Mobility and Transport of Inorganic Species in Weathered Hydraulic Disposed Coal Fly Ash: An Insight from Geochemical Fractionation and Statistical Evaluation
A large volume of coal fly ash generated through combustion process has raised environmental concerns due to possible release of potentially toxic species to the surface and groundwater systems. The chemical partitioning and mobility of elements in the hydraulic disposed ash dump was investigated using modified sequential extraction scheme. The geochemical distribution of the investigated elements in 33 drilled core samples was determined by x-ray fluorescence and inductively coupled plasma mass spectrometry. The ternary plot of major elements as determined by XRF showed that hydraulic disposed ash cores are sialic, ferrosialic and ferrocalsialic in chemical composition. The relationship between SiO2 and chemical index of alteration (CIA) showed low, moderate to high degree of weathering. These chemical compositions and degree of chemical weathering depend on the ash sampling point and ash interaction chemistry. The Na+ and K+ soluble salts showed evidence of leaching and downward migration in the water soluble fraction indicating that the hydraulic disposed ash dump is not a sustainable salt sink. The geochemical partitioning reveals that mobility and transport of potentially toxic metal species are governed by the pore water pH, ash interaction chemistry and the sampling point of the ash cores. The chemical interaction of drilled core ash with the ingress CO2 and percolating rain water led to dissolution and co-precipitation of soluble major components in fly ash. This had led to incoherent patterns of elements in carbonate fraction of the ash cores.
Key words: Modified sequential extraction; Hydraulic disposed ash; Chemical index of alteration; Pore water pH; Ash interaction chemistry; Moisture content; Chemical weathering
 Adriano, D. C., Page, A. L., Elseewi, A. A., Chang, A. C., & Straughan, I. (1980). Utilization and Disposal of Fly Ash and Other Coal Residues in Terrestrial Ecosystems. J. Environmental Quality, 9, 333-344.
 Akinyemi, S. A., Akinlua, A., Gitari, W. M., & Petrik, L. F. (2011a). Mineralogy and Mobility Patterns of Chemical Species in Weathered Coal Fly Ash. Energy Sources, Part A (33), 768–784. doi: 10.1080/15567030903261881.
 Akinyemi, S. A., Akinlua, A., Gitari, W. M., Akinyeye, R. O., & Petrik, L. F. (2011b). The Leachability of Major Elements at Different Stages of Weathering in Dry Disposed Coal Fly Ash. Coal Combustion and Gasification Products, 3, 28-40. doi: 10.4177/CCGP-D-11-00005.1.
 Akinyemi, S. A. (2011c). Geochemical and Mineralogical Evaluation of Toxic Contaminants Mobility in Weathered Coal Fly Ash: as a Case Study, Tutuka Dump Site, South Africa (Unpublished doctoral dissertation, University of the Western Cape, South Africa).
 Bruder-Hubscher, V., Lagarde F., Leroy, M. J. F., Coughanowr, C., & Engeuhard, F. (2002). Application of a Sequential Extraction Procedure to Study the Release of Elements from Municipal Solid Waste Incineration Bottom Ash. Analytical Chimica Acta, 451, 285–295.
 Campos, E., Barahona E., Lachica, M., & Migorance, M. D. (1998). A Study of the Analytical Parameters Important for the Sequential Extraction Procedure Using Microwave Heating for Pb, Zn and Cu in Calcareous Soils. Analytica Chimica Acta, 369, 235–243.
 Chang, C., Wang, C., Mui, D. T., ＆ Chiang, H. (2009). Application of Methods (Sequential Extraction Procedures and High-Pressure Digestion Method) to Fly Ash Particles to Determine the Element Constituents: A Case Study for BCR 176. Journal of Hazardous Materials, 163, 578–587.
 Donahoe, R. J. (2004). Secondary Mineral Formation in Coal Combustion Byproduct Disposal Facilities: Implications for Trace Element Sequestration. In Gieré R, Stille P (Eds.), Energy, Waste and the Environmental: a Geochemical Perspective (pp. 641–658). London: Geological Society, Special Publications, 236.
 Eskom Abridged Annual Report. (2009). Retrieved May 23, 2010, from http:// www.eskom.co.za
 Fourie, A., Blight, G. Bhana, Y., Harris, R., & Barnard, N. (1997). The Geotechnical Properties of Dry Dumped and Hydraulically Placed Power Station Fly Ash. Proceeding of 2nd International Conference on Mining and Industrial Waste Management. Midrand, South Africa (pp. 10).
 Fraser, J. L., & Lum, K. R. (1983). Availability of Elements of Environmental Importance in Incinerated Sludge Ash. Environ. Sci. Technol., 17, 52–54.
 Fulekar, M. H., & Dave, J. M. (1986). An Environmental Problem. International Journal of Environmental Studies, 26,191-215.
 Fytianos, K., & Shroder, H. (1997). Determination of Polychlorinated Dibenzodioxins and Dibenzofurans in Fly Ash. Chromatographia, 46, 280-284.
 Haynes, R. J. (2009). Reclamation and Revegetation of Fly Ash Disposal Sites – Challenges and Research Needs. Journal of Environmental Management, 90, 43–53.
 Helena, B. A., Vega, M., Barrado, E., Pardo, R., ＆ Fernandez, L. (1999). A Case of Hydrochemical Characterization of an Alluvial Aquifer Influenced by Human Activities. Water Air Soil Pollut., 112, 365–387.
 Horowitz, A. J. (1991). A Primer on Sediment-Trace Element Chemistry. Chelsea: Lewis Publication Incorporation.
