Membrane separations of volatile organic compounds from air offer many advantages in comparison with the conventional methods [1]: energy savings, environmental friendliness, easy handling, continuous process, compact design and small footprint. Mixed Matrix Membranes (MMMs), consisting of a dispersion of filler particles within a polymeric matrix, are potentially suitable to combine the exclusive advantages in separation performance of both inorganic and polymeric materials. Chemical structure, surface chemistry, size, and aspect ratio are the most important variables for filler selection, whereas filler-polymer compatibility and filler distribution are the key points for an effective MMMs preparation [2]. The elastomeric ethylene-octene copolymer (EOC) was chosen as it is more permeable than the semi-crystalline analogous polyolefins polyethylene and polypropylene [3]. MMMs based on EOC with three types of carbon fillers, virgin or oxidized multi-walled carbon nanotubes and carbon fibres, were investigated [4]. The mechanical properties and homogeneity of the samples were checked by stress-strain tests. Helium, hydrogen, nitrogen, oxygen, methane and carbon dioxide were used for gas permeation rate measurements. Theoretical Maxwell's model was used to predict and interpret gas transport properties in MMMs. Vapour transport properties were studied for aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water. Organic vapours result more permeable than permanent gases in EOC-based membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. Carbon-filled membranes show that the EOC is an organophilic material that offers perspectives for application in gas/vapour separation with improved mechanical resistance. Acknowledgements: The financial support from the Technology Agency of the Czech Republic (project TE01020080) is greatly appreciated. The financial support of the Italian National Program, "Programma Operativo Nazionale Ricerca e Competitività 2007-2013", project PON01_01840 "MicroPERLA" is gratefully acknowledged. The work was also supported by the Operational Program of Research and Development for Innovations co-funded by the European Regional Development Fund (ERDF), the National budget of Czech Republic within the framework of the Centre of Polymer Systems project (reg. number: CZ.1.05/2.1.00/03.0111). 1.P. Bernardo et al. Ind. Eng. Chem. Res. 48 (2009) 4638-4663. 2.T. S. Chung et al. Prog. Polym. Sci. 255 (2005) 13-22. 3.J. Togawa et al. J. Membr. Sci. 188 (2001) 39-48. 4.Z. Sedláková et al. Membranes, 4 (2014) 20-39.
Gas and vapour transport and mechanical properties of carbon nanotube and carbon fibre-reinforcement of ethylene-octene copolymer membranes
G Clarizia;P Bernardo;J C Jansen;
2014
Abstract
Membrane separations of volatile organic compounds from air offer many advantages in comparison with the conventional methods [1]: energy savings, environmental friendliness, easy handling, continuous process, compact design and small footprint. Mixed Matrix Membranes (MMMs), consisting of a dispersion of filler particles within a polymeric matrix, are potentially suitable to combine the exclusive advantages in separation performance of both inorganic and polymeric materials. Chemical structure, surface chemistry, size, and aspect ratio are the most important variables for filler selection, whereas filler-polymer compatibility and filler distribution are the key points for an effective MMMs preparation [2]. The elastomeric ethylene-octene copolymer (EOC) was chosen as it is more permeable than the semi-crystalline analogous polyolefins polyethylene and polypropylene [3]. MMMs based on EOC with three types of carbon fillers, virgin or oxidized multi-walled carbon nanotubes and carbon fibres, were investigated [4]. The mechanical properties and homogeneity of the samples were checked by stress-strain tests. Helium, hydrogen, nitrogen, oxygen, methane and carbon dioxide were used for gas permeation rate measurements. Theoretical Maxwell's model was used to predict and interpret gas transport properties in MMMs. Vapour transport properties were studied for aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water. Organic vapours result more permeable than permanent gases in EOC-based membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. Carbon-filled membranes show that the EOC is an organophilic material that offers perspectives for application in gas/vapour separation with improved mechanical resistance. Acknowledgements: The financial support from the Technology Agency of the Czech Republic (project TE01020080) is greatly appreciated. The financial support of the Italian National Program, "Programma Operativo Nazionale Ricerca e Competitività 2007-2013", project PON01_01840 "MicroPERLA" is gratefully acknowledged. The work was also supported by the Operational Program of Research and Development for Innovations co-funded by the European Regional Development Fund (ERDF), the National budget of Czech Republic within the framework of the Centre of Polymer Systems project (reg. number: CZ.1.05/2.1.00/03.0111). 1.P. Bernardo et al. Ind. Eng. Chem. Res. 48 (2009) 4638-4663. 2.T. S. Chung et al. Prog. Polym. Sci. 255 (2005) 13-22. 3.J. Togawa et al. J. Membr. Sci. 188 (2001) 39-48. 4.Z. Sedláková et al. Membranes, 4 (2014) 20-39.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.