Endimion17
International Hazard
Posts: 1468
Registered: 17-7-2011
Location: shores of a solar sea
Member Is Offline
Mood: speeding through time at the rate of 1 second per second
|
|
Activated charcoal and ammonia
Seems to me like someone planted a disinformation on Wikipedia.
| Quote: |
"Contrary to a claim repeated[citation needed] throughout the web, activated carbon does not adsorb ammonia." |
It was removed by one user, only to be written again. Of course, most of the editors "solve" problems by adding those pesky brackets instead of
looking for an information.
They often engage in pointless rants, too, so in order to create a real evidence to use in their potential flame war, I've conducted an experiment
which once and for all disprooves this lie I've seen elsewhere, too.
<iframe sandbox width="420" height="315" src="http://www.youtube.com/embed/bmsev_upccs" frameborder="0" allowfullscreen></iframe>
If this is not a solid piece of evidence, I don't know what is.
|
|
|
Takron
Harmless
Posts: 47
Registered: 19-5-2010
Member Is Offline
Mood: No Mood
|
|
I"m glad to see experimentation to prove a point has not been lost on the world.
|
|
|
hkparker
National Hazard
Posts: 601
Registered: 15-10-2010
Location: California, United States
Member Is Offline
Mood: No Mood
|
|
Fits BromicAcid's signature I'd say.
Well done, good editing.
My YouTube Channel
"Nothing is too wonderful to be true if it be consistent with the laws of nature." -Michael Faraday
|
|
|
TheNaKLaB
Hazard to Self
Posts: 51
Registered: 18-9-2011
Location: Australia
Member Is Offline
Mood: Elastic
|
|
Brilliant video! I agree with fully Takron. Now, someone needs to rewrite that statement on Wiki 
|
|
|
Chemistry Alchemist
Hazard to Others
Posts: 403
Registered: 2-8-2011
Location: Australia
Member Is Offline
Mood: No Mood
|
|
Where abouts is it? i could change it if you like... type what u want it to say an i can do it
|
|
|
Bot0nist
International Hazard
Posts: 1559
Registered: 15-2-2011
Location: Right behind you.
Member Is Offline
Mood: Streching my cotyledons.
|
|
Very nice experiment Endimion17!
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
|
|
|
Neil
National Hazard
Posts: 556
Registered: 19-3-2008
Member Is Offline
Mood: No Mood
|
|
Nifty, I use AC to strip the lemon-yellow satan spew out of store ammonia and have always thought that the first 100ml or so that ran through were
drastically reduced in ammonia.
Ignoring wiki and looking elsewhere it was hard to find a consensus answer on the absorption of ammonia by charcoal.
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
|
|
Activated charcoal is commonly used to strip ammonia out of water in aquariums, it also removes a lot of other higher molecular weight gunk from the
water.
Generally activated charcoal likes big molecules with plenty of reactivity eg tannins, caramels, etc are preferred to small neutral molecules eg
carbon monoxide or highly polar ions like sodium or chloride.
Thus it removes the crap that the fish do not like while leaving the things that they need like dissolved salts and oxygen.
|
|
|
Neil
National Hazard
Posts: 556
Registered: 19-3-2008
Member Is Offline
Mood: No Mood
|
|
Back when I saw a wee young lad that is what I used AC for, stripping ammonia out of my fish tanks. Now the AC online and the pet stores ramble about
needing special ammonia absorption and all this other gibberish.
A fast google shows the same, seems like marketing has sown seeds of disinformation.
google seach for "activated charcoal absorb ammonia"
[Edited on 2-11-2011 by Neil]
|
|
|
Endimion17
International Hazard
Posts: 1468
Registered: 17-7-2011
Location: shores of a solar sea
Member Is Offline
Mood: speeding through time at the rate of 1 second per second
|
|
Thanks.
I've edited the wiki article around the same time this thread came to life and added a note on the talk page. So far no bots appeared.
I think charcoal's affinity towards NH<sub>4</sub><sup>+</sup> is only a fragment of the affinity towards gaseous ammonia.
