A. Dyer

Studies on crystalline zirconium phosphate—I: Ion-exchanged forms of α-zirconium phosphate

Abstract Crystalline zirconium phosphate (H 2 ZrP) has been prepared in its α-modification and then converted to various ion-exchanged forms ( M 2 l ZrP, M ll ZrP). X-ray and thermoanalytical measurements have been made where M l - H + , Li + , Na + , K + , Rb + , Cs + , NH 4 + M II = Ca 2+ , Sr 2+ , Ba 2+ . Conclusions are drawn as to the instability and interlayer forms of these ion-exchanged derivatives.

The mobility of water in zeolites—I: Self-diffusion of water in analcite

Abstract Self-diffusion parameters of water in the zeolite analcite (Na 2 O, Al 2 O 3 , 4SiO 2 , 2H 2 O) have been measured by a radiochemical technique. The rate of self-diffusion was found to be slow and comparisons to water migration in other zeolites were made. The relevance of the results of previous studies of cation migration has been discussed.

Studies on crystalline zirconium phosphate-II: Self-diffusion of cations

Abstract Cation self-diffusion studies have been carried out by radiochemical techniques for the ions Na + , K + , Rb + , Cs + , Ca 2+ , Sr 2+ and Ba 2+ in α-zirconium phosphate and for Ca 2+ in γ-zirconium phosphate. Thermodynamic parameters have been estimated for the diffusion processes and conclusions drawn as to the cation sitings and mobilities in these ion-exchange materials.

The mobility of cations in synthetic zeolites with the faujasite framework — II: The mobility of calcium, strontium and barium ions in zeolite X at high temperatures

Abstract A radiochemical method has been used to examine the mobility of the Sr 2+ and Ba 2+ cations between high-energy sites in zeolite X . Thermodynamic parameters have been estimated and comparisons made to other cation self-diffusion measurements [1–3].

Studies on crystalline zirconium phosphate—III: Self diffusion of sodium ion into monosodium forms of crystalline zirconium phosphate

Abstract Self-diffusion of sodium ions in two forms of monosodium zirconium phosphate has been studied by radiotracer methods. Sodium ion migration occurs in two stages in a ∗ ·5H 2 NO*|(11.8 A ) and only one in HNa su∗ ·H2O(7.65 A). Reasons for this are discussed on the basis of values determined for Ea, ΔS ∗ and ΔG ∗ .

The mobility of cations in synthetic zeolites with the faujasite framework — IV: The mobility of zinc in X and Y zeolites

Abstract Radiochemical investigations were carried out to determine the ease of replacement of Na+ ions by Zn2+ ions in X and Y zeolites. Full replacement was difficult even at elevated temperatures. Self-exchange and ion exchange were performed at various temperatures and these, with thermal and X-ray analyses, yielded information on the sitings of the zinc ions in the zeolite frameworks.

The mobility of cations in synthetic zeolites with the faujasite framework — III: Self-diffusion of cations into X and Y zeolites from non-aqueous solutions

Abstract Cation self-diffusion parameters in non-aqueous solvents have been measured in zeolite X and in two Y zeolites having Si Al ratios of 1·86 and 2·60 respectively. The effect of variation in solvent media on the diffusion of Ca2+, Sr2+ and Ba2+ ions in methyl and ethyl alcohols is commented on. Conclusions are shown as to the nature of the rate-controlling step and comparisons made to diffusion in aqueous solution.

The mobility of cations in synthetic zeolites with the faujasite framework — V: The self-diffusion of zinc into X and Y zeolites

Abstract Self-diffusion parameters of zinc into zeolites X and Y, of Si:Al atios of 1·26, 1·87 and 2·62 respectively, have been determined at low and high temperatures. Derived values of EA and ΔS‡ have been rationalized in terms of mechanisms in which water played an important part, and a possible explanation for anomalous results obtained with X at low temperatures has been put forward.

Studies on natural clinoptilolites—I: Homoionic clinoptilolites

Abstract Nearly homoionic forms have been prepared from a natural clinoptilolite (Hector, California). X-Ray powder and thermal analyses were carried out as well as some wet chemical analysis. Discussion of the structural and thermal properties of the ion-exchanged minerals (Na, K, Rb, Cs, Ca and Ba) is included and some simple comparisons to an Itaya (Japan) clinoptilolite are made.

The mobility of cations in synthetic zeolites with the faujasite framework — I: The mobility of cations in homo- and heteroionic forms of X and Y zeolites

Radiochemical investigations have been carried out to determine the ease of replacement of Na+ ions from X and Y zeolites by the divalent calcium, strontium and barium cations. Full replacement often can be achieved only at elevated temperatures and fully-exchanged M2+ zeolites prepared in this way have a proportion of their cations which are difficult to exchange at room temperature. The significance of these results is discussed in relationship to the population of the various cation sites available.