Adding nex exchange speciese during transport simulation

[FlouretAlex]

Hello dear PHREEQC users

I would like to know if there is a way of adding some exchange species during transport simulation. I would like to add these species at a certain time of the transport so it should base on the function of time or number of shifts. Maybe with user punch and a bit of basic?
 If someone had some idea just let me know =).

[dlparkhurst]

No, I don't think there is any way to add an EXCHANGE_SPECIES or change a log K in the middle of a TRANSPORT simulation. You might be able to do it with KINETICS, but it may require making the entire exchange definition kinetic. I wouldn't try.

The answer is to split the TRANSPORT simulation. Run one TRANSPORT for a specified time, add a new EXCHANGE_SPECIES definition, and then run a second TRANSPORT for the remaining period. I think the new exchange species should appear  in the exchanger composition after the first shift of the second TRANSPORT. If nothing changes in the TRANSPORT definitions, you need only define the number of shifts in the second TRANSPORT definition, all other parameters (number of cells, cell lengths, dispersivity, etc) will remain the same.

[FlouretAlex]

So if I understand correctly the script should look like this

TRANSPORT
parameters for transport definition
END

EXCHANGE n
Hso_w XXX

TRANSPORT
parameters for transport definition
END

I was also thinking about doing it this way. I'll try and see, thank you for your help.

[dlparkhurst]

I thought you simply wanted to add an additional exchange species.

Code: [Select]

EXCHANGE_SPECIES
NaY
CaY2
END
EXCHANGE 1-10
Y 1
-eq 1
END
TRANSPORT
END
EXCHANGE_SPECIES
CsY
END
TRANSPORT

What you have will introduce an exchanger in cell n. (Your exchanger Hso_w looks more like a surface?) You should be careful about the initial exchange composition for the exchanger in the EXCHANGE definition. Are the exchange sites filled with a given composition (NaX)? or are they initially in equilibrium with a given solution composition (-eq 1)?

[FlouretAlex]

That's true you are right I should define my initial exchange composition. And I will do so.
Thank you!
Have a nice day!