The Effect of Porous Alkali Activated Material Composition on Buffer Capacity in Bioreactors

Authors: G. Bumanis, D. Bajare

Abstract:

With demand for primary energy continuously growing, search for renewable and efficient energy sources has been high on agenda of our society. One of the most promising energy sources is biogas technology. Residues coming from dairy industry and milk processing could be used in biogas production; however, low efficiency and high cost impede wide application of such technology. One of the main problems is management and conversion of organic residues through the anaerobic digestion process which is characterized by acidic environment due to the low whey pH (<6) whereas additional pH control system is required. Low buffering capacity of whey is responsible for the rapid acidification in biological treatments; therefore alkali activated material is a promising solution of this problem. Alkali activated material is formed using SiO2 and Al2O3 rich materials under highly alkaline solution. After material structure forming process is completed, free alkalis remain in the structure of materials which are available for leaching and could provide buffer capacity potential. In this research porous alkali activated material was investigated. Highly porous material structure ensures gradual leaching of alkalis during time which is important in biogas digestion process. Research of mixture composition and SiO2/Na2O and SiO2/Al2O ratio was studied to test the buffer capacity potential of alkali activated material. This research has proved that by changing molar ratio of components it is possible to obtain a material with different buffer capacity, and this novel material was seen to have considerable potential for using it in processes where buffer capacity and pH control is vitally important.

Keywords: Alkaline material, buffer capacity, biogas production.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1096543

References:

