Synthesis and ion-exchange properties of zirconium ferrocyanide

Samples of zirconium ferrocyanide have been prepared under different conditions of precipitation, and their properties, composition and ion-exchange behaviour are reported. The distribution ratios of 21 metal ions are given and some topical separations have been achieved using these data.     

Synthesis and ion-exchange properties of zirconium antimonate

Samples of zirconium antimonate have been prepared under varying conditions of precipitation. Their properties, composition, and ion-exchange behaviour are reported. The 1g K_d vs. pH curves are given for Rb⁺, Cs⁺, Zn²⁺, Ca²⁺ and Tl³⁺ ions. The distribution coefficients of 26 metal ions have been measured and several separations of analytical and radiochemical importance achieved.     

Synthesis and ion-exchange properties of crystalline titanium and zirconium phosphates

The preparation of novel types of inorganic ion-exchangers, titanium and zirconium phosphates and their ion-exchange properties towards strontium ions, are reported and discussed. Ti(HPO₄)₂·2H₂O is shown to be very stable to hydrolysis and to have high exchange capacity in strongly acid medium. In the case of zirconium phosphate, the titration curves with alkaline earth metal hydroxides are strongly affected by hydrolysis of the exchanger and precipitation of insoluble phosphate. The degree of conversion of the exchanger at which phosphate precipitation begins was found to be 80% for Sr²⁺. The comparison of Ti(HPO₄)₂·2H₂O with the corresponding zirconium phosphate dihydrated phase suggests that the former possesses a lattice structure different from that reported for the monohydrated exchanger.This revised version was published online in November 2005 with corrections to the Cover Date.     

Synthetic inorganic ion exchangers. XI. Preparation,properties and ion-exchange behaviour of zirconium tungstate

Summary Samples of zirconium tungstate have been prepared under different conditions and their physico-chemical properties, composition, IR spectra and cation-exchange behaviour are reported. Separations of a number of metal ions from Bi³⁺ and from Pb²⁺ have been worked out.Part X. Ref. [1].     

Synthesis and ion-exchange properties of zirconium molybdoarsenate (ZrMAs)

Zirconium molybdoarsenate (ZrMAs), an inorganic ion exchanger, has been synthesized and the suitable conditions to separate cesium-137 from fission products waste solution are suggested.     

Preparation and some properties of ion-exchange rhenium zeolite catalyst

Conclusions The rhenium zeolite catalyst, obtained from NaY by ion exchange with diethylenediaminedioxorhenium chloride, has a lower activity in the hydrogenation of benzene than the catalyst obtained by impregnating NaY with ammonium perrhenate solution.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1181–1183, May, 1976.The authors express their gratitude to B. N. Ivanov-Emin for assistance in the work.     

Preparation,properties and ion-exchange behavior of stannic silicomolybdate

Stannic silicomolybdate prepared in different conditions has showed good exchange properties. The change of the ratio of component and the pH values during precipitation led to the change in composition and in the exchange properties. The behavior of Cs⁺ and Sr²⁺ cations in the prepared exchanger has studied. It was found that the general behavior of these two cations is almost the same for these exchanger.     

Preparation and sorption properties of zirconium phosphate spherical particles

Spherical particles of zirconium phosphate ion-exchanger have been prepared by the conversion of hydrous zirconia prepared by the sol-gel method. Some physicochemical properties, stabilities and sorptions of 1–4-valent cations have been studied and compared with those of amorphous zirconium phosphate powder.     

Preparation and properties of lanthanum tungstate and studies of its ion-exchange and electrochemical behaviour

A new inorganic ion-exchanger lanthanum tungstate has been prepared by mixing lanthanum nitrate and sodium tungstate. The refluxed product has been found to be most suitable; therefore, most of the electrochemical and ion-exchange studies were performed on this product. The material is a weak cation exchanger with a capacity of 0.80 mmol per gram. Electrochemical studies are performed by preparing a pellet of this exchanger in polystyrene; charge density and membrane potential have been calculated. The results are discussed.     

Ion-exchange behaviour of pyridinium tungstoarsenate

The exchange behaviour of pyridinium tungstoarsenate has been investigated with some uni and bivalent cations. The compound shows high specificity towards Cs(+) and Ag(+) and the exchange is complete even in the low concentration range. The slopes of the isotherms of various cations are widely different suggesting that separation of these ions on a pyridinium tungstoarsenate column is feasible. From a linear plot of Barrer's equation, the thermodynamic equilibrium constant, the energy of interaction between the ions on the surface and the free energy change of the process have been evaluated.     