 International Energy Outlook (IEO). (2009). DOE/EIA- 0484 2009. Retrieved October 23, 2009, from www.eia.doe.gov/oiaf/ieo/index.html
 Jankowski, J., Ward, C. R., French, D., & Groves, S. (2006). Mobility of Trace Elements from Selected Australian Fly Ashes and Its Potential Impact on Aquatic Ecosystems. Fuel, 85, 243–256. doi:10.1016/j.fuel.2005.05.028
 Jegadesaan, G., Al-Abed, S. R., & Pinto P. (2008). Influence of Trace Metal Distribution on Its Leachability from Coal Fly Ash. Fuel, 87, 1887-1893.
 Khanra, S., Mallick, D., Dutta, S. N., & Chaudhuri, S. K. (1998). Studies on the Phase Mineralogy and Leaching Characteristics of Coal Fly Ash Water, Air, and Soil. Pollution, 107, 251–275.
 Liu, C. W., Lin, K. H., Y. M., & Kuo, Y. M. (2003). Application of Factor Analysis in the Assessment of Ground Water Quality in the Blackfoot Disease Area in Taiwan. Sci. Total Environ., 313, 77–89.
 Massart, D. L., Vandeginste, B. G. M., Deming, S. N., Michotte, Y., & Kaufman, L. (1988). Chemometrics. Amsterdam: A Textbook, Elsevier.
 Mester, Z., Cremisini, C., Ghiara, C., & Morabito, R. (1998). Comparison of Two Sequential Extraction Procedures for Metal Fractionation in Sediment Samples. Analytical Chimica Acta, 359, 133–142.
 Nesbitt, H. W., & Young, G. M. (1982). Early Proterozoic Climates and Plate Motions Inferred from Major Element Chemistry of Lutites. Nature, 299, 715-717.
 Ojo, O. I. (2009). Mineralogy and Chemical Mobility in Some Weathered Ash Dump Sites, South Africa. (Unpublished M.Sc dissertation, Earth Sciences Department, University of the Western Cape, South Africa, 2009).
 Page, A. L., Elseewi, A. A., & Straughan, I. R. (1979). Physical and Chemical Properties of 40 Fly Ash from Coal-Fired Power Plants with Reference to Environmental Impacts. Residue Reviews, 71, 83-120.
 Petit, M. D., & Rucandio, M. I. (1999). Sequential Extractions for Determination of Cadmium Distribution in Coal Fly Ash, Soil and Sediment Samples. Analytical Chimica Acta, 401, 283–291.
 Petrik, L. F., White, R. A., Klink, M. J., Somerset, S. V., Burgers, L. C., & Fey, V. M. (2003). Utilization of South African Fly Ash to Treat Acid Coal Mine Drainage, and Production of High Quality Zeolites from the Residual Solids. International Ash Utilization Symposium, Lexington, Kentucky, USA.
 Radojevic, M., & Bashkin, V. N. (1999). Practical Environmental Analysis (2nd Edition). Royal Society Chemistry.
 Rao, C. R. M., Sahuquillo, A., & Lopez Sanchez, J. F. (2008). A Review of the Different Methods Applied in Environmental Geochemistry For Single and Sequential Extraction of Trace Elements in Soils and Related Materials. Water Air Soil Pollut., 189, 291–333.
 Roy, W. R., & Griffin, R. A. (1982). A Proposed Classification System for Coal Fly Ash in Multidisciplinary Research. Journal of Envir. Qual., 11, 563-568.
 Singh, D. N., & Kolay, P. K. (2002). Simulation of Ash-Water Interaction and Its Influence on Ash Characteristics. Progress in Energy and Combustion Science, 28, 267-299.
 Smeda, A., & Zyrnicki, W. (2002). Application of Sequential Extraction and the ICP-AES Method for Study of the Partitioning of Metals in Fly Ashes. Microchemical, 72, 9–16.
 Smichowski, P., Polla, G., Gomez, D., Fernandez Espinosa, A. J., & Lopez, A.C. (2008). A Three Step Sequential Metal Fractionation Scheme for Fly Ashes Collected in an Argentine THERMAL POWER Plant. Fuel, 87, 1249–1258.
 Tessier, A. (1992). Sorption of Trace Elements on Natural Particles in Oxic Environments. In Buffle, J. & Van Leeuwen, H.P. (Eds), Environmental Particles, Environmental Analytical and Physical Chemistry Series (pp.425–453). Boca Raton, FL: J. Lewis Publishers.
 Tessier, A., Campbell, P. G. C., & Bisson, M. (1979). Sequential Extraction Procedure for the Speciation of Particulate Traces Metals. Analy. Chem., 51, 844-850.
 Theis, T. L., & Wirth, J. L. (1977). Sorptive Behavior of Trace Metals on Fly Ash in Aqueous Systems. Environmental Science & Technology, 11, 1096-1100.
 Valentim, B. V., & Hower, J. C. (2010). Influence of Feed and Sampling Systems on Element Partitioning in Kentucky Fly Ash. Int. J. of Coal Geology, 82, 94-104.
 Willet, P. (1987). Similarity and Clustering in Chemical Information Systems. Chichester: Wiley, Research Studies Press.
 Yazici, H. (2001). Utilization of Coal Combustion by Products in Building Blocks. Fuel, 86, 929-937.
- There are currently no refbacks.
If you have already registered in Journal A and plan to submit article(s) to Journal B, please click the CATEGORIES, or JOURNALS A-Z on the right side of the "HOME".
We only use three mailboxes as follows to deal with issues about paper acceptance, payment and submission of electronic versions of our journals to databases: firstname.lastname@example.org; email@example.com; firstname.lastname@example.org
Copyright © 2010 Canadian Research & Development Centre of Sciences and Cultures
Address: 758, 77e AV, Laval, Quebec, H7V 4A8, Canada
Telephone: 1-514-558 6138