troyer, T.L. and Tominello, R.S. (2005) Chemical Control of Colloidal Fouling of Reverse Osmosis Systems. Desalination, 172, 1-6. http://dx.doi.org/10.1016/j.desal.2004.06.192
[4]	Sheikholeslami, R., Al-Mutaz, I.S., Tan, S. and Tan, S.D. (2002) Some Aspects of Silica Polymerization and Fouling and Its Pretreatment by Sodium Aluminate, Lime and Soda Ash. Desalination, 150, 85-92. http://dx.doi.org/10.1016/S0011-9164(02)00932-3
[5]	Darton, E.G. (2001) Perma Care International, Aquazur Ltd., Chapel House, Alma.
[6]	Sahachaiyunta, P., Loo, T. and Sheikholeslami, R. (2002) Effect of Several Inorganic Species on Silica Fouling in RO Membranes. Desalination, 144, 373-378. http://dx.doi.org/10.1016/S0011-9164(02)00346-6
[7]	Higgin, R. (2009) Synergistic Behavior between Silica and Alginate. Separation and Purification Technology, 70, 112-117.
[8]	Cheng, H.-H., Chen, S.-S. and Yang, S.-R. (2009) In-Line Coagulation/Ultrafiltration for Silica Removal from Brackish Water as RO Membrane Pretreatment. Separation and Purification Technology, 70, 112-117. http://dx.doi.org/10.1016/j.seppur.2009.09.001
[9]	Amjad, Z. and Zuhl, R.W. (2010) The Role of Water Chemistry on Preventing Silica Fouling in Industrial Water Systems. NACE-International Corrosion Conference Series, 14 p.