UBC Theses and Dissertations
(Gamma minus) radiolytic generation of polysulphide from aqueous sodium sulphide solutions. You, Young-Soo
The mechanism of polysulphide formation by γ-radiation of aqueous sodium sulphide (Na₂S) solutions was investigated. The roles of solvated electron (ēaq ) and hydroxyl radicals (•OH), as primary products of water radiolysis, were studied in a systematic manner by using N₂O as ēaq and 2-propanol as •OH scavengers. Polysulphide formation in Na₂S solutions was found to be initiated by the oxidizing intermediate, the •OH radical. The scavenger experiments were supplemented by other studies on effects of solute concentration, dose at a single dose rate, pH, oxygen and hydrogen sulphide (H₂S) saturation. Rates of polysulphide formation increased according to presence of N₂O and H₂S, Na₂S concentration, irradiation dose and were highest at pH 7.0. In these experiments, highest polysulphide yield, 14 g/l, was obtained in the 80 g/l aq Na₂S-H₂S system at pH 12.7 and exposed for 20 Mrad dosage. The effect of oxygen was to increase radiation yield for lower dose ranges. At higher doses, however, G-values fluctuated markedly.
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