Polar water is in the way. Wet AC is ok for big molecules (dyes), but ammonium cation is very small and has to "fight" its way to the AC surface.
That's why gas masks work great and aquarium scrubbers... not so great. That might be one of the reasons why this myth appeared. 
|
|
|
ScienceSquirrel
International Hazard
Posts: 1863
Registered: 18-6-2008
Location: Brittany
Member Is Offline
Mood: Dogs are pets but cats are little furry humans with four feet and self determination!
|
|
That depends on the pH of the water.
Ammonia is quite a weak base so at fish tank pH I would guess that some is available as the free base so it will stick to the charcoal.
There is a lot of charcoal in the average filter and not a lot of ammonia in the tank so it does not have to be very efficient anyway.
|
|
|
Adas
National Hazard
Posts: 711
Registered: 21-9-2011
Location: Slovakia
Member Is Offline
Mood: Sensitive to shock and friction
|
|
Wow, cool experiment mate, keep up the good work
|
|
|
bahamuth
Hazard to Others
Posts: 384
Registered: 3-11-2009
Location: Norway
Member Is Offline
Mood: Under stimulated
|
|
Nice experiment.
Kinda neat to know that it does in fact adsorbes ammonia.
Have you tested it with different types of AC?
Know different types AC adsorbs variously to same molecule in both strength and amount.
From what kind of wood did you make the AC from and what methode? That might have a huge impact on the outcome of the experiment.
Any sufficiently advanced technology is indistinguishable from magic.
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
I found it surprising that the activated charcoal had enough affinity for NH3 that it could produce a pressure differential strong enough to raise the
column of mercury several cm [mercury is a very dense heavy liquid!], while absorbing several times its volume of the ammonia gas.
One would suspect the affinity of water for ammonia gas is much higher than the absorbtive properties of carbon, however.
| Quote: |
"Contrary to a claim repeated[citation needed] throughout the web, activated carbon does not adsorb ammonia." |
So this quote is generally true for most ordinary purposes, where the ammonia is in water, but certainly not in the strict scientific sense.
[Edited on 2-11-2011 by AndersHoveland]
|
|
|
White Yeti
National Hazard
Posts: 816
Registered: 20-7-2011
Location: Asperger's spectrum
Member Is Offline
Mood: delocalized
|
|
Nice work!
But that tub of mercury scared the wits out of me. Is there not something less hazardous?
"Ja, Kalzium, das ist alles!" -Otto Loewi
|
|
|
AndersHoveland
Hazard to Other Members, due to repeated speculation and posting of untested highly dangerous procedures!
Posts: 1986
Registered: 2-3-2011
Member Is Offline
Mood: No Mood
|
|
I do not think there were many other options besides mercury. The ammonia could not be soluble in the liquid, while at the same time the liquid could
not be absorbed into the activated charcoal. So mercury was probably the best choice, although there does exist an alloy of gallium, indium, and tin,
which is a liquid at room temperature, melting at [minus] -20°C.
|
|
|
White Yeti
National Hazard
Posts: 816
Registered: 20-7-2011
Location: Asperger's spectrum
Member Is Offline
Mood: delocalized
|
|
How about using a saturated aqueous solution of ammonia instead of mercury? The ammonia cannot dissolve into the water (since it's saturated) and the
charcoal can float on a piece of inert plastic. It would probably give less accurate results and you'd have to do a ton of vapour pressure
calculations, but you wouldn't need to go buy some mercury off the interwebs.
This is a nice demo, but it's not something too many people can replicate. Speaking for myself, if I were to replicate this experiment, I would
duplicate it with 20x less mercury, the same amount of ammonia and 4x more activated carbon. The thing that struck me in this demo, was the excess of
mercury and the small amount of carbon used. This experiment was demonstrated to prove a point, no? To make carbon's affinity for ammonia more
obvious, I would have definitely used more carbon, but that's just me.
"Ja, Kalzium, das ist alles!" -Otto Loewi
|
|
|
Endimion17
International Hazard
Posts: 1468
Registered: 17-7-2011
Location: shores of a solar sea
Member Is Offline
Mood: speeding through time at the rate of 1 second per second
|
|
Quote: Originally posted by bahamuth  | Nice experiment.
