Hydrogen Collection!
After many weeks in the lab, analysis of our cultures is finally beginning. Both wild type Rhodobacter and our genetically modified constructs produce hydrogen and carbon dioxide through their natural metabolism. While our constructs are set to produce significantly more hydrogen the carbon dioxide produced is still enough that we need a way to separate it from our final product.
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Our Initial Set Up:
While this provided a great starting point for our gas collection it didn't allow for the separation of carbon dioxide and hydrogen.
Throughout our project we've tried to maintain a theme of frugality as we want to be able to produce a cost effective source of green energy; this meant we also wanted a cost effective analytical method. We headed out of the lab and back to the drawing board to improve our method.
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The New & Improved:
Our improved method involves bubbling all the gas produced through a strong base that formed an insoluble precipitate, in our case barium hydroxide. This allows us to remove all carbon dioxide from the mix and be left with only pure hydrogen. Due to the dissolved carbon dioxide existing in equilibrium with carbonic acid. Carbonic acid reacts with barium hydroxide forming an insoluble precipitate, thereby removing carbon dioxide. Differing height between the syringe can then used to take readings and the geran bottle containing barium hydroxide allows Bernoulli's principle to be applied. From here any gas produced by Rhodobacter will lead to an increase in pressure in the 2 flasks, forcing liquid through the tubing and raising the water level in the syringe. By placing the syringe on a scale and knowing the density of the liquid used the exact volume of liquid displaced can be calculated. This can then be converted using the ideal gas law into a volume of hydrogen.
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Phew! With that sorted, we have some data coming your way with our hydrogen collection results -stay tuned!
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