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Water + Salt + Energy = Clean!
codesmith.ca writes "CTV News is reporting about a device built at the Russian Institute for Medical Engineering that can convert standard water and salt into an antimicrobial solution. Apparently it's works on almost anything (virii, bacteria, cysts...) and it's safe for human consumption to boot. I can't find a site for the institute, but there are articles around. This one is fairly detailed, but hard to reach. Here's the Google cache. Here's one about a paper shows it's not exactly super-new technology." Any chemist care to comment on what sounds to be too good to be true?
I can convert beer into a water and salts solution! What do I get?
Here's a report summary I found on the technology from the Foundation for Water Research. It's not all that and a bag of chips.
http://www.fwr.org/wrcsa/832100.htm
No rocket science here, don't understand why something as simple as the electrolysis of brine makes in on Slashdot ...
...
... as expected, Cl- -> Cl2 ... but the trick
here is that the formed chlorine reacts with water
and even better with the NaOH that diffuses from
the cathode to form ... bleach (hypochlorite that is) ! ... "The anolyte has powerful bactericidal characteristics and is effective in the control of harmful organisms like bacteria, viruses, cysts, and germs."
:-)
Freshman chemistry tells you:
NaCl -> Na+ + Cl-
H2O -> H+ + HO- (actually H3O+ instead of H+ but that's details)
Then, you add some electricity and you get:
At cathode (- electrode), H+ -> H2 (bubbles out) which means a lot of Na+ and HO- are left floating around - thus, per Google cached article in the original post: "The catholyte is a powerful alkaline solution used for [...]" -- not surprising at all, as you can see
Then, at anode (+ electrode) you've got HO- and Cl-
Cl2 + NaOH -> NaCl + NaClO
Now what does the article say?
Damn that highschool chem
END-OF-CHEM-LESSON
This is an experiment I did in elementary school.
It's called electrolysis. You separate salt water into
Use enough voltage, and maybe you bump oxygen to ozone, a superoxidizer (see above).
None of this takes any kind of chemist to see.
Note also that these chemicals are extremely hazardous in their uncombined forms. Remember Apollo 1 and its pure oxygen atmosphere at full sea-level pressure? Skin catches fire almost explosively in that sort of atmosphere - it's truly horrible what pure oxygen can do. Combine hydrogen and oxygen in the right proportions and they will explode. Sodium is poison and explosive when combined with water. Chlorine is poision.
Some of the more recent explorations into silver as a disinfectant with good tolerance in the body might be more profitable to follow, but also have snake-oil potential because too few people recognize that as another century-old technology that has a mass-market application in swimming pools today.
Were I you guys, I'd kill the story.
Bruce
Bruce Perens.
I built one of these things (salt water hydrolizer) in a (foolish) attempt to cut my pool chemical costs. Unfortunately, it leaked chlorine gas! I don't think my lungs have yet recovered, and it's been 20 years! Done right, however (and not being a putz as I was in the way I built it), people used to chlorinate their pools this way.
The Cl- ions form chlorine gas> If you can keep it involved in the water, the whole thing works. It does, however, produce lots of NAOH, which is not a nice thing to have around either!
Oh, and the design I used (I found it somewhere around town) used asbestos to separate the positive and negative regions.
In general, it was your all around chemical warfare and carcinogenic dream!
The only good weather is bad weather.
The reaction isn't, as some have said:
NaCl + 2H20 + electricity -> Na + Cl + 2H2 + O2
Rather, you get a hypochlorous acid ion, an a sodium hydroxide ion. In effect, the reverse of mixing hypochlorous acid and lye.
However, you get it in VERY dilute quantities, nowhere near what you'd need to damage human skin. But if you are an itty bitty microbe, the oxidizing effect is deadly.
Really, this is just a "bleach on demand" sort of thing.
www.eFax.com are spammers
Unfortunately, some of the things Bruce has stated are not entirely accurate. The general facts are correct. but some bits need modification.
Hydrogen is reactive. It's only 'highly' reactive if you haven't played with really reactive stuff, like fluorine, chlorine and, er, oxygen. Potasium is fun too.. (I have only seen Cesium once. That's quite enough).
Skin only catches fire if you get it very hot. An uncontrolled fire in a pure oxygen atmosphere is more likely to vaporize the skin; then the fat underneath will start to burn. Pure oxygen at reasonable (3atm) pressure will not cause spontaneous combustion of people. But if a fire starts in that environment, then you won't be able to put it out. The fire in Apollo 1 was not spontaneous. It was started by an electrical fault. The three astronauts suffocated in flame. Not nice.
You can happily mix hydrogen and oxygen in a 2:1 ratio. You can pressurize the mixture to astonishing levels. If there's a lot less oxygen, you can breathe the mixture for days at a time (google for "deep hydrogen diving"). If you make a spark, then you'll understand just how reactive oxygen is. The lesson learnt will be very short, and terminally instructive.
But hydrogen and oxygen are not hypergolic. Ask a rocket scientist. Even the Space Shuttle needs a match to get it going.
Sodium is a disinfectant. In the same way that a raging forest fire is disinfectant. Kids! treating your grazed knees with sodium metal may sting! Also, your parent's lawyers will have to contend with a stupidity counter-claim.
Oxidizing agents and reducing agents are defined by their ability to grab or release electrons.
If you want to understand this stuff, find somebody who knows what "Gibb's free energy" is about. Then, get them to explain it to me...