The intercalation behaviour of some organic derivatives of -zirconium phosphate was investigated. Prepared organic derivatives of -zirconium phosphate can be described by the general formula Zr(RPO3)X(R'PO3)2–X. It was found that only the compound with acidic P–OH groups is able to intercalate different species while the benzene derivatives with phosphite groups do not show any intercalation properties.
A direct curve simulation treatment has been worked out for the evaluation of the kinetic curves of heterogeneous isotope exchange. Based on the data obtained by a personal computer some considerations have been made on the transport processes in the fully and half exchanged sodium forms of crystalline zirconium phosphate.
Authors:S. Shakshooki, L. Szirtes, and Yu. Yakovlev
Mixed zirconium-titanium phosphates were synthesized by various methods and under various conditions. The effect of these conditions on the selectivity of synthetized samples toward the transition metal ions was investigated. It was found that the kd values are independent of the metal concentration and they give the selectivity order Zn2+>Cu2+
The prepared amorphous
γ-ZrP\SiO2 composite had a complicated composition,
since a part of γ-ZrP is converted to α-form during the exfoliation
of it. The γ-ZrP\SiO2 composite have specific surface
area of 421 m2g–1.
The acidic P–OH groups of the lamellae species placed on the surface
(it is ≈1.0 meq g–1), do not destroy until
the temperature of 1030 K. During the thermal treatment the total mass loss
of 7.79% was found. This value corresponds to 0.42 mole of H2O
per molecule unit. The water loss process was found very slow, because of
the placing of bilamellar species in the composite.
The thermal behavior of tin containing oxalate, EDTA, and inositol-hexaphosphate were investigated. The end products of synthesis were identified by Mössbauer-, XRD analyses, and FTIR studies. The thermal decompose of the samples was studied by DTA-TG analysis. The simultaneously obtained DTA and TG data makes it possible to follow the thermal decomposition of the investigated samples. The tin oxalate decomposed in the temperature range of 520–625 K through tin carbonate formation and finally yielded CO2 and SnO. The tin EDTA complex first lost its hydrate bound water till 520 K. The followed thermal events related to the pyrolysis of anhydrous salt. The intense exothermic process that exists in the temperature range of 820–915 K is due to the formation of SnO2. The tin sodium inositol-hexaposphate lost its hydrate bound water (∼10%), up to 460 K. The following sharp exothermic process, in the temperature range of 680–750 K is due to the decomposition and parallel oxidation of organic part of the molecule. At the end of this process, a mixture of phosphorous pentaoxide, sodium carbonate, and tin dioxide is obtained.
Tin(II/IV) phosphate was prepared by various synthetic methods. The different methods resulted in tin phosphate with different properties, i.e., different crystalline form and behaviour during thermal treatment. The prepared materials have 3 mol water of crystallisation, which they lose in different ways. Total mass loss was between 20 and 30%. This could be connected with water loss, going generally in two steps in parallel with endothermic processes. At the end of thermal treatment, tin pyrophosphate is obtained, irrespective of the method of preparation used.
Authors:L. Szirtes, S. Shakshooki, Z. Pokó, and L. Pavlovszki
The mixed amorphous glassy-type zirconium-titanium phosphates contain various quantities of adsorbed water per molecule unit. Pure zirconium phosphate lost the structural water in two steps. This character disappeared with increasing titanium content. However, glassy titanium phosphate lost its water in two steps at lower temperature in comparison with glassy zirconium phosphate.
Authors:L. Szirtes, J. Megyeri, L. Riess, and E. Kuzmann
The thermal decomposition of zirconium molybdate, tungstate and arsenate were investigated. The total mass losses of the investigated materials were 12.5, 11 and 8.5%, respectively. Despite having different crystal dimensions and structure the thermal decomposition of the samples takes place in a similar way. During heating two main endothermic processes with mass loss were observed. At the end of the thermal decomposition, oxides of the original materials were observed. The mentioned mass losses originate partly from the crystal water loss of the materials. The calculated crystal water content in the original molecule was 1.3 and 1 mole/molecule unit, respectively. Furthermore, for zirconium arsenate, a sublimation process was recorded above 960 K.