Email RIS file
Bookmark
Report an Issue

Anion retention in soil [electronic resource] : Possible application to reduce migration of buried technetium and iodine

Published
Rockville, Md. : U.S. Nuclear Regulatory Commission, 1991.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Physical Description
Pages: (33 pages) : digital, PDF file
Additional Creators
U.S. Nuclear Regulatory Commission and United States. Department of Energy. Office of Scientific and Technical Information
Access Online

Availability

I Want It
I Want It

Finding items...

Restrictions on Access
Free-to-read Unrestricted online access
Summary
This report summarizes a literature review of our present knowledge of the anion exchange properties of a number of soils and minerals, which may potentially be used as anion exchangers to retard migration of such anions as iodide (I{sup −}), iodate (IO₃{sup −}) and pertechnetate (TcO₄{sup −}) away from disposal site. The amorphous clays allophane and imogolite, are found to be among the most important soil components capable of developing appreciable amounts of positive charge for anion exchange even at about neutral pH. Decreases in the SiO₂/Al₂O₃ ratio and soil pH result in an increase in soil AEC. Allophane and imogolite rich soils have an AEC ranging from 1 to 18 meq/100g at pH about 6. Highly weathered soils dominated by Fe and Al oxides and kaolinite may develop a significant amount of AEC as soil pH falls. The retention of iodine (I) and technetium ({Tc}), by soils is associated with both soil organic matter, and Fe and Al oxides, whereas sorption on layer silicate minerals in negligible. Fe and Al oxides become more important in the retention of anionic I{sup −}, IO₃{sup −}, and TcO₄{sup −} as pH falls, since more positive charge is developed on the oxide surfaces. Although few studies, if any, have been conducted on I and {Tc} sorption by soil allophane and imogolite, it is estimated that a surface plough soil (2 million pounds soil per acre) with 5 meq/100g AEC, as is commonly found in andisols, shall retain approximately 5900 kg I and 4500 kg {Tc}. It is conceivable that an anion exchanger such as an andisol could be used to modify the near field environment of a radioactive waste disposal facility. This whole disposal system would then offer similar migration resistance to anions as is normally afforded to cations by usual and normal soils. 93 refs., 10 figs., 7 tabs.
Report Numbers
E 1.99:nureg/cr-5464
nureg/cr-5464
Subject(s)
Other Subject(s)
Note
Published through SciTech Connect.
10/01/1991.
"nureg/cr-5464"
"TI92002690"
Gu, B.; Schulz, R.K.
View MARC record | catkey: 14149205