soul_clothes
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Cleaning Glassware W/Acid-base Washes
If one were to clean glassware with washes of acid(say murcuric) and base(say sodium hydroxide), what concentrations would be ideal for both?
And, sodium hydroxide etches glass so... what kind of exposure are we talking about? Would one 'soak' glassware in both the acid and the base, or
would one just wash with the base?
Thanks in advance.
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densest
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As usual... it depends. What's on the glassware? Organics? Food products? Tars? You really want surfactants for those and maybe agitation as well.
Carbonates? Mild acid. Phosphates? dunno, gotta look that one up.
The people who make Alconox lab detergent also make a few variants with low, neutral, and high pH. Each one is best for certain soils & articles
to be cleaned. You might want to look them up because they've done the research for you 
The individual packages of Alconox are moderately expensive but you don't need very much at all to clean a flask or three. $10 could last you a year
or two. Larger boxes are much cheaper by weight. There are other manufacturers.
I often use "Charlie's Soap" detergent because it's FDA approved for food & beverage vessels. It's a detergent + Na2CO3 so it's moderately
alkaline but not so much as to etch borosilicate quickly.
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aonomus
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I've used FisherSci's 'sparkleen', though what I've noticed is that while its cheaper, I need to use more detergent powder. On the other hand I have
recently used alot of iron oxides which stain glassware, so the abrasive action is more valuable than just solvating/detergent power.
A base bath is typically KOH/EtOH, or KOH/MeOH, but be careful because it is highly corrosive to organics (yet not so much towards glassware).
Also, always follow up with 1 or more rinses with distilled water. Use more rinses of small volume instead of one large one (basic extraction theory).
Additional reading: http://chem.rochester.edu/~nvd/cleaningglassware.html
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The WiZard is In
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Quote: Originally posted by soul_clothes  | | If one were to clean glassware with washes of acid(say murcuric) and base(say sodium hydroxide), what concentrations would be ideal for both?
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Many/many moons ago my second lab job was in a rendering plant.
You know where all the animal carcasses from the arbitrator and
animals the died on the street on NY (the Dept. of Sanitation
has a special truck to pick up bodies of carriage horses that die
on the street) in zoo's &c. Mostly I took sample of meat/bone that
had first been cooked to removed fat and then treated with
heptane to remove all the fat and ran it though a hammer mill.
I don't remember what happened to it after that. I also washed the
beakers - used for fat samples. I put the in La sink - add water -
turned on the steam valve under the sink and then threw in
ad lib. sodium carbonate turning the fat into soap. The beakers
were gradual etched and the ones whose edges had been chipped
being bumped around by the steam, had by the second wash their
edges rounded off.
By da my first lab job was sorting feathers.
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Picric-A
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I have just bought a reflux condensor which was fairly heavily stained yellow. I am guessing these are iron oxide stains just by sight however they
may be something else completly.
Does anybody know the best way to get rid of these stains?
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DJF90
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It'll be iron deposits from hard water. Citric acid will do the job nicely.
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The WiZard is In
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Oxalic acid even more nicely. Don't be knowing 'bout the
oxalic acid substitute they sell in stores.
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densest
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The sodium/sulfur/oxygen compounds sold for removing rust (hydro/pyro/sub/poly/meta/???/sulfite - choose your nomenclature, it's a mixture of many and
unstable too) work pretty well. If you can get a soft brush in as well that helps a great deal.
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Picric-A
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I have tried citric, oxalic and sodium dithionite and none have worked!
I cant get a soft brush in there, the opening is too small as its inside the jacked to the condenser.
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DJF90
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Leave it to soak for a day or so, its not going to be instantaneous cleansing.
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entropy51
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| Quote: Originally posted by Picric-A | I have just bought a reflux condensor which was fairly heavily stained yellow. I am guessing these are iron oxide stains just by sight however they
may be something else completly.
Does anybody know the best way to get rid of these stains? |
I would try rather strong HCl. I have used it to
remove Fe stains after doing Fe reductions. Give it time to react.
Your mileage may vary.
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Panache
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| Quote: Originally posted by Picric-A | I have tried citric, oxalic and sodium dithionite and none have worked!
I cant get a soft brush in there, the opening is too small as its inside the jacked to the condenser. |
Use the french technique, give up!
if is just inside the condenser jacket its irrelevant, esp if you've tried all those, aqua regia will work though if anything is to, and if you are
tres tres keen.
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soul_clothes
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| Quote: | | A base bath is typically KOH/EtOH, or KOH/MeOH, but be careful because it is highly corrosive to organics (yet not so much towards glassware).
