A low cost cation exchange membrane to be used in a specific bioelectrochemical system has been developed using poly(ether ether ketone) (PEEK). This material is presented as an alternative to current commercial ion exchange membranes that have been primarily designed for fuel cell applications. To increase the hydrophilicity and ion transport of the PEEK material, charged groups are introduced through sulfonation. The effect of sulfonation and casting conditions on membrane performance has been systematically determined by producing a series of membranes synthesized over an array of reaction and casting conditions. Optimal reaction and casting conditions for producing SPEEK ion exchange membranes with appropriate performance characteristics have been established by this uniquely systematic experimental series. Membrane materials were characterized by ion exchange capacity, water uptake, swelling, potential difference and NMR analysis. Testing this extensive membranes series established that the most appropriate sulfonation conditions were 60 °C for 6 h. For mechanical stability and ease of handling, SPEEK membranes cast from solvent casting concentrations of 15%–25% with a resulting thickness of 30–50 μm were also found to be most suitable from the series of tested casting conditions. Drying conditions did not have any apparent impact on the measured parameters in this study. The conductivity of SPEEK membranes was found to be in the range of 10 ？3 S cm ？1, which is suitable for use as a low cost membrane in the intended bioelectrochemical systems.
Pant, D.; van Bogaert, G.; de Smet, M.; Diels, L.; Vanbroekhoven, K. Use of novel permeable membrane and air cathodes in acetate microbial fuel cells. Electrochim. Acta 2010, 55, 7710–7716, doi:10.1016/j.electacta.2009.11.086.
[3]
Kreuer, K.D. On the development of proton conducting polymer membranes for hydrogen and methanol fuel cells. J. Membr. Sci. 2001, 185, 29–39, doi:10.1016/S0376-7388(00)00632-3.
[4]
Zaidi, S.M.J.; Mikhailenko, S.D.; Robertson, G.P.; Guiver, M.D.; Kaliaguine, S. Proton conducting composite membranes from polyether ether ketone and heteropolyacids for fuel cell applications. J. Membr. Sci. 2000, 173, 17–34, doi:10.1016/S0376-7388(00)00345-8.
[5]
Li, X.; Zhao, C.; Lu, H.; Wang, Z.; Na, H. Direct synthesis of sulfonated poly(ether ether ketone ketone)s (SPEEKKs) proton exchange membranes for fuel cell application. Polymer 2005, 46, 5820–5827, doi:10.1016/j.polymer.2005.04.067.
[6]
Gil, M.; Ji, X.; Li, X.; Na, H.; Hampsey, J.E.; Lu, Y. Direct synthesis of sulfonated aromatic poly(ether ether ketone) proton exchange membranes for fuel cell applications. J. Membr. Sci. 2004, 234, 75–81, doi:10.1016/j.memsci.2003.12.021.
[7]
Park, H.S.; Seo, D.W.; Choi, S.W.; Jeong, Y.G.; Lee, J.H.; Kim, D.I.; Kim, W.-G. Preparation and characterization of branched and linear sulfonated poly(ether ketone sulfone) proton exchange membranes for fuel cell applications. J. Polym. Sci. A Polym. Chem. 2008, 46, 1792–1799, doi:10.1002/pola.22522.
Harrison, W.L.; Wang, F.; Mecham, J.B.; Bhanu, V.A.; Hill, M.; Kim, Y.S.; McGrath, J.E. Influence of the bisphenol structure on the direct synthesis of sulfonated poly(arylene ether) copolymers. J. Polym. Sci. A Polym. Chem. 2003, 41, 2264–2276.
[10]
Wang, F.; Li, J.; Chen, T.; Xu, J. Synthesis of poly(ether ether ketone) with high content of sodium sulfonate groups and its membrane characteristics. Polymer 1999, 40, 795–799, doi:10.1016/S0032-3861(98)00292-4.
[11]
Balster, J.; Krupenko, O.; Pint, I.; Stamatialis, D.F.; Wessling, M. Preparation and characterisation of monovalent ion selective cation exchange membranes based on sulphonated poly(ether ether ketone). J. Membr. Sci. 2005, 263, 137–145, doi:10.1016/j.memsci.2005.04.019.
[12]
Zhang, S.; Jian, X.; Dai, Y. Preparation of sulfonated poly(phthalazinone ether sulfone ketone) composite nanofiltration membrane. J. Membr. Sci. 2005, 246, 121–126, doi:10.1016/j.memsci.2004.04.013.
[13]
Hu, K.Y.; Xu, T.W.; Fu, Y.X.; Yang, W.H. Preparation of a novel semi-homogenous cation permeable membranes from blends of sulfonated poly(phenylene sulfide) (SPPS) and sulfonated phenolphthalein poly(ether ether ketone) (SPEEK-C). J. Appl. Polym. Sci. 2004, 92, 1478, doi:10.1002/app.13719.
