So, here is the Mercury (Hg) that I need to clean up.
Above it, there is a large layer of water to keep the mercury vapors down.
Unfortunately though, I got my mercury from various different sources where
some were stored under oil and some was stored under water.
I like to store mercury under water because then I don't have oil contamination when I use it in a reaction
So my two goals in this clean up
will be removing the oil that the Mercury is contaminated with
And I also wanna filter out any of the solid impurities
A lot of this Mercury is from old broken thermometers
And for this reason there's a bunch of broken glass mixed in
I actually cleaned up my Mercury a little bit before
So it's actually relatively shiny here
This technique, though, still work very well even for Mercury that's really dirty.
In the end we should have pretty clean shiny mercury that is more than usable in any reaction
However it's important to point out that this process doesn't really get rid of a lot of the soluble impurities
To get rid of the soluble impurities the mercury should be prepared like I show in this video
And then needs to be destilled
I plan to do the destilation in a future video but right now it's winter and I really need to do the destilation outside
For the first part of the process
we need to filter the mercury
and I find the best way to do this is
is using a syringe and some cotton balls.
To prepare our filter it's really easy
and we just put some cotton balls into the syringe
and then jam it down to the bottom using the plunger
Its important to pack the cotton balls down as tightly as possible
the next thing I do is I open my mercury bottle and I pour out as much of the water oil mixture as i can
I wanna get rid of as much of this as possible because its really a waste of time to filter this through
I then prepare my filtering set up like you see here
Everything is placed inside a bucket just in case there's any spills or splashes.
I highly suggest to do this when you work with mercury
because a spill is a huge pain to clean up.
Also the syringe is placed inside a bottle so any mercury can splash out
When I'm ready, I open my mercury bottle
and I start to pour it into the syringe
When you pour it in, it's important to be careful because
you don't wanna miss the syringe and have mercury splash everywhere.
Also, if you pour it too quickly, the Mercury is heavy enough that it can displace your cotton filters.
The bottle with the mercury is then recapped, just in case it's knocked over.
Then, when we're ready we put the plunger into the syringe and we squeeze down.
You can actually see here that some of my cotton filter did get displaced by the mercury when i poured it in.
This is usually ok though as long as you still have some cotton to act as a filter at the bottom.
Even if you use relatively dirty mercury it should come out pretty shiny.
So this is after filtering the first half of the mercury and we add the second half into the syringe.
At the top, there's a little bit of an oily water layer and it's removed using a glass pipette.
So just like before, we put the plunger back in, squeeze and filter the mercury through.
So, the filtering step was successful, but you can still see that there's oil there.
If you're really just looking to get rid of the oxide scum or dirt, broken glass, et cetera; you can stop here. The filtering process is enough.
In other words, if you're looking for just aesthetics, filtering it through the cotton will make it look extremely clean and shiny.
Because I want to remove the oil and get rid of some of the soluble impurities, I proceed on to some washing steps.
In the syringe, you can see that there's some mercury that doesn't make it through and it's inevitably lost.
My mercury was already quite clean and didn't have a crazy amount of insoluble impurities, so you actually can't really see them on the cotton.
So, to continue cleaning up the mercury, it's poured into a separatory funnel.
The mercury is then quickly drained back into the bottle so we can separate it from that oily water layer above.
Once all the mercury's removed, we can place it to the side and then we can collect the water-oil waste in a beaker.
Before re-adding the mercury back to the separatory funnel, it's washed out with a little bit of water.
So, the separatory funnel is capped and shaken, and then the water waste is collected in the same beaker.
Now that the separatory funnel is cleaner, we can re-add the mercury.
I then pour in two hundred milliliters (200 mL) of a ten percent sodium hydroxide solution (10% NaOH).
This was made approximately by putting about twenty grams of sodium hydroxide (20 g NaOH) into a beaker and then topping it off to about two hundred milliliters (200 mL) with distilled water.
The separatory funnel is removed from the stand and it's shaken vigorously.
