Recovering Waste Sulfuric Acid

[@nobody4248]

I would love to see more recycling videos

[@yodxxx1]

Finally I know how to create the forbidden Whisky

[@tahallium]

you’re using the same short path condenser as me! where did you get it from

[@integral_chemistry]

Lol that's a pretty funny coincidence. I got mine from some random dude on ebay because he was selling is crazy cheap compared to what these typically cost (think it was $40)

[@What0veriss]

Hi! I'm doing a undergraduate research project wich uses the piranha solution. What did you use to "filter" the waste off of the acid in the 2nd method?

[@integral_chemistry]

Fritted funnel and Celite. Obviously sulfuric acid will absolutely destroy anything organic so that's all I've been able to make work

[@What0veriss]

Thank you!

[@TylerZoucha]

To clear up that color at the end would activated carbon work at all? If not, I'd probably just put up with a little less pure sulfuric acid and clear the color with h2o2.

[@zenongranatnik8370]

It depends. If the color comes from organic stuff/carbon, then sure, you can add peroxide to oxidize the contaminants and then boil off the water but if it comes from inorganics like iron salts then only distillation works.

[@integral_chemistry]

Yeah @zenon basically put it best. I wouldn't do activated carbon as it probably wouldn't do all that much. Peroxide would work to clear up organic contamination, but burnt carbon contamination generally won't interfere with the vast majority of reactions so I just leave it. To remove inorganics the only option is distillation or MAYBE some sort of extreme electrolysis

[@TylerZoucha]

@@integral_chemistry @zenon Makes sense. I completely forgot about inorganic salts ironically since it'll want to turn many things into a salt.

[@experimental_chemistry]

Is it really advisable to distill used piranha acid? If some leftover hydrogen peroxide is still in there, this will also be concentrated and might even decompose explosively at such high temperatures - especially if organic residues are involved... Doesn't the heating mantle reach its limits at the high boiling point of sulfuric acid? I've read of cases where - when trying to reach such high temperatures inside the round bottom flask - the glass already started to soften... All questions that a hobby chemist in the EU no longer needs to ask himself anyways... 😞

[@integral_chemistry]

I've found that the peroxide tends to decompose long before the BP of sulfuric acid. I'm not sure if that's just due to the excess of organic contamination for it to react with, or just thermal decomposition. Either way it's never been an issue in my experience.. and I think it depends on the heating mantle, this one goes to 375°C which is plenty hot enough for this distillation, but even still (and wrapped with foil) it's a very, very slow distillation.. or maybe I'm just spoiled after years of low-boiling organic distillations lol.

[@integral_chemistry]

And you mentioned it's illegal in the EU to sell concentrated sulfuric acid, but is it legal to simply make it yourself?

[@experimental_chemistry]

@@integral_chemistry No, it's illegal, too.

[@experimental_chemistry]

@@integral_chemistry I've also reconsidered my own question, and think that at these temperatures, hydrogen peroxide should have vaporized or destroyed long before that. I also often use boiling to remove excess peroxide, although I've never attempted this with concentrated sulfuric acid - even when it was still legal. What you should definitely avoid is cleaning glass frits with peroxosulfuric acid after running organic solvents through them - this has definitely already led to nasty explosions... 🤕

[@user255]

If I need concentrated sulfuric acid I make some. I don't care about the law and no one else will either (in Finland) unless you do something stupid/damage with it. I think that is the most common case in EU.