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COVID-19 Emergency - Using UV Lamps to sanitize Face Masks overnight

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SiliconWizard:
The poor guy may still have to get out once in a while...

I think you can make your own mixture with water and IPA to get about 70% alcohol mix, then add some liquid soap (very little so it doesn't make foam) to the mixture to make it more gel-like. Glycerin would be better though if you have any available.

But quoting Wikipedia:

--- Quote ---The World Health Organization has published a guide to producing large quantities of hand sanitizer from chemicals available in developing countries, where commercial hand sanitizer may not be available. According to this guide, to produce 10 liters of hand sanitizer, the following are mixed together, and topped up with distilled or cold boiled water to 10 liters:

    8333 ml of 96% ethanol, 417 ml of 3% hydrogen peroxide, and 145 ml of 98% glycerol, or:
    7515 ml of 99.8% isopropyl alcohol, 417 ml of 3% hydrogen peroxide, and 145 ml of 98% glycerol.[2]

--- End quote ---

Martinn:
COVID-19 has a lipid coat which is easy to destroy with alcohol, so a > 62% (IIRC) alcohol solution would do, up to 99% ethanol or isopropyl alcohol.
However, killing bacteria requires a certain water content. Best stick to the 75% water content as in the WHO recipe.

https://en.wikipedia.org/wiki/Hand_sanitizer

not1xor1:

--- Quote from: najrao on March 20, 2020, 12:23:15 pm ---I am an old man stuck at home with only the woman I married 50 years ago. Neither of us is infected, so far as we know. I live in Bangalore, India, which has very low incidence of the virus infection just yet.
Hand sanitizers are in short supply. But I have a large hoard of isopropyl alcohol, 99+% strength which I use to clean pcb's and assemblies. Would it work as well as ethyl?
Let me have a quick reply please, thank you.

--- End quote ---

it has been showed that isopropyl alcohol (ethanol too) does kill the viruses within 30 seconds, but somebody else suggested just wash you hands accurately with hot water and soap as that is as effective as alcohol and leave the alcohol for objects you can't clean with water

jfiresto:
Doctors scramble for best practices on reusing medical masks during shortage: "Referring to a paper published in the journal Annals of Occupational Hygiene in 2009, among others, the researchers compared and contrasted ... different methods for sterilizing N95 masks, many of which were ineffective."

Two were, however: "70 C / 158 F heating in a kitchen-type of oven for 30 min, or hot water vapor from boiling water for 10 min...."

profdc9:
Alcohol unfortunately can not be used to disinfect masks.  It destroys a charged layer in the N95 masks that attracts virus particles.  I wrote up a proposal for building a UV sterilizer for mask a couple days ago.  Anyone who is interested please E-mail me:

https://drive.google.com/open?id=1wF4yYgSE1n0Jqewb8JdwosTRhx0X89wF

This is a Google Drive link.

It is a difficult problem because UV can also potentially destroy the elastomers in the mask so that the mask no longer fits well on the wearer.   There is also cumulative damage to the filtration capability.  But it presently seems the most promising approach.   A paper in 2015 studied this:

W.G. Lindsley, S. B. Martin Jr., R. E. Thewlis, K. Sarkisian, J. O. Nwoko, K. R. Mead, and J. D. Noti,  “Effects of Ultraviolet Germicidal Irradiation (UVGI) on N95 Respirator Filtration Performance and Structural Integrity,” Journal of Occupational and Environmental Hygiene, v 12., pp. 509-517 (2015).
https://www.researchgate.net/publication/274090116_Effects_of_Ultraviolet_Germicidal_Irradiation_UVGI_on_N95_Respirator_Filtration_Performance_and_Structural_Integrity

There's a crowdsourced actively maintained document of resources at http://ppereuse.com/ .

Best,

Dan

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