Pervaporation application of toluene removal from aqueous solutions by ECTFE membranes (Abstract/Comunicazione in atti di convegno)

Type
Label
  • Pervaporation application of toluene removal from aqueous solutions by ECTFE membranes (Abstract/Comunicazione in atti di convegno) (literal)
Anno
  • 2013-01-01T00:00:00+01:00 (literal)
Alternative label
  • F. Galiano, A. Figoli, S. Simone, S. Santoro, S. M. Alfadul, Omar A. Al-Harbi, E. Drioli (2013)
    Pervaporation application of toluene removal from aqueous solutions by ECTFE membranes
    in International Scientific Conference on Pervaporation, Vapor Permeation and Membrane Distillation, Torun (Polonia), 12-15/05/2013
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • F. Galiano, A. Figoli, S. Simone, S. Santoro, S. M. Alfadul, Omar A. Al-Harbi, E. Drioli (literal)
Note
  • Comunicazione (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Institute of Membrane Technology, ITM-CNR, University of Calabria, Cosenza, Italy. National Center for Water Technology, King Abdulaziz City for Science and Technology (KACST), Kingdom of Saudi Arabia. Department of Chemical Engineering and Materials, University of Calabria, Cosenza, Italy . (literal)
Titolo
  • Pervaporation application of toluene removal from aqueous solutions by ECTFE membranes (literal)
Abstract
  • Volatile Organic Compounds (VOCs) are usually present as contaminants in the effluents of many industries. Most toxic VOCs, such as toluene, benzene or xylene, in fact, are widely used in paint and synthetic resin industries [1]. Their removal with traditional techniques such as distillation or liquid/liquid extraction could be expensive and not suitable for components which lead, at a certain concentrations, to the formation of azeotropic mixtures. Among the different membrane separation techniques, pervaporation (PV) can be considered a very promising technology offering numerous advantages such as low environmental impact, high standards, low energy requirements and the possibility to separate components with close boiling point [2]. Hydrophobic PV, in particular, was successfully used for the removal of VOCs present in the wastewaters of many industries [3]. The objective of this work was the removal of toluene from aqueous solutions by PV using Ethylene-Chlorotrifluoroethylene copolymer (ECTFE) solvent resistant membranes prepared by thermal induced phase separation (TIPS) [4]. Due to the hard processability of this polymer, four different additives have been added to the polymeric solution: glycerol triacetate (GTA), tri-ethyl citrate (CTF), dibutyl itaconate (DBI) and diethyl adipate (DEA). The use of these plasticizers allowed to lower the preparation temperature of ECTFE membranes from 230-260°C (as reported in literature [5,6]) to 180°C using N-methyl pyrrolidone (NMP) as solvent. SEM analyses of the obtained membranes, showed a dense skin over a support layer with a spherulitic structure, providing, respectively, a dense top layer and a porous support. Contact angle measurements testified the hydrophobic nature of all prepared membranes with a higher contact angle for the bottom side (? 100°) than the one of the top side (? 90°). This result was explained considering the effect of the higher roughness and porosity of the bottom side of the membrane. The organic solvent resistance of ECTFE membranes was demonstrated by solvent uptake tests. After immersion of the membranes , in fact, in some aggressive solvents, such as DMA, DMF, toluene, MeOH, THF, Acetone, Chloroform and NMP no damages or cracks were observed. Therefore, the obtained membranes, were considered good candidates to be used for organic/organic and organic/water separation. In this study, toluene removal from water by PV using ECTFE membranes was studied. From the pervaporation test results, membrane prepared using GTA as additive showed the best selectivity toward toluene (? = 4628 at 40 mbar) while membrane prepared with CTF presented higher fluxes due to its lower thickness. Furthermore, the increase of downstream pressure (from1 to 40 mbar) resulted in higher selectivity as a consequence of the more pronounced decrease of the water vapor pressure difference with respect to toluene. Volatility of toluene, in fact, is higher than water and it easily permeated trough the membrane. REFERENCES [1] S. Chovau, A. Dobrak, A. Figoli, F. Galiano, S.Simone, E. Drioli, S.K. Sikdar, B. Van der Bruggen, Pervaporation performance of unfilled and filled PDMS membranes and novel SBS membranes for the removal of toluene from diluted aqueous solutions, Chemical Engineering Journal 159 (2010) 37-46. [2] E. Quiñones-Bolaños, H. Zhou, R. Soundararajan, L. Otten, Water and solute transport in pervaporation hydrophilic membranes to reclaim contaminated water for micro-irrigation, Journal of Membrane Science 252 (2005) 19-28. [3] K. Konieczny, M. Bodzek, D. Panek, Removal of volatile compounds from the wastewaters by use of pervaporation, Desalination 223 (2008) 344-348. [4] S. Simone, A. Figoli, S. Santoro, F. Galiano, S.M. Alfadul, Omar A. Al-Harbi, E. Drioli, Preparation and characterization of ECTFE solvent resistant membranes and their application in pervaporation of toluene/water mixture, Separation and Purification Technology 90 (2012) 147-161. [5] S. Ramaswamy, A.R. Greenberg, W.B. Krantz, Fabrication of poly (ECTFE) membranes via thermally induced phase separation, J. Membr. Sci. 210 (2002) 175-180. [6] D. Mullette, H.J. Muller, Halar membranes, US Patent Application Publication No. 2005/ 0098494 A1 (2005). Acknowledgments The authors acknowledge the financial support of the King Abdulaziz City for Science and Technology (KACST), Kingdom of Saudi Arabia (literal)
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