title: Tailor-made anion-exchange membranes for salinity gradient power generation using reverse electrodialysis.
abstract: Reverse electrodialysis (RED) or blue energy is a non-polluting, sustainable technology for generating power from the mixing of solutions with different salinity, that is, seawater and river water. A concentrated salt solution (e.g., seawater) and a diluted salt solution (e.g., river water) are brought into contact through an alternating series of polymeric anion-exchange membranes (AEMs) and cation-exchange membranes (CEMs), which are either selective for anions or cations. Currently available ion-exchange membranes are not optimized for RED, whereas successful RED operation notably depends on the used ion-exchange membranes. We designed such ion-exchange membranes and for the first time we show the performance of tailor-made membranes in RED. More specifically, we focus on the development of AEMs because these are much more complex to prepare. Herein we propose a safe and more environmentally friendly method and use halogenated polyethers, such as polyepichlorohydrin (PECH) as the starting material. A tertiary diamine (1,4-diazabicyclo[2.2.2]octane, DABCO) was used to introduce the ion-exchange groups by amination and for simultaneous cross-linking of the polymer membrane. Area resistances of the series of membranes ranged from 0.82 to 2.05 Ω cm² and permselectivities from 87 to 90 %. For the first time we showed that tailor-made ion-exchange membranes can be applied in RED. Depending on the properties and especially membrane thickness, application of these membranes in RED resulted in a high power density of 1.27 W m⁻², which exceeds the power output obtained with the commercially available AMX membranes. This shows the potential of the design of ion-exchange membranes for a viable blue energy process.
authors.affiliation: Membrane Science & Technology, Mesa+, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Enver
authors.initials: E
authors.lastname: Guler
authors.forename: Yali
authors.initials: Y
authors.lastname: Zhang
authors.forename: Michel
authors.initials: M
authors.lastname: Saakes
authors.forename: Kitty
authors.initials: K
authors.lastname: Nijmeijer
mesh_terms: D003956:Dialysis / Q000379:methods*; D003959:Diamines / Q000737:chemistry; D011211:Electric Power Supplies; D007474:Ion Exchange; D008567:Membranes, Artificial; D011108:Polymers / Q000737:chemistry; D054712:Salinity
chemical_list: D003959:Diamines; D008567:Membranes, Artificial; D011108:Polymers