Synthesis and ion-exchange properties of ceric tungstate

Ceric tungstate has been prepared under varying conditions of precipitation. Its properties and ion-exchange behaviour have been studied. Separations of Hg(2+) from Zn(2+), Cd(2+) and Pb(2+) ; Co(2+) from Mn(2+) and Fe(3+) ; and Al(3+) from Cr(3+) and Fe(3+) have been carried out on ceric tungstate columns.     

Modified lignin with ion-exchange properties

Polyfunctional ion-exchangers were synthesized by heterophase amination of α-oxide derivatives of hydrolyzed lignin with aliphatic di-and polyamines. Optimal conditions for their preparation were determined. Certain physicochemical properties were studied. __________ Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 492–495, September–October, 2007.     

Preparation and evaluation of physicochemical properties and anti-leishmanial activity of zirconium/tioxolone niosomes against Leishmania major

Due to the limitations of current chemotherapy for the treatment of leishmaniasis, there is an urgent requirement to search for new anti-leishmanial compounds and nano-drug delivery systems including niosomes. Therefore, the aim of this study was to prepare zirconium/tioxolone niosomes using the film hydration method and evaluate the physicochemical properties of the produced niosomes including morphology, size distribution, stability, and encapsulation efficiency. The best formulation was chosen as Span/Tween 40 (NZT₁) due to its physicochemical properties, and leishmanicidal activity against promastigotes and amastigotes was measured using both 3-(4,5-dimethylthiazol2yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry methods. In addition, to assess the mechanism of action of the prepared niosomes, apoptosis, levels of gene expression, reactive oxygen species (ROS) generation, superoxide dismutase (SOD) activity, and nitrite production were evaluated. The prepared formulation indicated log-normal particle size distribution curves, high encapsulation efficiency (more than 95.72 %), and good physical stability after one week, three months, and six months. Our findings demonstrated that amphotericin B was more effective than Zr/tioxolone niosomes (NZTs) due to the selectivity index (SI). However, the niosomal formulation of Zr/tioxolone showed no cytotoxic effect within the range of our experimental concentrations (CC₅₀ of 308.21 μg/mL). Moreover, the prepared niosomes increased the expression level of interleukin (IL)-12 and inducible nitric oxide synthase (iNOS) and significantly decreased the expression level of the IL-10 gene, which confirms the immunomodulatory role of NZTs. According to our findings in this study, the niosomal form of this combination can be considered for further therapeutic approaches against L. major in future planning.     

Preparation,characterization and catalytic properties of perfluorosulfonated ion-exchange membranes containing surface-concentrated,hydrated ruthenium oxide particles

Microparticulate hydrated ruthenium oxide precipitates have been prepared in Nafion ion-exchange membranes by treatment of the Ru-exchanged membranes with KOH or NaOH solutions. These precipitates are concentrated near both membrane surfaces giving a concentration profile which depends on the conditions of preparation. The particle size, nature and distribution across the membrane thickness of the precipitates were characterized by scanning electron microprobe analysis, transmission electron microscopy, electron microdiffraction and X-ray diffraction. The oxide is present as very fine crystalline spherical particles whose size ranges from 200 to 1000 Å. Precipitation was also achieved at one side only in free-standing membranes with ruthenium oxide at one side and uranium oxide at the other. Nafion-coated modified electrodes containing precipitated ruthenium oxide particles catalyse the oxidation of water to oxygen and the reduction of oxygen to hydrogen peroxide and water in the presence of mediators. The relevance of these results to the construction of solid polymer electrolyte devices containing active electrocatalysts is discussed.     

Chelation ion-exchange properties of salicylic acid-urea-formaldehyde copolymers

Chelation ion-exchange properties of copolymers prepared from salicylic acid, urea and formaldehyde by condensation in presence of acid catalyst were studied for Cu²⁺, Fe³⁺, UO²⁺, Mn²⁺,Zn²⁺ and Co²⁺ ions. A batch equilibration method was adopted to study the selectivity of metal ion uptake. This method involved the measurement of distribution of a given metal between the copolymer sample and a solution containing the metal ions. The study was carried out over a wide pH range and in media of various ionic strengths. The copolymer showed a higher selectivity for UO₂ ²⁺, Cu²⁺ and Fe³⁺ ions than Mn²⁺, Co²⁺ and Zn²⁺ ions.