Transport properties of phosphonic acid and sulfonic acid cation exchange membranes

The Electrochemical Properties of Polysulfone Ion-Exchange Membranes

“…The ion-exchange equilibrium constant of Ca 2+ over Na + ions for phosphonic acid and sulfonic acid cation exchange membranes was about 2 and 4, respectively (15). The selectivity order was Cs…”

Preparation and study of cellulose acetate membranes modified with linear polymers covalently bonded to Starburst polyamidoamine dendrimers

“…Size exclusion and noncovalent interactions of species in solution and specifically positioned functional groups within a membrane structure have been successfully used to prepare materials that offer the possibility of the efficient separation of compounds in a given mixture; this has resulted in a wide variety of economically and technically feasible technologies that are currently being used in various industrial processes. 1,2 Among the many reports directed toward the development of novel membrane materials, Sata and coworkers [3][4][5][6] have reported extensive and interesting work on the preparation and modification of ionexchange membranes. They have, for instance, successfully used chloromethylstyrene and divinylbenzene copolymers to synthesize phosphonic acid and sulfonic acid cation-exchange membranes, 3 and they have modified commercial ion-exchange membranes with polyaniline in the presence of ammonium peroxodisulfate 4 and cyclodextrins 5 to improve membrane permeability properties.…”

“…1,2 Among the many reports directed toward the development of novel membrane materials, Sata and coworkers [3][4][5][6] have reported extensive and interesting work on the preparation and modification of ionexchange membranes. They have, for instance, successfully used chloromethylstyrene and divinylbenzene copolymers to synthesize phosphonic acid and sulfonic acid cation-exchange membranes, 3 and they have modified commercial ion-exchange membranes with polyaniline in the presence of ammonium peroxodisulfate 4 and cyclodextrins 5 to improve membrane permeability properties. In a complementary fashion, other groups have also studied the transport properties of diverse membrane-type materials, including thin films of Prussian blue [7][8][9] or thiolated compounds chemically adsorbed on gold nanotubules, 10,11 which, as it was shown, could be electronically manipulated to allow or exclude the passage of either anions or cations.…”

“…The modified materials thus prepared showed that, as expected, the permeability of electroactive probe molecules was pH dependent and that the ionexchange capacity (mmol/g) values, as measured with the Fisher and Kunin method, [37][38][39] fell within the range that characterizes commercial ionexchange membranes. 3 , and Na 2 CO 3 were purchased from J. T. Baker, and LiCl was purchased from Fluka Chimie. Whereas the supporting electrolyte solutions for electrochemical experiments consisted of phosphate buffer solutions (pH 12, 7, and 2; ionic strength ¼ 0.1) made with KH 2 PO 4 , Na 2 HPO 4 , and H 3 PO 4 (all obtained from J. T. Baker), the solutions used for ion-exchange capacity determinations were prepared from NaOH and HCl solutions.…”

“…The membranes thus prepared were characterized by chemical, physical, and spectroscopic measurements, and the results indicate that the dendrimer peripheral functional groups were the species that participated in the ion-exchange events. The prepared materials were also evaluated for their ion-exchange permeability with sampled current voltammetry experiments involving cationic and anionic species {[Ru(NH 3 ) 6 ] 3þ and [Fe(CN 6 )] 3À , respectively} as redox probe molecules under different pH conditions. As expected, although permeability was favored by opposite charges between the dendrimer and the electroactive probe, a clear blocking effect took place when the charge in the dendritic polymer and the electroactive complex was the same.…”