An isotopic analysis of ionising radiation as a source of sulphuric acid
نویسندگان
چکیده
Sulphuric acid is an important factor in aerosol nucleation and growth. It has been shown that ions enhance the formation of sulphuric acid aerosols, but the exact mechanism has remained undetermined. Furthermore some studies have found a deficiency in the sulphuric acid budget, suggesting a missing source. In this study the production of sulphuric acid from SO2 through a number of different pathways is investigated. The production methods are standard gas phase oxidation by OH radicals produced by ozone photolysis with UV light, liquid phase oxidation by ozone, and gas phase oxidation initiated by gamma rays. The distributions of stable sulphur isotopes in the products and substrate were measured using isotope ratio mass spectrometry. All methods produced sulphate enriched in 34S and we find an enrichment factor (δ34S) of 8.7± 0.4 ‰ (1 standard deviation) for the UV-initiated OH reaction. Only UV light (Hg emission at 253.65 nm) produced a clear non-mass-dependent excess of 33S. The pattern of isotopic enrichment produced by gamma rays is similar, but not equal, to that produced by aqueous oxidation of SO2 by ozone. This, combined with the relative yields of the experiments, suggests a mechanism in which ionising radiation may lead to hydrated ion clusters that serve as nanoreactors for S(IV) to S(VI) conversion.
منابع مشابه
Isotopic analysis of mineral phases to unravel the origin of altered volcanic rocks: an example from the Leucite Hills lamproites
Study of lamproites from Leucite Hills, Wyoming, indicates that the isotopic compositions of some specimens have been modified due to the alteration and/or the presence of secondary carbonate impurities within the whole rocks. Leachate test shows that while phlogopite lamproites are not affected by secondary processes, the transitional madupitic lamproites from Middle Table Mountain and on...
متن کاملDiffusion measurement in ferrous infused gel dosimeters
Background: The compositions of Ferrous sulphate, Agarose and Xylenol orange dye (FAX) and Ferrous sulphate, Gelatin and Xylenol orange dye (FGX) in solution of distilled water and sulphuric acid are two tissue-equivalent gel dosimeters. Ionizing radiation causes oxidation of Fe2+ ion to Fe3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours af...
متن کاملEffects of using radiation processing in nutrition science and their restriction: a review
Isotopic and nuclear techniques play an important role in food and agriculture, health and industry. In the agricultural sciences and food technology sectors, recent research has elucidated the new potential application of radiation for microbial decontamination, food preservation, improve the nutritional quality of foods and effectively utilise its potential as human food or animal feed. The...
متن کاملEffects of using radiation processing in nutrition science and their restriction: a review
Isotopic and nuclear techniques play an important role in food and agriculture, health and industry. In the agricultural sciences and food technology sectors, recent research has elucidated the new potential application of radiation for microbial decontamination, food preservation, improve the nutritional quality of foods and effectively utilise its potential as human food or animal feed. The...
متن کاملPlant sink-source relationships and carbon isotopic labeling techniques . Taher Barzegar* and Fatemhe Nekounam
The concept of source and sink strength is presently well-recognized and accepted by the scientific community as a pertinent approach describing the mechanisms of carbohydrate partitioning into the different and competing organs at a whole plant or canopy scales. Sink–source relationships have a clear role in the size of sink organs. Besides the effect on organ size, sink/source ratio might also...
متن کامل