Abstract
Leachable chromium in the incineration fly ash and wastewater sludge has been thermally stabilized by plasma melting at the temperature of 1,773 K. To better understand how chromium is stabilized with the high-temperature treatment, chemical structure of the slags sampled at temperature zones of 1,100–1,700 K has been studied by synchrotron X-ray absorption spectroscopy. The component-fitted X-ray absorption near edge structure spectra of chromium indicate that the main chromium compounds in the sludge and fly ash are Cr(OH)3, Cr2O3, and CrCl3. A small amount of toxic CrO3 is also observed in the fly ash. In the plasma melting chamber under the reducing environment, the high-oxidation state chromium is not found. The slags in the plasma melting chamber have much less leachable chromium, which is due to chemical interactions between chromium and SiO2 in the slags. The existence of the interconnected Cr-O-Si species is observed by refined extended X-ray absorption fine structure spectroscopy. In the Cr2O3 phase of the slags, their bond distances, and coordination numbers for the first (Cr-O) and second (Cr-(O)-Cr) shells have insignificant perturbation when experienced with different melting temperatures between 1,300 and 1,700 K. It seems that Cr2O3 and chromium encapsulated in the silicate matrix of the slags have relatively much lower leachability. With this concept, to obtain a low chromium leachability slag from the plasma melting process, the residence time of the melting chamber may be decreased, and the slag discharge temperatures may be increased to 1,300 K. This work also exemplifies utilization of molecule-scale data obtained from synchrotron X-ray absorption spectroscopy to reveal how chromium is thermally stabilized in a commercial scale plasma melting process.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Abielaala, L., Aouad, H., Mesnaoui, M., Musso, J. A., et al. (2011). Characterization and vitrification of fly ashes from incineration of waste of infectious risk cares (WIRC). Sustainable Environment Research, 21, 195–201.
Chiu, Y. M., Huang, C. H., Chang, F. C., Kang, H. Y., Wang, H. P., et al. (2011). Recovery of copper from a wastewater for preparation of Cu@C nanoparticles. Sustainable Environment Research, 21, 279–282.
Chou, J.-D., Wey, M.-Y., Chang, S.-H., et al. (2009). Evaluation of the distribution patterns of Pb, Cu and Cd from MSWI fly ash during thermal treatment by sequential extraction procedure. Journal of Hazardous Materials, 162, 1000–1006.
Cohen, M., Kargacin, B., Klein, C., Costa, M., et al. (1993). Mechanisms of chromium carcinogenicity and toxicity. Critical Reviews in Toxicology, 23, 255–281.
Costa, M. (2003). Potential hazards of hexavalent chromate in our drinking water. Toxicology and Applied Pharmacology, 188, 1–5.
Costa, M., & Klein, C. B. (2006). Toxicity and carcinogenicity of chromium compounds in humans. Critical Reviews in Toxicology, 36, 155–163.
Fedje, K. K., Ekberg, C., Skarnemark, G., Steenari, B.-M., et al. (2010). Removal of hazardous metals from MSW fly ash—an evaluation of ash leaching methods. Journal of Hazardous Materials, 173, 310–317.
Gomez, E., Amutha Rani, D., Cheeseman, C. R., Deegan, D., Wisec, M., Boccaccini, A. R., et al. (2009). Thermal plasma technology for the treatment of wastes: a critical review. Journal of Hazardous Materials, 161, 614–626.
Koningsberger, D. C., & Prins, R. (1998). X-ray absorption principles, applications, techniques of EXAFS, SEXAFS and XANES. New York: Wiley.
Kourti, I., Amutha Rani, D., Bustos, A. G., Deegan, D., Boccaccini, A. R., Cheeseman, C. R., et al. (2011). Geopolymers prepared from DC plasma treated air pollution control (APC) residues glass: properties and characterisation of the binder phase. Journal of Hazardous Materials, 196, 86–92.
Ku, C. C., Wang, H. P., Lee, P. H., Hsiao, M. C., Huang, H. L., Wang, H. C., et al. (2003). Speciation of chromium in an electroplating sludge during thermal stabilization. Bulletin of Environmental Contamination and Toxicology, 71, 860–865.
Kuo, Y. M., Lin, T. C., Tsai, P. J., et al. (2004). Metal behavior during vitrification of incinerator ash in a coke bed furnace. Journal of Hazardous Materials, B109, 79–84.
