In chemical adsorption (chemisorption) of inhibitor on metal surface, the amount of surface coverage and inhibitor efficiency (%IE) increased with temperature . In the same time, temperature increased the rate of reaction (corrosion rate). What is the correlation between these two effects? Is the effect of temperature on corrosion rate higher than effect on adsorption process or vise versa?
In Chemical adsorption, an association of inhibitor molecules takes place on the surface of the metal to form an activated complex rather than dissociation process which depends upon the nature of the inhibitor (some inhibitors are ready to form the complex between iron and some other metals). In addition complexation between the inhibitor molecule and the metal surface may be induced by the temperature through the transfer of electrons from the inhibitor to the metal surface to form coordinate bond/ sharing the charges between the inhibitor molecule and metal surface.
Dear Anees Abdullah Khadom
In chemical adsorption (chemisorption) on metal surface at a certain inhibitor's concentration, the amount of surface coverage and inhibitor efficiency (%IE) decreased with increasing temperature. Now, if I assumed that the inhibitor is structurally stable within the temperature range that you used in, so higher concentration become necessary at higher temperatures to maintain its efficiency at the same level. Now, if you still keeping the inhibitor's concentration at the same initial value with increasing temperature, you got dangerous case with more sever corrosion than in the complete absence of inhibitor. Therefore, in this case, the effect of temperature on corrosion rate is higher than the effect of the insufficient adsorption process .
Best regards
the higher the temperature the easier to break the monolayer protective film
- You have to compare the Activation Energy of each process. A good discussion could be found in "Don't act like a novice about reaction engineering by Jonathan Worstell. CEP (https://www.aiche.org/publications/cep) March 2001, p. 68-72.
Thank you Joao G.R. Poco , do you have a copy of Jonathan Worstell paper? I appreciate your assistance.
You could ask directly to the author: Article Don't act like a novice about reaction engineering
I hope you get.