Heavy Metal Toxicity of Fly Ash Exposed to Acidic Environments

Authors

  • Manish Agrawal Indian Institute of Technology Kanpur
  • Ankit Modi
  • Pranveer Singh Satvat
  • Vidya Batra

Keywords:

Fly ash, Heavy metals, Leaching, Toxicity, Acidic environment

Abstract

Fly ash is an industrial solid waste product, produced in huge quantity from industries comprising coal combustion units, especially thermal power plants. Improper Fly ash disposal practices results in severe-long-term environmental problems. The conveying disposal practice of Fly ash involves carrying with water from point of generation to holding ponds or lagoons, heaping and trucking, utilization in cement or concrete making and rest (about 40 percent) fraction is openly dumped into environment as landfill or else. During these practices, Fly ash disperses through all environmental segments and exposed to varying environmental conditions causing prolonged exposure, leaching and accumulation of many toxic metals in biosphere food chain. Comparatively, acidic environment favors more metal leaching, enhance the associated risks and become a great concern. The present study proceeded to evaluate the probable heavy metal toxicity caused by exposing Fly ash to various acids of different concentration and contact time. Metals showed varying degree of leachability from Fly ash exposed to different acid. However, the prominent order of leaching was found as in sequence of Cr > Cu> Pb > Co> Cd. The paper also describes involved possible toxic effects of metals leached from Fly ash exposed to acidic environments.

References

1. Ahmaruzzaman M., 2010. A review on the utilization of fly ash. Progress in Energy and Combustion Science, 36, 327-363.

2. Cenni, R., Janisch, B., Spliethoff, H., Hein, K.R.G., 2001. Legislative and environmental issues on the use of ash from coal and municipal sewage sludge co-firing as construction material. Waste Management 21, 17–31.

3. Draft Manual on Municipal Solid Waste Management (2014), Ministry of Urban Development, (http://moud.gov.in/sites/upload_files/moud/files/pdf/Draft%20on%20manual.pdf).

4. Gupta, D.K., Tripathi, R.D., Rai, U.N., Dwivedi, S., Mishra, S., Srivastava, S., Inouhe, M., 2006. Changes in amino acid profile and metal content in seeds of Cicerarietinum L. (chickpea) grown under various fly-ash amendments. Chemosphere 65, 939–945.

5. Hansen, L. D., Silberman, D., Fisher, D., Fisher, G. L., Etaough, D. J., 1984. Chemical speciation of elements in stack-collected, respirable-size, coal Fly ash. Environ Sci Technol 18, 181–186.

6. Henery, W. M., Knapp, K. T., 1980. Compound forms of fossil fuel Fly ash emissions. Environ Sci Technol 4, 450–456.

7. Karuppiah, M., Gupta, G., 1997. Toxicity of metals in coal combustion ash leachates. J Hazard Mater 56, 53–58.

8. Khanra, S., Mallick, D., 1998. Studies on the phase mineralogy and leaching characteristics of coal Fly ash. Water Air Soil Pollut 10, 251–275.

9. Kim, A. G., 2006. The effect of alkalinity of Class F PC Fly ash on metal release. Fuel 85, 1403–1410.

10. Li L., Wang S., Zhu Z., Yao X., and Yan Z., 2008. Catalytic decomposition of ammonia over Fly ash supported Ru catalysts, Fuel Processing Technology 89, 1106 – 1112.

11. Paoletti, L., Diociaiuti, M., Gianfagna, A., Viviano, G., 1994. Physico- chemical characterization of crystalline phases in Fly ash. MikrochimikaActa114/115, 397–404.

12. Patel, H., Pandey, S., 2009. Exploring the Reuse Potential of Chemical Sludge from Textile Wastewater Treatment Plants in India-A Hazardous Waste. American Journal of Environmental Sciences 5, 106-110.

13. Paul, M., Seferinoglu, M., Aycvk, G. A., Sandstrom, A. k., Smith, M. L., Paul, J., 2006. Acid leaching of ash and coal: Time dependence and trace element occurrences Int. J. Miner. Process 79, 27– 41

14. Pengthamkeerati P., Satapanajaru T., and Chularuengoaksorn P., 2008. Chemical modification of coal fly ash for the removal of phosphate from aqueous solution. Fuel 87, 2469–2476.

15. Piekos, R., Pasławska, S., 1998. Leaching of assimilable silicon species from Fly ash. Fuel Processing Technology 56, 201–213.

16. Ram, L. C., Srivastava, N. K., Das, M. C., Singh, G., 1999. Leaching behavior of Fly ash under simulated conditions vis-a` -vis quality of the leachate. In: Ram LC et al (eds) Proceedings of the national seminar on bulk utilization of Fly ash in agriculture and for value-added products. Dhanbad (India), ISBN 81–7525, 184-0.

17. Ramesh, A., Kozinski, J. A., 2001. Investigations of ash topography/morphology and their relationship with heavy metals leachability. Environ Pollut 111, 255– 262.

18. Seidel, A., Sluszny, A., Shelef, G., Zimmels, Y., 1999. Self-inhibition of aluminum leaching from coal Fly ash by sulfuric acid. Chemical Engineering Journal 72, 195-207.

19. Singh, G., 2005. Environmental assessment of Fly ash from some thermal power stations for reclamation of mined out areas. Fly ash Utilization Programme (FAUP), TIFAC, DST, New Delhi – 110016.

20. Smith, I. M., 1987. Trace elements from coal combustion: emissions. Source of trace elements, chap 2, IEACR/01 IEA Coal Research, London.

21. Xuan X., Yue C., Li S., Yao Q., 2003. Selective catalytic reduction of NO by ammonia with fly ash catalyst. Fuel 82, 575–579.

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Published

2016-11-17