TY - JOUR
T1 - Arsenic Speciation in Bituminous Coal Fly Ash and Transformations in Response to Redox Conditions
AU - Deonarine, Amrika
AU - Kolker, Allan
AU - Foster, Andrea L.
AU - Doughten, Michael W.
AU - Holland, James T.
AU - Bailoo, Jeremy D.
N1 - Publisher Copyright:
© This article not subject to U.S. Copyright. Published 2016 by the American Chemical Society.
PY - 2016/6/7
Y1 - 2016/6/7
N2 - The risk of the mobilization of coal ash into the environment has highlighted the need for the assessment of the environmental behavior of coal ash, particularly with respect to toxic trace elements such as arsenic (As). Here, we examined As speciation in coal fly ash samples and transformations in response to aquatic redox conditions. X-ray absorption spectroscopy indicated that 92-97% of total As occurred as As(V), with the remainder present as As(III). Major As-bearing hosts in unamended ashes were glass, iron (oxyhydr)oxides, and calcium arsenate. Oxic leaching resulted in immediate As mobilization to the aqueous phase, reprecipitation of As-iron ferrihydrite, and As adsorption to mineral surfaces. Under anoxic conditions, the (reductive) dissolution of As-bearing phases such as iron ferrihydrite resulted in increased dissolved As compared to oxic conditions and reprecipitation of iron arsenate. Overall, As in coal ash is not environmentally stable and can participate in local biogeochemical cycles.
AB - The risk of the mobilization of coal ash into the environment has highlighted the need for the assessment of the environmental behavior of coal ash, particularly with respect to toxic trace elements such as arsenic (As). Here, we examined As speciation in coal fly ash samples and transformations in response to aquatic redox conditions. X-ray absorption spectroscopy indicated that 92-97% of total As occurred as As(V), with the remainder present as As(III). Major As-bearing hosts in unamended ashes were glass, iron (oxyhydr)oxides, and calcium arsenate. Oxic leaching resulted in immediate As mobilization to the aqueous phase, reprecipitation of As-iron ferrihydrite, and As adsorption to mineral surfaces. Under anoxic conditions, the (reductive) dissolution of As-bearing phases such as iron ferrihydrite resulted in increased dissolved As compared to oxic conditions and reprecipitation of iron arsenate. Overall, As in coal ash is not environmentally stable and can participate in local biogeochemical cycles.
UR - http://www.scopus.com/inward/record.url?scp=84973596248&partnerID=8YFLogxK
U2 - 10.1021/acs.est.6b00957
DO - 10.1021/acs.est.6b00957
M3 - Article
C2 - 27186791
AN - SCOPUS:84973596248
SN - 0013-936X
VL - 50
SP - 6099
EP - 6106
JO - Environmental Science and Technology
JF - Environmental Science and Technology
IS - 11
ER -