Evaluation of chemical speciation and environmental risk levels of heavy metals during varied acid corrosion conditions for raw and solidified/stabilized MSWI fly ash

Bibliographische Detailangaben
Veröffentlicht in:	Waste management (New York, N.Y.). - 1999. - 87(2019) vom: 15. März, Seite 407-416
1. Verfasser:	Li, Weihua (VerfasserIn)
Weitere Verfasser:	Sun, Yingjie, Huang, Yaomin, Shimaoka, Takayuki, Wang, Huawei, Wang, Ya-Nan, Ma, Li, Zhang, Dalei
Format:	Online-Aufsatz
Sprache:	English
Veröffentlicht:	2019
Zugriff auf das übergeordnete Werk:	Waste management (New York, N.Y.)
Schlagworte:	Journal Article Acid corrosion Chemical speciation Environmental risk Heavy metals Leaching pattern MSWI fly ash Coal Ash Metals, Heavy Particulate Matter mehr... Solid Waste Carbon 7440-44-0

Beschreibung
Zusammenfassung:	Copyright © 2019 Elsevier Ltd. All rights reserved. In this work, the leaching pattern, chemical speciation, and environmental risks of various heavy metals (Pb, Zn, Cu, Cd, Cr, and Ni) were investigated synchronously under different acid corrosion conditions through end-point pH leaching experiments. The heavy metals were present in raw, stabilized (phosphoric acid; chelating agent), and solidified (Portland cement) municipal solid waste incineration (MSWI) fly ash. The results showed that the stabilization and solidification pre-treatment could effectively decrease the leaching of most heavy metals. However, phosphoric acid stabilization and Portland cement solidification increased the solubility of Ni and Pb/Cu/Cd under low end-point pH conditions, while that of Cr and Pb increased under high end-point pH conditions. Overall, the leaching pattern of heavy metals was not affected by the addition of binders/additives. The results from speciation analysis showed that the bioavailable fractions (exchangeable and carbonate-bound) were leached out from initial raw or solidified/stabilized fly ash after distilled water leaching. However, with the decrease in end-point pH levels, the bioavailable fractions increased again due to the increase in acid corrosion on metal-bearing mineral matrixes. The risk assessment results indicated that, after exposing the raw or solidified/stabilized fly ash to highly acidic conditions, not only the high-content Pb/Zn/Cu, but also some low-content Cd posed potential risks to the environment. During the leaching process, under extremely acidic conditions, the increased environmental risks posed by Pb/Zn/Cu/Cd in residual fly ash solids were greatly ascribed to the increase in bioavailable fractions, which might result in the re-leaching of some heavy metals to the environment
Beschreibung:	Date Completed 12.09.2019 Date Revised 12.09.2019 published: Print-Electronic Citation Status MEDLINE
ISSN:	1879-2456
DOI:	10.1016/j.wasman.2019.02.033