Sciencemadness Discussion Board

Mercury cleanup

nimgoldman - 30-3-2019 at 14:08

I found very little information about cleaning glassware that went into contant with elemental mercury or mercury salts.

Today I saw a video about mercury vapour and how insidious it actually is. I work under a fume hood so there is no immediate exposure to the vapour. However, I am concerned about the glassware.

The video shows that a Petri dish releases mercury vapour, even after it was poured off and wiped with a paper towel.

This seems to be a big issue regarding toxicity and I am wondering how to properly clean up the glassware.

My first thought would be to rinse everything with conc. nitric or sulfuric acid (to form water soluble nitrate or sulfate) several times, then combine the rinses in a single container, adding sodium polysulfate to it, converting any Hg salt to HgS.

Finally, excess water will be evaporated outside (on sun) and the residue probably mixed with excess sulfur and stored in as dry waste (hazardous).

I am still not sure how well the procedure cleans up mercury off the glassware and I should take more care about the cleanup. For example, should I leave the glassware in a fume hood for some time before cleaning with other glassware? Of maybe blow it with heat gut to promote evaporation of microscopic mercury residues?

I purchased mercury test strips so I can test any suspicious rinsing water for mercury before flushing it.

XeonTheMGPony - 30-3-2019 at 14:37

unless you're sleeping with it, no problem.

Chemphobia at full retard, never go full retard!
The tape idea is handy though, I all ways just sucked it up with a syringe.

fyi Never take seriously a video made by some one trying to sell you some thing.

In this case their fear and services!

How oh how did we ever survive befor now!

*Goes and plays with 4pounds of mercury*

[Edited on 30-3-2019 by XeonTheMGPony]

nimgoldman - 30-3-2019 at 16:40

Sure, I am trying not to be chemophobic, but it's hard to find a practical amount of safety, since all the safety videos and manuals repeat the same extreme safety measures... and you know, better safe than sorry (or dead).

I like Cody's Lab, he's on the other side of the spectrum, but Cody works with metallic mercury in containers he won't probably use for anyhting else than mercury. I will be experimenting with mercury salts, which are much more toxic and I would like to use my precious glassware for other experiments later - unfortunately I cannot dedicate entire set of glassware just for mercury experiments - hence the concern about washing...

XeonTheMGPony - 30-3-2019 at 18:26

just treat it like any other toxic salt. don't eat it, or inhale it and all's good.

Washing with Nitric acid is a good method, then neutralize as a carbonate / Sulfate.

Poisen is in the dose, I work to separate my toxic salt work by a couple of months to give the body to remove any exposure to safe levels.

I recently mad e 60grams of lead salts, few months ago I made mercury salts.

Oh and skin absorption be mindful of.

Sadly things are over hyped now days, and IMO this does a disservice, as you teach people to fear some thing, then they learn it is bs they toss out all the dangers! even if some are true.

Realistically, mercury is no more dangerous then lead salts when handled with due diligence, with the exception Mercury is more cumulative then the lead variances.

Main exception is DiMethyle mercury, 1 drip can deliver 3 grams of mercury, which is several lethal dosses that are highly fat soluble = ded!

[Edited on 31-3-2019 by XeonTheMGPony]

if convuluted sorry I been testing the strength of ethanol mixes in soda!

[Edited on 31-3-2019 by XeonTheMGPony]

I just washed the glass wear with water, then neutralize the waste water with sulfure compound to precipitate the mercury

https://www.youtube.com/watch?v=S4T57SFntIs

[Edited on 31-3-2019 by XeonTheMGPony]

A general observation;

Sulaiman - 31-3-2019 at 02:31

Mercury has a vapour pressure of 0.5 to 1 Pa at typical ambient temperatures,
about 20 mg/m3 ... if there is NO ventilation,
with ventilation the risk is lower than eating fish
https://www.fda.gov/Food/FoodborneIllnessContaminants/Metals...
So don't be careless with elemental mercury,
but for infrequent exposures, don't be scared of it either.

