Why does diluted bleach fail to remove bat poop stains?

  • Thread starter Thread starter Hornbein
  • Start date Start date
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
Sign up Log in
3 replies · 2K views
Hornbein
Gold Member
Messages
4,142
Reaction score
3,305
A tall tree looms over my property. Bats eat its fruit then dump their purple poop on my sidewalk. Bleach removes the stains in seconds. But dilute the bleach by a factor of five and nothing happens. I thought it would take five times longer to have the same effect. Nope, nothing doing. Can anyone suggest an experiment that might explain this?
 

Discussion

Chemistry news on Phys.org
Hornbein said:
A tall tree looms over my property. Bats eat its fruit then dump their purple poop on my sidewalk. Bleach removes the stains in seconds. But dilute the bleach by a factor of five and nothing happens. I thought it would take five times longer to have the same effect. Nope, nothing doing. Can anyone suggest an experiment that might explain this?
Bleach interacts with the chromophore, the coloured part of the molecule, in your case fruit juice/ cells.

Diluting it down just has less effect, less molecules are effected to the point where you cannot notice it.

You would need to take concentrations of bleach using the same concentration of bat faeces to assess it.

What species of fruit bat is it?

Animal faeces can make good compost but I would be wary with bats because of possibility of diseases

https://www.crittercontrol.com/wildlife/bats/bat-guano

EDIT. Info on UK bats and disease but globally a different matter

https://www.bats.org.uk/about-bats/bats-and-disease
 
There could be some pH effect happening.
Bleach has a pH dependancy, it more reactive below 6.8.
At alkaline pH values of about 8.5 or higher, more than 90 percent of the bleach is in the form of the chlorite ion (OCl-), which is relatively ineffective antimicrobially. At acidic pH values of about 6.8 or lower, more than 80 percent of the bleach is in the form of hypochlorite (HOCl).
Bleach is typically around pH 11.

The particular proportions of bat poop and bleach could result in different pH solutions that could affect its ability to clean (based on bleach's oxidizing ability).

On the other hand, some of bleach's cleaning ability is just due to its high pH.