It's also vented occasionally by opening the stopcock at the front, to let out any pressure that might build up.
This basic sodium hydroxide solution will help wash out the oil from the mercury.
Afterwards, it's placed back onto the ring stand and allowed to settle.
I repeated the process of shaking it and then letting it settle several times over the course of about an hour.
It's very important before you start [to] set up some sort of mercury vacuum.
You can see when I turn on the vacuum and I put the pipette into the water, it sucks it all up and shoots it into the Erlenmeyer flask.
This is a very simple vacuum cleaner that I just made out of different pieces of glassware, but it's really important if you're gonna work with mercury.
Mercury droplets from a spill are extremely hard to pick up, but with a vacuum apparatus like this it's very easy.
After about an hour, it looked a lot cleaner and it didn't really look like there was any oil floating around.
The now nearly oil-free mercury was then drained.
The sodium hydroxide washing, still in the separatory funnel was poured into a waste beaker.
The separatory funnel was washed with a little bit of water, and then the mercury was poured back into it.
I then poured in a few hundred milliliters (~300 mL) of just regular distilled water.
The regular water serves to wash out any sodium hydroxide that might have been left behind in the mercury.
Just like before, we shake it thoroughly, and vent frequently.
It's placed back on the ring stand, the lower mercury layer is drained and the water washing is poured into the beaker.
We now proceed on to our third washing, and to do this we pour our mercury back into the separatory funnel.
For the third washing, we use a hundred milliliters of three molar nitric acid (100 mL 3M HNO₃)
This step serves to remove metals that might be dissolved into the mercury.
So, we quickly take it off the ring stand and shake it thoroughly to make sure everything's mixed very well.
Afterwards, it's placed back on the ring stand and it's allowed to sit for a few minutes.
Just like with the sodium hydroxide washing, I repeat this mixing process several times over the course of an hour.
What's important to note about this step is we will be producing a little bit of mercury nitrate, which will dissolve into the water.
Mercury (I) nitrate (Hg₂(NO₃)₂) is really toxic, so this must be handled with care.
After an hour, we're ready to drain away the mercury.
The mercury is drained into a clean bottle, and the mercury waste is again poured into the beaker.
I should mention that the waste of all of these washings must go to an appropriate mercury waste container.
It's arguable whether you need to put water washings of metallic mercury into a waste container, because metallic mercury really doesn't dissolve into water.
However, for the nitric acid washing, we are gonna convert some of the mercury metal to salt and this will be dissolved into the water.
Now to the bottle containing our relatively clean mercury, I pour in some distilled water.
I then put the cap on and shake it thoroughly.
This step serves to wash out any mercury nitrate or nitric acid that might be left.
I found it was easy to do a couple quick water washings this way, before I added it back to the separatory funnel.
I decanted as much as I could of the top water layer into the waste beaker.
I did this quick method of washing it a total of two times (2x).
To a nice, clean separatory funnel, I pour the mercury back in.
On top of the mercury I pour in a few hundred milliliters (~300 mL) of distilled water.
Then, just like with all of the other washings, I cap it, shake it, vent it and put it back on the ring stand to separate.
The bottom mercury layer is then drained off, excluding as much as possible.
As one final cleaning step, which probably isn't necessary, I pass it again through a cotton filter.
Just like before, the mercury's poured in and then we squeeze down with the plunger.
The filtered mercury is drained directly into fresh, clean bottle, already containing some distilled water.
This is what our final, clean mercury looks like.
The mercury at the end of this process should be more than usable for most any reaction.
It should be relatively free of soluble impurities, but there's inevitably gonna be some left over.
As I said earlier, to get the cleanest mercury possible, we need to carry out a distillation.
I do plan to do that when it hits spring here, which should be in a few months.
I also plan to do an element series for the mercury, but, like I've said in some other videos, I have a lot on my plate right now and I'm not exactly sure when I'll get around to doing that.
Anyway, as usual, that's all I have to say for now and I'll see you guys on the next one.
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