I once made mercury(II)nitrate for no particular reason other than curiosity,
my level of paranoia was too great for me to mess with soluble mercury salts again - without a good reason.
With mercury we have health concerns, and chemical contamination concerns,
I guess that if your glassware has been 'de-contaminated' sufficiently to handle,
the ppm contamination of future experiments in the same glassware will be negligible
(at my level of precision and purity of starting reactants)
...................................

Teenagers feel immortal and have many years ahead to suffer from unwise choices,
middle-aged people seem to be scared of life, the universe and everything,
old folk, like me, aint got too long to go,
so compared to all of the other ways I've messed up my body,
I'm not worried about a little mercury vapour now and then.
(from memory: the body can excrete 20 ug/day mercury)
but I do try to not endanger others - directly or via waste.

Here in UK we are now forbidden to posess mercury or any mercury compounds without an EPP license.

unionised - 31-3-2019 at 05:38

Quote: Originally posted by Sulaiman  
Mercury has a vapour pressure of 0.5 to 1 Pa at typical ambient temperatures,
about 20 mg/m3 ... if there is NO ventilation,
with ventilation the risk is lower than eating fish
https://www.fda.gov/Food/FoodborneIllnessContaminants/Metals...


I eat a few hundred grams of cod a week, and I suspect that the fat will do me more harm than the mercury.

However, I breathe a lotof air. Something like 100,000 litres per week
My fish supper delivers a few tens of micrograms of mercury.
Saturated vapour would give me the same dose in a few litres of air.

So, unless you can be sure that the vapour is diluted something like ten thousand fold before you breathe it, then breathing gives the bigger dose.

That might be the case, or it might not.
It depends on too many factors.
However, it's unlikely that playing with mercury will do any harm by inhalation.

draculic acid69 - 31-3-2019 at 05:57

Could reflux some nitric acid in your thoroughly cleaned but still possibly mercury containing glassware.if your cleaned glassware only has ppm of mercury residue on it then a nitric acid reflux should clean out the last of it.a second reflux should clean it even further.get some test strips to see if your glassware is clean enough.

[Edited on 31-3-2019 by draculic acid69]

draculic acid69 - 31-3-2019 at 06:10

If someone left a few ml of elemental Hg on a watchglass inside a house at 25'c how long would it take to fully evaporate.a day ,a week, a month or a year? How fast does this stuff evaporate.its just it's so dense as a liquid I can't picture it being volatile without heat.

nimgoldman - 31-3-2019 at 07:39

Thanks I feel much safer now.

I purchased some SenSafe Mercury Detection test strips. The seller has also offers heavy metal test strips (Cu, Zn, Pb etc.) si this will be a great addition for the lab.

As for the storage, I use double container with sulfur powder in between (see pic). It will be opened only in the fume hood to avoid immediate exposure to vapours that built up. There is more vapour than when storing Hg under water, but the advantage is dryness.
Quote: Originally posted by draculic acid69  
If someone left a few ml of elemental Hg on a watchglass inside a house at 25'c how long would it take to fully evaporate.a day ,a week, a month or a year? How fast does this stuff evaporate.its just it's so dense as a liquid I can't picture it being volatile without heat.


The number I've heard was mercury evaporates 16 000 times slower than water.

Water droplets can be very persistent in closed areas where the vapour saturates the sorroundings so the evaporation rate goes down. It can be the case the mercury droplets stuck in small areas can survive there for a very very long times (months to years possibly?).

But on a watchglass, it would be faster, maybe units of nanongrams per second?

Here is one study, but the link is broken on booksc.org and the original is beind paywall.

[Edited on 31-3-2019 by nimgoldman]

[Edited on 31-3-2019 by nimgoldman]

IMG_20190329_005500.jpg - 142kB

Keras - 31-3-2019 at 08:26

If you feel unsafe after using mercury, get N-acetylcysteine from your local drug store. It's totally OTC, and it has that S-S disulphide bond which will bind with Hg to form the insoluble HgS which will be later eliminated by the kidneys. N-Acetylcystein has been known for a while as a great chelating agent, and will even replenish your liver with glutathione, which is an essential antioxidant, and is given as an antidote against paracetamol poisoning. (see, e.g. this link).

