Sorption of cobalt by ion-exchange resins from aqueous organic solutions of mineral acids

Conclusions The sorption of cobalt on the ion-exchange resins KU-2 and AV-17 from aqueous alcohol and aqueous acetone solutions of perchloric, sulfuric, nitric, and hydrochloric acids was studied.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 1955–1959, September, 1970.     

Sorption of Hf, Zr and Nb on organic and inorganic ion-exchangers from mineral acids solutions

Sorption coefficients of Hf, Zr and Nb on nickel-potassium hexacyanoferrate(II) (NF), nickel hexacyanoferrate(II) composite ion exchanger (NCF) and on the ion exchange resins (Dowex-1 and Dowex-50) from inorganic acids solutions were determined. The results obtained indicate that hafnium, zirconium and niobium in dilute sulphuric and hydrochloric acids form anionic and cationic complexes which sorbed on the ion exchangers studied.     

Sorption behavior of gamma-irradiated silica gel

The effect of Pb(II) and non-ionic surfactants (oxyethylate alcohols OS-10 and ALM-10) on the rate of intraparticle diffusion and on to the equilibrium sorption on Purolite C 106 cation exchanger in hydrogen form was investigated. The sorption of Pb(II) cations and in free state and bonded to the surfactant was measured. The coefficients of intraparticle diffusion were also calculated.     

Chromatographic investigations of adsorption of some aromatic compounds on aluminium oxide and silica gel from solutions

Summary Using adsorption TLC R_M values were measured for a number of aromatic compounds on aluminium oxide and silica gels having different specific surface areas, using the following binary mobile phases: benzene+toluene, benzene+carbon tetrachloride and chloroform+carbon tetrachloride. The results are graphically presented and compared with theoretically calculated values. Generally, a good agreement was found between the calculated and measured R_M values. The agreement is valid both when the R_M values were calculated using experimentally (indirectly) determined partition coefficients or when the coefficients are obtained with help of Ocik's equation [cf. Roczn. Chem.34, 745 (1960) and Chromatographia4, 516 (1971)]. One can assume that in the case of systems in which strong intermolecular interactions are absent, the statically determined partition coefficients of the compounds may be used for the calculation of their R_M values.     

On the extraction of mineral acids and uranium from alcoholic and acetonic solutions with tri-N-butyl phosphate

The extraction of hydrochloric, nitric, and sulphuric acids with TBP was studied as a function of methanol, ethanol, isopropanol, and acetone concentration in the aqueous phase. Extraction increases in the order: methanol相似文献   

Use of organophosphorus extractants impregnated on silica gel for the extraction chromatographic separation of minor actinides from high level waste solutions

Silica-gel has been used as an inert support for the extraction chromatographic separation of actinides and lanthanides from HNO₃ and synthetic high level waste (HLW) solutions. Silica-gel was impregnated with tri-butyl phosphate (TBP), to yield STBP; 2-ethylhexyl phosphonic acid, mono 2-ethylhexyl ester (KSM-17, equivalent to PC-88A), SKSM; octyl(phenyl)-N,N-diisobutyl carbamoylmethylphosphine oxide (CMPO), SCMPO; and trialkylphosphine oxide (Cyanex-923), SCYN and sorption of Pu(IV), Am(III) and Eu(III) from HNO₃ solutions was studied batchwise. Several parameters, like time of equilibration, HNO₃ and Pu(IV) concentrations were varied. The uptake of Pu(IV) from 3.0M HNO₃ followed the order SCMPO>SCYN>SKSM>STBP. With increasing HNO₃ concentration, D _Pu increased up to 3.0M of HNO₃ for STBP, SKSM and SCMPO and then decreased. In the case of Am and Eu with SCMPO, the D values initially increased between 0.5 to 1.0M of HNO₃, remained constant up to 5.0M and then slightly decreased at 7.5M. Also, the effects of NaNO₃, Nd(III) and U(VI) concentrations on the uptake of Am(III) from HNO₃ solutions were evaluated. With increasing NaNO₃ concentration up to 3.0M, D _Am remained almost constant while it was observed that it decreases drastically by adding Nd(III) or U(VI). The uptake of Pu and Am from synthetic pressurized heavy water reactor high level waste (PHWR-HLW) in presence of high concentrations of uranium and after depleting the uranium content, and finally extraction chromatographic column separation of Pu and Am from U-depleted synthetic PHWR-HLW have been carried out. Using SCMPO, high sorption of Pu, Am and U was obtained from the U-depleted HLW solution. These metal ions were subsequently eluted using various reagents. The sorption results of the metal ions on silica-gel impregnated with several phosphorus based extractants have been compared. The uptake of Am, Pu and rare earths by SCMPO has been compared with those where CMPO was sorbed on Chromosorb-102, Amberchrom CG-71 and styrene divinylbenzene copolymer immobilized in porous silica particles.     