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Thanks. I had no idea that a typical base bath is a mixture, with an alcohol. What if all one has is NaOH? And what is the recommended ratios?
| Quote: | | I would try rather strong HCl. |
Would hardware store muriatic be strong enough?
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peach
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You could use a syringe to squirt it in. Soaking works magic, releasing stoppers and deposits that would otherwise render the glass bin worthy.
The hardware acid will probably work fine. Brick cleaner might work even better, as it'll have additives in it to help shift gunk. Squirt it in there
and then tilt the condenser or plug up one barb so you can let it sit overnight. Next day, empty it out, rinse the coil through. If it's still there,
put the acid back in and wait.
If you have extremely difficult organic staining to remove from things like fritted glassware, piranha mix is supposed to be very good. Also extremely
corrosive and I have heard actual stories of things exploding in genuine labs when there's been compatibility issues; e.g. "my sintered funnel
exploded as I poured the mix on". One best left for the more devoted of nerds with serious issues other things won't shift.
When I'm cleaning my glass, I usually put my Marigolds on, empty a handful of KOH in, which I pass between the flasks. I'll rinse the flasks three or
four times with copious amounts of water under the tap. I stack all the glass up, then fill it with roasting hot tap water and let it heat up. Then
quickly empty it out, flick as much of the remaining water out as I can and squirt acetone in from a wash bottle. It rinses it perfectly clean and
forms an azeotrope with the water, which rapidly boils the flask dry from the remaining heat.
Concentrated base or 98% sulphuric on your hands will rip every drop of oil out of the skin and make them look decades older than they are. Gloves are
a good idea.
That's just from KOH washing. They went brown around sulphuric, as it dehydrated the organics. The rotting seems to have only affected the thin top
layer, not the bulk base substrate.
I expect the bones from the rendering plant where being sent off to be boxed up as organic phosphate fertilizer, perhaps after a roasting in a kiln.
Can say one thing for the meat processing industry, they squeeze every last bit of use out of the carcass; very often unlike people 'processing' it
for dinner at home, who'll throw a lot of the still useful bits in the bin (simmer the carcass for a few hours, strain the solids off and use the
stock to make taaaaaaasty soup, Michelin restaurant style).
[Edited on 25-7-2010 by peach]
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The WiZard is In
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| Quote: Originally posted by peach |
I expect the bones from the rendering plant where being sent off to be boxed up as organic phosphate fertilizer, perhaps after a roasting in a kiln.
Can say one thing for the meat processing industry, they squeeze every last drop of use out of the carcass.
[Edited on 25-7-2010 by peach] |
Rendering -
Bones were used for two things - bone glue or bone meal for plant
fertilizer. Dry solvent fat removed flesh and bone was sold by
the RR freight car full for chicken food. If the protein content
wasn't up to specification they added hydrolized chicken feathers
which didn't smell ... unless it got wet then it smell like ---.
Fat was sold by the RR tank car(s) or barge, million gallons (?)
a barge.
"Meat product" was sold for animal food once again by the
box car full.
There was an under ground tank for blood - was told once a year
they got an order and pumped it out and dried it. You can buy
dried blood in your local garden supply store.
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peach
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Interesting stuff.
In another thread, you'll see me going on about animal slaughter and I posted some videos from the slaughter houses. In quite a few, I've seen the
slaughter cut into what I think is the pulmonary artery and then hold a bucket up to it to collect the blood. The rate it comes out of a cow is
immense, it's quicker than an open ended hose pipe.
If they don't do that, they'll have grated floors that I expect lead to the tanks. It'd be a swimming pool of blood in no time if not.
In yet another video, they have things that look like very large OD cannulas (about an inch or more across), connected to long lengths of hose. They
stun the animal and then jab it in somewhere around that suspect artery.
I know they use blood for garden fertilizers. Here in Blighty, we have black pudding as well. Which is essentially blood thickened with various other
things (lots of fat). Great for when you're hung over and in need of a big greasy breakfast and massive mug of tea to recover. It comes from Germany,
where it's called Blutwurst (blood sausage).
Carelessly feeding meat back into the farming cycle as feedstock is one of the suspected causes of BSE, as I'm aware of things. I know that cannibals
are okay so long as they don't consume parts of the nervous system, which can contain infectious prions. In human cannibal tribes, this leads to the
wonderfully worryingly worded 'Shaking death'. They noted this transmission in the tribes as the women would usually eat the nervous system tissues,
and suffered from the related problems more often; with the main one being, death from brain rot.
Must have to be very careful with temperatures around all that biological waste. Let it warm up and you have a seriously dangerous pathological
infection hazard developing. Anthrax is an issue with cattle.
[Edited on 26-7-2010 by peach]
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