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rate of CO2 sequestration

PostPosted: Wed Feb 11, 2009 1:29 pm
by nivedhitha
I would like to know how to calculate the rate of CO2 sequestration using different species of algae?

Re: rate of CO2 sequestration

PostPosted: Mon Dec 14, 2009 5:39 pm
by HexOmega
Hi nivedhitha,

There are a number of techniques available. If you have access to online journal databases, there are a number of papers that outline these methods. For example, Eriksen et al. (2006) on the kinetics of O2 evolution and CO2 fixation. de Morais and Costa (2007) looked at biofixation in Spirulina sp.. The former cultured Chlorella sp. and C. reinhardtii in a gas tight reactor and calculated the rate of CO2 uptake from the difference between the CO2 added and the CO2 vented, as well as the pH change. The authors derived a series of equations to account for the CO2 locked up in biomass using this process (it was an estimate, since they did not accurately measure the vented CO2), which can be seen in the paper (I won't post them here). The latter made batch cultures in a serial set of photobioreactors and analyzed the carbon content using an element analyzer, subtracting the difference from the total CO2 sparged into the reactor (and the estimated losses to venting). Carbon fixation can also be measured via dissolved oxygen (stoichiometrically, 1 mole of CO2 is required to evolve 1 mol of O2; empirically this may deviate, e.g. Pirt (1985) on the thermodynamic efficiency of photosynthesis).

These are two of the more common means for measuring the rate of CO2 uptake, although they have their limitations (mainly used in batch cultures and require expensive equipment). You could just dry the biomass, then combust it and measure the output gases (CO2 and H2O; some other NOx etc. gases also). This method is fraught with experimental error (just by the sheer number of steps required to get the value) and assumes that biomass productivity = CO2 fixed (doesn't account for lipids formed and other secondary products, that may evaporate during the drying process).

I'm not aware of any online measurements of CO2 uptake, although if they do exist they would be fairly expensive and complicated.

Re: rate of CO2 sequestration

PostPosted: Thu Mar 17, 2011 11:18 am
by Krupali
To know more about Co2 sequestration:

http://www.powerplantccs.com/ref/glos/carbon_sequestration.html

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