The effect of H₂SO₄ and FeSO₄ concentrations and temperature on the efficacy of decontamination of spent ion-exchange resins was estimated. The study was performed on model spent ion-exchange resins purposefully contaminated with hematite and Co-57 radionuclide. It was found that an increase in solution temperature up to 50 °C and the addition of FeSO₄ increases the efficacy of decontamination of spent ion-exchange resins by 1 M and 2 M H₂SO₄ solutions by 1–2 orders of magnitude, whereas the decontamination factor value here is >10³. Since under static conditions, the secondary adsorption of Co-57 was observed, the extra washing of ion-exchange resins by 3 M solution of NaNO₃ is required. Decontamination under dynamic conditions excludes the secondary adsorption of Co-57, so that the necessity of the extra stage of washing can be skipped. Under dynamic conditions, the consumption of a solution of the composition H₂SO₄ (1 mol/L) + FeSO₄ (0.2 mol/L) is 1.5-fold lower in comparison with the 2M solution of H₂SO₄ at compatible values of the decontamination factor. Such an approach enables reduction in the volume of secondary waste and the equipment corrosion due to the decrease in H₂SO₄ concentration.

The actual material for the present work were the results of elemental analysis of soil samples taken in the Central part of the neighborhood Novotroitsk city Baleya, the section from the former tailings processing plant for the extraction of thorium from monazite concentrate sand through the valley of the river with waste monazite alluvial bulk to the tailings gold processing plants. The interpretation of the obtained data showed high contents of a number of elements, significantly exceeding the MPC. The total indicator of soil pollution (pollution indicator), calculated for five chemical elements (Pb, As, Sb, Ag, Th), indicates a dangerous and extremely dangerous environmental situation for public health and the need for detailed geochemical monitoring of soils. An urgent problem is also the assessment of the contribution of aerosol transport of pollutants during the transportation of sludge from gold recovery factories on the territory of the district Novotroitsk

Composite adsorbents based on a natural biopolymer matrix of chitosan, to which 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide and its Se derivative were attached, were synthesized. A complex of physicochemical analysis methods indicates that the direct introduction of a matrix with high ionic permeability into the reaction mixture contributes to the formation of homogeneous particles of composite with developed surface morphology, which enhances the kinetic and capacitive parameters of uranium sorption in liquid media. It has been established that the direct introduction of a matrix with high ionic permeability into the reaction mixture contributes to the formation of homogeneous particles with a developed surface morphology, which enhances the kinetic and capacitive parameters of uranium sorption in liquid media. The synthesized materials had increased sorption-selective properties towards uranium in the pH range from 4 to 9 under static sorption conditions. The formation of the Se derivative of amidoxime during its attachment to the polymer matrix (Se-chit) contributes to the creation of a more chemically stable and highly effective adsorbent, compared to the direct binding of 4-amino-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide with chitosan (43AF-chit). The optimal parameters for the synthesis of materials were established. It was demonstrated that the ratio of amidoxime to chitosan should be within the range of 2:1 to 1:2. As the mass content of chitosan increases, the material gradually dissolves and transforms into a gel, resulting in the formation of liquid radioactive waste with a complex chemical composition. It was found that the kinetic sorption parameters of composite materials increase 2–10 times compared to those of non-composite materials. The sorption capacity of uranium in solutions with pH 6 and pH 8 can reach approximately 400–450 mg g⁻¹. Under dynamic sorption conditions, the effective filtration cycle values (before uranium slips into the filtrate ≥ 50%) improve significantly when transitioning from a non-composite adsorbent to a composite one: increasing from 50 to 800 b.v. for pH 6 and from 2700 to 4000 b.v. for pH 8. These results indicate that the synthesized sorbents are promising materials for uranium removal from liquid media, suitable for both purification and the recovery of radionuclides as valuable raw materials.

Ash and slag waste from coal combustion is considered as a source of valuable metals. The results of a study of ash and slag waste from CHPPs in Primorye,