Sorption of some azo-dyes on wool fiber from aqueous solutions

Sorption of some azo-dyes (acid violet 17, acid blue 90, acid red 1 and direct red 80) on locally available wool fiber from aqueous solution has been investigated as a function of shaking time, pH and dyes concentration as a function of temperature. Sorption isotherms for dyes on wool fiber were obtained. It was found that the increasing temperature induces positive effect on the sorption process. Isosteric heat of adsorption (q_st) have also been calculated at different surface coverage indicating that wool fiber used possessed heterogeneous surface with site of different activity. The results also indicate that initial sorption whether chemical or physical means, occurs first on the most active sites and then, as the concentration of dyes is increased, on sites of lesser activity.     

Sorption of molybdenum(VI) from mineral salt solutions

Changes in the ionic forms of molybdenum and conditions of sorption on the anionite AV-17 × 8 from mineral salt solutions at concentrations of 0.05–2 N and pH of medium 1–6 were revealed.     

Thermodynamic characteristics of adsorption of some 1,3,4-oxadiazoles and 1,2,4,5-tetrazines from water-acetonitrile solutions on phenyl-bonded silica gel

Standard differential molar changes of the Gibbs energy, enthalpy, and entropy during adsorption in the Henry region of 17 derivatives of 1,3,4-oxadiazole and 1,2,4,5-tetrazine from water-acetonitrile solutions with acetonitrile concentrations of 20 to 80 vol % and a variation step of 5 vol % on silica gel with grafted phenyl groups at column temperatures of 313.15 to 333.15 K with at a step of 5 K are determined under dynamic conditions by high-performance liquid chromatography. The dependence of the thermodynamic characteristics of adsorption on the molecular structure of adsorbates is discussed. It is established that the absolute values of the changes in the Gibbs energy and enthalpy during adsorption as a whole increase with increasing Van der Waals surface area and volume of the adsorbate molecules, while the adsorption of most 1,3,4-oxadiazoles is characterized by a dependence close to isentropic. It is assumed that the determining role in the change of entropy during adsorption from solutions is played by the polarity of the adsorbate molecule and the conformational flexibility of its substituents.     

Sorption of aldonic acids from ethyl alcohol-water solutions on anion exchangers

Aldonic acids can be retained quantitatively from ethyl alcohol-water solutions by means of anion exchangers in the sulfate form. After the sorption step the aldonic acids can be easily displaced by washing with water. The sorption is explained by a partition mechanism of the same type as demonstrated in earlier work with strongly polar non-electrolytes. Precautions have to be taken to prevent uptake by means of an ion exchange mechanism. The method permits a separation from exchangeable anions and from non-adsorbable solutes.     

