The leaching characteristics of selenium from coal fly ashes

Journal Article · Thu Nov 15 04:00:00 EST 2007 · Journal of Environmental Quality

DOI:https://doi.org/10.2134/jeq2007.0143· OSTI ID:21004559

Wang, T; Wang, J; Burken, J G; Ban, H; Ladwig, K ^[1]

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1. University of Missouri, Rolla, MO (USA). Dept. of Civil Architectural &

The leaching characteristics of selenium from several bituminous and subbituminous coal fly ashes under different pH conditions were investigated using batch methods. Results indicated that pH had a significant effect on selenium leaching from bituminous coal ash. The minimum selenium leaching occurred in the pH range between 3 and 4, while the maximum selenium leaching occurred at pH 12. The release of selenium from subbituminous coal ashes was very low for the entire experimental pH range, possibly due to the high content of calcium which can form hydration or precipitation products as a sink for selenium. The adsorption results for different selenium species indicated that Se(VI) was hardly adsorbable on either bituminous coal ashes or subbitumminous coal ashes at any pH. However, Se(I) was highly adsorbed by bituminous coal ashes under acidic pH conditions and was mostly removed by subbitumminous coal ashes across the entire pH range. This result suggests that the majority of selenium released from the tested fly ashes was Se(IV). A speciation-based model was developed to simulate the adsorption of Se(IV) on bituminous coal fly ash, and the pH-independent adsorption constants of HSeO{sup 3-} and SeO{sub 3}{sup 2-} were determined. The modeling approach is useful for understanding and predicting the release process of selenium from fly ash.

• OSTI ID: 21004559
• Journal Information: Journal of Environmental Quality, Journal Name: Journal of Environmental Quality Journal Issue: 6 Vol. 36; ISSN JEVQAA; ISSN 0047-2425
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ADSORPTION
BITUMINOUS COAL
CALCIUM
CHEMICAL STATE
COAL RANK
FLY ASH
LEACHING
PH VALUE
SELENIUM
SIMULATION
SUBBITUMINOUS COAL