Evaporation of water and urea solution in a magnetic field; the role of nuclear isomers
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2023Access:
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Poulose, S., Venkatesan, M., M?bius, M., Coey, J.M.D., Evaporation of water and urea solution in a magnetic field; the role of nuclear isomers, Journal of Colloid and Interface Science, 629, 2023, 814 - 824Download Item:
Abstract:
Hypothesis
Ortho and para water are the two nuclear isomers where the hydrogen protons align to give a total nuclear spin of 1 or 0. The equilibrium ratio of 3:1 is established slowly in freshly evaporated water vapour while the isomers behave distinct gasses, with their own partial pressures. Magnetic-field-induced ortho ⟷ para transformations are expected to alter the evaporation rate.
Experiment
Evaporation from beakers of deionized water and a 6 M solution of urea is monitored simultaneously for periods from 1 to 60 h with and without a 500 mT magnetic field, while logging the ambient temperature and humidity. Balances with the two beakers are shielded in the same Perspex container. Many runs have been conducted over a two-year period.
Findings
The evaporation rate of water is found to increase by 12 ± 7% of in the field but that of water with dissolved urea decreases by 28 ± 6%. Two effects are at play. One is dephasing of the Larmor precession of adjacent protons on a water molecule in a field gradient, which tends to equalize the isomer populations. The other is Lorentz stress on the moving charge dipole, which can increase the proportion of the ortho isomer. From analysis of the time and field dependence of the evaporation, we infer that the ortho fraction is 39 ± 1% in fresh vapour from water and 60 ± 5% in fresh vapour from urea.
Sponsor
Grant Number
Marie Curie
MAMI contract No 766007
Science Foundation Ireland (SFI)
12/RC/2278 AMBER
Author's Homepage:
http://people.tcd.ie/mobiusmhttp://people.tcd.ie/venkatem
http://people.tcd.ie/jcoey
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Journal of Colloid and Interface Science629
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Full text availableKeywords:
Magnetic water treatment, Magnetic fields, Halbach magnet, Evaporation of water, Evaporation of urea solution, Ortho and para water molecules, Larmor precession, Lorentz stress, Hydrogen bondingSubject (TCD):
Nanoscience & Materials , Applied physics , Condensed matter, electronic, magnetic and superconductive properties , Magnetism and spin electronics , NanotechnologyDOI:
https://doi.org/10.1016/j.jcis.2022.09.021Source URI:
https://pubmed.ncbi.nlm.nih.gov/36195021/ISSN:
0021-9797Metadata
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