Modification of transport properties of ion exchange membranes, X formation of polyethyleneimine layer on cation exchange membrane by acid‐amide bond

Abstract

In order to give the monovalent cation permselectivity to the cation exchange membrane permanently, polyethyleneimine layer was formed on the membrane surface by acid-amide bond between polyethyleneimine and the -SQCl groups of a styrene-divinylbenzene copolymer membrane. After the reaction, the -SQCl groups remaining in the inner part of the membrane were hydrolyzed by immersing the membrane into an aqueous sodium hydroxide solution.The resultant cation exchange membranes were evaluated by electrodialysis of sea water from the point of view of the monovalent cation permselectivity, electric resistance of the membrane, current efficiency, and transport number of sodium ions calculated by membrane potential in connection with reduced viscosity of the various commercial polyethyleneimines, ATR-IR measurements on the membrane surface suggested that the acid-amide bond was stable for severe hydrolysis reaction. ZUSAMMENFASSUNG: Um bei Kationen-Austauschmembranen eine dauerhafte Selektivitlt fur die Durchlbsigkeit von einwertigen Kationen zu erzielen, wurde eine Polyethylenimin-Schicht auf der Membranoberfllche durch Saureamidbindung zwischen Polyethylenimin und den -SQCl-Gruppen einer Styrol-co-Divinylbenzol-Membran erzeugt. Nach der Reaktion wurden die im Inneren der Membran verbleibenden -SQCl-Gruppen durch Tauchen in wurige Natronlauge hydrolysiert . Die so gewonnenen Kationen-Austauschmembranen wurden mittels Elektrodialyse von Seewasser hinsichtlich ihrer Selektivitlt fur die Durchlksigkeit von einwertigen Kationen, ihres elektrischen Widerstandes, ihrer Stromleistung und ihrer Uberfiih-* Part IX, submitted to J. Membrane Sci. 0 1989 HUthig & Wepf Verlag, Base1 OOO3-3146/89/$03.00T. Sata and R. Izuo rungszahlen fur Natrium-Ionen untersucht. ATR-IR-Messungen auf der Membranoberflache belegen, da8 die Shreamidbindung gegenllber starker Hydrolyseeinwirkung stabil war.

Diazonium-induced anchoring process: an application to improve the monovalent selectivity of cation exchange membranes

“…8 During the last twenty years, a surface modification route with the aim of contributing to improve the monovalent permselectivity of cation exchange membranes has been tackled by many works. 5,6,[9][10][11][12][13] This modification involved the formation and/or deposition of a cationic polymer such as polyethyleneimine, polyaniline or polypyrrole on the membrane surface. Nevertheless, since the polyethyleneimine layer is primarily maintained at the surface of the membrane by electrostatic interaction, the detachment of the polyelectrolyte layer was observed in certain cases during electrodialysis processes.…”

The Electrochemical Properties of Polysulfone Ion-Exchange Membranes

“…It had been previously reported that a cation exchange membrane is preferentially permeable to cations with a lower valency rather than a higher valency and to larger hydrated cations rather than smaller cations (42)(43)(44)(45). Differences in Neosepta membranes may be their higher permselectivity toward the Ca 2+ ion.…”

Imines, Cyclic

“…In membranes, PEI can act as a proton source in the generation of a photocurrent (456). The formation of a PEI coating on ion-exchange membranes modifies the transport properties and results in permanent selectivity of the membrane (457). The electrochemical testing of salts (458) is another possible application of PEI.…”