Kinda neat to know that it does in fact adsorbes ammonia.
Have you tested it with different types of AC?
Know different types AC adsorbs variously to same molecule in both strength and amount.
From what kind of wood did you make the AC from and what methode? That might have a huge impact on the outcome of the experiment.
|
I didn't have the time to try it out with different samples. I used a piece of wood (I have no idea what kind of wood), wrapped in an aluminium foil
and heated over a flame.
It would be interesting to try it out using different materials (tree bark, dry blood, bones, meat, etc.).
I doubt different kinds of wood would make a huge difference. Charred animal tissues, certainly.
| Quote: Originally posted by AndersHoveland | | I found it surprising that the activated charcoal had enough affinity for NH3 that it could produce a pressure differential strong enough to raise the
column of mercury several cm [mercury is a very dense heavy liquid!], while absorbing several times its volume of the ammonia gas.
|
I knew what should happen but it was interesting nonetheless. If it was water (disregarding the fact ammonia dissolves in it), the column would be
almost 34 cm tall. 
Thanks.
There was ventilation and I left the room while the camera was filming.
Mercury is really the best choice. If you ventilate the area and follow the rules, there is no danger. It's not like you're going to do this more than
2-3 times in your life... Are you? 
| Quote: Originally posted by White Yeti | | How about using a saturated aqueous solution of ammonia instead of mercury? The ammonia cannot dissolve into the water (since it's saturated) and the
charcoal can float on a piece of inert plastic. It would probably give less accurate results and you'd have to do a ton of vapour pressure
calculations, but you wouldn't need to go buy some mercury off the interwebs. |
That is an option, but it's not just the vapor pressure. It's the water vapor fighting for the charcoal.
| Quote: | | This is a nice demo, but it's not something too many people can replicate. Speaking for myself, if I were to replicate this experiment, I would
duplicate it with 20x less mercury, the same amount of ammonia and 4x more activated carbon. The thing that struck me in this demo, was the excess of
mercury and the small amount of carbon used. This experiment was demonstrated to prove a point, no? To make carbon's affinity for ammonia more
obvious, I would have definitely used more carbon, but that's just me. |
I was in a hurry, having only 30 minutes to complete the experiment. If there was more time, I'd use more charcoal.
Less mercury is possible, but as I don't have a great deal of appropriate handy glassware, and got lots of mercury (not a flask, but certainly much
more than you see in the video), I just made the setup nice as possible.
Plus my camera can't use macro while filming. Larger setup means I can record the experiment better.
IIRC, this is how it was done back in the old days, except everyone was sniffing the vapors. It's a shame no one does these things today.
|
|
|
mr.crow
National Hazard
Posts: 884
Registered: 9-9-2009
Location: Canada
Member Is Offline
Mood: 0xFF
|
|
Wow!!!
Nice synth music too
Big pools of mercury were how everyone did experiments back in the old days. I love how its back to basics
Was the activated charcoal totally dry? It would be a shame if your results were just ammonia dissolving in the water (like the ammonia fountain).
Double, double toil and trouble; Fire burn, and caldron bubble
|
|
|
Endimion17
International Hazard
Posts: 1468
Registered: 17-7-2011
Location: shores of a solar sea
Member Is Offline
Mood: speeding through time at the rate of 1 second per second
|
|
I'm just waiting for the Youtube nincompoops to send me a copyright notice, even if I did nothing wrong.
It was dry in a sense it was made from a piece of wood some ten minutes before it was used. So yeah, I'd say it was reasonably dry.
|
|
|
Magpie
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
That's a nice experimental proof - simple, clean, and neat.
I wanted to comment on the pool of mercury. I view this as basically non-hazardous as long as it is at room temperature and is not dispersed. It
always amazes me how people seem to over-react to metallic mercury. I once saw a professor of chemical engineering go bananas when he found out
someone had dropped a Hg thermometer and it broke. And just today a professor (PhD in organic chemistry) was telling me "that he questioned the
wisdom of using mercury although he had once used some in an instrument of some kind." It was like he was talking about some substance from another
planet.
