Chemical speciation and mobility of heavy metals in municipal solid waste incinerator fly ash

Article type: Research Article

Authors: LIU, Feng | LIU, Jian-guo | YU, Qian-feng | NIE, Yong-feng

Affiliations: Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China | Department of Environmental Engineering, Osaka University, Osaka 565-0861, Japan

Note: [] Corresponding author. E-mail: [email protected]

Abstract: Chemical speciation is a significant factor that governs the toxicity and mobility of heavy metals in municipal solid waste incinerator fly ash. Sequential extraction procedure is applied to fractionate heavy metals (Pb, Zn, Cd, Cu, and Cr) into five defined groups: exchangeable, carbonate, Fe-Mn oxide, organic, and residual fractions. The mobility of heavy metals is also investigated with the aid of toxicity characteristic leaching procedure. In the fly ash sample, Pb is primarily presented in the carbonate (51%) and exchangeable (20%) fractions; Cd and Zn mainly exist as the exchangeable (83% and 49% respectively); Cu is mostly contained in the last three fractions (totally 87%); and Cr is mainly contained in the residual fraction (62%). Pb, Zn and Cd showed the high mobility in the investigation, thus might be of risk to the natural environment when municipal solid waste incinerator fly ash is landfilled or reutilized.

Keywords: municipal solid waste incinerator fly ash, heavy metals, chemical speciation, mobility

Journal: Journal of Environmental Sciences, vol. 16, no. 6, pp. 885-888, 2004