Alkali silicates and structured mesoporous silicas from biomass power station wastes: the emergence of bio-MCMs

The waste ashes from a commercial biomass combustion facility are successfully converted into mesoporous structured silica utilising a biorefinery approach, with potential high value applications in catalysis, adsorption and separation processes. Potassium silicate solutions are formed via a simple hydrothermal extraction of miscanthus bottom ashes, rich in amorphous silica, with a reproducible extraction of 60–70%. The extension and validation of a rapid and facile infrared method for the quantification of the silicate solutions is demonstrated with important industrial applications for continuous online screening and tuning of the silicate solution ratio and concentration. The alkali solutions from the waste ashes are used for the formation of a structured high surface area mesoporous silica, MCM-41 (1043 m2 g−1, 1.12 cm3 g−1). The resulting mesoporous silica was analysed by XRD, N2 adsorption porosimetry and TEM.

[1]  Tzong-Horng Liou.  A green route to preparation of MCM-41 silicas with well-ordered mesostructure controlled in acidic and alkaline environments , 2011 .

[2]  Stephen P. Long,et al.  Seasonal nitrogen dynamics of Miscanthus×giganteus and Panicum virgatum , 2009 .

[3]  Ian Shield,et al.  Study of Miscanthus x giganteus ash composition – Variation with agronomy and assessment method , 2012 .

[4]  Larry L. Baxter,et al.  Boiler deposits from firing biomass fuels , 1996 .

[5]  B. Steenari,et al.  Chemical fractionation for the characterisation of fly ashes from co-combustion of biofuels using different methods for alkali reduction , 2009 .

[6]  J. S. Falcone,et al.  The Determination of Sodium Silicate Composition Using ATR FT-IR , 2010 .

[7]  K. Sing.  Reporting physisorption data for gas/solid systems with special reference to the determination of surface area and porosity (Recommendations 1984) , 1985 .

[8]  R. B. Williams,et al.  Release of Inorganic Constituents from Leached Biomass during Thermal Conversion , 1999 .

[9]  U. Kalapathy,et al.  A simple method for production of pure silica from rice hull ash , 2000 .

[10]  Niki Baccile,et al.  Introducing ecodesign in silica sol–gel materials , 2009 .

[11]  O. Andrén,et al.  Ash from Cereal and Rape Straw Used for Heat Production: Liming Effect and Contents of Plant Nutrients and Heavy Metals , 1997 .

[12]  Avelino Corma,et al.  From Microporous to Mesoporous Molecular Sieve Materials and Their Use in Catalysis. , 1997, Chemical reviews.

[13]  S. Chiarakorn,et al.  Utilization of mesoporous molecular sieves synthesized from natural source rice husk silica to Chlorinated Volatile Organic Compounds (CVOCs) adsorption , 2003 .

[14]  I. Halász,et al.  Vibrational spectra and dissociation of aqueous Na2SiO3 solutions , 2007 .

[15]  C. Chao,et al.  Synthesis of MCM-41 from coal fly ash by a green approach: influence of synthesis pH. , 2006, Journal of hazardous materials.

[16]  T. Voigt,et al.  Miscanthus × giganteus productivity: the effects of management in different environments , 2012 .

[17]  J. B. Higgins,et al.  A new family of mesoporous molecular sieves prepared with liquid crystal templates , 1992 .

[18]  S. Chiarakorn,et al.  Influence of functional silanes on hydrophobicity of MCM-41 synthesized from rice husk , 2007 .

[19]  Oliver Lindqvist,et al.  High-temperature reactions of straw ash and the anti-sintering additives kaolin and dolomite , 1998 .

[20]  Egon Matijević,et al.  Chemistry of silica , 1980 .

[21]  A. J. Hunt,et al.  The chemical value of wheat straw combustion residues , 2011 .

[22]  A. J. Hunt,et al.  Elemental sustainability: Towards the total recovery of scarce metals , 2012 .

[23]  J. S. Beck,et al.  Recent advances in the synthesis, characterization and applications of mesoporous molecular sieves , 1996 .

[24]  J. L. Bass,et al.  Anion Distributions in Sodium Silicate Solutions. Characterization by 29SI NMR and Infrared Spectroscopies, and Vapor Phase Osmometry , 1997 .

[25]  L. L. Oden,et al.  The behavior of inorganic material in biomass-fired power boilers: Field and laboratory experiences , 1998 .

[26]  Lee Ji Yun,et al.  Utilization of rice husk ash as silica source for the synthesis of mesoporous silicas and their application to CO2 adsorption through TREN/TEPA grafting. , 2010, Journal of hazardous materials.

[27]  Gao Qing Lu,et al.  Advances in mesoporous molecular sieve MCM-41 , 1996 .

[28]  J. S. Beck,et al.  Ordered mesoporous molecular sieves synthesized by a liquid-crystal template mechanism , 1992, Nature.

[29]  Sirkku Sarenbo,et al.  Wood ash dilemma-reduced quality due to poor combustion performance , 2009 .

[30]  A. J. Hunt,et al.  Use of green chemical technologies in an integrated biorefinery , 2011 .

[31]  Luis F. Vilches,et al.  Plant optimisation and ash recycling in fluidised bed waste gasification , 2009 .

[32]  Larry L. Baxter,et al.  Impact of Mineral Impurities in Solid Fuel Combustion , 2013 .