London, August 19 (ANI): In a new experiment, US navy chemists have processed seawater into unsaturated short-chain hydrocarbons that with further refining could be made into kerosene-based jet fuel.
According to a report by New Scientist, the process involves extracting carbon dioxide (CO2) dissolved in the water and combining it with hydrogen - obtained by splitting water molecules using electricity - to make a hydrocarbon fuel.
It uses a variant of a chemical reaction called the Fischer-Tropsch process, which is used commercially to produce a gasoline-like hydrocarbon fuel from syngas, a mixture of carbon monoxide and hydrogen often derived from coal.
Robert Dorner, a Naval Research Laboratory chemist in Washington DC and first author of a new paper on the technique, said that CO2 is rarely used in the Fischer-Tropsch process because of its chemical stability.
"But CO2's abundance, combined with concerns about global warming, make it an attractive potential feedstock," Dorner said.
"Although the gas forms only a small proportion of air - around 0.04 per cent - ocean water contains about 140 times that concentration," he added.
The navy team has been experimenting to find out how to steer the CO2-producing process away from producing unwanted methane to produce more of the hydrocarbons wanted.
In the conventional Fischer-Tropsch process, carbon monoxide and hydrogen are heated in the presence of a catalyst to initiate a complex chain of reactions that produce a mixture of methane, waxes and liquid fuel compounds.
Dorner and colleagues found that using the usual cobalt-based catalyst on seawater-derived CO2 produced almost entirely methane gas.
Switching to an iron catalyst resulted in only 30 per cent methane being produced, with the remainder short-chain hydrocarbons that could be refined into jet fuel.
According to Heather Willauer, the navy chemist leading the project, the efficiency needs to be much improved, perhaps by finding a different catalyst. (ANI)