Straight Dope Message Board

[Ins&Outs&What-have-yous]

If I understand this correctly, hydrogen peroxide (H2O2) is sold and stored in opaque (usually brown) bottles in order to prevent the peroxide from being exposed to light which breaks down the H2O2 into water (2H2O) and oxygen (O2).

Hydrogen Peroxide ( above ~3% volume solution) is extremely harmful if swallowed.

My question: Can the household hydrogen peroxide be stored in a transparent container and then be safely consumed in the form of water after some time period?

The time period would of course vary depending on temperature and initial pH, but let's assume the time period is ample for all H2O2 to break down. 1

[slaphead]

Yes. No idea what the timeframe is, but if you toss in some catalyst (Manganese, IIRC) it happens pretty quickly. This is the principle used to allow you to sterilise contact lenses in H202 solution without nuking your corneas - a little catalyst 'brick' in the bottom of the soaking container that ensures by morning all the peroxide is gone. Having once cut short the recommended soaking time, I can confirm that having trace amounts of peroxide in the eye is not nice 2

[Ins&Outs&What-have-yous]

Can the household hydrogen peroxide be stored in a transparent container and then be safely consumed in the form of water after some time period?

I meant industrial strength (like 35% H2O2) rather than household hydrogen peroxide. 3

[Ins&Outs&What-have-yous]

Originally Posted by slaphead

...having trace amounts of peroxide in the eye is not nice

I can imagine. Even the 3% solution causes a moderate burning and tingling sensation on an open would. Having never worn contacts myself, I wasn't aware of the role of peroxide in lens sterilization.

I'm not sure how dilute the H2O2 must be before consumption is completely safe so I specified "time period is ample for all H2O2 to break down." 4

[Walloon]

Originally Posted by slaphead

This is the principle used to allow you to sterilise contact lenses in H202 solution without nuking your corneas

"nuking"?? 5

[Malacandra]

Originally Posted by Walloon

"nuking"??

Pretty much. Actually it's the inside of the eyelids that reports the irritation, which is probably just as well as even small amounts of atomic oxygen would likely do horrid things to the cornea if it was left there for any length of time. Trust me, this is one mistake that you don't make twice. (Another is thinking that it's enough to wash your hands a mere three or four times after preparing chilli peppers before handling your contacts. It isn't. Trying to get the offending contact out of an eye that has reflexively clamped shut in agony is a never-to-be-missed experience.) 6

[Walloon]

[QUOTE=Malacandra]Pretty much.[QUOTE]Pretty much what? I'm asking what nuclear anything has to do with hydrogen peroxide? 7

[Electronic Chaos]

Originally Posted by Walloon

Pretty much what? I'm asking what nuclear anything has to do with hydrogen peroxide?

Probably nothing. It's just a figure of speech. 8

[Malacandra]

Originally Posted by Electronic Chaos

Probably nothing. It's just a figure of speech.

Per-zakly. Ever heard of "nuking" something in a microwave? That's a sloppy usage too. 9

[Lemur866]

To answer the OP, of course industrial hydrogen peroxide will eventually break down into drinkable water and oxygen. Exactly how long it takes would depend on exactly how it's stored, the concentration, etc, etc. 10

[twhitt]

Just for the record, I would strongly advise no one attempt this feat. With all chemicals, household or industrial, that are not meant for human consumption, it is possible that there are additives which do NOT break down and are NOT safe to consume. I'm given to understand that this is commonly the case with lab grade ethanol, for example.

Pure H2O2 would degrade, I believe under ultraviolet light, though chemistry has been several years back, into H20 and Oxygen. The problem with drinking it arises because the peroxide is a strong oxidizing agent, and causes trouble by reacting with, and creating, those free radicals you hear about in the news. The enzyme which attempts to safely catalyze this reaction in the body is Catalase. It's very efficient; it speeds up the rate of the reaction so much that the speed is limited by the rate of diffusion of H2O2 molecules in water. That's quick. 11

[CC]

Well, I doubt that Walgreens puts much of anything in their peroxide, but, yes, light does break it down and that's exactly why they sell it in those opaque brown bottles. If they didn't, you'd have little oxygen pressure bombs on all the shelves as the H2O2 they were trying to sell to the customers was busy turning into water and oxygen under the light of day, creating havoc in aisle 9. Mass hysteria, dogs and cats playing together - it'd be crazy, I tell ya. 12

[CynicalGabe]

Originally Posted by Malacandra

Per-zakly. Ever heard of "nuking" something in a microwave? That's a sloppy usage too.

Excuse me, I have to go Xerox something. Literally. 13

[JustAnotherGeek]

Originally Posted by Malacandra's Sig

A man, a plan, a canoe, pasta, heros, rajahs, a coloratura, snipe, percale, macaroni, a gag, a banana bag, a tan, a tag, a banana bag again (or a camel), a crepe, pins, a rut, a Rolo, cash, a jar, sore hats, a peon, a canal – Panama.

You, sir, either are far too clever by half or have waaaaaaaaaay too much time on your hands!

Nice sig, tho.