Sorption of uranium using silica gel with benzoylthiourea derivatives

Benzoylthiourea derivatives (N,N-diphenyl-N′-(3-methylbenzoyl)thiourea and diphenyl-N′-(4-methylbenzoyl)thiourea) were impregnated onto silica gel. The preconcentration of uranium(VI) from aqueous solution was investigated. Extraction conditions were optimized in batch method prior to determination by uv–visible absorption spectrometry using arsenazo(III). The optimum pH for quantitative adsorption was found as 3–7. Quantitative recovery of uranium (VI) was achieved by stripping with 0.1 mol L^?1 HCl. Equilibration time was determined as 30 min for 99% sorption of U(VI). Under optimal conditions, dynamic linear range of for U(VI) was found as 0.25–10 μg mL^?1. The relative standard deviation as percentage and detection limit were 5.0% (n = 10) for 10 μg mL^?1 U(VI) solution and 8.7 ng mL^?1, respectively. The method was employed to the preconcentration of U(VI) ions in soil and tap water samples.     

Separation of germanium from some elements by adsorption on silica gel

In the search for an efficient method of recovery of germanium from concentrated mineral acid solutions, silica gel has been found to be a selective adsorbent for this element. A method of quantitative separation of gallium from germanium is described which can be applied for the preparation of⁶⁸Ge−⁶⁸Ga isotope generator and for the isolation of⁶⁸Ge from a zinc target. The applicability of the present method was also studied for the separation of a gertarget. The applicability of the present method was also studied for the separation of a germanium matrix in determining admixtures in semiconductor germanium samples by activation analysis.     

Sorption of elements from mineral acid solutions by alkylated dibenzocrown ethers

Sorption of various elements by alkylated dibenzocrown ethers (CE) from HCl and HNO₃ solutions was studied. The distribution coefficients of elements depend on the size of the macrocyclic ring of CE and the type and concentration of the acid. Di-tert-butyldibenzo-24-crown-8 possesses optimal properties upon sorption of Au, Ga, Fe, Mo, Sb, Sn, and Re from 5 M HCl. In these cases, the elements are selectively sorbed from mixtures of complex composition, which can be used to develop methods of recovery and separation of elements.     

Adsorption behaviour of some actinides on zirconium phosphate stability constant determinations

The adsorption behaviour of thorium, protactinium, uranium, neptonium and plutonium on zirconium phosphate from nitric acid and ammonium nitrate solutions was investigated. Partition data from the mentioned media together with that from chloride solutions were used to calculate formation constants for the concerned elements in the range of Cl⁻ and NO ₃ ⁻ activities <1M. Obtained β values were compared with those reported in the literature and indicated reasonable agreement.     

Sorption of the peroxocomplex of titanium on silica gel and its analytical use

Summary Sorption of the titanium peroxocomplex on silica gel was studied in dependence on the pH and on the presence of various complexing substances, especially tartaric and citric acids. The distribution coefficients for the titanium peroxocomplex and for some other components were determined. Optimum conditions were established for the separation of small amounts of titanium from a number of accompanying cations and anions on a column and under static conditions.     

Sorption of traces of strontium ions on silica gel containing crown ether

This paper is concerned with the synthesis of silica gel sorbents by the sol method. A sorbent selective for trace amounts of Sr ions has been prepared. This method of synthesis is shown to be preferable to the tradition of impregnating the carrier.L. V. Pisarzhevskii Institute of Physical Chemistry, Ukrainian Academy of Sciences, Ukraine, 252039 Kiev, Science Prosp., 31. Translated from Teoreticheskiya i Éksperimental'naya Khimii, Vol.32, No. 4, pp. 258–260, July–August, 1996. Original article submitted October 17, 1995.     

On the extraction of acids and neptunium from alcoholic and acetonic solutions

The extraction of nitric acid with tridodecylamine (TDA) was studied as a function of methanol, ethanol, isopropanol, and acetone concentration in the aqueous phase. Extraction increases in the order: methanol <ethanol <isoproppanol <acetone. The extraction of nitric acid by TDA is affected by these additives more than the extraction of hydrochloric acid.     

Adsorption behaviour of some lanthanides on zirconium phosphate silicate (ZPS) in mineral acids

The distribution coefficients of tervalent eruopium, terbium, thulium and scandium between zirconium phosphate silicate and mineral acids have been determined. The distribution coefficients were found to change from one element to another and to depend on the acid used and its concentration. Separation factors were calculated and a separation scheme for these elements was worked out.