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Abstract  

Sorption of macroamounts of the technetium thiourea complex cation by a cation exchange resin was studied in HNO3 and HClO4 solutions as a function of the concentration and reaction time for pertechnetate with thiourea. The distribution ratio reaches the value of 103 and may be even higher (>104) when sorption proceeds from a solution of the solid complex in dilute perchloric acid. The complex cation is extracted from 0.25–1M HNO3 with solutions of the bis(1,2-dicarbollyl)cobalt(III) anion in nitrobenzene—chloroform (1:1), log D=2.75−2.95 being obtained. The preconcentration and separation of technetium on cation exchangers from dilute mineral acids would seem to be one field of application.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: F. Macášek, V. Mikulaj, P. Rajec, R. Čech, L. Mátel, R. Kopunec, J. Kuruc, and A. Švec

Abstract  

Radiolytical decomposition of phenol was investigated at60Co gamma irradiation (1–2 Gy·s–1, 10 kGy) of pre- and continuously aerated aqueous solutions at concentrations of phenol 1–100 mg· ·dm–3 and in the presence of sodium hydroxide, sulphuric acid, sodium and ferrous sulphate, formaldehyde, 2-propanol,n-hexane, xylene, benzene, and commercial gasoline. From the decomposition rate at doses 50–400 Gy, a phenomenological model of linear relation between the dose acquired for 37% decomposition (D 37), initial concentration (g·m–3) of phenol (p 0) and of an admixture (s 0) was confirmed in the formD 37=52f tr(p 0+f eq s 0), wheref's are constants which can be attributed to the relative transformation resistance of phenol towards the OH radicals in given matrix (f tr, for pure waterf tr=1) and relative acceptor capacity of competing substrate (f eq). In real wastewaters, the efficient decrease of phenols content may be substantially lower than that in model solutions, obviously due to radiation oxidation of aromates, as proved by irradiation of aqueous solutions of benzene. Technical and economical feasibility of the process is discussed.

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