FIXATION OF LEAD CONTAMINANTS IN Pb-DOPED
SOLIDIFIED WASTE FORMS |
Dongjin Lee†, David Chung, Jongyeon Hwang, and Hyunjin Choi |
National Institute of Environmental Research, Environmental Research Complex, Kyungseo-dong, Seo-gu, Incheon, 404-708, South Korea |
Corresponding Author:
Dongjin Lee , |
Received: September 8, 2006; Accepted: June 9, 2007. |
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ABSTRACT |
Fixation of lead contaminants in the solidification/stabilization using Portland cement has been
investigated by X-ray diffraction, scanning electron microscopy and compressive strength. The presence of
lead was observed to produce lead carbonate sulfate hydroxide (Pb4SO4(CO3)2(OH)2), lead carbonate
hydroxide hydrate (3PbCO3·2Pb(OH)2·H2O) and two other unidentified lead salts in cavity areas and was
observed to significantly retard the hydration of cement. By 28 days, howevere, the XRD peaks of most of
the lead precipitates have essentially disappeared with only residual traces of lead carbonate sulfate
hydroxide and lead carbonate hydroxide hydrate evident. After 28 days of curing, hydration appears well
advanced with a strong portlandite peak present though C-S-H gel peaks are not particularly evident. Lead
species produced with the dissolution of lead precipitates are fixed into the cement matrix to be calcium
lead silicate hydrate (C-Pb-S-H) during cement-based solidification. |
Keywords:
Cement | Solidification/Stabilization(S/S) | Lead | X-Ray Diffraction | SEM |
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