Another radical question: oxidation limited by radicals

  • Thread starter rwooduk
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I am seeing from my results that an oxidation process is taking place, the pollutants degradation correlates closely with the formation of radicals.

However, in one case there are less radicals produced and there is no degradation....

Picture1.png


I would like to ask if on occasions there must be a certain number of radicals to attack the pollutant? Or it is likely due to the change in conditions?

Thanks again for any help / ideas on this (!)
 

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  • #2
jim mcnamara
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First off, pollutants can be defined as a resource out of place. Some definitions place them as waste products.

So. Pollutants can be any one or more of a vast array of molecules and mixtures. Many of which are resistant to chemical attack. Radicals are likewise inordinately diverse. Can you please be more specific?

As stated, I do not see how anyone can answer.
 
  • #3
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First off, pollutants can be defined as a resource out of place. Some definitions place them as waste products.

So. Pollutants can be any one or more of a vast array of molecules and mixtures. Many of which are resistant to chemical attack. Radicals are likewise inordinately diverse. Can you please be more specific?

As stated, I do not see how anyone can answer.
Hmm, apologies if I was unclear. I'll use an analogy, which could potentially make things even more convoluted but here goes...

Imagine a small child was attacking a large group of men who are held in some type of defensive formation. 1 child would not cause any effect, nor would 2 children. However 100 children attacking the group of men would cause them to start to break apart, and once they start to break apart a further increase in children attacking them would cause them to break apart much more readily as the initial 'threshold' to breakage has been broken.

Is there a similar effect for radicals whereby a certain number are initially required to break apart the pollutant, and once that initial breakdown has occurred degradation occurs much more quickly with increase in the number of radicals (see graph in OP).

I noticed the reverse effect while trying to degrade phenol, if the concentration was too high no degradation occurred, at lower concentrations I was able to see some degradation. It's although the radicals weren't able to break the phenol unless the concentration was reduced significantly.

But yes, re-reading the question none of this makes sense really, apologies (!).
 
  • #4
jim mcnamara
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What you are asking 'Is there a model that portrays a minimum threshold concentration of one reagent before any reaction at all begins?'

Maybe @TeethWhitener or @Borek can help
 
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  • #5
HAYAO
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Well if you are taking about "ifs" then it is always "possible", but we always have to look at specific situation because chemical reactions of pollutants, which may contain variety of molecules, is not very simple...not to mention we are provided with no information on what oxidants were used.

Basically, the OP is lacking information for us to help you.
 
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  • #6
TeethWhitener
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Basically, the OP is lacking information for us to help you.
Yes. To start with, the y axis isn't even labeled in OP. Also, no mention is made of the length of time for which these reactions were run. People can run across hot coals without getting burned, but you'd better believe they would get burned if they simply stood there.
 
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