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

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.

• G. Bumanis
• D. Bajare

• Alkaline material
• buffer capacity
• biogas production.

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