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The results reported in this paper suggest that titanium(IV) oxyhydroxyphosphates can be used for sorption extraction of valuable metal cations from solutions, followed by desorption and concentration of the metal cations and simultaneous regeneration of the titanium phosphate material for further use. Conditions for effective desorption processes (desorbing agent concentration and desorption time) have been studied and optimized. The sorption/desorption process effectiveness in the case of multistep use of the sorbent has been shown to decline as a result of steric hindrances associated with its dehydration. As the sorption properties of the sorbent degrade, it can be used for extraction of trace amounts of highly toxic metal cations and then buried. [ABSTRACT FROM AUTHOR]

This paper demonstrates the feasibility of using titanium(IV) oxyhydroxyphosphate-based materials for sorption extraction of heavy metal cations from solutions. We have determined Pb2+ and Cd2+ sorption characteristics of ion exchangers, examined the kinetics of Pb2+ and Cd2+ sorption on the titanium phosphate materials, and assessed the effect of ionic radius on the affinity of the sorption matrices for metal cations. Conditions for effective use of the ion exchange materials for extracting Pb2+ and Cd2+ cations from solutions (liquid : solid ratio and pH) have been optimized experimentally. [ABSTRACT FROM AUTHOR]

Sorbents based on titanium(IV) compounds have been shown to be potentially attractive for quantitative removal of antimony(III) anions from liquid radioactive waste with complex chemical composition. Evidence is presented that titanium(IV) oxyhydroxyphosphates have enhanced affinity for antimony(III) cations. Selectivity of sorption matrices increases with increasing solution acidity and with an increase in the concentration of hydrogen phosphate groups in the composition of the material. Having enhanced affinity for negatively charged antimony(III) ions, titanium(IV) oxyhydroxides are potentially attractive for extraction of anionic species. [ABSTRACT FROM AUTHOR]

It has been demonstrated that titanyl hydrogen phosphate-based sorption materials can be effectively used for the extraction of cesium and strontium radionuclides from liquid radioactive waste similar in chemical composition to seawater. We have optimized conditions (pH, liquid : solid ratio, and temperature) for the coextraction of cesium and strontium cations. The titanium(IV) cesium or strontium double phosphate formed after heat treatment of the spent sorbent ensures proper immobilization of the radionuclides. [ABSTRACT FROM AUTHOR]

The effect of temperature and the cesium concentration in the external solution on the sorption capacity of titanium phosphate obtained upon the heterogeneous interaction of the (NH4)2TiO(SO4)2 · H2O crystalline salt with phosphoric acid is studied. Sorption on titanium phosphate is shown to be best described by the Langmuir isotherm. When describing the sorption kinetics of solutions, it is necessary to consider both the possibility of diffusion and adsorption limiting the process rate. The use of the chemical kinetic models shows that the stage of chemical interaction of metal ions with functional groups of the sorbent also contributes to the overall rate of the process. [ABSTRACT FROM AUTHOR]

We have proposed compositions of titanyl hydrogen phosphate-based sorption materials modified with zirconium(IV) cations and containing both cation and anion exchange functional centers, represented by НРО and OH– groups, respectively. The synthesized materials were tested in sorption of antimony(III) cations and anions from high-salt solutions. Increasing the concentration of functional groups in ion exchange matrices has been shown to increase their affinity for antimony(III) ions. Such compositions can be regarded as promising ion exchange materials for efficient extraction of antimony radionuclides from multicomponent high-salt liquid radioactive waste. [ABSTRACT FROM AUTHOR]