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NOTE: Please do not delete this question. It is not a personal health question. The question has broad utility, in cases where others find themselves in social-distancing or quarantine with need for surface sanitizer, and their only available ingredients are water and powdered oxy-bleach.

I need a quantity of surface sanitizer to decontaminate boxes delivered to the house during the Coronavirus19 social-distancing period.

CDC and WHO say 0.5% hydrogen peroxide solution will destroy coronavirus19. And powdered oxy-bleach a.k.a. Sodium percarbonate contains 32.5% by weight of hydrogen peroxide, I'll call it roughly a third.

So to make a water solution of hydrogen peroxide using powdered oxy-bleach, I'm thinking I need to add enough powdered oxy-bleach (by weight) to equal 3 x 0.5% of the weight of the water. I.e, for a gallon of solution, 1.5% of 8.3 pounds, thus 0.12 lb, or ~2 oz.

A friend checked this and agreed, saying: "A 0.5% H2O2 solution in water will consist of (per gallon): 0.42 lbs of H2O2 and 7.9 lbs of H2O. To get 0.42 lbs of H2O2 out of Oxy-bleach (32.5% H2O2), divide 0.42 by 0.325, which = 0.128 lbs or 2.0529230769 ounces...😁"

Can anyone poke holes in our thinking? Or refine it? Or suggest ways to make it easier for the lay-person locked-in without access to other surface sanitizers?

Thank you in advance!

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    $\begingroup$ Tell them to wash their hands after handling the boxes for heavens sake. There is no way of telling if this disinfecting scheme of yours will work, but rubbing your hands for thirty seconds with soap is definitely effective. $\endgroup$ – Karl Mar 17 at 6:55
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    $\begingroup$ I voted to close this medical que4stion. We are not qualified to give medical advice. $\endgroup$ – MaxW Mar 17 at 7:54
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    $\begingroup$ Your first paragraph says ."It is not a personal health question" and then you say it is a personal health question, using different words. $\endgroup$ – user253751 Mar 17 at 11:26
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    $\begingroup$ "Personal medical questions are off-topic on Chemistry. We can not safely answer questions for your specific situation and you should always consult a doctor for medical advice." is a general criterion on ChemSE. About Covid-19, in particular, the site refrains from medical advice other than proper hygiene (e.g., efficient hand washing), too (chemistry.meta.stackexchange.com/questions/4668/…). $\endgroup$ – Buttonwood Mar 17 at 12:59
  • $\begingroup$ You math looks fine but be careful if you intend to scale up this (use proper protective clothes and ventilation). see also: chemistry.meta.stackexchange.com/questions/4668/… $\endgroup$ – Buck Thorn Mar 17 at 15:26
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Yes, do use household dilute H2O2 but, in general, do not use commercial percarbonates powders as they can contain an additive to convert the friendly percarbonate into more powerful Peracetic acid (PAA). The latter allows the otherwise weak bleaching power of the H2O2 to compete with chlorine-based bleaching. However, this comes at a price (safety). Hence, the dire warning labels, usually in at least two languages, on Oxi-Bleach and generic related products.

I quote myself on this subject:

Sodium percarbonate is chemically just an addition compound of Na2CO3 and Hydrogen peroxide.

Also, while Sodium carbonate and Sodium percarbonate (basically Na2CO3 and 3Na2CO3.2H2O2) are often listed as the main ingredients in typical chlorine free bleach, an additive, TAED, which acts as a key activator (see, for example) is not even listed on the label. TetraAcetylEthyleneDiamine is apparently commonly employed as a bleach activator in many laundry products (see this). TAED reacts with H2O2 in alkaline conditions (referred to as perhydrolysis) creating, in part, Peracetic Acid. The latter PAA is actually preferred over sluggish H2O2 for bleaching. In other words, it is not the H2O2 as the active bleaching agent, but PAA created in situ. So, other than possibly misleading implying that eco friendly hydrogen peroxide is the active agent, it is, in reality, PAA, a probematic compound with associated health concerns (see Marquand, E. C.; et al. , 2007. "Asthma Caused by Peracetic Acid-Hydrogen Peroxide Mixture". J. Occup. Health. 49 (2): 155–158.). Here is a MSDS on an actual PAA mix ( 76-61% water, PAA 20-35%, 3% Acetic acid and 1% H2O2) available at which is far from friendly but does eventually totally decompose into harmless O2, CO2, H2O,...

As such anyone using a commercial percarbonate product should at least be aware of safety issues and that one is likely employing a Peracetic acid mix.

However, such more powerful PAA based mixtures do have their use and is recommended by the U.S. Military as a chemical/biological warfare decontamination protocol (see "Development of Bicarbonate-Activated Peroxide as a Chemical and Biological Warfare Agent Decontaminant"). So, it is up to the user to weigh the relative risks of the situation.

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