Evaluation of the Stability of Waste-Based Geopolymeric Artificial Aggregates for Wastewater Treatment Processes under Different Curing Conditions

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Waste geopolymeric artificial aggregates (WGA) with different atomic ratios of mining waste mud/Na2SiO (4 to 5) and Na2SiO/NaOH (1.25 to 5) were produced using curing temperatures of 20°C and 130°C and its structural stability and pH variation after immersion in water was observed during 3 months. Results showed that WGA with mud/Na2SiO and Na2SiO/NaOH of 5 and 4, respectively, cured at 20°C presented good stability in water and pH decreased from 10 to 7 in 24 days. Compressive strength was determined in additional samples cured at 20°C and 80°C in dry conditions, for 13 curing ages and 15 water immersion periods (up to 14 weeks). Results of this second stage showed that increasing temperature to 80°C accelerated compressive strength gain but only during the first 3 weeks (up to 15.4 MPa). After 24 h in water compressive strength decreased to half of the initial values determined in dry conditions in all samples and, therefore, the increase of temperature did not bring benefits to WGA strength in water. Regardless the curing temperature and the dry curing age comprehensive strength stabilizes between 1 MPa and 2 MPa after 4 weeks immersion in water, which are values that makes WGA suitable to be used as bed material for wastewater treatment processes.

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Edited by:

Pietro VINCENZINI and Cristina LEONELLI

Pages:

86-91

Citation:

I. C. Silva et al., "Evaluation of the Stability of Waste-Based Geopolymeric Artificial Aggregates for Wastewater Treatment Processes under Different Curing Conditions", Advances in Science and Technology, Vol. 69, pp. 86-91, 2010

Online since:

October 2010

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$41.00

[1] Metcalf and Eddy, Wastewater Engineering: Treatment, Disposal and Reuse. Fourth edition. McGraw-Hill, New York, USA, 2002, 1848 p.

[2] A. Albuquerque, J. Oliveira, S. Semitela, l. Amaral, Influence of bed media characteristics on ammonia and nitrate removal in shallow horizontal subsurface flow constructed wetlands, Bioresource Technology, 100 (2009), 6269-6277.

DOI: https://doi.org/10.1016/j.biortech.2009.07.016

[3] D. Mohan, K. Singh, V. Singh, Wastewater treatment using low cost activated carbons derived from agricultural byproducts—a case study, J. Hazardous Materials, 152 (2008), 3, 1045-1053.

DOI: https://doi.org/10.1016/j.jhazmat.2007.07.079

[4] R. van Deun, M. van Dyck, Expanded clay and lava rock as potential filter media for nutrient removal in vertical subsurface flow constructed wetlands, Proc. Society of Wetland Scientists European Chapter Meeting, SWS, Kuressaare, Saaremaa, Estonia, 23 p., (2008).

[5] F. Pacheco-Torgal, J. Castro-Gomes, S Jalali, Investigations on mix design of tungsten mine waste geopolymeric binder, Construction and Building Materials, 22 (2008), 9, 1939-(1949).

DOI: https://doi.org/10.1016/j.conbuildmat.2007.07.015

[6] Silva I., Castro-Gomes J., Albuquerque A., Mineral wastes geopolymeric artificial (WGA) aggregates as alternative materials for wastewater treatment processes – study of structural stability and pH variation in water, Proc. of the International Conference on Sustainable Building Affordable to All (SB10), Vila Moura, Portugal, 10 pp, 17-19 March (2010).

DOI: https://doi.org/10.1061/(asce)mt.1943-5533.0000429

[7] F. Pacheco-Torgal, Development of alkali-activated binders using waste mud from Panasqueira mine, PhD thesis, University of Beira Interior, 2007 [in Portuguese].

[8] S. Wang, K. Scrivener, P. Pratt, Factors affecting the strength of alkali-activated slag, Cem. Concr. Res., 24 (1994), 1033-1043.

DOI: https://doi.org/10.1016/0008-8846(94)90026-4

[9] A. Katz, Microscopic study of alkali-activation fly ash, Cem. Concr. Res., 28 (1998), 197–208.

[10] A. Kirschner, H. Harmuth, Investigation of geopolymer binders with respect to their application for building materials. Ceram. Silic., 48 (2004), 117–20.

[11] P. Duxson, J. Provis, G. Lukey, S. Mallicoat, W. Kriven, J. van Deventer, Understanding the relationship between geopolymer composition microstructure and mechanical properties, Colloids and Surfaces A: Physicochem. Eng. Aspects, 269 (2005).

DOI: https://doi.org/10.1016/j.colsurfa.2005.06.060

[12] J. van Jaarsveld, J. van Deventer, G. Lukey, The effect of composition and temperature on the properties of fly ash- and kaolinite-based geopolymers. Chem. Eng. J., 89 (2002), 63-73.

DOI: https://doi.org/10.1016/s1385-8947(02)00025-6