Plants Give Up Secret Of Splitting Water

IOL ^ | 2-6-2004

[blam]

Plants give up secret of splitting water

February 06 2004 at 07:21AM

Washington - Researchers said on Thursday they had taken another step toward understanding how plants split water into hydrogen and oxygen atoms - which may provide a cheap way to produce clean-burning hydrogen fuel.

Producing hydrogen from water is the stuff of science fiction - and some comments by US President George Bush. But the team at Imperial College London and Japan Science and Technology Corp. in Yokohama said they had taken the best pictures yet of the plant structures that do it every day.

They used high-resolution x-ray crystallography to make an image of the tiny atomic splitter that separates the two hydrogen atoms from an oxygen atom in a water molecule.

"Results by other groups, including those obtained using lower resolution x-ray crystallography at 3.7 angstroms have shown that the splitting of water occurs at a catalytic center that consists of four manganese atoms," said So Iwata of Imperial's Department of Biological Sciences.

'Together this arrangement gives strong hints about the water-splitting chemistry'

"We've taken this further by showing that three of the manganese atoms, a calcium atom and four oxygen atoms form a cube-like structure, which brings stability to the catalytic center," Iwata added in a statement.

"Together this arrangement gives strong hints about the water-splitting chemistry."

Writing in the journal Science, Iwata and colleagues said they looked at a plant bacterium called Thermosynechococcus elongatus. "Without photosynthesis life on Earth would not exist as we know it," Jim Barber of Imperial's Department of Biological Sciences said in a statement.

"Oxygen derived from this process is part of the air we breathe and maintains the ozone layer needed to protect us from ultraviolet radiation.

"Now hydrogen also contained in water could be one of the most promising energy sources for the future. Unlike fossil fuels it's highly efficient, low-polluting and is mobile so it can be used for power generation in remote regions where it's difficult to access electricity."

Water has always seemed a logical source for hydrogen but the only known feasible method to separate it, electrolysis, costs ten times as much as natural gas, and is three times as expensive as gasoline, Barber said.

[Constantine XIII]

There is a lot of work being done now to fashion a container out of carbon nanotubes. The hydrogen would be suspended in a substrate of the nanotubes, so that even if the tank was split wide open it wouldn't all escape at once. Nifty stuff, those nanotubes.

[js1138]

Excuse me, but if you had solar cells or artifical photosynthetic cells that lasted for centuries, their effective cost woild be nil. The difference between nil and free is not much. Whether this happens is an engineering question yet to be worked out. Things look different from one century to the next.

Granted the word free is an exaggeration. With current technology, cheap would be an exaggeration. I'll check back in fifty years and see how things are going.

[Flightdeck]

"I really don't think you are equipped for this discussion."

LOL, my PhD advisor in the #1 heat transfer group in the world would disagree. As for this sentence:

Notice that if the third term is positive (and it usually is)

That is absolutely correct, unless the system is a perfect vacuum, so what was your point again?

When I TEACH thermodynamics to undergrads, this argument doesn't happen, because they're not stupid.

[RockyMtnMan]

So we should expect a car from Kia in the future called the Kia Chia, powered by a Chia pet?

[templar]

Easy -- don't coat the skin of your Zeppelin with the equivelent of rocket fuel and everything will be just fine.

The 'Hindenberg effect' is the hysteria about using hydrogen resulting from people having seen the films of the Hindenberg, not the actual fire or explosion danger. Even around here, you will notice a number of people that actually think that hydrogen is an excessively dangerous substance, when in reality it disperses so quickly (because it is so light) that it is safer than gasoline or propane. Visions of 'hydrogen bombs' from the cold war don't help much either.

[Lee'sGhost]

"Like I pointed out earlier, while gasoline is explosive, the likelihood of death is MUCH greater with a hydrogen explosion."

NO,NO,NO,NO,NO!!! Will this misperception EVER end?

There was a TV special on this years ago. I can't find it on the net but here's similar info.

http://www.hydrogenus.com/advocate/ad22zepp.htm

[Lee'sGhost]

"Laquer or something similar?"

Yeah, like, super explosive laquer. Check out my post #86.

[Lee'sGhost]

"super explosive laquer."

Uh, got a little excited. Probably should have said super "flammable" lacquer.

[Nov3]

Notice that if the third term is positive (and it usually is)

Do they teach the difference between endothermic and exothermic reactions at your number 1 school? I just have a MSME from a lowly State University but I could grasp that concept.

Again your first statement is ludicrous

"The laws of physics show that it will never be possible to get cheap hydrogen and therefore it is a waste of time to even look for a solution.

Tell me the law of physics, and I'll tell you where you you're wrong. There is not cost-benefit analysis in any one of them. "

The hydrogen in water has been oxidized and, catalyst or not, it will require at least the energy that was liberated when the bond was formed to break it. There is no free lunch.

