Plant absorption

[FlouretAlex]

Hello PHREEQC users,
I'm willing to model the adsorption of potassium by a plant from a solution. I want to model this absorption by using a kinetic reaction with the Michaelis-Menten approach.
And right now I don't know how to proceed, the initial idea was to create like kinetic precipitation of the K+ in solution with another species let's say called "Plant_".
From this idea I see two point that I don't like :
- First for this to precipate I need to "inject Plant_" into the solution for me it's seems a bit weird to ad other species event if it wiil just react with the K+ in soltuion, it also mean that I have to find the rigth concentration to represent the plant.
- The seond problem is that after precipitation Plant_K is still in solution and I don't like that as I want to remove them from the solution.
I know that plant absorption have already been modelized by other with PHREEQC like
"(Novack 2006) Verification and intercomparison of reactive transport codes to describe root-uptake" but I can't figure out the perfect way of modelized it for myself. If some of you have some idea or experience on this topic and share it with me that would be wonderful.

[dlparkhurst]

The question is what ion balances the removal of K+. Does the plant simultaneously uptake HCO3-? or release H+? or something else?

Once you decide on the reaction, to model the effects on solution, you can simply use KINETICS to simulate the reaction with, for example, -formula KHCO3 -1 or -formula K -1 H+1.

[FlouretAlex]

Hello,
 I didn't think about using the production of H+ by the plant during the absorption process, that a really nice idea. I'll try this and see how it's work, but I think it will change the pH of my solution too drasticly in comparison of what I have in my experiement.
Thank you for your help.

[MichaelZ20]

Typical organic acids found in root exudates are malic, malonic, acetic, citric, fumaric, succinic, lactic, tartaric, oxalic, and others. All are weak acids.