Sciencemadness Discussion Board

Removal of malachite green from formaldehyde solution?

applesnail - 5-1-2011 at 04:07

can somone pls point me in the right direction, if its covered in this forum somewhere pls post a link,have read so many pages looking for info on best way to separate -any ideas would be greatly appreciated.(could it be as simple as filtration through activated carbon to remove the dye?)

ScienceSquirrel - 5-1-2011 at 04:32

That might actually work.
Filtering through gas masks which contain activated charcoal or through beds of activated charcoal to remove the dye was used during the war to divert commercial fuel to domestic motoring and more recently by Irish paramilitaries to fund their activities.
http://www.rrbew.co.uk/FeatureHtms/F-Excise-PB.htm

http://www.belfasttelegraph.co.uk/news/local-national/northe...


applesnail - 5-1-2011 at 06:48

Thanks for the reply squirrel any extra info is always appreciated!
"Formaldehyde is very weakly adsorbed on activated carbon or any other untreated adsorbent. Often, oxidation catalysts are deposited on adsorbents which convert the formaldehyde to formic acid which is more strongly held by physical adsorption on the adsorbent surfaces than formaldehyde. However, the oxidation product, formic acid is still a toxic compound and it eventually desorbs from oxidant treated adsorbents."
So heres the theory malachite/formaldehyde is aqueous in dH20 & small amount of stabilizer MeOH to stop oxidation,so filter malachite out with activated carbon, formaldehyde is highly soluble in water,theoretically should filter fine,formaldehyde converts to gas at room temperature so do filtration as a cooled solution or inside the fridge!

formaldehyde and malachite

questions - 10-4-2011 at 23:37

Hey, I noticed that you were trying to remove malachite from formaldehyde solution and you suggested that maybee activated carbon would work.
I was wondering if you had a chance to try it and if so did it work and how well did it work?
Quote: Originally posted by applesnail  
Thanks for the reply squirrel any extra info is always appreciated!
"Formaldehyde is very weakly adsorbed on activated carbon or any other untreated adsorbent. Often, oxidation catalysts are deposited on adsorbents which convert the formaldehyde to formic acid which is more strongly held by physical adsorption on the adsorbent surfaces than formaldehyde. However, the oxidation product, formic acid is still a toxic compound and it eventually desorbs from oxidant treated adsorbents."
So heres the theory malachite/formaldehyde is aqueous in dH20 & small amount of stabilizer MeOH to stop oxidation,so filter malachite out with activated carbon, formaldehyde is highly soluble in water,theoretically should filter fine,formaldehyde converts to gas at room temperature so do filtration as a cooled solution or inside the fridge!

jon - 11-4-2011 at 03:09

well it always cleaned my heroin up pretty well
oh shit!
did i say heroin? i meant phenanthrene alkaloids.

[Edited on 11-4-2011 by jon]

crystalXclear - 11-4-2011 at 03:46

malachite is a mineral of copper carbonate if it helps. Xtal

ScienceSquirrel - 11-4-2011 at 04:30

Malachite green has nothing to do with malachite apart from a similar colour.

Malachite

http://en.wikipedia.org/wiki/Malachite

Malachite green

http://en.wikipedia.org/wiki/Malachite_green

jon - 11-4-2011 at 04:32

i think that's used in fact i know it's used to catch thieves green handed you put malchite green on a piece of money and see who's hands turn green.
it's a good way to find out who's got sticky fingers.

applesnail - 11-4-2011 at 19:20

yes it will filter out eventually although purity would be in question as there could be trace amounts of malachite left.
A better way i think would be evaporation of formaldehyde to gase and recollection this in theory would leave the dye behind.
Although this may be a little more complicated(perhap malachite may evaporate also?Perhaps fractional distillation may work?) I havnt researched this any further since my first post months ago as i was able to obtain formaldehyde without malachite so there was no need to further carry on with this venture....

ScienceSquirrel - 12-4-2011 at 02:48

Even trace amounts of malachite green will make the solution green.
Dyes are strongly absorbed on activated carbon, that is why when treating fish tanks with dyes to kill diseases you stop the filters or remove the carbon.
Malachite green is an involatile solid, if you distill the formalin all the malachite green will be left behind.