Sciencemadness Discussion Board

Powdered Zinc is stuck inside my sep funnel, how do I clean this out?

alking - 17-11-2016 at 13:39

I don't even know what I did to get this mess in there, I think I forgot to filter something and poured it in directly without thinking, I'm not sure. Either way I now have this mess to clean up : /. I also have some in a boiling flask. It sure is proving a pain.

So far I have well, of course swished it with water. I've also tried acetone and acetone + salt. If only I could reach it it comes off quite easily if I can simply scrub it but I can't fit my hand or a sponge in there and I do not have a brush nor can even find a suitable one to purchase to do the job. If I did have a brush on a stick I'm not sure if it could reach anyway due to the angle on the flask. Currently it is soaking in a solution of expired pirhana solution and hcl that I had sitting around, so in other words it's basically hcl, h2s04, a bunch of water, and random organic crap at this point. I would imagine fresh pirhana solution might work, but I'm running low on h2s04 and don't want to make ~500ml+ just to clean this stuff off either (it's a 2L sep funnel), especially if there's a better way. Zinc just likes to cling to everything and it has equally poor solubility. A few seconds of forethought would have saved me from this whole mess.

Maroboduus - 17-11-2016 at 13:51

Zinc ought to dissolve in HCl quite easily.

As for brushes, the common ones on a twisted wire handle can be bent to get at most anywhere in an RBF or a sep funnel.

I keep a couple just for bending up so the others can be left straight.

DraconicAcid - 17-11-2016 at 14:06

If your zinc is being stubborn, add some copper(II) ions to catalyze the reaction.

alking - 17-11-2016 at 14:40

Awesome, thanks. I will try the hcl and if that fails get some copper. I did notice that it looked cleaner upon adding the h2so4 solution, I now assume because of the hcl, but I wasn't sure and it did not seem to improve over time so I thought maybe I was wrong. It must have just used up all of the free hcl however.

AJKOER - 19-11-2016 at 08:01

If short on acid, use NaOH.

Careful, exothermic with hydrogen gas generation.
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You could also insert a zinc blocked glass funnel in a bowl of vinegar, dilute H2O2 and salt. Place in a microwave to start the reaction.

Adding a copper source here forming cupric acetate also is likely beneficial in creating some activated zinc assuming the formation of a zinc-copper couple. Per Wkipedia (https://en.m.wikipedia.org/wiki/Zinc-copper_couple ) on the latter, the treatment of zinc powder with copper(II) acetate monohydrate in hot acetic acid is a highly reproducible path to a Zn/Cu couple and activated zinc.
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I would NOT try using a combination of say chlorine bleach (NaOCl) and a weak acid (very dilute mineral acid, critic acid from lemons, vinegar,..) as a possible formation of an insoluble basic copper salt on standing.

[Edited on 19-11-2016 by AJKOER]