Sciencemadness Discussion Board

Cleaning up iron(III)ferrocyanide stains

kaviaari - 9-3-2007 at 10:06

I made prussian blue in a ground joint erlenmeyer flask. Everything turned out nice, but when it was time to wash the flask the joint seemed to have sucken the compound in itself (didn't come out with violent brushing and hot water, nor with ethanol or ether). What would be the easiest way of cleaning this mess up?

[Edited on 9-3-2007 by kaviaari]

Polverone - 9-3-2007 at 17:45

Dilute HF should do it without damaging the glass or your health.

Prussian blue

Pyridinium - 9-3-2007 at 21:36

If you had some Geobacter metallireducens they would eat it for you :D

I don't think dil. HF is even necessary... dilute HCl should dissolve it without releasing HCN gas (don't use conc. acids).

kaviaari - 9-3-2007 at 23:56

Hot, dillute HCl-solution worked just fine for me. It needed some brushing but now it is as clean as new.

Texium - 18-4-2015 at 12:05

I made some Prussian blue a couple days ago and got some stuck in my fritted funnel (I used filter paper to prevent this from happening, but it tore when I was removing it and some got through). I tried running some dilute HCl through the funnel multiple times as this thread suggests, and while this seemed to work slightly, the frit is still badly stained. Any other suggestions for getting these stains off would be appreciated. Thanks.

Edit: Well, would you look at that, it's my 1111th post

[Edited on 4-18-2015 by zts16]

Boffis - 18-4-2015 at 13:20

Sodium hydroxide destroys prussian blue almost instantly leaving a residue of fine grained but readily soluble ferric oxide hydrate which is easily removed with citric acid, oxalic acid, dilute HCl, dilute phosphoric etc.

Texium - 19-4-2015 at 13:12

Thanks Boffis, that worked perfectly!

The Volatile Chemist - 19-4-2015 at 13:58

Interesting... I've noticed that a solution containing a ferri- o ferro-cyanide and iron compound is oxidized or reduced easily to Prussian blue. Literally, a residual drop of a solution of Ferric(II) ions and Ferrocyanide ions converts to Prussian blue in minutes, by air oxidation, it seems...