New Hydrogen Purification Method
This feeling is making inroads into many hearts and minds that we need clean and green fuel. Hydrogen is the simplest element known to us. Its atom contains just one proton. It is also lighter than air and doesn’t exist alone on this planet. It is always found in combination with other elements. People see hydrogen as an alternative fuel but it has its own drawbacks. One of the biggest hurdles in hydrogen fuel is its purification. It can act as fuel for fuel cells but present methods of purification are not so efficient and effective.
But a Northwestern University chemist Mercouri G. Kanatzidis, together with postdoctoral research associate Gerasimos S. Armatas, has come with a solution. They have developed new porous materials shaped like honeycomb. And we think only poets have imagination! This porous honeycombed like structure is very effective at separating hydrogen from gas mixtures. Carbon dioxide and methane carry hydrogen gas in substantial amount. And this honeycombed shaped porous structure shows best selectivity in separating hydrogen from these two gases. The materials used in constructing hydrogen purification structure are a new family of germanium-rich chalcogenides. “We are taking advantage of what we call ’soft’ atoms, which form the membrane’s walls,” said Kanatzidis. “These soft-wall atoms like to interact with other soft molecules passing by, slowing them down as they pass through the membrane. Hydrogen, the smallest element, is a ‘hard’ molecule. It zips right through while softer molecules, like carbon dioxide and methane take more time.”
Why this separation method can be better than current methods? Till now scientists are depending on the size of the gas molecules while separating hydrogen from carbon dioxide or methane. First they get hydrogen in combination with carbon dioxide and methane. This method involves more steps and is difficult to execute. Kanatzidis and Armatas have a better idea. They don’t depend on the size of the gas molecules for hydrogen separation. They take help of polarization. Here interaction of gas molecules with the surface of the honeycombed like structure is crucial. Kanatzidis and Armatas tested their membrane on a complex mixture of four gases. They had chosen four gases for their experiment. They were hydrogen, carbon monoxide, methane and carbon dioxide. As the smallest and hardest molecule, hydrogen showed least affinity with the membrane, and carbon dioxide, as the softest molecule of the four, interacted the most.
Kanatzidis, Charles E. and Emma H. Morrison, Professor of Chemistry in the Weinberg College of Arts and Sciences, and the paper’s senior author, speaks out, “A more selective process means fewer cycles to produce pure hydrogen, increasing efficiency.” He further adds, “Our materials could be used very effectively as membranes for gas separation. We have demonstrated their superior performance.” Heavy elements such as germanium, lead and tellurium make the selection of hydrogen separation from carbon dioxide four times more effective.
According to Kanatzidis, another advantage of the process is “convenient temperature range.” which varies from zero degrees Celsius to room temperature!
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March 5th, 2009
The huge focus on hydrogen as the ideal fuel is a mistake, a distraction from the search for a practical and realistic solution. Hydrogen is not a viable solution for many reasons. It has that wonderfully desirable property of being “clean” and of being simple and obvious…. it is compelling but it is NOT practical at all and never will be…….. Let’s look for something that makes sense!!
March 5th, 2009
Is this method only effective for separating hydrogen from greenhouse gasses? Could this be used to separate oxygen and hydrogen in water?
March 9th, 2009
Howard Wilkinson, you state that there are many reasons for hydrogen not being a sufficient fuel however you do not name any. Could you possible explain your many reasons.
March 11th, 2009
Howard Wilkinson,over the past 125 years or more, we have made progress towards pure hydrogen as our energy carrier; from wood (cellulose)with its’ complex H to C ratio to coal(better ratio) to gasoline (hexane, octane etc.) and the alcohols (ethanol) with a 2 to 1 ratio and even natural gas (methane) with its’ 4 to 1 ratio. We will get to a stage where we will have a pure hydrogen energy source without CARBON but it will take longer with people like you blocking the way.
William (from Canada eh?)
March 18th, 2009
I heard that hydrogen powered cars have 42% efficiency, with hybrids at 26%, and gasoline cars at 12%. So I think it is too efficient.
March 25th, 2009
Emma. How can you say that hydrogen powered cars are too efficient? The more efficient the vehicle is then the better it will run. I also agree with what william has to say.
April 15th, 2009
Mr. Wilkonson, I don’t sincerely think you know anything about hydrogen. Open your heart and brain than you will see that, Hydrogen is the energy source which has been suppressed for more than 100+ years by people who shares your talk. But it is 21’st century and it is here and pretty soon you will be using it everyday.
July 28th, 2009
Mr Wilkinson you provide no alternatives and only criticize. Have you researched at all? Hydrogen is highly combustible so what sense does your comment make? There could possibly be a better solution however thats years to come. We have what we have so lets make progress with that. It’s people like you that slow this world down. Lets go green!
July 30th, 2009
Hydrogen is still too far away. Sure we can make hydrogen, but how to use it? Fuel Cells? Currently fuels cells are very expensive and use precious (read: expensive) metals in their construction. Even if we just burned it, storage is very dangerous. Essentially we’d all be driving our own personal hydrogen bombs. Plus, the tanks we use currently are very heavy and have low capacity (range).
Hydrogen is still a viable alternative for the future, but let’s not get ahead of ourselves. Unless some big advances are made the “hydrogen economy” is a pipe dream. EV’s, Plug-in Hybrids running on ever higher bio-fuel/petrol mixtures and especially public transportation are the directions we need to take and take now.
When it comes to hydrogen all advances are welcome, but let’s hold off on the ticker tape parades until hydrogen becomes feasible as a transportation fuel.
Oh and don’t mention the Honda public experiment with hydrogen vehicles to me as the production cost of those things is greater than the value of your house (before the real estate bust).
September 25th, 2009
Boneheaded1:
Did you know that when hydrogen leaks it leaks in a drizzle and does not combine to form explosive material, whereas gasoline does? You call driving hydrogen powered cars driving a hydrogen bomb. Well when you are driving a gasoline powered car aren’t you essentially driving a ticking time bomb? Have you seen what the Albertan tar sands look like? Have you seen the destruction done? Do you know what it’s like to be in a war over oil? Gasoline is the bomb, not hydrogen.
As well there have been big advances like the idea to extract hydrogen from ammonium for better efficiency. I think people need to stop putting it down because the governments are seeing that as a thumbs down to the idea. We have been researching alternative energy for years, and hydrogen has been our best bet. If we don’t change our ways soon, it’ll be too late an