Ion exchange in beryllophosphate-G. Part 1.—Ion-exchange equilibria
Abstract
Ion-exchange isotherms and selectivity plots are presented for beryllophosphate-G, the synthetic beryllophosphate analogue of the zeolite gismondine. Exchange reactions involving Na+ and K+ or NH+4 were accompanied by changes in crystal symmetry and hysteresis loops were seen in the isotherms. Exchange of K+ by NH+4 was fully reversible without hysteresis and the two end members were found to have very similar symmetry. Only Limited exchange of Na+ by Ca2+ or Mg2+ could be achieved under the conditions used and no symmetry change was observed.
The phases present across the Na+–K+ exchange field were studied in depth using X-ray powder diffraction, solid-state NMR and scanning electron microscopy. Unit-cell parameters were calculated for fully K-exchanged beryllophosphate-G.
Please wait while we load your content...
