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Membrane rejection of nitrogen compoundsRejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.
Document ID
20040112347
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lee, S.
(Northwestern University Evanston, Illinois 60208, United States)
Lueptow, R. M.
Date Acquired
August 21, 2013
Publication Date
July 15, 2001
Publication Information
Publication: Environmental science & technology
Volume: 35
Issue: 14
ISSN: 0013-936X
Subject Category
Environment Pollution
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Life Support Systems
Non-NASA Center

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