Determination and evaluation of hexavalent chromium in power plant coal combustion by-products and cost-effective environmental remediation solutions using acid mine drainage.
The chromium species leaching from a coal combustion fly ash landfill has been characterized as well as a novel approach to treat leachates rich in hexavalent chromium, Cr(VI), by using another natural waste by-product, acid mine drainage (AMD), has been investigated during this study. It is observed that as much as 8% (approximately 10 microg g(-1) in fly ash) of total chromium is converted to the Cr(VI) species during oxidative combustion of coal and remains in the resulting ash as a stable species, however, it is significantly mobile in water based leaching. Approximately 1.23 +/- 0.01 microg g(-1) of Cr(VI) was found in the landfill leachate from permanent deposits of aged fly ash. This study also confirmed the use of AMD, which often is in close proximity to coal combustion by-product landfills, is an extremely effective and economical remediation option for the elimination of hexavalent chromium in fly ash generated leachate. Speciated isotope dilution mass spectrometry (SIDMS), as described in EPA Method 6800, was used to analytically evaluate and validate the field application of the ferrous iron and chromate chemistry in the remediation of Cr(VI) runoff.
Kingston
H M Skip
HM
Department of Chemistry & Biochemistry, Duquesne University, Pittsburgh, PA 15282, USA. kingston@duq.edu
Cain
Randy
R
Huo
Dengwei
D
Rahman
G M Mizanur
GM
D000143:Acids; D002857:Chromium / Q000032:analysis*; D003031:Coal; D004787:Environmental Pollution / Q000191:economics / Q000517:prevention & control; D005296:Ferrous Compounds / Q000032:analysis; D006801:Humans; D017745:Incineration; D013058:Mass Spectrometry; D008906:Mining; D010084:Oxidation-Reduction; D011210:Power Plants; D012037:Refuse Disposal; D014867:Water / Q000737:chemistry
D000143:Acids; D003031:Coal; D005296:Ferrous Compounds; D014867:Water; D002857:Chromium; C074702:chromium hexavalent ion