Investigations of sequential leaching behaviour of Cu and Zn from coal fly ash and their mobility in environmental conditions.

The quantitative evaluation of chemical fraction of Cu and Zn in the coal fly ash by methods of five-step sequential extraction was carried out in order to characterize metal mobility in environmental conditions. The research involved (i) water-soluble (pH 7), (ii) acid-soluble (pH 5), (iii) oxide, (iv) difficult reducible and (v) residual metal fractions. It was discovered, that the total extraction of the studied metals from coal fly ash to solutions take place in the following quantities Cu-39.0mgkg(-1) and Zn-89.0mgkg(-1). The investigations of chemical fractions proved that the subject metals occur mainly in coal fly ash as: oxide (Cu-12.0mgkg(-1), Zn-37.0mgkg(-1)) and residual (Cu-9.5mgkg(-1), Zn-27.0mgkg(-1)) as well as difficult reducible (Cu-16.5mgkg(-1), Zn-22.0mgkg(-1)). Low concentrations of metals for water-soluble fraction (Cu<d.l., Zn-0.5mgkg(-1)) and acid-soluble fraction (Cu-1.0mgkg(-1), Zn-2.5mgkg(-1)) were observed. The fractions of Cu and Zn leachable from the ash in environmental conditions contain: 2.6% (Cu) and 3.4% (Zn) of metal total amount in the coal fly ash. The obtained mobility parameter of Cu and Zn can be applied to estimate the concentration increase of mobile and hardly mobile forms of these metals in soil polluted with the ash.

[1]  P. Cloirec,et al.  Removal of Cu2+, Zn2+ and Pb2+ by adsorption onto fly ash and fly ash/lime mixing , 1999 .

[2]  J. Hwang,et al.  Determination of Hexavalent Chromium in Environmental Fly Ash Samples by an Inductively Coupled Plasma-Atomic Emission Spectrometer with Ammonium Ion Complexation , 1994 .

[3]  A. A. Levinson.  Book Review: Analytical methods for atomic absorption spectrophotometry. The Perkin-Elmer Corporation, Norwalk, Connecticut, 06852, U.S.A., 1968. $25.00 (looseleaf). Order as part number 303-0152 , 1969 .

[4]  M. Armienta,et al.  Distribution, origin and fate of chromium in soils in Guanajuato, Mexico. , 1996, Environmental pollution.

[5]  Y. Noma,et al.  Chemical speciation and leaching properties of elements in municipal incinerator ashes , 1996 .

[6]  A. Tessier,et al.  Sequential extraction procedure for the speciation of particulate trace metals , 1979 .

[7]  J. Qian,et al.  Nickel speciation of fly ash by phase extraction , 1997 .

[8]  J. F. Cerbus,et al.  Elemental characterization of coal ash and its leachates using sequential extraction techniques , 1995 .

[9]  S. Oikawa,et al.  The role of metals in site-specific DNA damage with reference to carcinogenesis. , 2002, Free radical biology & medicine.

[10]  B. Bayat.  Comparative study of adsorption properties of Turkish fly ashes. I. The case of nickel(II), copper(II) and zinc(II). , 2002, Journal of hazardous materials.

[11]  A. J. Pedersen,et al.  Speciation and mobility of cadmium in straw and wood combustion fly ash. , 2001, Chemosphere.

[12]  A. Bradshaw,et al.  Toxic Metals in Soil-Plant Systems. , 1995 .

[13]  E. Voudrias,et al.  Leachability of heavy metals in Greek fly ash from coal combustion , 1998 .

[14]  H. Sigel,et al.  Handbook on metals in clinical and analytical chemistry , 1994 .

[15]  R. Carignan,et al.  Trace metals in oxic lake sediments: possible adsorption onto iron oxyhydroxides , 1985 .

[16]  B. Van der Bruggen,et al.  Application of computer modelling to predict the leaching behaviour of heavy metals from MSWI fly ash and comparison with a sequential extraction method , 2000 .

[17]  J. Kalembkiewicz,et al.  Investigations of Sequential Extraction of Chromium from Soil , 2002 .

[18]  F. Adams,et al.  Metal Speciation in the Environment , 1990 .