To the OP: Yes.

That's what you get for asking a yes/no question... 14

[CC]

Originally Posted by JustAnotherGeek

You, sir, either are far too clever by half or have waaaaaaaaaay too much time on your hands!

Nice sig, tho.

I, too, was massively amused and impressed. By the way, backward that's Able was I ere I saw Elba. 15

[Colophon]

Originally Posted by CC

I, too, was massively amused and impressed. By the way, backward that's Able was I ere I saw Elba.

...........a sig is a sig is a sig is a sig is a sig is a sig is a sig is a..........

16

[Spiff]

Doesn't shaking a bottle of hydrogen peroxide in solution speed up the process of breaking it down into water?

I think that's why bottles of hydrogen peroxide state "DO NOT SHAKE" -- that and it causes a dangerous pressure build-up, right? 17

[CC]

Yes, hydrogen peroxide is an unstable compound. Lots of things will exacerbate its breakdown, including rockin and rollin. The most stable configuration of those materials is the familiar H2O, which it will revert to at the least provocation, e.g. light, physical disturbance, or the presence of a catalyst, several of which have been mentioned above. Just pour some on a cut and watch it foam. Or mix it with some bleach. That extry oxygen atom is just hangin' on for dear life and won't stay for long. 18

[Tim@T-Bonham.net]

Originally Posted by Malacandra

Per-zakly. Ever heard of "nuking" something in a microwave? That's a sloppy usage too.

Yes, but here we are trying to "fight ignorance", so such 'sloppy' usage probably should be avoided. Especially here in GQ. 19

[JustAnotherGeek]

Originally Posted by t-bonham@scc.net

Yes, but here we are trying to "fight ignorance", so such 'sloppy' usage probably should be avoided. Especially here in GQ.

Did this usage really make any one think that their eye would be exposed to nuclear radiation or a nuclear explosion? It's a fairly common colloquialism. You might as well yell at someone for abusing shrubberies if they don't quickly and directly answer a question.

20

[NukemD]

Originally Posted by Malacandra

Per-zakly. Ever heard of "nuking" something in a microwave? That's a sloppy usage too.

Nuking is a broad term that means 'Destroy; get rid of: "I fertilized the lawn and nuked the weeds".' 21

[robert_columbia]

Originally Posted by NukemD

Nuking is a broad term that means 'Destroy; get rid of: "I fertilized the lawn and nuked the weeds".'

My sister was once nuked by a zombie. 22

[NukemD]

This topic never bothers to answer the question. The straight dope my 4$$. Riddle me this: how much time does it take 3% of food grade (that is NOT stabilized with any additives, just Distilled H2O & H2O2) H2O2 to break down? 23

[Szlater]

Originally Posted by twhitt

Just for the record, I would strongly advise no one attempt this feat. With all chemicals, household or industrial, that are not meant for human consumption, it is possible that there are additives which do NOT break down and are NOT safe to consume. I'm given to understand that this is commonly the case with lab grade ethanol, for example.

Pure H2O2 would degrade, I believe under ultraviolet light, though chemistry has been several years back, into H20 and Oxygen. The problem with drinking it arises because the peroxide is a strong oxidizing agent, and causes trouble by reacting with, and creating, those free radicals you hear about in the news. The enzyme which attempts to safely catalyze this reaction in the body is Catalase. It's very efficient; it speeds up the rate of the reaction so much that the speed is limited by the rate of diffusion of H2O2 molecules in water. That's quick.

Classic experiment in British schools in the '80s and early '90s, take a test tube full of hydrogen peroxide and add a chunk of raw calf's liver, and then do the glowing splint test on the gas produced. The experiment is then repeated after boiling the liver in water for several minutes to denature the catalase.

I think I did that experiment every year for the first three years of secondary school.

And liver remains can be placed in the class spanner's blazer pocket for shits and giggles (and much retching later in the week).... Although bull's eyeballs make for more gross out comedy fun by far. 24

[johnpost]

zombie or no

Duke are we talking in the light or not? what is the wavelength? what is the intensity? what is the opacity of the container? 25

[robert_columbia]

Originally Posted by johnpost

zombie or no

Duke are we talking in the light or not? what is the wavelength? what is the intensity? what is the opacity of the container?

I think the fundamental question is not exactly how long it would take, but whether or not what is left after sufficient time is actually, really and truly-o safe to drink, or whether or not there are sufficient lingering impurities that will forever (or at least for the rest of your life) leave the sample not safely able to be drunk until it is processed through a water treatment plant or something. 26

[Michael63129]

Originally Posted by NukemD

Nuking is a broad term that means 'Destroy; get rid of: "I fertilized the lawn and nuked the weeds".'

Just curious, what made you sign up on this board just to post that (also, odd username-post combo)? This is one thing that really gets me about zombie posts, which are almost all by people who have just signed up, and often their only post. 27

[TriPolar]

You have to watch out for additives in most commercially available peroxide. These are added to slow the natural breakdown, and in addition if not intended for consumption there may be other contaminents. But many catalysts will break down peroxide. Yeast, or any cell (I think) will contain something I can't remember that breaks it down. This is why pouring peroxide on an open would will cause foaming. The cells have to be dry, or broken I believe. 28

[Joey P]

Originally Posted by slaphead

Yes. No idea what the timeframe is, but if you toss in some catalyst (Manganese, IIRC) it happens pretty quickly.

