New effective sorbents for purification of aqueous media from technogenic contaminants

Created are the sorbents based on silica gel non-covalently modified with partially hydrogenated heterocyclic compounds (PHHC), containing nitrogen as donor atoms for purification of aqueous media from technogenic contaminants. The investigations show that the modified silica gel is characterized by a sorption capacity relatively higher than that of unmodified one. The sorption degree of metal ions is studied depending on their concentrations, total mineralization and pH value of the solutions. Conditions for selective sorption of microquantities of Eu³⁺ which has been used as chemically identical to ²⁴¹Am are described. Moreover it was shown that PHHC modified silica gel was potential to use as the sorbent to concentrate the Eu³⁺ and Sr²⁺ metal ions with initial concentrations near 1 mg∙L⁻¹ for the quantitative analysis. Also the possible mechanism of metal ion sorption on the developed sorbents was proposed. Remove selecte

Merrifield resin modified with thiacalixarene-tetraphosphonates: synthesis, characterization and europium sorption

Tetrahydroxythiacalixarene tetraphosponates were synthesized and chemically linked to chloromethylated polystyrene (Merrifield resin) surface via the Williamson reaction. In order to evaluate the effect of thiacalixarene platform structure on the properties of sorbents, phosphorylated resins with P=O groups attached to the polymer surface via methylene spacers were synthesized by the Arbuzov reaction of the iodomethylpolysterene with trialkylphosphites. Composition and structure of the obtained materials was established by elemental analysis and IR spectroscopy. The sorbents obtained remove up to 99 % of Eu(III) ions from aqueous solutions of average mineralization level at pH of 5.5-6. The optimum contact time was established to be 2 h. Due to cooperative (macrocyclic) effect of P=O binding groups pre-organized at the upper rim of the thiacalixarene platform the resins exhibit better uptake parameters than the resins modified with para-unsubstituded, para-tert-butylsubstituted thiacalixarenes or the resins bearing the phosphonate groups directly bound to the Merrifield resin surface. Europium distribution coefficient for the best sorbents obtained was equal to 11.3

Luminescent properties of ZnSxSe₍₁₋x₎ mixed crystals obtained by solid-phase synthesis and melt-growing

The luminescence characteristics of ZnSxSe₍₁₋x₎ mixed crystals (MC) obtained by solid-phase synthesis and melt-growing were studied. In X-ray luminescence spectra of ZnSxSe₍₁₋x₎ powdered MC synthesized from ZnS and ZnSe powders, where x = 0.90 to 0.99, a non-elementary band with λmax ~ 520 nm (I₁) was observed, but for ZnSxSe₍₁₋x₎ with low concentrations of ZnS (x = 0.05) the luminescence band with λmax = 600-630 nm (I₂) was a dominate. In X-ray luminescence spectra of ZnSxSe₍₁₋x₎ MC (x = 0.05 to 0.3) obtained by the melt growth only I₂ luminescence band with shifted maximum from 610 nm to 590 nm at sulfur concentration increasing was observed. It is shown that for the composition of ZnS₀.₁₅Se₀.₈₅ MC annealed in zinc vapor the light yield of X-ray luminescence is 1.6 times higher than in the commercial ZnSe(Te) crystals. In consideration of this fact it might be supposed, that this MC can find application in scintillation detectors of X-ray and low-energy gamma radiation