Environmentalists & the Green movement have it all wrong. I've long said that we should view carbon dioxide (CO2) as a something positive, an input or a fundimental building block or feedstock and not as something negative to get rid of, hide or sequester underground.
Now, according to Penn State engineers, methanogenic microorganisms can take electricity and directly convert carbon dioxide (C02) and water into methane, producing a portable energy source with a potentially neutral carbon footprint.
"We were studying making hydrogen in microbial electrolysis cells and we kept getting all this methane," said Bruce E. Logan, Kappe Professor of Environmental Engineering, Penn State. "We may now understand why."
Methanogenic microorganisms do produce methane in marshes and dumps, but scientists thought that the organisms turned hydrogen or organic materials, such as acetate, into methane. However, the researchers found, while trying to produce hydrogen in microbial electrolysis cells, that their cells produced much more methane than expected.
"All the methane generation going on in nature that we have assumed is going through hydrogen may not be," said Logan. "We actually find very little hydrogen in the gas phase in nature. Perhaps where we assumed hydrogen is being made, it is not."
Microbial electrolysis cells do require an electrical voltage to be added to the voltage that is produced by bacteria using organic materials to produce current that evolves into hydrogen.
The researchers found that the methanogenic microorganisms Archaea, using about the same electrical input, could use the current to convert carbon dioxide and water to methane without any organic material, bacteria or hydrogen usually found in microbial electrolysis cells. They report their findings in this week's issue of Environmental Science and Technology