Posted: February 15, 2008

Chemist explores nanotechnology to address greenhouse gases at source

(Nanowerk News) Much of the discussion about fighting global warming centers on new technologies and behaviors that could limit carbon dioxide emissions – the substance that causes climate change – such as using hybrid cars, nuclear power instead of coal, and biofuels instead of diesel.
UConn chemistry professor Challa Kumar and ThoughtVentions Inc. (TvU), a Connecticut company, are developing a prototype device that will test another approach.
Instead of trying to produce energy without creating CO2 gases, they are looking for a way to “sequester” the greenhouse gases that are produced at the source so they don’t reach the atmosphere, literally creating a kind of chemical filter for, say, a coal power plant.
Their work is funded by a joint $100,000 Small Business Innovation Research grant from the National Science Foundation.
“Currently, coal-fired power plants emit nearly 60 percent of the total carbon emissions, but our current economy can not afford to shut these plants down,” says Kumar.
“Instead, we believe that our approach would mean that the CO2 pollutants produced at a power plant are stopped from escaping into the air, thereby reducing their build-up in the atmosphere. This approach could buy us enough time to develop alternate, cleaner sources of energy.”
A large fraction of power in the U.S. is generated by burning coal and it is estimated that the nation has enough coal reserves to last for more than 200 years, says Kumar.
Clean coal technology may reduce our dependence on oil imports from the Middle East, he adds.
The technology would work this way: Kumar and his collaborators would attach a specific enzyme to nanoparticles that would trap the carbon dioxide molecule, after it is created but before it is released into the atmosphere.
Enzymes are catalysts that can accelerate specific chemical and biological processes.
For example, the enzyme the research team is investigating for carbon sequestration also plays a key role in respiration, where it facilitates the sequestration and exhalation of carbon dioxide through our lungs.
A similar enzyme in saliva is responsible for the zing of cola drinks, causing the sudden release of carbon dioxide bubbles in the mouth.
The enzyme-laden nanoparticles created by the research team would then convert the carbon dioxide from the flu-gases of a power plant into water-soluble “bicarbonate” – a harmless material.
The research teams at UConn and TuV will develop a particle gas absorber that will be used to sequester carbon dioxide for disposal in geologic formations such as depleted gas fields, deep ocean bottoms, or deep saline formations.
Alternatively, the sequestered CO2 can be used as a major ingredient in the manufacture of pharmaceutical intermediates, polymers, or economic building materials.
“Such new technologies can transform CO2 from a pollutant into a huge resource,” says Kumar.
“For example, our atmosphere currently contains enough CO2 to build storm-resistant, affordable, fire-proof houses for every human being on this planet and still use only a fraction of CO2 in the atmosphere.”
But first, an economic method of carbon dioxide sequestration needs to be established and that is what Kumar’s team is working on.
“We are testing nanomaterials laden with enzymes for this purpose, and there are several challenges to be overcome,” he says.
The research team has successfully stabilized several enzymes in nanomaterials, in a study that is also currently being supported by the NSF via another large grant.
“When successful, this new approach would allow the major sources of CO2 to go green, that is, operate on traditional energy without adding to global warming since little or no CO2 would be released into the atmosphere,” Kumar says.
One of the major obstacles to sequestering carbon dioxide using current technologies is the cost – between $100 and $300 per ton of carbon emissions – which would substantially increase the cost of the power generated.
Given that hundreds of millions of tons of carbon fuels are burned annually by the power industry, this cost would be prohibitively high.
If successful, Kumar’s method is expected to reduce the cost substantially, making it far more economical for use on a large scale.
The $100,000 grant from NSF is “seed money” to begin building a prototype device to test and check whether it works the way Kumar and his collaborators believe that it will.
Says Kumar, “This is a radically new approach to battling pollution and global warming.”
Source: University of Connecticut
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