Studies in the membrane permeability of chromic ferro and ferricyanides

• Published in: Journal of colloid science Vol. 18; no. 2; pp. 161 - 173
• Main Authors: Malik, Wahid U, Siddiqi, Fasih A
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1963
• ISSN: 0095-8522
• DOI: 10.1016/0095-8522(63)90006-0

The permeability of various electrolytes (with a common cation) through parchment-supported chromic ferro- and ferricyanide membranes was investigated, employing the constant flow method. The permeability order was found to be Cl − > Br > NO 3 − > CNS − > CH 3COO − > SO 4 = > FeCy 6 =− > FeCy 6 == in both cases. A considerable decrease in these values was observed when potassium ferro- and ferricyanide treated membranes were used. Adsorption and membrane potential studies revealed an order that was just the reverse of that for permeability. The energy of activation for the diffusion process for various electrolytes was found to lie between 5000 and 6500 calories per mole, values which are higher than those determined for the free diffusion of electrolytes. The role of Hofmeister series has been considered in relation to the peptizing of the membrane material during the diffusion process and such peptizing appears to be one of the factors controlling the permeability phenomenon.