Acid, Safety, and Suppliers.

You can buy just about anything on the web these days; everything from acid to xylene is a mouse click or two from from website to doorbell. It’s harder to know what’s safe than it is to recognize the hazardous so permit me to give a little example. -K

The weather this winter has conspired with my professional obligations to prevent (so far) the collection and mounting of any snowflakes. I’ve kept busy with other things and a fair bit of reading; some of that reading involved methods in diatom mounting. As a result, I found myself extending my chemical supplies in preparation to include some acids I normally wouldn’t keep on hand. I ended up ordering a bottle of concentrated (31%) hydrochloric acid from a supplier I hadn’t dealt with in the past.

Everything was nicely packaged with appropriate hazard labels and an externally attached pocket housing the applicable MSDS. Very professional really and beyond compliance with applicable regulations. When I opened the package I was unpleasantly surprised to find that the bottle of acid had leaked (I’ll blame the thermal effects of sitting on my doorstep in freezing weather and a delivery man who doesn’t understand what a arrow is in this case) and that bag around the bottle held about 20ml of exuded acid and one very dissolved label. Wonderful.

I could have left the bag unopened until such time as I needed the acid, but that’s not good practice. Naturally in dealing with an unfamiliar chemical my first action was to go to my chemical atlas and verify the properties of the chemical with the information on the MSDS. That complete I got together my protective equipment. Gloves and goggles are a must for handling acid and most people would certainly know that, however, the type of gloves might not be so readily known. If I wore latex gloves I would suffer an acid burn in moments and nitrile gloves would only be worse (spontaneous oxidation). Thankfully I have a number of heavy PVC gloves and a rubber apron.

I might have gone a bit overboard but safety is important and never more-so than when dealing with the unfamiliar. I cleared a table in my work area set up a ring stand with a funnel and labeled a clean HDPE bottle. I then stoppered my chemical resistant plastic sink (the entire make up of the sink and it’s stopper is plastic which is important as there are a lot of things one wouldn’t want to put in a metal sink) and got my canister of soda ash from the shelf. Then I suited up with a chemical resistant lab coat, rubber apron, elbow length PVC coated canvas gloves, chemical respirator, goggles and let my wife know what I was doing. Communication is as big a part of safety as anything!

Most every acid can be safely put into a sanitary sewer once it has been neutralized and the MSDS will provide instructions for handling spills. Check with local ordinances before putting any chemicals down the drain and don’t do it if your not sure. Soda ash (sodium carbonate) is a vital safety precaution when working with acid and is among the least expensive methods of neutralizing acid that one can have. If you’re going to have any of the strong acids around, have a few pound of soda ash on hand too.

Well, I put on my exhaust fan (if I had a fume hood I’d have used it, but a fan and a window is better than nothing) and, working over the sink, I opened the bag; low and behold, fumes. It wasn’t unexpected but it’s never fun to see. I would have been fine without respirator or fan just because of the size of the room I was working in but again, safety. With the bag opened I liberally applied a scoop of soda ash and waited for the reaction (not much of one) to stop. One more scoop to absorb the liquid in the bag and the residue on the bottle and that’s that, the hard part is over.

I poured the acid from the bottle into the new container and capped it. Moving the funnel to the sink I put the soda ash mixture from the bag into the old bottle through the funnel to get the remaining residue. I slowly filled the sink with water and verified the neutrality of it with a pH tester before letting it run out. If that doesn’t sound fun then consider a different method of cleaning diatoms!

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