Competing Ion Effect of Stabilization by Cr(III) & Cr(VI) in Ettringite Crystal Structure

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Abstract:

In this study, the degree of the substitution of Cr3+ and Cr6+ into the ettringite structure has been investigated to extent the immobilization potential of ettringite in the field under specific conditions. Aqueous suspension containing calcium hydroxide, alumium sulfate, CrCl2(trivalent chromium) and CrO3(hexavalent chromium) was subjected to ultrasound irradiation under atmospheric pressure to investigate their effects on synthesis of Cr-ettringite. In the result, the substitution of Cr3+ into Al site takes place in ettringite structure in solution with Cr3+, and monosulfate/friedel’ salt phase is also formed by occurrence of extra Al ion in solution. However, in the case of Cr6+, owing to a higher affinity of sulfate anion to form ettringite than that of Cr6+,most of Cr6+ did not substituted into the crystal structure of ettringite.

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Solid State Phenomena (Volumes 124-126)

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1629-1632

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June 2007

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© 2007 Trans Tech Publications Ltd. All Rights Reserved

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[1] M�Okushima�R�Kondo�H�Muguruma and Y�Ono�Development of Expansive Cement with Calcium Sulpho aluminous Cement Clinker�Proceedings of 5 th International Symposium On the Chemistry of Cement�Tokyo�4�pp�419� 438�1968�.

Google Scholar

[2] Mehta, PK and Klein, A., 1965, formation of Ettringite by hy-. dration of A system containing an Anhydrous calcium Sul-. foaluminate, Journal of the American Ceramic Society,. Vol. 48, No. 8, P. 435.

DOI: 10.1111/j.1151-2916.1965.tb14786.x

Google Scholar

[3] P. K Mehta and F. Hu, Further Evidence for Expansion of Ettringite by Water. Adsorption, J . Am. Cerum. Soc., 61. [3-41 179-81 (1978).

Google Scholar

[4] M. Zhang, E.J. Reardon, Removal of B, Cr, Mo, and Se from wastewater by incorporation into hydrocalumite and ettringite, Environ. Sci. Tech no l. 37 (13) (2003) 2947-2952.

DOI: 10.1021/es020969i

Google Scholar

[5] V. Albino, R. Cioffi, M. Marroccoli, L. Santoro, Potential application of ettringite-generating systems for hazardous waste immobilization, J. Hazard. Mater. 51 (1996) 241-252.

DOI: 10.1016/s0304-3894(96)01828-6

Google Scholar

[6] Kumarathasan, P., McCarthy, G.J., Hassett, D.J., Plfughoeft- Hassett, D.F. 1990. Oxyanion substituted ettringites: syn-thesis and characterization; and their potential role in immobilization of As, B, Cr, Se and V. In: Materials Research Society Symposium, pp.83-104.

DOI: 10.1557/proc-178-83

Google Scholar

[7] Myneni, S.C.B., 1995. Oxyanion-mineral surface interactions in alkaline environments: AsO4 and CrO4 sorption and desorption in ettringite. Dissertation thesis, Ohio State University.

Google Scholar