A. F. Seliverstov

Oxidative degradation of EDTA in aqueous solutions under UV irradiation

The efficiency of high-intensity pulsed UV irradiation for degradation of organic compounds in decontamination solutions was examined. The conditions ensuring virtually complete degradation of EDTA in alkaline and acidic solutions simulating decontamination solutions T and T-Ts were determined. The optimal ratios of H2O2 and EDTA providing complete photochemical oxidation of the complexone were evaluated.

Recovery of Radioactive Cobalt from Aqueous EDTA Solutions Using Concentrated Ozone

Oxidative decomposition of EDTA in aqueous solution under the action of ozone was studied. Conditions providing complete decomposition of EDTA and precipitation of radioactive cobalt in the form of hydroxide were found.

Effect of complexing agents and surfactants on coprecipitation of cesium radionuclides with nickel ferrocyanide

The effect of organic complexing agents and surfactants on coprecipitation of Cs tracer with nickel ferrocyanide was studied. In the presence of oxalate and ethylenediaminetetraacetate anions in solutions, the degree of Cs coprecipitation sharply decreases. The effect of surfactants of various kinds on coprecipitation is considerably weaker. To decrease the interfering effect of organic substances on the coprecipitation of Cs, their treatment with ozone was tested. The ozonation of solutions was found to eliminate completely the negative effect of organic complexing agents and surfactants on the Cs coprecipitation with nickel ferrocyanide.

Sorption of Pu and Np on chitin-containing materials from strongly alkaline solutions

Sorption of Pu and Np on chitin, chitosan, and chitin-containing materials from strongly alkaline (1–4 M NaOH) solutions was studied under the static and dynamic conditions in the presence of large amounts of NaNO3. The Pu(IV) distribution coefficient (Kd) between the solutions with the NaOH concentration ranging from 1 to 4 M and different chitin-containing sorbents varies from 3000 to 6000 cm3 g−1. The Kd of Np(V) with different sorbents decreases from 2000–4000 to 600–1200 cm3 g−1 with increasing NaOH concentration.

Metal Nanoparticles on Polymer Surfaces: 2. Catalytic Activity of Platinum Nanoparticle Ensembles on Polystyrene

Catalytic properties of platinum nanoparticles deposited onto polystyrene surface from their hydrosol stabilized with sodium polyacrylate are studied. It is shown that, during the adsorption on polymer substrate, metal nanoparticles form rather densely packed ordered monolayer ensembles with high catalytic activity in the model reaction of hydrogen reduction of methyl viologen. This allows one to measure the reaction rate with standard spectrometric method using polymer film with the surface area of 1 cm2 or less as a catalyst support.

Oxidative decomposition of oxalate ion with ozone in aqueous solution

The oxidation of oxalate ions with ozone in aqueous solution has been studied, and the effects of pH, temperature, and reactant concentrations on the reaction rate and efficiency have been estimated. The oxidative decomposition is most effective in alkaline medium (pH ≥ 10) at 50°C. Under these conditions, the consumption of ozone is 0.6±0.1 g per gram of oxalate or 1.1±0.1 mol per mole of oxalate, which corresponds to the stoichiometry (COO–)2 + O3 + H2O → 2CO32– + O2 + 2H+.

Sorption of arsenic onto inorganic sorbents modified with iron compounds

Granulated inorganic sorbents based on silica gel of KSKG grade and aluminum oxide and modified with Fe(III) compounds were developed for water treatment to remove As(V). The influence of the particle size of the modifying additive on the ability of silica gel to take up As(V) was examined. The KSKG-based sorbents modified with nanoparticles of Fe(III) compounds exhibit the highest sorption capacity. The capacity of silica gel based sorbents modified with nanoparticles of iron compounds for As(V) is higher than that of analogous sorbents modified with iron oxides prepared by thermal decomposition of Fe(III) nitrate.

Recovery of 60Co from EDTA-containing aqueous solutions

The possibility of recovering radioactive cobalt from EDTA-containing aqueous solutions using oxidation (O3) and photooxidation (UV/H2O2) methods was examined. The optimal amounts of reagents ensuring complete decomposition of EDTA and recovery of radioactive cobalt were determined. The procedures developed for oxidative decomposition of EDTA and for recovery of radioactive isotopes from aqueous media were tested with real liquid radioactive solutions.

Dissolution of actinide oxides in HNO3 using a concentrated ozone-oxygen mixture in the presence of Ce(IV) ions

Accumulation of Ce(IV) in HNO3 solutions as a result of Ce(III) oxidation with an ozone-oxygen mixture (OOM) was studied. An increase in the ozone concentration in OOM from 30 to 180 mg dm−3 leads to a considerable increase in the rate of Ce(III) oxidation to Ce(IV). With concentrated OOM, the Ce(III) to Ce(IV) oxidation yield of two ions per ozone molecule is attained. An increase in the steady-state concentration of Ce(IV) in the solution leads to considerable acceleration of the dissolution of highly calcined UO2.

Aqueous solutions of colloidal ruthenium: The radiation-chemical preparation and optical absorption

The radiation-chemical reduction of Ru(III) is studied in aqueous RuCl3 solutions containing isopropyl alcohol. In the presence of sodium polyacrylate, the stable sols of metal are formed with spherical particles 4–8 nm in diameter. The optical spectrum of nanoparticles is characterized by an increasing absorption in the UV spectral region with no maximum (ε200 = 7.2 × 1030 l mol–1 cm–1). The colloids of ruthenium in an aqueous solution are stable in the open air.