[Vancouver2010]

Hello,

I was reading up on adsorption from my undergrad physical chemistry course and came across a few [modified] Langmuir isotherms which could relevant to my masters research.

I cannot seem to develop a proper kinetic derivation for the following surface reactions of some molecule A and some surface S:

A + S <--> B-S (reversible) (forward reaction rate: k(1), reverse reaction rate: k(-1))
B-S --> C+S (conformational change; irreversible; molecule C is alwayson surface; does not desorb)

The transient data which we were given was theta (surface coverage; note: thetaB+thetaC=theta i.e. surface coverage of B + surface coverage of C = total surface coverage) versus reaction coordinate (time) for several points. Plotting this shows a common type I isotherm curve with 0 < t < 800s at which point the reaction is pretty much in equilibrium.

I developed the following equation through adsorption kinetics:
where N = total number of adsorption sites available
dtheta/dt = k(1)*N*(1-theta)*[A,sol'n]-k(-1)*theta1

Let me know how you suggest proceeding from here to model the data and solve for the EQ constants... My textbook as no solution manual.