[1] F. Malaspina, C. M. Cellamare, L. Stante, and A. Tilche, "Anaerobic treatment of cheese whey with a downflow-upflow hybrid reactor,” Bioresour. Technol., vol. 55, pp. 131–139, 1996.
[2] S. Montalvo, L. Guerrero, R. Borja, E. Sánchez, Z. Milán, I. Cortés, and M. Angeles de la laRubia, "Application of natural zeolites in anaerobic digestion processes: A review,” Applied Clay Science, vol. 58. pp. 125– 133, 2012.H. Poor, An Introduction to Signal Detection and Estimation. New York: Springer-Verlag, 1985, ch. 4.
[3] A. Saddoud, I. Hassaïri, and S. Sayadi, "Anaerobic membrane reactor with phase separation for the treatment of cheese whey,” Bioresour. Technol., vol. 98, pp. 2102–2108, 2007.E. H. Miller, "A note on reflector arrays (Periodical style—Accepted for publication),” IEEE Trans. Antennas Propagat., to be published.
[4] K. Rugele, G. Bumanis, L. Erina, and D. Erdmane, "Composite Material for Effective Cheese Whey Anaerobic Digestion,” Key Eng. Mater., vol. 604, pp. 236–239, Mar. 2014.C. J. Kaufman, Rocky Mountain Research Lab., Boulder, CO, private communication, May 1995.
[5] M. C. G. Juenger, F. Winnefeld, J. L. Provis, and J. H. Ideker, "Advances in alternative cementitious binders,” Cem. Concr. Res., vol. 41, no. 12, pp. 1232–1243, Dec. 2011.M. Young, TheTechincal Writers Handbook. Mill Valley, CA: University Science, 1989.
[6] C. Li, H. Sun, and L. Li, "A review: The comparison between alkaliactivated slag (Si+Ca) and metakaolin (Si+Al) cements,” Cem. Concr. Res., vol. 40, no. 9, pp. 1341–1349, Sep. 2010.
[7] S. A. Bernal, R. Mejía de Gutiérrez, and J. L. Provis, "Engineering and durability properties of concretes based on alkali-activated granulated blast furnace slag/metakaolin blends,” Constr. Build. Mater., vol. 33, pp. 99–108, Aug. 2012.
[8] A. Fernández-Jiménez, M. Monzó, M. Vicent, a. Barba, and a. Palomo, "Alkaline activation of metakaolin–fly ash mixtures: Obtain of Zeoceramics and Zeocements,” MicroporousMesoporous Mater., vol. 108, no. 1–3, pp. 41–49, Feb. 2008.
[9] C. E. White, J. L. Provis, A. Llobet, T. Proffen, and J. S. J. van Deventer, "Evolution of Local Structure in Geopolymer Gels: An In Situ Neutron Pair Distribution Function Analysis,” J. Am. Ceram. Soc., vol. 94, no. 10, pp. 3532–3539, Oct. 2011.
[10] S. Alonso and A. Palomo, "Alkaline activation of metakaolin and calcium hydroxide mixtures: influence of temperature, activator concentration and solids ratio,” Mater. Lett., no. Jan. 2001.
[11] J. Temuujin, A. Minjigmaa, W. Rickard, M. Lee, I. Williams, and A. van Riessen, "Preparation of metakaolin based geopolymer coatings on metal substrates as thermal barriers,” Appl. Clay Sci., vol. 46, no. 3, pp. 265–270, Nov. 2009.
[12] J. Temuujin, a van Riessen, and R. Williams, "Influence of calcium compounds on the mechanical properties of fly ash geopolymerpastes.,” J. Hazard. Mater., vol. 167, no. 1–3, pp. 82–8, Aug. 2009.
[13] M. R. Rowles and B. H. O’Connor, "Chemical and Structural Microanalysis of AluminosilicateGeopolymers Synthesized by Sodium Silicate Activation of Metakaolinite,” J. Am. Ceram. Soc., vol. 92, no. 10, pp. 2354–2361, Oct. 2009.
[14] S. a. Bernal, R. M. de Gutierrez, J. L. Provis, and V. Rose, "Effect of silicate modulus and metakaolin incorporation on the carbonation of alkali silicate-activated slags,” Cem. Concr. Res., vol. 40, no. 6, pp. 898–907, June. 2010.
[15] C. K. Yip, G. C. Lukey, J. L. Provis, and J. S. J. van Deventer, "Effect of calcium silicate sources on geopolymerisation,” Cem. Concr. Res., vol. 38, no. 4, pp. 554–564, Apr. 2008.
[16] P. Duxson, J. L. Provis, G. C. Lukey, and J. S. J. van Deventer, "The role of inorganic polymer technology in the development of ‘green concrete,’” Cem. Concr. Res., vol. 37, no. 12, pp. 1590–1597, Dec. 2007.
[17] C. K. Yip, G. C. Lukey, and J. S. J. van Deventer, "The coexistence of geopolymeric gel and calcium silicate hydrate at the early stage of alkaline activation,” Cem. Concr. Res., vol. 35, no. 9, pp. 1688–1697, Sep. 2005.
[18] G. Bumanis, D. Bajare, and J. Locs, "The Effect of Activator on the Properties of Low-Calcium Alkali-Activated Mortars,” Key Eng. Mater., vol. 604, pp. 169–172, Mar. 2014.
[19] W. K. W. Lee and J. S. J. van Deventer, "The effect of ionic contaminants on the early-age properties of alkali-activated fly ashbased cements,” Cem. Concr. Res., vol. 32, no. 4, pp. 577–584, Apr. 2002.
[20] P. Duxson, G. C. Lukey, F. Separovic, and J. S. J. van Deventer, "Effect of Alkali Cations on Aluminum Incorporation in Geopolymeric Gels,” Ind. Eng. Chem. Res., vol. 44, no. 4, pp. 832–839, Feb. 2005.
[21] S. Hong and F. P. Glasser, "Alkali sorption by C-S-H and C-A-S-H gels Part II . Role of alumina,” Cem. Concr. Res., vol. 32, no. 7, pp. 1101– 1111, 2002.
[22] R. R. Lloyd, J. L. Provis, and J. S. J. van Deventer, "Pore solution composition and alkali diffusion in inorganic polymer cement,” Cem. Concr. Res., vol. 40, no. 9, pp. 1386–1392, Sep. 2010.
[23] D. Bajare, A. Korjakins, J. Kazjonovs, and I. Rozenstrauha, "Pore structure of lightweight clay aggregate incorporate with non-metallic products coming from aluminium scrap recycling industry,” J. Eur. Ceram. Soc., vol. 32, pp. 141–148, 2012.
[24] D. Bajare, A. Korjakins, and J. Kazjonovs, "Application of Aluminium Dross and Glass Waste for Production of Expanded Clay Aggregate,” in Civil Engineering ’11 - 3rd International Scientific Conference, Proceedings, 2011, vol. 3, pp. 27–31.
[25] Snoeyink, V.L. and D. Jenkins, Water Chemistry. New York: John Wiley & Sons, 1980.