Let us take the example of Zn with Fe3+ reaction. Zn wants to oxidize and Fe3+ wants to reduce to Fe2+ with that electron. Now assume there is no cell.
1) If i simply add Fe3+ solution to Zn pellets how would the reaction proceed?
2) Do I still need to consider the Nernst Plank eqn for transport of ions in this case since there is no external voltage applied?
3) What are the constitutive equations that I need to look at trying to model this cell?
What exactly are you trying to model?
If you want to ignore mixing - i.e., assume that instantenious mixing creates uniform mixture BEFORE the chemical process starts - then it is a balance of bimolecular reaction of oxidation vs monomolecular of complex decay.
If you want to add mixing, you have to add the mechanical mixing and diffusion , to measure dell dynamics of mixture creation that overlap chemical processes.
Hi Andrei K Dioumaev,
Thank you for your answer. The system I want to model is the reaction of Fe(CN)6 3+/4+ species with Zn/ZnO 0/2+ species. The Zn are in the form of particles that are encapsulated in a form of alginate bead structure. The Fe species will react by losing/gaining electron on the surface of the bead and the ions travel through the bead to the inside of bead where Zn particles are randomly distributed. Now how would the kinetics look like?
Hi, K. Anish Kumar,
You have outlined your ultimate GOAL, but now you need to consider WHAT you want to include in and what to exclude from your analysis. I do not think anyone beside you (or your colleagues) can make these decisions, since this should be based on fine specifics of your project.
Only once these decisions are made, you could proceed to the planning of HOW you are to model this.
Thus, in which stage of your planning are you currently?
Good luck
Hi Andrei K Dioumaev,
Thank you for your reply. Yes, you are tight in the sense that I have outlined the ultimate goal of my project. I am a PhD student who started 4 months back so I am still doing literature review so forgive my poor phrasing of the question without any context.
Right now I am trying to model the system as a volume averaged model which is macro-homogeneous with respect to Zn particles and the alginate throughout the bead. The relevant equations would be mass conservation in spherical coordinates with the flux having diffusion and electro-migration terms. Electronic (solid current) and ionic (electrolyte in the bead) currents will be equal and opposite. and the reaction term will depend on butler-volmer kinetics which depends on electrostatic potential in solid and liquid phase. thus i will solve for the concentration of species, solid potential and electrolyte potential at every discretized point in r domain thorough time.
Does this idea make sense?
Could you please provide some direction in terms of videos or books where I can learn about writing these conservation equations correctly for electrochemical systems in a volume-averaged way? So I want to learn to set up the equations necessary to solve these electrochemical systems correctly.
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