Trying to model a membrande

[R.Schmidt]

Hi there,

I was wondering if it is possible to model a membrane at PhreeqC?

My current idea would be that, for example, for an F reduction, a REACTION with -0.98*TOT("F") is specified. However, the calculation with BASIC does not work in REACTION. Is there a trick to imitate this? I haven't found any yet so I thought I'd ask here.

Maybe someone already had this problem or has a direct solution for it. I would be very happy about solutions, ideas or suggestions. Thanks in advance! :)

Best regards,
Robert

[dlparkhurst]

With REACTION, you must define absolute moles that are removed; there is no way to remove say 50 percent of the amount present. You could use KINETICS to simulate a first-order reaction of the removal of fluoride over a period of time.

However, you need to be be careful. You do not want to remove only F, which would represent elemental fluorine. It would simulate reducing and basic conditions as follows:

H2O + F- = F + 0.5H2(aq) + OH-

You could remove HF if you are losing HF(g) from solution, or you could remove CaF2 if you are precipitating fluorite, but you probably do not want to remove only F.