Kuo, Y. M., Tseng, H. J., Chang, J. E., Wang, J. W., Wang, C. T., Chen, H. T., et al. (2008). An alternative approach for reusing slags from a plasma vitrification process. Journal of Hazardous Materials, 156, 442–447.
Kuo, Y. M., Wang, C. T., Tsai, C. H., Wang, L. C., et al. (2009). Chemical and physical properties of plasma slags containing various amorphous volume fractions. Journal of Hazardous Materials, 162, 469–475.
Lampris, C., Stegemann, J. A., Pellizon-Birelli, M., Fowler, G. D., Cheeseman, C. R., et al. (2011). Metal leaching from monolithic stabilized/solidified air pollution control residues. Journal of Hazardous Materials, 185, 1115–1123.
Lin, K. L., & Chang, C. T. (2006). Leaching characteristics of slag from the melting treatment of municipal solid waste incinerator ash. Journal of Hazardous Materials, B135, 296–302.
Lin, K.-S., & Wang, H. P. (2000a). Supercritical water oxidation of 2-chlorophenol catalyzed by Cu2+ cations and copper oxide clusters. Environment Science and Technology, 34, 4849–4854.
Lin, K.-S., & Wang, H. P. (2000b). Byproduct shape selectivity in supercritical water oxidation of 2-chlorophenol effected by CuO/ZSM-5. Langmuir, 16, 2627–2631.
Lin, K.-S., & Wang, H. P. (2001). Catalytic oxidation of 2-chlorophenol in confined channels of ZSM-48. The Journal of Physical Chemistry. B, 105, 4956–4960.
Liu, Y., Zheng, L., Li, X., Xie, S., et al. (2009). SEM/EDS and XRD characterization of raw and washed MSWI fly ash sintered at different temperatures. Journal of Hazardous Materials, 162, 161–173.
Moustakas, K., Xydis, G., Malamis, S., Haralambous, K.-J., Loizidou, M., et al. (2008). Analysis of results from the operation of a pilot plasma gasification/vitrification unit for optimizing its performance. Journal of Hazardous Materials, 151, 473–480.
Park, Y. J., & Heo, J. (2002). Vitrification of fly ash from municipal solid waste incinerator. Journal of Hazardous Materials, B91, 83–93.
Rehr, J. J., Zabinsky, S. I., Ankudinov, A., & Albers, R. C. (1995). Atomic-XAFS and XANES. Physica B: Condensed Matter, 208&209, 23–26.
Taiwan EPA. (2009) Toxicity characteristics leaching procedure (TCLP), NIEA R201.14C.
Teo, B. K. (1986). EXAFS: basic principles and data analysis. New York: Springer.
Wei, Y.-L., Hsu, L.-H., Wang, H. P., Chen, K.-W., et al. (2007). XAS study of chromium recoverable from plating sludge. Journal of Electron Spectroscopy and Related Phenomena, 156–158, 204–207.
Wise, J. P., Sr., Wise, S. S., Little, J. E., et al. (2002). The cytotoxicity and genotoxicity of particulate and soluble hexavalent chromium in human lung cells. Mutation Research, 517, 221–229.
Yang, Y., Xiao, Y., Wilson, N., Voncken, J. H. L., et al. (2009). Thermal behaviour of ESP ash from municipal solid waste incinerators. Journal of Hazardous Materials, 166, 567–575.
Yang, S.-F., Wang, T.-M., Lee, W.-C., Sun, K.-S., Tzeng, C.-C., et al. (2010). Man-made vitreous fiber produced from incinerator ash using the thermal plasma technique and application as reinforcement in concrete. Journal of Hazardous Materials, 182, 191–196.
Acknowledgments
The financial supports of Taiwan National Science Council, Bureau of Energy, and National Taiwan Synchrotron Radiation Research Center (NSRRC) are gratefully acknowledged. We also thank Prof. Jyh-Fu Lee of the NSRRC for his EXAFS experimental assistance.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Tuan, YJ., Wang, H.P. & Chang, JE. Tracking of Chromium in Plasma co-Melting of Fly Ashes and Sludges. Water Air Soil Pollut 223, 5283–5288 (2012). https://doi.org/10.1007/s11270-012-1278-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11270-012-1278-2