[14]
Dai, Y.; Jian, X.; Zhang, S.; Guiver, M.D. Thin film composite (TFC) membranes with improved thermal stability from sulfonated poly(phthalazinone ether sulfone ketone) (SPPESK). J. Membr. Sci. 2002, 207, 189–197, doi:10.1016/S0376-7388(02)00226-0.
[15]
Li, L.; Zhang, J.; Wang, Y. Sulfonated poly(ether ether ketone) membranes for direct methanol fuel cell. J. Membr. Sci. 2003, 226, 159–167, doi:10.1016/j.memsci.2003.08.018.
[16]
Xue, S.; Yin, G. Methanol permeability in sulfonated poly(etheretherketone) membranes: A comparison with Nafion membranes. Eur. Polym. J. 2006, 42, 776–785, doi:10.1016/j.eurpolymj.2005.10.008.
[17]
Huang, R.Y.M.; Shao, P.; Burns, C.M.; Feng, X. Sulfonation of poly(ether ether ketone)(PEEK): Kinetic study and characterization. J. Appl. Polym. Sci. 2001, 82, 2651–2660.
[18]
Xing, P.; Robertson, G.P.; Guiver, M.D.; Mikhailenko, S.D.; Wang, K.; Kaliaguine, S. Synthesis and characterization of sulfonated poly(ether ether ketone) for proton exchange membranes. J. Membr. Sci. 2004, 229, 95–106, doi:10.1016/j.memsci.2003.09.019.
[19]
Klaysom, C.; Ladewig, B.P.; Lu, G.Q.M.; Wang, L. Preparation and characterization of sulfonated polyethersulfone for cation-exchange membranes. J. Membr. Sci. 2011, 368, 48–53, doi:10.1016/j.memsci.2010.11.006.
[20]
Gohil, G.S.; Nagarale, R.K.; Binsu, V.V.; Shahi, V.K. Preparation and characterization of monovalent cation selective sulfonated poly(ether ether ketone) and poly(ether sulfone) composite membranes. J. Colloid Interface Sci. 2006, 298, 845–853, doi:10.1016/j.jcis.2005.12.069.
[21]
Basile, A.; Paturzo, L.; Iulianelli, A.; Gatto, I.; Passalacqua, E. Sulfonated PEEK-WC membranes for proton-exchange membrane fuel cell: Effect of the increasing level of sulfonation on electrochemical performances. J. Membr. Sci. 2006, 281, 377–385, doi:10.1016/j.memsci.2006.04.006.
[22]
Guenther, J.; Bremner, T.; Blumel, J. Characterization of PEEK (polyetheretherketone) Polymers by Solid-State NMR Spectroscopy. In Proceedings of High Performance Thermoplastics and Composites for Oil and Gas Applications, Houston, TX, USA, 11–12 October 2011.
[23]
Gohil, G.S.; Shahi, V.K.; Rangarajan, R. Comparative studies on electrochemical characterization of homogeneous and heterogeneous type of ion-exchange membranes. J. Membr. Sci. 2004, 240, 211–219, doi:10.1016/j.memsci.2004.04.022.
[24]
Drioli, E.; Regina, A.; Casciola, M.; Oliveti, A.; Trotta, F.; Massari, T. Sulfonated PEEK-WC membranes for possible fuel cell applications. J. Membr. Sci. 2004, 228, 139–148, doi:10.1016/j.memsci.2003.07.023.
[25]
Li, X.; Wang, Z.; Lu, H.; Zhao, C.; Na, H.; Zhao, C. Electrochemical properties of sulfonated PEEK used for ion exchange membranes. J. Membr. Sci. 2005, 254, 147–155, doi:10.1016/j.memsci.2004.12.051.
[26]
Okada, T.; Xie, G.; Gorseth, O.; Kjelstrup, S.; Nakamura, N.; Arimura, T. Ion and water transport characteristics of Nafion membranes as electrolytes. Electrochim. Acta 1998, 43, 3741–3747, doi:10.1016/S0013-4686(98)00132-7.
[27]
Sevada, S.; Xominguez-Benetton, X.; Vanbroekhoven, K.; Sreekrishnan, T.R.; Pant, D. Characterization and comparison of the performance of two different separator types in air-cathode microbial fuel cell treating synthetic wastewater. Chem. Eng. J. 2013, 228, 1–11, doi:10.1016/j.cej.2013.05.014.
[28]
Li, L.-F.; Ma, F.; Faris, S.M.U.S.; Kukovitskiy, B. Polyelectrolyte membranes as separator for battery and fuel cell applications. U.S. Patent 20070020501, 25 January 2007.
