Comparison of the Separation Characteristics of Polyvinyl Alcohol Membrane in Dehydration of Benzene and Toluene Using Pervaporation

Document Type: Research Paper


1 Chemical Polymeric & Petrochemical Technology Development Research Division, Research Institute of Petroleum Industry, Tehran, IRAN

2 Chemical, Polymeric & Petrochemical Technology Development Research Division Research Institute of Petroleum Industry


Pervaporation (PV) is a well-established membrane technique used in separation; especially dehydration of organic solvents. Along with other parameters such as permeate pressure and feed temperature; feed composition is an important parameter, which affects separation characteristics and membrane performance in pervaporation. In this paper, the separation characteristics of a hydrophilic polyvinyl alcohol (PVA) membrane in the dehydration of benzene and toluene by pervaporation in the temperature range of 30-60 °C and permeate pressure of 7 mmHg have been compared. The results show that the difference in the molecular sizes of benzene and toluene and their mutual solubilities with water cause differences in separation parameters, so that for example at 50 °C, in dehydration of benzene water flux and water concentration in the permeate are 0.53 (g/hm2) and 2.03 (wt.%) respectively, while the corresponding values in toluene dehydration are 0.61 (g/hm2) and 3.19 (wt.%) respectively. Therefore these amounts result in higher pervaporation separation index (PSI) for toluene compared to benzene.


Joshi S. and Fair J. R., “Adsorptive Drying of Hydrocarbon Liquids,” Ind. Eng. Chem. Res., 1991, 30(1), 177-185.

Neel J. and Huang R. Y. M., “Introduction to Pervaporation. In: Pervaporation Membrane Separation processes,” Amsterdam, the Netherlands: Elsevier Science, 1991, 36-37.

Bruggen B. V. and Luis P., “Pervaporation, in Progress in Filtration and Separation,” R. J. Wakeman, Ed., Chapter 4, Elsevier Scientific, 1979, University of California, 2015.

Ling L. Y., Chieh H. C., Yih L. J., and Ling L. Y., “Crosslinked Polybenzoxazine Based Membrane Exhibiting In-situ Self-promoted Separation Performance for Pervaporation Dehydration on Isopropanol Aqueous Solutions,” J. Membr. Sci., 2017, 531, 10-15.

Liu J. and Bernstein R., “High-flux Thin-film Composite Polyelectrolyte Hydrogel Membranes for Ethanol Dehydration by Pervaporation,” J. Membr. Sci., 2017, 534, 83-91.

Paramita D., Ray S.K Kuila S. B., Samanta H. S., and Singha N. R., “Systematic Choice of Crosslinker and Filler for Pervaporation Membrane: A Case Study with Dehydration of Isopropyl Alcohol–water Mixtures by Polyvinyl Alcohol Membranes,” Sep. Purif. Technol., 2011, 81(2), 159-173.

Chen M., Wu X., Soyekwo F., Zhang Q., and et al., “Toward Improved Hydrophilicity of Polymers of Intrinsic Microporosity for Pervaporation Dehydration of Ethylene Glycol,” Sep. Purif. Technol., 2017, 174, 166-173.

Jen Han Y., Chiung Su W., Yih Lai J., and Ling Liu Y., “Hydrophilically Surface-modified and Crosslinked Polybenzimidazole Membranes for Pervaporation Dehydration on Tetrahydrofuran Aqueous Solutions,” J. Membr. Sci., 2015, 475, 496-503.

Lixin Y., Cuixian C., Liping Z., Jun Y., and Weijun J., “Study on the Dehydration of Organic Solvents by Pervaporation and the Mass Transfer Mechanism of Pervaporation,” Tsinghua Science and Technology, 1996, 1, 351-356.

Gutch P. K., Pandey L. K., and Saxena C., “Dehydration of Benzene through Fluorine Containing Aromatic Polyamide Membrane by Pervaporatio,” J. Appl. Polym. Sci., 2008, 110, 203-209.

Li J., Chen C., Han B., and Peng, Y., “Laboratory and Pilot-scale Study on Dehydration of Benzene by Pervaporation,” J. Membr. Sci., 2002, 203, 127-136.

Khatinzadeh G., Mhadyarfar M., Mehdizadeh A., Esmailzadeh A., and et al., “Effect of Permeate Pressure and Feed Flow Rate on Benzene Dehydration by Pervaporation,” J. Pet. Sci. Technol., 2016, 6(2), 30-36

Immelman E., Sanderson R. D., Jacobs E. P., and Van Reenen A. J., “Poly(vinyl alcohol) Gel Sublayers for Reverse Osmosis Membranes. I. Insolubilization by Acid-catalyzed Dehydration,” J. Appl. Polym. Sci., 1993, 50, 1013-1034.

Vijaya K. N. B., Krishna R. K .S. V., and Aminabhavi T. M., “Pervaporation Separation of Water + 1,4-dioxane and Water + Tetrahydrofuran Mixtures Using Sodium Alginate and its Blend Membranes with Hydroxyethylcellulose-A Comparative Study,” J. Membr. Sci., 2005, 260, 131–141.

Kuan Y. H., Ren J., Hua M. X., and Liang X. Z., “Dehydration of Ethyl Acetate Aqueous Solution by Pervaporation Using PVA/PAN Hollow Fiber Composite Membrane,” Desalination, 2011, 280, 252–258.

Binning R. C., Lee R. J., Jenning J. F., and Martin E. C., “Separation of Liquid Mixtures by Permeation,” Ind. Eng. Chem., 1961, 53, 6-50.

Wijmans J. G. and Baker R. W., “The Solution-Diffusion Model: A Review,” J. Membr. Sci., 1995, 107, 1-27.

Graziano G., “Benzene Solubility in Water: A Reassessment,” Chem. Phys. Lett., 2006, 429, 114-118.

Polak j. and Benjamin C. Y. L., “Mutual Solubilities of Hydrocarbons and Water at 0 and 25 oC,” Can. J. Chem., 1973, 51, 4018-4023.

Svang-Ariyaskul A., Huang R. Y. M., and Douglas P. L., “Blended Chitosan and Polyvinyl Alcohol Membranes for the Pervaporation Dehydration of Isopropanol,” J. Membr. Sci., 2006, 280, 815-823.

Cabasso I., Grodzinski J. J., and Vofsi D., “Polymeric Alloys of Polyphosphonates and Acetyl Cellulose: Sorption and diffusion of benzene and cyclohexane,” J. Appl. Polym. Sci., 1974, 18, 2117-2136.

Jyoti G., Keshav A., and Anandkumar J., “Review on Pervaporation: Theory, Membrane Performance, and Application to Intensification of Esterification Reaction,” Journal of Engineering, 2015, 1-24.

Nawawi M. G. and Huang R.Y.M., “Pervaporation Dehydration of Isopropanol with Chitosan Membranes,” J. Membr. Sci., 1997, 124, 53-62.