Doc B
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Airborne release of Sodium Hydroxide pellets
I've noticed a respiratory irritation when dispensing NaOH pellets in STP conditions. There is no visible dust or fine particulate matter present in
any such instances, however the irritation is comparable to that from inhalation when making an aqueous NaOH solution. I've heard of the ARF from such
solutions explaining the irritant but I'm curious if it is caused by the same phenomena just how it can't be explained?
I considered that there may be fine particulate matter but I've not seen any nor detected any by placing containers of water around the work space,
from which I've measured an initial pH prior to dispensing and compared a post dispensing pH measurement.
Has anyone noticed the irritant or can explain it?
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JJay
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I've noticed it before... I figure it is from NaOH particulates... these days I simply handle NaOH in my fume enclosure, but goggles and a dust mask
worked ok for me when I didn't have one.
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LearnedAmateur
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I commonly notice a peculiar odour when working with reagent grade NaOH (ruling out discernible contamination), solid or in solution, so it seems as
if it somehow reacts with the air, physically or chemically. Due to its strong hygroscopicity and high enthalpy of solution, I'd put my money on
microscopic droplets of hydroxide solution being emitted which are easily breathed in. However, I don't get any irritation from being near it, that's
probably down to individual differences regarding detection thresholds.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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Doc B
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Fine particulates does seem to be the most elegant explanation, however the pH test of the surrounds, after dispensing approximately 10kg in 4 to 5
molar lots, indicated that there was insufficient particulate matter dissolved to elevate the surrounding water. As such I am not sure if it's an
accurate explaination to the phenomenon.
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Morgan
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Maybe off topic but it's amazing how much you can't see that's going on with everyday items. If you pull a Kleenex from a box or clean the lint from a
clothes dryer screen outdoors in bright sunlight, there's a virtual blizzard of particles launched into the air that you get to breathe. Sunlight does
for dust what schlieren photography does for studying airflow.
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symboom
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The same particular dust is observed with lithium into water while hydrogen is given off some lithium hydroxide becomes airborne in the stream of
hydrogen gas and its really choking gas. Same with sodium metal and water forms a cloud of hydrogen and sodium hydroxide
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NEMO-Chemistry
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I buy 25Kg of sodium Hydroxide at a time, some for soap and some for Bio Diesel. It comes in a kind of plastic sack, i separate it into two plastic
containers when I get it. I noticed the irritation when doing this.
But I also notice when making soap, the solution of hydroxide gives off fumes when first mixed, so i had always assumed that when pouring the prills
out into the store bins, the irritation was due to the fumes given off from the tiny amounts of sodium hydroxide solution produced as it sucks water
from the air.
I havnt really noticed any dust, but the irritation is the same as i get when making solution of hydroxide up for soap making.
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zed
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NaOH effect on respiration? Oh yeah! I've noticed it. It hits the sinuses and soft palate pretty hard. Doesn't seem to effect Ph paper. Can't see
dust, mist, or spatter. But, something is going on.
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LearnedAmateur
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I've set up an experiment which I'm going to conduct over the next week. On the left is a beaker of 0.8g (0.02 mol) hydroxide pellets and the same
amount in 20mL distilled water, making a concentration of 1M. The pH strips are held in place by the cling film so any microscopic droplets should be
able to travel up and make contact without escaping. Hopefully enough will be absorbed by this time next week to show a result, and if not then we'll
need to find another mechanism.
In chemistry, sometimes the solution is the problem.
It’s been a while, but I’m not dead! Updated 7/1/2020. Shout out to Aga, we got along well.
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gatosgr
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I get the same irritation form NaOH pellets and eye irritation as well. The culprit is dried 1M NaOH solution on latex gloves I think, when you
continue to do work with these gloves dust particles travel in the air. I have safety glasses on but the plastic attracts the NaOH dust by
electrostatic attraction. I have never been told anything about the dust of dried solution of chemicals in my chemistry lab courses maybe some more
experienced chemist can elaborate on this?
Do you think fine aerosol is emitted from NaOH solutions? I got some hydrogen evolution from NaOH today, didn't notice any aerosol, it should be
really fine if it exists.
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This alkaline substance does not form vapors but may form aerosol dust which can be inhaled. Reports from cases of inhalation of caustic soda suggest
that this compound has the ability to irritate the respiratory tract lining. A lung injury known as pulmonary edema or the accumulation of fluid in
the lungs may happen. Workers exposed to a hot mist of this compound in unventilated area will experience tightness of chest, difficulty in breathing,
and cough. This is due to the bodys defense mechanism against the irritant. There was a reported case of a man who sustained severe pulmonary
injury due to inhalation of aerosol containing the substance. This happened when water was poured onto sodium hydroxide pellets.
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So maybe fine aerosol is emitted from NaOH pellets when exposed to air moisture.
It seems that soap makers experience this kind of trouble: http://www.tikvah.com/medical/lye.html
http://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC12854...
It's pretty self-explanatory that if you heat NaOH solution the evaporated water will contain NaOH but aerosol from just dissolution is a first for
me.
Do you guys get eye irritation as well or just respiratory irritation?
Someone told me that NaOH aerosols are forming from stirring, bubbling and pouring (which I did all three at
once) causing eye irritation, has anyone experienced any of that?
[Edited on 23-12-2017 by gatosgr]
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