HYDROGEN PEROXIDE YIELDS FROM COBALT-60 GAMMA IRRADIATION OF ALKALINE SOLUTIONS
The chain-transformation reaction of ferriprotoporphyrin, FPP, was used to determine the observed initial yield of hydrogen peroxide, G(H/sub 2/O/sub 2/)/ sub obs/, and the initial yield of total chain-initiating agents, G(R), from cobalt-60 gamma -irradiation of aerated alkaline solutions, pH 7.7 to 14, by comparing the initial yields of transformation product from the thermal hydrogen peroxide reaction with those from the postirradiation and irradiation reaction of FPP, respectively. The values for G(H/sub 2/O/sub 2/)/sub obs/ and G(R) were found to be approximately constant for alkaline solutions at pH <10.5, with averages of 1.5 and 1.03 molecules per 100 ev, respectively. The values for G(R) above pH 10.5 and those for G(H/sub 2/O/sub 2/)/sub obs/ above pH 12.5 were found to increase to maxima at pH 13.3, with values of 6.25 and 4.1, respectively. The values for G(R) in alkaline solutions at pH <10.5 are essentially equal to the value for F + 2E in neutral solution, where F + E is the yield of hydrogen peroxide from water decomposition and E is the yield of hydrogen peroxide from the reduction of dissolved oxygen by the H atoms formed in excess of OH radicals. It is proposed that, in alkaline solutions at pH <10.5, FPP reacts successively with OH radicals and H atoms (or HO/sub 2/ radicals), resulting in their recombination and unchanged FPP. It is further proposed that, in alkaline solutions at pH >10.5, new radical species are formed from water decomposition, which presumably do not react in a reversible reaction with FPP, but rather augment the chain-transformation reaction. (auth)
- Research Organization:
- Univ. of California, Los Angeles
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-17-027180
- OSTI ID:
- 4697286
- Journal Information:
- Radiation Res., Journal Name: Radiation Res. Vol. Vol: 19
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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