I am having some difficulty in identifying what are the operational parameters for using urine in Microbial Fuel Cells to generate electricity. I have read articles that this type of technology can be implemented in toilets at refugee camps to help power lighting. There are many articles regarding the problem in the material used for MFCs, but not so many on the fuel source. So what are the factors that are considered when using urine as the fuel source?
Dear Hisham,
Allow me this modest comment on the subject.
We can produce hydrogen in large quantities with hydrocarbons, but it is not easy to store and distribute. The other possibility is to separate hydrogen and oxygen from water to introduce hydrogen directly in a fuel cell ... But the process of separation of hydrogen from water consumes as much energy hydrogen product.
The idea is to use urine instead of water. By weight, urine contains about 2% urea, urea and each molecule contains four hydrogen atoms, which are less strongly attached to the urea as hydrogen in water. Therefore, separating hydrogen urea requires less energy and allows a more efficient production of hydrogen.
A team of researchers has succeeded in producing hydrogen from urine using an electrochemical cell with conventional nickel electrodes and a voltage of only 0.37 volts, while it takes 1.23 volts to extract hydrogen from water. Pure hydrogen was produced at the cathode, while nitrogen and carbon dioxide formed in the anode.
Calculations have shown that with improved electrodes, it could produce hydrogen from urine for less than a dollar per kilogram. This technology could then be useful in places of large amounts of urine are collected: "In a building where 200 or 300 people working, we can produce about 2 kilowatts of electricity."
But all these uses of urine can operate with a certain concentration of urea. The urine evacuated in the house is too diluted in the sewage system to be used as well. When it reaches the treatment plant wastewater, urine is diluted and contaminated with various and varied chemicals. In addition, the majority of the precious urea is decomposed into ammonia.
With my best regards
Prof. Bachir ACHOUR
Dear Hisham,
Allow me this modest comment on the subject.
We can produce hydrogen in large quantities with hydrocarbons, but it is not easy to store and distribute. The other possibility is to separate hydrogen and oxygen from water to introduce hydrogen directly in a fuel cell ... But the process of separation of hydrogen from water consumes as much energy hydrogen product.
The idea is to use urine instead of water. By weight, urine contains about 2% urea, urea and each molecule contains four hydrogen atoms, which are less strongly attached to the urea as hydrogen in water. Therefore, separating hydrogen urea requires less energy and allows a more efficient production of hydrogen.
A team of researchers has succeeded in producing hydrogen from urine using an electrochemical cell with conventional nickel electrodes and a voltage of only 0.37 volts, while it takes 1.23 volts to extract hydrogen from water. Pure hydrogen was produced at the cathode, while nitrogen and carbon dioxide formed in the anode.
Calculations have shown that with improved electrodes, it could produce hydrogen from urine for less than a dollar per kilogram. This technology could then be useful in places of large amounts of urine are collected: "In a building where 200 or 300 people working, we can produce about 2 kilowatts of electricity."
But all these uses of urine can operate with a certain concentration of urea. The urine evacuated in the house is too diluted in the sewage system to be used as well. When it reaches the treatment plant wastewater, urine is diluted and contaminated with various and varied chemicals. In addition, the majority of the precious urea is decomposed into ammonia.
With my best regards
Prof. Bachir ACHOUR
Although I don't know all the details, I know there is plenty of work in this area at UWE... here is a link to their website, where I'm sure you can find plenty of information or can contact them directly: https://info.uwe.ac.uk/news/UWENews/news.aspx?id=3050
There is a European project named ValuefromUrine (see link below) that was working individually in recover nutrients and energy using Bioelectrochemical Systems (BES). The research is based on the work of Philipp Kuntke, Annemiek ter Heijne, Tom Sleutels and Prof. Cees Buisman. You can find some of their work in Research Gate .
Regarding your question, the final electron donor and source of energy is mainly acetate. To produce hydrogen it is required an external power source, and during the process ammonia is produced. However to produce electricity, you just need a catalyst for oxygen reduction or other reduction reaction at lower energy level (more positive potential) than acetate reaction. The power that you will be able to extract will depend on the kinetics of the anode or cathode reaction and the voltage that both reactions are able to deliver. There are plenty of studies done by ISMET members (see link below=
http://www.valuefromurine.eu
http://www.is-met.org/
Article Bioelectrochemical Systems: An Outlook for Practical Applications
Article Source-separated urine opens golden opportunities for microb...
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