The selective behaviour of ion-exchange membranes at high concentrations

✍ Scribed by G.G. Madgwick

• Publisher: Elsevier Science
• Year: 1957
• Tongue: English
• Weight: 659 KB
• Volume: 6
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(57)85001-5

✦ Synopsis

Abatrac

-The eelective properties of the ion-permeable membrane " Permaplex A-10 " and " Permaplex C-10 " in concentrated sodimu-chloride solutions have been studied. Transport numbers have been obtained aa a function of the mean concentration and concentration ratio existing outside the membranea. For a given mean concentration, both membranes show higher selectivity for high concentration ratios. Membrane tramport numbers approach O-6 at saturation. It has been shown that a three compartment cell, operating under special conditions, may demon&rate the true nelectivity of the membranes. Back diffusion of electrode producta was limited by high ilow ratea and short running times. Current efhciencies fall below those predicted from transport numbem, largely due to electro-osmosis, and are less than 90% at saturation. &%um&L'auteur titudie lea prori&.& dlectivea dea membranes semi-permeables " Permaplex A-10 " et '( Permaplex C-10 " dana des solutions concentr&s de chlorure de sodium. 11 a obtenu les nombres de transfer% en for&ion de la concentration moyenne et du rapport den concentrations B l'ext&ieur des membranes. Pour une concentration moyenne don&e, lea deux membranes montrent une s&ctivit4 plus grande pour des rapports de concentration elevt+s. A la saturation, lea nombrea de tramfert s'approchent de 0.6. L'auteur montre qu'avec une cellule B troia compartlmenta travaillant dam de13 conditions d&ermim%s, on peut mettre en evidence la &?ctivit4 r&lle des membranes. G&e B den vitemea d'ecoulement rapidea et des dur4es mftlsamment courtes, on peut aloe limiter la diffu&n en retard des produita aux &&odes.

Les rendements en courant descendent au-dessoua des valeura prdvu~ B partir des nombrea de transport, en grande partie B cause de l'&ctro-osmose. A la saturation, ils sent r&iuits de 90%.