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 thecannuck
Big daddylumberjack
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 H2o2 breakdown 
#1199845 - 01/08/03 08:32 AM (14 years, 6 months ago) |
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Anyone have a ball park estimate of the rate that light breaks down h2o2?
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debianlinux
Myconerd - DBK
 
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that would be greatly dependent on temperature and other air factors (like the amount of other gases in the air, tho for this question, "normal" air would be a practical constant). other than that curve ball I have no idea :P
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 daussaulit
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This is what I found out using google, perhaps you should try it.
"The primary factors contributing to H2O2 decomposition include: increasing temperature (2.2 factor increase for each 10 deg-C); increasing pH (especially at pH > 6-8); increasing contamination (especially transition metals such as copper, manganese or iron); and to a lesser degree, exposure to ultraviolet light. In most cases, pH and contamination work in tandem as the dominant factors.
Concentrations > 8% H2O2 (by weight) are classified Oxidizers."
It appears that decompisition is very fast if there is high temperature, a catalyst, and light.
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debianlinux
Myconerd - DBK
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so a really low pH is ok?
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daussaulit
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Quote:
so a really low pH is ok?
Uhm, ok for what?
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comario2
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so, when making peroxidated agar, one should let the agar cool as much as possible before mixing in the c2o2?
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comario
"crusaders against emotional poverty"
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Seuss
Error: divide byzero
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Re: H2o2 breakdown [Re: comario2]
#1200426 - 01/08/03 12:03 PM (14 years, 6 months ago) |
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Quote:
so, when making peroxidated agar, one should let the agar cool as much as possible before mixing in the c2o2?
I assume you mean h2o2... if so, then yes... but don't wait until it starts to solidify or you will not get an even mix.
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Just another spore in the wind.
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debianlinux
Myconerd - DBK
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ok for nothing  basically I was just wondering that since a high pH acts as a ctalyst then what would an acidic pH do? would it have no effect or also act as a catalyst or what? not expecting you to know the answer or anything.
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daussaulit
Forgetful
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I have no idea. I just pulled that information from a website I found on google. Why would you want to lower pH to prevent H2O2 from breaking down? Just go to the store and pick up another bottle for 49 cents.
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debianlinux
Myconerd - DBK
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that was my point. it was a useless question. just thought that if high pH caused breakdown then what would low pH do. I knew you were just copying search info, and didn't expect anyone to know the answer. just a little musing. I'm glad h202 is so cheap.
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H2O2shrooms
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H2O2 is an acid.
Acids have a low ph (parts hydrogen), while bases have high ph.
Acids nuetralize bases, so having a high ph means it is a base and will breakdown the acid (Peroxide). When you add Peroxide to an agar solution you are lowering the overall ph of the system. Most mushrooms don't like a ph lower than 6.4 (or so I've read) so lowering the ph too much will only hurt the mycelium/spores.
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Mycology is a lot like quantum mechanics in that we don?t have causal relationships like in Newtonian physics, only probabilities of various outcomes.<=== Misapropriated from Mycofile
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Anno
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>Acids have a low ph (parts hydrogen),
ph doesn?t mean "parts hydrogen" though.
Read those links to find out what?s it all about:
http://www.nanfa.org/archive/nanfa01/nanfadec01/0049.html
http://mathforum.org/library/drmath/view/56363.html
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comario2
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Re: H2o2 breakdown [Re: Anno]
#1203005 - 01/09/03 06:05 AM (14 years, 6 months ago) |
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Quote:
>ph doesn?t mean "parts hydrogen" though.
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comario
"crusaders against emotional poverty"
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comario2
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Re: H2o2 breakdown [Re: Seuss]
#1203009 - 01/09/03 06:07 AM (14 years, 6 months ago) |
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thank you, seuss, gotcha (yes i was meaning h2o2) :
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comario
"crusaders against emotional poverty"
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debianlinux
Myconerd - DBK
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Quote:
H2O2 is an acid.
Acids have a low ph (parts hydrogen), while bases have high ph.
Acids nuetralize bases, so having a high ph means it is a base and will breakdown the acid (Peroxide). When you add Peroxide to an agar solution you are lowering the overall ph of the system. Most mushrooms don't like a ph lower than 6.4 (or so I've read) so lowering the ph too much will only hurt the mycelium/spores.
i understand that but it's not a strong acid (ala hcl, h2s04), I'm curious what happens to the h202 molecule in the presence of a STRONG acid.
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H2O2shrooms
Couch Potato
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Anno I bow to your superior knowledge.
As for what H2O2 does in a strong acid I don't know, but it doesn't really matter for cultivation seeing as how you wouldn't want to soak your jars in H2SO4, OR HCL.
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Mycology is a lot like quantum mechanics in that we don?t have causal relationships like in Newtonian physics, only probabilities of various outcomes.<=== Misapropriated from Mycofile
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debianlinux
Myconerd - DBK
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sorry, i got off topic there, i was not in any way interested in lowering the pH of h202 for any cultivation purposes (hence, OT) and am smart enough to know that would be stupid. i was merely asking the question out of curiosity. while anno's knowledge is indeed great, I would not consider the particular information offered here to be superior in any way, anyone who has graduated HS should know this.
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jelsert
Jelsert
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Where the hell is mycofile on this thread?
He is just about the most knowledgable person when it comes to h2o2, myco where you at!
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Fungusmaximus
Stranger
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I believe that H2o2 begins decomposition @ aproximately 140 degrees F. I add to agar @ about 130 - 120. Peroxide is merely water with an extra oxygen molecule. When h202 comes in contact w/ bacteria, spores etc. the extra oxygen molecule breaks away or ruptures killing the bacteria. Under normal circumstances, h202 holds its extra oxygen molecule up to three days even when diluted in water.
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