Six and a half years later...but it's platinum (unless that's since I started using it). 29

[TriPolar]

Originally Posted by Joey P

Six and a half years later...but it's platinum (unless that's since I started using it).

There are a lot of catalysts. Silver is a good one, but expensive. 30

[Joey P]

Originally Posted by TriPolar

There are a lot of catalysts. Silver is a good one, but expensive.

I mean platinum is the one used with the contact kit. They plate the little metal disc you see in Step 1 of that link which is what was being referred to.

Rereading that post, I realize Slaphead wasn't referring to the contact kit in the first sentence. Oh well. 31

[NukemD]

Originally Posted by Michael63129

Just curious, what made you sign up on this board just to post that (also, odd username-post combo)? This is one thing that really gets me about zombie posts, which are almost all by people who have just signed up, and often their only post.

You got me I signed up to get an answer:
How long does it take 3% hydrogen peroxide to break down when exposed to twelve hours of light a day in a translucent container like a 1 gal distilled water bottle 32

[NukemD]

Originally Posted by johnpost

zombie or no

Duke are we talking in the light or not? what is the wavelength? what is the intensity? what is the opacity of the container?

Indirect light from the sun in my house, or I could put it outside I guess. Full spectrum I would guess. It doesn't stay very sunny all the time where I live. Not completely translucent, more like the opacity or semi-translucence of a milk carton. I want to inject a small amount of 35% H2O2 into a 1 gal bottle of distilled water to make it 3%, and have it break down into H2O as quickly as possible without introducing a catalyst other than light. 33

[NukemD]

Or vibration could be introduced as well, I'm just looking to sanitize the water without introducing any chemical agents other that the H2O2 which will break down to H2O.
Also, How would one test for H2O2 in the water? 34

[TriPolar]

Originally Posted by NukemD

Or vibration could be introduced as well, I'm just looking to sanitize the water without introducing any chemical agents other that the H2O2 which will break down to H2O.
Also, How would one test for H2O2 in the water?

You test using a catalyst. If will foam if there's any significant amount of peroxide left. Dried yeast would be inexpensive and easy to test with. Just put a few drops of your water on a smidgen of dried yeast. 35

[commasense]

I'm interested in an aspect of this question, because I use hydrogen peroxide to disinfect my anti-snoring mouthpiece. I put a few ounces in a small glass and drop the mouthpiece in each morning, and until reading this thread, I'd use the same few ounces for days at a time, topping it up to compensate for evaporation.

Now I'm wondering if what I have in the glass is mostly water. How can I tell? 36

[commasense]

Sorry, I didn't notice TriPolar's test idea. Theoretically, how long should it take H202 to break down in the conditions I mentioned? I.e., how often should I refresh the stuff in the glass? 37

[ChockFullOfHeadyGoodness]

For my son's birthday party we were thinking of doing the "elephant's toothpaste" science experiment, where you mix diluted H202 with yeast and watch it foam. My "it's-cool-to-blow-up-stuff" gene trumped my "be-a-responsbile-dad" gene, and I decided "forget the wimpy 3% stuff from Walgreens; let's get the heavy duty 30% stuff from the swimming pool supply store" (some people use H2O2 as an alternative to chlorine). So I prepared individual kits consisting of H2O2 in one empty water bottle and a yeast-warm water mix in another. After watching a bunch of hyperactive 10-year-old boys shoot Diet Coke & Mentos in each others faces, pummel each other with water balloons, and get silly string in all sorts of uncomfortable places, I realized the H2O2 experiment might not be a good idea. So I hid the kits and brought them home from the park unused. I left the box outside on the side of the house.

4 months later, I stumbled across the box and decided to give it a go. The premixed yeast had gone flat, but when I added a fresh packed of yeast and closed the water bottle lid (sport-top lid), I got very powerful geysers (higher than our roof, so at least 12-15 feet) of foam.

Short answer: For 30% H2O2, left in clear plastic bottles in indirect sunlight, it will take more than 4 months to become plain drinkable water. 38

[CC]

Excellent answer. Also, did you just happen to leave out, or do you not use in your recipe for "elephant's toothpaste" dishwashing detegent, or food coloring? Detergent helps keep the bubbles in tact, enabling you to stick a lighted splint in there and having it burst into a bright flame because of all the free O2. (Science classroom demo). Food coloring makes it look cool. 39

[ChockFullOfHeadyGoodness]

Originally Posted by CC

Excellent answer. Also, did you just happen to leave out, or do you not use in your recipe for "elephant's toothpaste" dishwashing detegent, or food coloring?

You're right, I forgot about the dish soap, which was added to the bottle with the peroxide. I had food coloring for the party, but didn't bother with it when I was setting them off at home. 40