Chronopotentiometric study of ceramic cation-exchange membranes based on zirconium phosphate in contact with nickel sulfate solutions

Abstract

Martí Calatayud, MC.; García Gabaldón, M.; Pérez-Herranz, V.; Sonia; SERGIO MESTRE (2013). Chronopotentiometric study of ceramic cation-exchange membranes based on zirconium phosphate in contact with nickel sulfate solutions. Desalination and Water Treatment. 51(1): 597-605. doi:10.1080/19443994.2012.714629. Chronopotentiometric study of ceramic cation-exchange membranes based on zirconium phosphate in contact with nickel sulfate solutions. Abstract.In this article, the innovative cation-exchange membranes obtained from ceramic materials are presented. Different microporous ceramic supports were obtained from an initial mixture of alumina and kaolin, to which a varying content of starch was added in order to obtain supports with different pore size distributions. The deposition of zirconium phosphate into the porous supports generates membranes with cation-exchange properties. The fabrication of ionexchange membranes which could resist aggressive electrolytes such as strong oxidizing spent chromium plating baths or radioactive solutions would allow the application of electro-dialysis for the decontamination and regeneration of these industrial effluents. The perfor-mance of the manufactured membranes was studied in nickel sulfate solutions by means of chronopotentiometry. An increase of the membrane voltage drop during chronopotentiometric measurements was observed in some membranes, which seems to be a consequence of concentration polarization phenomena resulting from the ionic transfer occurred through the membranes. Current-voltage curves were obtained for the different ceramic membranes, allowing the calculation of their ohmic resistance. The ohmic resistance of the membranes increased when the open porosity (OP) of the samples was incremented up to a value of 50%. For values of OP higher than 50%, the resistance of the membranes decreased significantly with porosity.

Ceramic anion-exchange membranes based on microporous supports infiltrated with hydrated zirconium dioxide

“…Specically, the deposition of zirconium phosphate was reported to occur uniformly in pores of different diameters. 19 Therefore, it seems that in the present case the addition of starch during the formation of the microporous supports is essential in order to create pores of an optimum diameter where the deposition of ion exchanger takes place preferentially. Moreover, from the evolution of the pore size distributions with n, it can be concluded that the ZrO 2 is signicantly deposited over previously inltrated ZrO 2 particles.…”

“…Previous studies have demonstrated the suitability of these supports to act as separators in electrochemical reactors. 19,20 Moreover, their pore size distribution can be tuned by adding pore formers to the alumina-kaolin mixture. 20,21 Subsequently, particles of hydrated zirconium dioxide, which provide the membranes with anion-exchange properties, were embedded in the voids of the ceramic supports.…”

“…The effect of the starch addition on similar alumina-kaolin ceramic supports was investigated in a previous study, and it was observed that the interconnection of small pores occurring when the starch particles are burnt provoked the formation of pores of higher diameter ($1.75 mm). 19 For the membranes modied with up to 4 inltration cycles (n ¼ 2 and n ¼ 4 in Fig. 4), the characteristic diameter of the highest pores diminishes gradually (from $1.75 mm for n ¼ 0 to around 0.7 mm for n ¼ 4).…”

“…Previous studies have demonstrated the suitability of these supports to act as separators in electrochemical reactors. 19,20 Moreover, their pore size distribution can be tuned by adding pore formers to the alumina-kaolin mixture.…”