How many ppm of O2 does H2O2 add to water?

  • Thread starter Thread starter bland
  • Start date Start date
  • Tags Tags
    Water
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
Sign up Log in
5 replies · 4K views
bland
Messages
150
Reaction score
44
TL;DR
Trying to work out how to raise the oxygen ppm of a litre of water by a measure quantity using hydrogen peroxide.
I'm starting with a litre of distilled water with a dissolved oxygen content of zero ppm, and I wish to raise the ppm of the dissolved O2 to 10ppm or 10mg/L using a 6% solution of H2O2. That is 10 extra molecules of oxygen in a litre!

I've had no luck looking for through web based conversion calculators and other technical papers. So I am reaching out here hoping that someone can explain the correct way to calculate this.

thanks in advance.
 
Chemistry news on Phys.org

Discussion

bland said:
That is 10 extra molecules of oxygen in a litre!
No, 10 ppm doesn't mean 10 molecules.

Technically adding hydrogen peroxide you don't add oxygen, oxygen will be produced when the hydrogen peroxide decomposes - which takes time. Kinetics of the process will be a nightmare to describe, as it depends on other dissolved substances catalyzing the reaction.

What you can do is to calculate amount of oxygen that will be produced from the introduced hydrogen peroxide (rather simple stoichiometry), that will help you estimate maximum possible concentration of oxygen after the decomposition (with assumption none of the produced oxygen runs out).
 
I wanted to work this out just for fun as I am not a real chemist. Molar Mass of hydrogen peroxide is 34, and of oxygen 32. The reaction is 2 H2O2 gives O2. So 68g of hydrogen peroxide give 32g of oxygen, a yield of 32/68 x100=47%.
To provide 10ppm in 1 litre of water will require 1000 x 10^-5 = 10^-2 g of oxygen. This will require (10^-2) x 100/47 = 0.02 g of hydrogen peroxide. Using a 6% solution will require 0.02 x 100 / 6 = 0.33g of hydrogen peroxide.
As this is a very small amount to measure, maybe dilute the hydrogen peroxide a further ten times before measuring the dose.
 
Reply
  • Like
Likes   Reactions: bland and BillTre
tech99 said:
This will require (10^-2) x 100/47 = 0.02 g of hydrogen peroxide.
OK
tech99 said:
Using a 6% solution will require 0.02 x 100 / 6 = 0.33g of hydrogen peroxide.
Of the hydrogen peroxide solution, to be precise :smile:
 
tech99 said:
I wanted to work this out just for fun as I am not a real chemist. Molar Mass of hydrogen peroxide is 34, and of oxygen 32. The reaction is 2 H2O2 gives O2. So 68g of hydrogen peroxide give 32g of oxygen, a yield of 32/68 x100=47%.
To provide 10ppm in 1 litre of water will require 1000 x 10^-5 = 10^-2 g of oxygen. This will require (10^-2) x 100/47 = 0.02 g of hydrogen peroxide. Using a 6% solution will require 0.02 x 100 / 6 = 0.33g of hydrogen peroxide.
As this is a very small amount to measure, maybe dilute the hydrogen peroxide a further ten times before measuring the dose.

Okie dokie that is some decent ball park figures to work with, it is indeed a small quantity. thanks.
 
If your water is open to the atmosphere, then a small amount of air (mostly nitrogen, but about 19% oxygen) will dissolve in the water. To remove it, you will need to boil the water. That also makes it sterile (until the air re-dissolves into the liquid). For fun, buy Clean&Clear or Oxysept used for dis-infecting contact lenses. C&C uses a platinum disc (catalyst) to decompose the H2O2 to water. Oxysept uses catalase, an enzyme, with a pink indicator to decompose the H2O2 to water. You can see the Oxygen bubbling out almost immediately. Process to convert all H2O2 to plain water requires 6 hours. I am a chemist and a contact lens wearer.