Self-diffusion of selenate and selenite in overburden

Journal Article · · Journal of Environmental Quality; (United States)

OSTI ID:6131689

Ahlrichs, J S ^[1]; Hossner, L R ^[2]

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1. Cenex/Land O'Lakes, St. Paul, MN (United States)
2. Texas A and M Univ., College Station (United States)

Self-diffusion coefficients (D) for selenate (SeO{sub 4}{sup 2{minus}}) and selenite (HSeO{sub 3}{sup {minus}}) were evaluated as a function of overburden pH (2,3,5,7,9) and volumetric water content ({Theta}{sub v} = 0.22, 0.28, 0.34). Selenate self-diffusion coefficients were least (D = 0.23 {times} 10{sup {minus}6} cm{sup 2} s{sup {minus}1} in overburden adjusted to pH 3 and {Theta}{sub v} = 0.22) and greatest (D = 1.8 {times} 10{sup {minus}6} cm{sup 2} s{sup {minus}1} and 1.7 {times} 10{sup {minus}6} cm{sup 2} s{sup {minus}1}) in overburden adjusted to pH 9 and {Theta}{sub v} = 0.28 and 0.34. Self-diffusion coefficients for HSeO{sub 3}{sup {minus}} were 2 to 3 orders of magnitude slower than for SeO{sub 4}{sup 2{minus}}. The most rapid HSeO{sub 3}{sup {minus}} diffusion was observed at pH 2 and {Theta}{sub v} = 0.34 (D = 53.2 {times} 10{sup {minus}9} cm{sup 2} s{sup {minus}1}). The slowest was at pH 3 and {Theta}{sub v} = 0.22 (D = 0.2 {times} 10{sup {minus}9} cm{sup 2} s{sup {minus}1}). For both SeO{sub 4}{sup 2{minus}} and HSeO{sub 3}{sup {minus}} the self-diffusion coefficients increased with increasing water content and were related to adsorption characteristics of the soil and the Se species present at each soil pH.

• OSTI ID: 6131689
• Journal Information: Journal of Environmental Quality; (United States), Vol. 18:4; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
54 ENVIRONMENTAL SCIENCES
COAL MINING
ENVIRONMENTAL IMPACTS
SELENATES
SELF-DIFFUSION
SELENITES
SOILS
CONTAMINATION
ADSORPTION
CALIFORNIA
OVERBURDEN
PH VALUE
SURFACE MINING
TEXAS
DEVELOPED COUNTRIES
DIFFUSION
FEDERAL REGION VI
MINING
NORTH AMERICA
OXYGEN COMPOUNDS
SELENIUM COMPOUNDS
SORPTION
USA
010900* - Coal
Lignite
& Peat- Environmental Aspects
540220 - Environment
Terrestrial- Chemicals Monitoring & Transport- (1990-)