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Abstract  

A precipitation method was used to prepare amorphous mixed zirconium-titanium phosphates with various titanium contents. In this way the acidic solutions of ZrOCl2.8H2O and TiCl4 in various ratios were rapidly mixed with a phosphoric acid solution under continuous stirring. The resulting precipitate, characterized as [ZrxTi/1–x//HPO4/2.n H2O] was contacted with water of ethanol, then washed to pH 3.0 and dried at room temperature. The samples were irradiated with -rays of a60Co source giving a 6.6×107 Gy total dose. The thermal, chemical and ion-exchange properties of irradiated samples were investigated.

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Abstract  

Solid amorphous zirconium phosphate /ZPa/ and hafnium phosphate /HPa/ are mixed with an excess of solid oxalic acid dihydrate and are digested in molten oxalic acid. Then oxalic acid is removed by extraction or by heating. The residue is washed with dilute HCl /0.01M/ and redistilled water. By this method -ZP and -HP is formed from amorphous ones.

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Abstract  

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+ Co2+, Ni2+>Mn2+.

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Abstract  

Mixed crystalline zirconium-titanium arsenates ZrxTi(1–x) (HAsO4)2·H2O and harnium-titanium arsenates HfxTi(1–x) (HAsO4)2 H2O (where x=0–1) of various compositions with different Zr/Ti or Hf/Ti ratios have been prepared. The compounds have been characterized by X-ray, thermal analysis, chemical analysis, and pH-titrations. For powder X-rays, the compounds appear to be homogeneous crystalline materials with structures similar to -ZrP, -TiP or -ZrTiP. The thermograms show a loss of approximately two moles of H2O, followed by a small loss of O2 with probable formation of ZrO2, As2O3, HfO2, As2O3, ZrO2, As2O5, HfO2, As2O5 from which As2O3 and As2O5 are practically sublimed in two steps. The exchange capacities at r.t. are generally similar to -ZrP and -TiP but are found to be much lower in value.

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Mixed insoluble acidic salts of tetravalent metals

VII. Conversion of sodium form amorphous pure and mixed zirconium-titanium phosphates into crystalline form via molten oxalic acid

Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Shakshooki, L. Szirtes, A. Azrak, M. Ahmed, and S. Khalil

Abstract  

Solid amorphous Zr-, Ti- and ZrxTi(1–x) phosphates (where x=0.10, 0.33, 0.66, and 0.90) in various sodium forms were contacted with an excess of solid oxalic acid dihydrate to its molten state for a given time. The oxalic acid was removed by extraction and the residue was washed with redistilled water. As a result of this, crystalline forms of Zr-, Ti-, and ZrxTi(1–x) phosphates were obtained. Using various sodium forms of the initial samples, higher rate of crystallisation resulted than that found in case of hydrogen forms of initial samples.

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Abstract  

Solid amorphous mixed zirconium-titanium phosphates, with general formula ZrxTi/1–x//HPO4/2.n H2O/ where x=0.1–1, and n=3–5/, are mixed with an excess of solid oxalic acid dihydrate and digested in molten oxalic acid. Then oxalic acid is removed by extraction and the residue washed with dilute /O.OlM/ HCl solution and bidistilled water. As a result of this method, crystalline mixed zirconium-titanium phosphate is formed.

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Thermal behaviour of acidic salts of mixed tetravalent metals

IV. Thermal decomposition of crystalline zirconium-titanium phosphate prepared through the fluorine complex (HF method)

Journal of Thermal Analysis and Calorimetry
Authors: S. Shakshooki, S. Khalil, A. Abuhamaira, L. Szirtes, and Z. Pokó
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Abstract  

The selectivity of glass type mixed Zr+Ti phosphates with various Ti contents has been investigated toward rare earth metal ions. The kd values were determined by radiotracer technique both in HCl and HNO3 solutions of various concentrations. At room temperature and at pH=4 the following selectivity orders were found: Yb>TmEu>Sm>La (HCl) and Eu>La>Sm>Yb>Tm (HNO3).

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Mixed insoluble acidic salts of tetravalent metals

VIII. Investigations of amorphous, glassy type, mixed zirconium-titanium, and hafnium-titanium arsenates

Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Shakshooki, F. Masaodi, A. Dehair, L. Szirtes, and J. Kowalczyk

Abstract  

Mixed amorphous, glassy type, zirconium-titanium arsenate (ZrTiAs) and hafniumtitanium arsenate (HfTiAs) have been prepared. The composition and exchange capacity of the prepared samples were investigated in comparison with pure zirconium, titanium and hafnium arsenates, respectively. For the samples the ZrxTi(1-x)(HAsO4)2·2H2O and the HfxTi(1-x)(HAsO4)2·2H2O compositions (where 0<x<1) were found. The exchange capacity values were found less than those for pure arsenates, but they do not change their values under the effect of high dose of gamma-radiation.

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Mixed insoluble acidic salts of tetravalent metals

IX. Effect of γ-radiation and drying temperature on mixed glassy type hafnium-titanium phosphates

Journal of Radioanalytical and Nuclear Chemistry
Authors: S. Shakshooki, Y. Elmismary, A. Dehair, and L. Szirtes

Abstract  

Mixed amorphous glassy type hafnium-titanium phosphates have been prepared. The composition and ion exchange capacity of the samples were investigated before and after -irradiation. In addition, the effect of temperature on the ion exchange capacity of the samples was determined. Based on the data obtained, neither the composition nor the ion exchange behavior of the investigated materials was altered by the irradiation. An increased drying temperature led to a decrease in the ion exchange capacity of the samples.

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