Mechanism of Action of Bleach

[hpfanatic]

I have looked through some resources to find out what is the mechanism of action of bleach as a disinfectant, but have been unable to find it. Could someone please point out a good place to find this information/ or tell me more about it?

Thanks,

Nonie

[JanelleSchlossberger]

Hi Nonie,

This topic sounds like it can be a very interesting one to learn about.
When I did a bit of searching on the topic I seem to come across the common phrase of "Antimicrobial Pesticide" when describing the classification of bleach as a disinfectanct. I've provided a couple of interesting links to some articles that talk about the usage of sodium hypochlorite as a disinfectant for a number of kinds of bacteria.

Have a look at these web pages and perhaps it will lead you on to refining your searches to discover what the exact mechanism is.

Hope this helps.

Good Luck with your investigation.

Regards,
Janelle

http://www.ehso.com/bleach.htm

http://www.epa.gov/oppad001/ad_info.htm

http://www.hawaii.edu/ehso/bio/Hypochlorite.pdf

http://www.epa.gov/pesticides/factsheet ... tsheet.htm

http://www.waterandhealth.org/newslette ... leach.html

[donnahardy2]

Hi Nonie,

Janelle has given you some very useful information that should help you get started on your topic, and I would like to add just one more suggestion. To understand how bleach kills microorganisms, you need to learn about the chemistry of bleach. Hopefully you have had some chemistry, so you can include the chemical equations for bleach in your science project to help explain how it works. Here is a website that includes the chemistry of bleach, or sodium hypochlorite. Sodium hypochlorite reacts with water to produce hypochlorous acid and sodium hydroxide. The hypochlorous acid is an oxidizing agent that breaks double bonds and converts them to single bonds, and this damages microorganisms. The sodium hydroxide has a high pH, which is also toxic to microorganisms. The combination of oxidizing agent and high pH makes sodium hypochlorite a very effective antimicrobial agent.

http://www.americanchemistry.com/s_chlo ... TYPEID=113

I hope this helps.

Donna Hardy

[hpfanatic]

Thank you both!

I am still looking for more information, but you have given me a good start.
Since the hypochlorous acid that is produced is what actually kills the microbes, I will have to look more into that part of it.

It would be great if anyone else could provide me with more information too!

Thanks again,

Nonie

[deleted-71447]

Hi Nonie,
It is not necessarily the hypochlorous acid that kills the microbes. Different types of microbes have different types of resistance to chemical and physical damage, and as Donna Hardy mentioned, it is the combination of high pH and concentrated oxidizing agent that makes bleach effective against many microbes. So, I recommend that you continue to seek information on sodium hydroxide as well as hypochlorous acid.
Good luck!
Chris