The Mechanism of Ion Exchange on Microcrystals of Inorganic Oxide-Hydroxides

Abstract

Insoluble hydrous oxides of the trivalent and tetravalent metals have been of interest as ion exchangers since the mid 1950s (1). Early researches showed that most hydrous oxides had pseudo-amphoteric exchange properties, with pH variable capacities, anionic in acid, cationic in alkali. Experimental curves relating capacity to pH for these materials have been widely reported (2,3), but because they were gels and difficult to prepare reproducibly, these curves showed wide variations, even between samples prepared batch-wise in the same laboratory (4,5).