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National Academy of Sciences of Ukraine. State Scientific Institution “Institute for Single Crystals” (SSI ISC NASU). A.V. Grygorova, K.Yu. Bryleva, A.Yu. Andryushchenko, N.N. Grebenyuk, I.B. Shcherbakov, K.N. Belikov. Sr and Cs selective calixarene -based sorbents:
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National Academy of Sciences of Ukraine State Scientific Institution “Institute for Single Crystals” (SSI ISC NASU) A.V. Grygorova, K.Yu. Bryleva, A.Yu. Andryushchenko, N.N. Grebenyuk, I.B. Shcherbakov, K.N. Belikov Sr and Cs selective calixarene-based sorbents: analytical application in environmental chemistry
Radionuclides normalized in water of economical and drinking water supply sources* *Норми радіаційної безпеки України (НРБУ-97); Державні гігієнічні нормативи. – Київ: Відділ поліграфії українського центру держсанепіднагляду МОЗ України, 1997. – 125с.
Composite materials for α- and β- emitting nuclides determination in water The existing methods for radionuclide determination in natural waters are not sufficiently sensitive and precise Goal of the work: • Obtaining materials, combining radionuclide concentration and detection processes for utilization in radiation monitoring • Development of their application methods for selective determination of radionuclide content in natural waters Preliminary concentration of small amounts of radionuclides from large volume of investigated solution Use of 4π-geometry emission registration Ways of accuracy improvement
Aim of the work –creating material with the specified properties: selectivity towards radionuclide or radionuclide family; presence of through pores of desired size and location; high light output and registration efficiency; analysis performance and low cost. Analyzed solution Radionuclide Sorbent Scintillator Pore forming agent
Material composition Optimal scintillating matrix p-Terphenyl(PTF) activated 1,3-diphenylbutadiene-1,4 • PTF characteristics: • λmax= 420nm • tf = 3-5 ns • Zef = 5.8 PTF Advantages: • Short luminiscence time; • Stability in characteristics under influence if atmosphere and radiation; • Light output stability in broad temperature range (-60º…+140ºС); • Absence of scintillation characteristics anisotropy throughout volume; • Possibility of growing crystals with the diameter up to 80 mm. Optimal pore forming agent NH4HCO3. Tdec.= 36ºC. Optimal sorbent Sorbent characteristics: • high exchange capacity; • mechanical durability; • color absence; • absence of own luminescence; • thermo- and radiation stability. For the determination of Sr and Cs we have used calixarene-impregnated polymer matrix and zeolite.
R 6 CH2 O A l k O N k A l The structures of calixarenes with different functionality used in the present work as highly selective chelating agents Compounds were given by V.I. Kalchenko, Corresponding Member of the National Academy of Sciences of Ukraine, Professor, Vice-director of the Institute of Organic Chemistry, Kyiv, Ukraine Calix[4]arene-crown-6 derivatives with the selectivity for Cs ions Calixareneamides exhibiting selectivity for Sr ions
SEM images of polymer spheres cross-section in back-scattered electron mode
Investigation methods Inductively coupled plasma atomic emission spectrometry (ICP-AES), Thermo Jarrell Ash, USA Operating conditions Flame atomic emission spectrometry Saturn, USSR Operating conditions
100 90 Recovery rate, % 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5 6 7 8 9 pH Sr (a) and Cs (b) extraction rate dependencies on pH (a) Divinyl bezene-styrene co-polymer impregnated with calix [6]-areneamide (b) Recovery rate, % Divinyl bezene-styrene co-polymer impregnated with calix [4]-arene-crown-6 pH
4,5 4 3,5 3 А, mg/g 2,5 2 1,5 1 0,5 0 0 2 4 6 8 10 12 14 C, мg/l Absorption isotherms (a) (b), C – ion equilibrium concentration, mg/l; A – equilibrium sorption capacity, mg/g; A∞ - maximum sorption capacity, mg/g; КL - Langmuir constant, l/mg КF – Freindlich constant, mg/g; n – Freindlich isotherm constant, indicating sorption intensity where Absorption isotherm of Sr2+ on the calix[6]areneamide impregnated polymer Absorption isotherm of Cs+on the calix[4]crown[6]arene impregnated polymer
Scheme of mordenite impregnation with calix[6]arene Mordenite in -Na form d < 0.125 mm Mordenite soaked in NaCl solution during 24 hours at ambient temperature Washing with distilled water Treated actively during 60 min Washing with distilled water Washing with methanol Drying at 50ºC during 3 hours 1g of calix[6]arene dissolved in 10 ml of CH2Cl2 tri-n-butyl phosphate dissolved in CH2Cl2 Impregnation Removing diluent at 100ºC Drying at 120ºC
IR spectra of mordenite before and after impregnation with calix[6]arene Sr recovery rates in systems containing calixarene-impregnated mordenite
Prospective work • Design of highly selective scintillating sorbent with the use of materials investigated • Investigation and optimization of physicochemical parameters of the composite materials obtained • Developing the experimental technique for measuring the radionuclide concentration in water samples with the use of porous scintillator obtained The work is supported by STCU Grant No 4955 “Composite materials on the basis of highly selective calixarene sorbents for determination of radionuclides in environments”