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Abstract  

A sensitive and selective solid phase extraction procedure for the determination of trace of uranium(VI) has been developed. An alumina-sodium dodecyl sulfate coated on with pyrocatechol violet was used for preconcentration and determination of uranyl ions by spectrophotometry method using Arsenazo III reagent. Sorbed ions were quantitatively eluted using 5 mL of 0.25 mol L−1 HNO3. The effects of parameters such as pH, amount of alumina, amount of ligand, flow rate, type and concentration of elution agent were examined. The capacity of the sorbent for U(VI) was found to be 0.92 mmol g−1. The relative standard deviation was 1.28% for 10 replicate determinations of U(VI) ion in a solution with a concentration of 1.0 μg mL−1. The practical applicability of the developed sorbent was examined using synthetic and real samples such as standard reference material 2709 (San Joaquin Soil) and 2711 (Montana Soil).

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Abstract  

Specific surface area and pore size distribution are determined usually from adsorption isotherms at low temperatures using nitrogen or noble gases. These are not absolute parameters and the measuring methods are fraught with serious difficulties. General problems of sorption measurements and recent developments are discussed. To obtain information for practical purposes these measurements need to be supplemented by investigations of the sorbate/sorbent system used in practice. Results of the measurement of nitrogen and water vapour adsorption on different materials are compared.

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Abstract  

The mechanism of Pd(II) and198Au(III) sorption on 4(benzylcellulose)phenylthiocarbamoylamine has been investigated. The data obtained from the sorption dependence on medium acidity and temperature, from isotherms, IR spectra and diffuse reflectance spectra led to the conclusion that the physical sorption of the two elements is accompanied by the formation of chelates. The sorbent might be employed for the concentration of Pd(II) and Au(III) from dilute solutions.

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Abstract  

The sorption of uranium from aqueous solutions on titanium and zirconium phosphates in H+ and K+ forms modified by iron or aluminum ions has been investigated. The modified pattern of porosity is much better, than for none modified analogous, owing to their increased sorption capacity and kinetics of uranium absorption. The modified sorbents display selectivity towards uranium, that allows to purify solutions up to the content of uranium below the limit of its analytical definition.

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Abstract  

The purpose of this study was to test a method for 99Tc determination in soil samples from locality Bratislava Podunajske Biskupice by using solid phase extraction technique with a new sorbent AnaLig® Tc-02—molecular recognition technology product. The method is suitable for analyzing soil samples in a relatively short time and high recoveries. The use and effectiveness of AnaLig® Tc-02 were successfully tested by analysis of soil and spiked soil samples.

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Abstract  

Fourteen samples of wastes from algal plants were tested for possible analytical and/or technological use for90Sr and137Cs extraction from natural waters. Sorption experiments were carried out in static and dynanic conditions. It was noted that the examined sorbents posses high affinity for Sr2+. The sorption capacity reached the value of 4.72·10−3 mole/g. Simple and express analytical procedures for90Sr determination were developed and tested in the Dnieper estuary region.

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Summary  

Self Assembled Monolayers on Mesoporous Supports (SAMMS) are nanostructured silica sorbents that offer fast uptake kinetics, high material loading, and excellent selectivity. We have found that these materials rapidly preconcentrate radionuclides from solution and enable direct assay. We will discuss the utilization of SAMMS for measurement of alpha-, beta- and gamma-emitters. The issues involved in direct counting of SAMMS with various methods are explored. We will discuss the advantages, challenges, and limitations involved in using SAMMS for radiochemical analysis.

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Abstract  

Silver-impregnated silica gels prepared by us have very good adsorption characteristics for both organic and inorganic radioiodine. Under the operating conditions applied, the adsorption capacity is up to 200 mg I g–1 and the utilization of silver on the sorbent is higher than 90%. The adsorbent can be used to remove iodine from nuclear fuel reprocessing off-gases and from air cleaning systems of nuclear reactors.

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Abstract  

We have studied the sorption properties of some granular inorganic ion-exchangers synthesized by gel technology, such as titanium and zirconium hydroxophosphates (THP, ZHP), titanium and zirconium molybdophosphates and titanium and zirconium phosphate-ferrocyanides. A high selectivity of THP and ZHP modified with ferrocyanide and molybdate ions to137Cs has been found. The possibility of applying inorganic sorbents for the purification of cesium-137 contaminated foodstuff is illustrated on the examples of fish treatment.

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Abstract  

A silica-titania (Si–Ti) mixed hydroxide gel with Ti to Si mole ratio of 11 was prepared. Studies on the sorption of radiostrontium from alkaline solutions having various concentrations of sodium were carried out with Si–Ti. The distribution coefficient (K d) of strontium decreased with increasing concentrations of sodium from 0.1 to 4.0 mol·dm–3. The plot of logK d versus log [Na+] gave a slope of –0.55 as against the theoretical value of –2.0. This suggests that some other paths in addition to the simple stoichiometric ion exchange is also existing for sorption. From pH titrations the pHpzc of Si–Ti was found to be 4.22 coinciding nearly with the pH sorption edge. An attempt was made to correlate the sorption results with the surface characteristics of the sorbent. It was found that sorption is favored when the surface of the sorbent transforms into an anionic form. Sharp increase in the sorption of strontium was observed when the equilibrium pH was between 7 and 10. This behavior could be attributed to the abrupt increase in net negative charge on the surface of the sorbent.

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