I don't use mercury. It's not worth the risk. I also eat only fish which is as low as possible in the food chain, like pilchards, for example. I always have the case of Karen Wetterhahn in mind when I think about mercury.

PS : for mercury's vapour pressure try this link.

[Edited on 31-3-2019 by Keras]

Sulaiman - 31-3-2019 at 10:12

That is exactly the document that I got the figure of 0.5 to 1 Pa from :D

XeonTheMGPony - 31-3-2019 at 10:44

I keep my mercury on the shelf, that's it, well plastic bottle.

Oh and I have don the black light demo for people, and still have zero worry about it.

morganbw - 31-3-2019 at 12:54

I do respect the mercury salts and avoid totally the organomercury salts.

This being said mercury is really low on my scale of worries in chemistry. Lots and lots to worry with a chemistry hobby but mercury is not high on my list.
Respect and care handling, but.

woelen - 1-4-2019 at 00:13

@nimgoldman: I see you store your Hg over sulphur. Nice idea. How long did you keep it in that bottle? Your sulphur still looks pure and yellow. Even a tiny fraction of HgS will give a dark brown/black color. I think that even after years of storage in this way your sulphur will be as yellow as when you purchased it.

Indeed, nowadays there is a lot of fear mongering and even over here, this fear eats away rational behavior. Sulaiman's advice is worth a lot in this case. Be careful, not fearful. Have respect for your chemicals, but not fear.

I myself have investigated the risk of working with Hg-salts some years ago. I made Hg(NO3)2 by dissolving a big blob of mercury (5 grams or so) in concentrated nitric acid. I used an erlenmeyer for this. I proceeded as follows:
- Put appr. 30 ml of 60% HNO3 in the erlenmeyer.
- Add the blob of mercury.
- Initially, there was a violent reaction, releasing a lot of brown gas (NO2). I put a paper tissue over the opening of the erlenmeyer, allowing the gas to escape, but absorbing small droplets (if any) of liquid.
- At the end, the reaction become slow. I carefully heated, until all mercury was dissolved. Then I kept on heating, to make the liquid colorless (it was green/brown, due to dissolved NO2, N2O3).

After this experiment, I kept the liquid with mercury, and diluted this somewhat and bottled it to do experiments with mercury salts (e.g. making the beautiful HgI2).

I tested the tissue paper for mercury. On addition of a drop of dilute Na2S-solution, it turned dark, so there was noticeable mercury in the tissue.
I rinsed the erlenmeyer, used a test tube brush to clean it, and then added solution of Na2S. No visible coloration or darkening. If there still were any mercury in the glass, then it must be a very very low amount, not having any practical meaning.

Conclusions:
- Working with mercury-containing solutions must be done with care, when the solution bubbles due to production of gas (this also applies to boiling!!). Any gas escaping from the liquid brings with it sufficient mercury to be detectable easily.
- When you do experiments with solutions of mercury salts and you expect gases to be formed, such as CO2 with acid and carbonates, NO2 with nitric acid, or Cl2 with chloride and some oxidizer, then DO use a paper tissue, which you loosely push into the open end of the vessel or test tube. This allows the gas to escape, but keeps droplets of liquid inside.
- I see no risk at the level of glassware reuse. There certainly is no risk for health, but also no risk of spoiling future experiments with mercury ions which affect the experimental outcome.

nimgoldman - 1-4-2019 at 22:04

I will note the paper towel tip. Several people already advised that.
Quote: Originally posted by woelen  
How long did you keep it in that bottle?


Just a few days. It's a new acquistion to the chemical cabinet. I wonder how it will evolve over time. I have a blacklight (UV fluorescent tube) so maybe I could monitor the vapours.