[frgoff]

True, we have a really good knowledge of how genetic expression can be influenced by outside environmental factors, but that's not evolution. What you are describing is completely different than evolution as it is commonly understood in laymans terms, and it is disingenuous for you to confuse microevolution with macro evolution. The two are completely different events.

[Flightdeck]

Look, I don't know where you got the idea that I said it takes less than the bond energy to break a molecular bond. (Unless you are using that as the red herring for your argument.) All I said was that we can put energy into a substance, initiating a reaction which will release more energy than we put in. This happens every day in a car cylinder. You, on the other hand, said that the laws of physics prove it is impossible to "get" cheap hydrogen. Then you quoted energy conservation, but didn't indicate where that proved your point.

Refer to thermonuclear fusion: Two particles have a given amount of internal energy by themselves. When these particles are together, and provided with so much energy that the nuclei are fused, a new particle is formed out of the two, which has a much lower internal energy than the two on there own. This difference in energy is released, and is MUCH greater than the energy required to heat up the particles in order to fuse them together. Hence the concept of fusion as an energy source. Does this violate the first law of thermo? NO.

It is possible that you and I are arguing over different things. But it is definitely not a waste of time to look for a good way of extracting hydrogen from water. If a natural source of energy (like the sun) can consistently provide enough energy so that what we have to provide in the form of electricity or heat is less than that provided by the hydrogen product, it would indeed be worth it.

[Nov3]

I hope we are on the same page here because though I don't consider myself an expert on all engineering matters I am pretty sure I am right here. Breaking water down requires energy. When it is burned we get the energy back. With losses included we are better off skipping the step. Now this is a novel idea but the energy flux from the sun is not that great and the environmentalists are not going to let us carpet the country in solar collectors to get enough energy to be meaningful. Then you add the storage and transportation issues and this thing is a mess.

And that term is negative in many reactions!

[moonhawk]

"...I personally am holding out for a rhododendron-powered Corvette!..."

Think "Watercress..."

Have your fuel and eat it, too.

[Still Thinking]

Gasoline is hard to beat in the mass-to-energy department. That's why nothing has replaced it yet. And the same reason propane/LNG powered cars have to have larger fuel tanks to travel the same distance.

Well, maybe we shouldn't think of hydrogen as a gasloine alternative, but maybe as a precursor. Since the h2 is already in the high energy state (from the process in the original post), could we add carbon and synthesize gasoline? If so, we would avoid all the investment, infrastructure, tank size, and leak prevention issues which have been mentioned as hurdles to acceptance of hydrogen fuel. Plus, if we were making it from scratch, perhaps we could come up with a cleaner burning formula. I don't know if the pollution producing components of gasoline are dictated by the way it is used or are a side effect of the petroleum feedstock.

[myself6]

I don't think that is correct. A diesel sub can stay down a predetermined amount of time before refueling. Therefore the amount of space it has for fuel equals x amount of energy. A nuclear sub is about the same size as a diesel sub and I believe the fuel rods will keep it going for many years. If people didn't have to live on these things they would never have to stop. The amount of space for fuel on a nuclear sub equals infinite (relatively speaking) amount of energy to do work.

Obviously I was taking liberties with the language here but the concept is clear. 20 gallons of gas and a 20 gallon tank of compressed hydrogen do equal the same amount of energy.

[myself6]

do = do not.


I hate typos

[yhwhsman]

Hey a twofer! Drink the water, then put it in the car!

Well, you could probably drive twice as far if you drank beer instead. LOL

Reminds me of a story about some marines in an anti-aircraft tower on a battleship during the Pearl Harbor attack. They had water cooled machine guns, and when they ran out of water they urinated in the water jacket. They sent down a request to have several cases of beer sent up so they could keep fighting.

[DuncanWaring]

... it would be pointless to go chop some wood,...

Remember, though, that "He who chops his own wood is twice warmed".

[yhwhsman]

Apparently when it comes to creation, everything can be explained by looking at a few hundred words in Genesis. If it isn't in there, then it didn't happen. Sure, that makes a lot of sense.

Well, as I see it, Creationists and Evolutionists both base their beliefs on several assumptions. And from reading these threads, it seems to me the Evolutionists act more like 'Bible-thumpers' then the Creationists do. Or better yet, like militant Islamics defending their religous beliefs.

No, Genesis doesn't talk about Dinosaurs (although Leviathon appears in Job I believe), nor does it talk about zebras, water buffalo, amoebas, or DNA. In fact, after the first few chapters, it doesn't talk about much more then the small area of the middle east either.

But just because they're not mentioned doesn't change my belief that God created them. And that He created them in a logical manner, with potential for 'adjustments' (ie the ability to adapt) built in.

All the scientific discoveries coming to light in the last few years--DNA, genetics, archeology, astronomy, space exploration--are absolutely fascinating and exciting. Because it shows how little we really know about what we think we know.

[DuncanWaring]

... the likelihood of death is MUCH greater with a hydrogen explosion.

Jason Schecterle and other drivers of the Ford Crown Victoria Police Interceptor might argue that one with you.