Abstract
To develop potassium ion memorized inorganic ion-exchangers, potassium ions of specially selected synthetic potassium tungstate (K2W4O13) samples, which have tunnel crystal structures, have been ion-exchanged for sodium ions in molten sodium nitrate at 330°C or for protons in aqueous nitric acid solutions at 25°C.
Proton-exchangedpotassium tungstates (for example, H0.25K1.75W4O13) were found to have the feasibility of the potassium memorized exchangers, but sodium-exchanged potassium tungstates (NaxK2-xW4O13) were not easily exchanged for potassium ions in aqueous solution at room temperature, because of stabilized sodium ions in the exchanged samples.
The study in this paper is the first stage of the development of potassium ion memorized ionexchangers and details will be discussed in following papers.
