Thermal treatment on composite γ-zirconium phosphate-silica

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.     

Thermoanalytical investigation of layered titanium salts

The investigated materials have similar routes of thermal decomposition; i.e. they lose their crystal water first, then at a higher temperature their structural one. At least the result TiP₂O₇ goes through a phase change at about 1000 K. The amorphous titanium phosphate lost its crystal and structural water at higher temperature than those of crystalline forms. Both α- and γ-titanium phosphates and also their transition metal containing forms have layered structure. In case of α- and γ-forms after the loss of crystal water a phase change occurs which is followed by the decomposition of the molecule. Various transition metals containing γ-titanium phosphates lose their crystal water at the same temperature, with the exception of Ni containing ones. The process is finished in this case at temperature 90 K higher than that of the others. This revised version was published online in July 2006 with corrections to the Cover Date.     

Structural investigations on zirconium phosphate-phosphite and on itsn-butylamine intercalate

Zirconium phosphate-phosphite have various structure belonging to the drying heat of the sample. While sample dried above sat. NaCl solution had interlayer distance of 1.30 nm (result fromd ₁=0.74 nm andd ₂=0.56 nm for phosphite layer), the sample dried under IR lamp on air having interlayer spacingd=0.74 nm charactderistic for -Zr(HPO₄)₂·H₂O containing little amount of phosphite groups. The composition of the first sample can be characterized by chemical formula, as Zr(HPO₄)_0.7(HPO₃)_1.3· ·0.5H₂O. The X-ray powder diffraction data ofn-butylamine intercalate suggest that in the process take place only the phosphate region of zirconium phosphate-phosphite (ZrPP).     

Adsorption and microcalorimetric investigations ofn-butylamine intercalation in α- and γ-zirconium phosphates

The intercalation process ofn-butylamine was investigated. The adsorption ofn-butylamine in interlamellar space had stepwise character in case of both crystalline forms of zirconium phosphate. The intercalatedn-butylamine existed at low concentration as bilayered complex. The reaction heat was determined by a microcalorimetric method. It was found that about 90% of it refers to the neutralization ofn-butylamine and only about 10% is related with surface adsorption (ion exchange). The steps of adsorption are 6.0 J/g and 1.0 J/g reaction heat values, respectively. The enthalpy balance of total process in dilute solution system (c ₀=3.0 vol%) is 14.67 kJ/mol. The calculated value for ion adsorption (exchange) was 1.37 kJ/mol.     

Polar organic compounds with derivatized crystalline zirconium phosphates

Layered organic derivatives of crystalline zirconium phosphate were synthesized and investigated for their intercalation behaviours. Derivatized zirconium phosphates having hydroxy groups take up different polar molecules such as alcohols, amines etc. by increasing the interlayer distance determined by X-ray diffraction method. The intercalation processes on these materials can be considered as heterogenous phase acid-base reactions.     

Mixed insoluble acidic salts of tetravalent metals

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.     

Mixed insoluble acidic salts of tetravalent metals

Solid amorphous Zr-, Ti- and Zr_xTi_(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 Zr_xTi_(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.     

Mixed insoluble acidic salts of tetravalent metals IV. Crystalline mixed zirconium — Titanium phosphates

Mixed crystalline alpha zirconium — titanium phosphates with variable zirconium to titanium ratios have been prepared both by the well known gel reflux method and a modified HF method. Chemical analysis, X-ray, i.r. and thermal analysis were used to characterize the materials. Exchange capacities for these ion-exchangers have been evaluated by pH-titration combined with radioisotope tract technique for Na⁺, K⁺, Rb⁺ and Cs⁺.     

Thermal treatment on tin(II/IV) oxalate,EDTA and sodium inositol-hexaphospate

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.     

FT-IR studies on intercalates and organic derivatives of crystalline (α- and γ-forms) zirconium phosphate and zirconium phosphate-phosphite

FT-IR studies were carried out for various α- and γ-crystalline intercalates of zirconium phosphate (ZrP) and also for zirconium phosphatephosphite (ZrPP). The characteristic peaks of n-alkanols, n-alkylamines, benzylalcohol and benzylamine, diethyleneglycol and also some amino acid intercalates/derivatives were determined. Based on the data assumptions are made about the type of bonding between the layers and also the variety of intercalates of various crystalline form zirconium phosphates was determined.