M. NASIM BEG, FASIH A. SIDDIQI, and RADHEY SHYAM. Can. J. Chem. 55, 1680Chem. 55, (1977. Effective fixed charge densities of cobalt and nickel sulphide (parchment supported) membranes in contact with various 1 : 1 electrolyte solutions have been evaluated from membrane potential n~easurements. The methods used for the estimation of charge densities were: (a) the Teorell-Meper-Sievers method (TMS) and (b) the methods developed recently by Kobatake and co-workers. The two limiting forms of Kobatake's equation for dilute and concentrated solutions gave identical values of charge densities. The theoretical predictions for membrane potential were borne out quite satisfactorily by experimental results obtained with both the membranes. Apparent transference numbers of coions and permselectivities of the membranes for electrolytes have also been calculated. A method based on permselectivity values for the determination of charge density was also used. It was interesting to note that the charge densities evaluated from different methods of Kobatake and co-workers gave identical values and that the results were comparable to those derived from the TMS method.M. NASIM BEG, FASIH A. SIDDIQI et RADHEY SHYAM. Can. J. Chem. 55. 1680Chem. 55. (1977. On a evalue, a partir de mesures de potentiel dc mcmbrancs, les densites effectives de chargcs fixes pour des membranes de sulfures de cobalt et de nickel (supportes sur du parchemin) en contact avec diverses solutions d'Clectrolytes 1: I. Les rnethodes utiliskes pour tvaluer les densites de charges sont: (a) la methode de Teorell-Meyer-Sievers et (b) les methodes developptes recemn~ent par Kobatake et ses collaborateurs. Les deux formes limites de I'equation de Kobatake pour des solutions diluees et concentrkes conduisent a des valeurs identiques pour les densites de charge. Les predictions theoriques pour les potentiels des membranes concordent bien avec les resultats experimentaux obtenus avec les deux membranes. On a aussi calcule les nombres apparents de transferts des coions et les permselectivitts des membranes pour les Plectrolytes. On a aussi utilise une methode basee sur des valeurs de permselectivitt pour la determination de la densite de charge. I1 est interessant de noter que les densites de charges tvaluecs par diverses methodes de Kobatake et ses collaborateurs conduisent toutes a des valeurs identiques et que les rtsultats sont comparables a ceux que l'on peut obtenir a partir de la mithode TMS.[Traduit par le journal]In a series of co~nmunicatio~ls (1-10) on parchment supported membranes, Siddiqi, Beg, and co-workers (1-6) have, on the basis of the Eisenman-Sherry model of membrane selectivity (1 1, 12) and by the application of the theory of rate processes to diffusion (13). demonstrated the small density of fixed charge on the membrane matrix. In order to substantiate these findings, membrane potential measurements have been carried out for the evaluation of effective fixed charge density which is an important characteristic of a membrane by various methods (1...

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Thermodynamically effective fixed charge densities of mercuric and cupric iodide parchment supported membranes were estimated by methods of Teorell, Meyer, and Sievers; Altug and Hair; and the most recent one of Kobatake and co‐workers based on the thermodynamics of irreversible processes. The two limiting forms of Kobatake's equation for dilute and concentrated ranges gave identical values of charge densities. It is interesting to note that these two values of limiting cases are closer to the Teorell‐Meyer‐Sievers and Altug‐Hair values. The theoretical predictions for membrane potential by the Kobatake equation were borne out quite satisfactorily by experimental results obtained with both the membranes.

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FASIH A. SIDDIQI, M. NASIM BEG, M. IBADUR RAHMAN KHAN, ABDUL HAQ, S. K . SAKSENA, and BADRUL ISLAM. Can. J. Chem. 56,2205Chem. 56, (1978.The various ionic processes in the membrane system, notably (a) ionic transport, (6) membrane potential, (c) electrical conductivity, (d) ionic distribution equilibria, and (e) spatial distribution of ions and the potential within the membrane have been thoroughly studied with parchment-supported membranes. By applying the theory of absolute reaction rate, various thermodynamic parameters, namely, enthalpy of activation A H * , energy of activation AF*, and entropy of activation AS* were evaluated. The AS* values were found to be negative, indicating that diffusion takes place with partial immobilization in the membrane phase. A formal relation between AHhydralion, AFhydrPlion, and AS,,,,,,,,, of cations with corresponding values of A H * , AF*, and AS* for diffusion was also worked out. Thermodynamically fixed charge density was evaluated using methods based on thermodynamics of irreversible processes. Potentiometric selectivity and recent theory of bi-ionic potential based on nonequilibrium thermodynamics was tested and found applicable to parchment membranes. On a trouve que les valeurs de AS* sont negatives; ceci indique que la diffusion a lieu par une immobilisation partielle dans la phase de la membrane. On a aussi pu etablir une relation formelle entre les AH,IYdIPldllOn, AFhydr.lil,ion et des cations avec les valeurs correspondantes de A H * , AF* et AS* pour la diffusion. On a evalue la densite de charge fixe thermodynamique en faisant appel a des methodes basCes sur la therrnodynamique de processus irreversibles. On a Cvalue la selectivitk potentiometrique et la thtorie ricente du potentiel bi-ionique, basee sur la thermodynamique des phenomenes irreversibles, et on a trouvC qu'on peut I'appliquer aux membranes de parchemin.