I feel fortunate that I had experience handling mercury, literally, when I was young, not routinely but once or twice. We boys rubbed it onto some
coins to make them shiny, just for fun. I also managed to get it all over my gold ring and had to take it to a jeweler to get the Hg removed. I have
no irrational fear of mercury and will use it, with the proper precautions, when it is needed.
According to this site, which has much information about mercury, "...at 20°C...its vapor pressure is 1.2 μmHg...":
http://mysite.du.edu/~jcalvert/phys/mercury.htm
The single most important condition for a successful synthesis is good mixing - Nicodem
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
Has the experiment been performed without and absorbent material to be 100% sure that the Ammonia is not dissolving in the large excess of Hg? I doubt
it myself but there will always be those who will attempt to use this as "proof" of a failed experiment.
[Edited on 3-11-2011 by Sedit]
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
|
|
|
Endimion17
International Hazard
Posts: 1468
Registered: 17-7-2011
Location: shores of a solar sea
Member Is Offline
Mood: speeding through time at the rate of 1 second per second
|
|
@Magpie: I have experience with the kind of academics you've described. Sometimes it goes to the absurd levels, as if something "radiates with evil".
Nerds (not geeks!) that have the power of sucking in everything they read into their brains (like AC with ammonia) but critical thinking, naaaaah.
Such dipshits slowly but surely destroy science in a country, and if there's a critical mass, might even consider pseudoscience to be a nice thing
(happened here more than once).
When dealing with mercury, exposed surface and temperature are important. The temperature was 15 °C and the surface was ~36
cm<sup>2</sup>. Time of exposure to air was ~12 minutes.
@Sedit: That's a very good point... No, it hasn't.
AFAIK, ammonia solubility in mercury is negligible for this demo experiment. You're welcome to try, as is anyone else. Fill a piece of one side sealed
glass tubing with ammonia and dunk it in a test tube with some mercury. Record the results and post here. Why not, that's a great idea.
BTW my video already got one negative vote. Few more and all that will be left then is a memewhore saying: "n people were adsorbed by
charcoal." 
|
|
|
Sedit
International Hazard
Posts: 1939
Registered: 23-11-2008
Member Is Offline
Mood: Manic Expressive
|
|
I might attempt this I'm not really sure yet. I have some Hg but its sealed in glass vials I would have to break open then deal with storage of it.
I want to think it through before I even consider dealing with the handling of the Hg because I don't wish to carry it in for my children to get even
if it is trace amounts on my cloths or what not. I'm not so concerned with my brain but they are still developing nerve sheaths and I don't wish to
foul that up any time soon.
Variables I wish to exclude is the temperature of the Ammonia gas and solubility of Ammonia in Hg. Both of these issues I feel could be solved by
placing the Test tube in the Hg and leaving it there for a bit with observation... then once stabilized insert a small piece of AC with tweezers under
the Hg so that it would float up and into the test tube, that it would prove without any doubt that the AC is absorbing the NH3 if the Hg stayed level
until the AC was placed in.
Knowledge is useless to useless people...
"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the
fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story
before."~Maynard James Keenan
|
|
|
MrHomeScientist
International Hazard
Posts: 1806
Registered: 24-10-2010
Location: Flerovium
Member Is Offline
Mood: No Mood
|
|
Great experiment! It's really satisfying to see a problem and be able to demonstrate the solution so cleanly and clearly.
| Quote: Originally posted by Sedit | | Variables I wish to exclude is the temperature of the Ammonia gas and solubility of Ammonia in Hg. Both of these issues I feel could be solved by
placing the Test tube in the Hg and leaving it there for a bit with observation... then once stabilized insert a small piece of AC with tweezers under
the Hg so that it would float up and into the test tube, that it would prove without any doubt that the AC is absorbing the NH3 if the Hg stayed level
until the AC was placed in. |
I like this plan a lot. That would difinitively prove that it is in fact the AC, and AC alone, that the ammonia is interacting with. Go play with
mercury!
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
