Influence of humic acid on sorption of neptunium(V) onto soil

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:382877

Sakamoto, Y; Nagao, S; Ohnuki, T; Senoo, M ^[1]; Ohashi, A; Sato, S; Ohashi, H ^[2]

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1. Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Dept. of Environmental Safety Research
2. Hokkaido Univ., Sapporo (Japan). Dept. of Nuclear Engineering

The pH dependence of the stability constant of Np(V)-humate and the sorption of Np(V) onto soil was studied to clarify the influence of dissolved organic carbon on the migration behavior of Np(V) in soil layer. The stability constant of Np(V)-humate was expressed by log{beta}{sub 1} = (0.35 {+-} 0.03)pH + 0.04 {+-} 0.01 in the pH region from 5.3 to 8.7, and the intrinsic stability constant by log{beta}*{sub 1} = 3.66 {+-} 0.05. The sorption of Np(V) increased with pH up to pH 7, and tended to reach maximum, about 95%, at pH 9 in the absence of humic acid. In the presence of humic acid more than 140 mg/l, the sorption of Np(V) was lower than that in the absence of humic acid above pH 7, while any influence of humic acid on the sorption of Np(V) onto soil was not observed below pH 7. The sorption behavior of Np(V) onto soil was explained by reversible sorption of NpO{sub 2}{sup +} and sorption of NpO{sub 2}CO{sub 3}{sup {minus}} and/or NpO{sub 2}OH. Further, the influence of the size distribution of Np(V) on the sorption onto soil was examined and discussed.

• OSTI ID: 382877
• Report Number(s): CONF-941075--; ISBN 1-55899-253-7
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
ADSORPTION
CATALYTIC EFFECTS
EXPERIMENTAL DATA
HUMIC ACIDS
NEPTUNIUM
NEPTUNIUM 237
NEPTUNIUM CARBONATES
NEPTUNIUM HYDROXIDES
NEPTUNIUM OXIDES
PH VALUE
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTE FACILITIES
RADIONUCLIDE MIGRATION
SAFETY
SOILS
SORPTIVE PROPERTIES
UNDERGROUND DISPOSAL