Tracertest with uranine

[Hydroman]

Hello everbody,
to estimate hydraulic parameters of a column experiment i like to a tracer test by using uranine. Subsequently i like to model the tracer test and the colimn experiment by using phreeqc.
So my question is if there is a possibility to use uranine in phreeqc?

thank you for your advices and help

BR Hydroman

[Pak]

Yes, but you willl have to implement it on the database. Look at the first example of the Phreeqc manual.

Also, you can use several databases developed by nuclear agencies where uranium has been implemted into the database. Such thermochemie of Andra, Thereda of HZDR, PSI/Nagra Chemical Thermodynamic Database 12/07.

Good luck

[Hydroman]

Hello, thanks for your advice.

Is it necessary to implement that on database, because all elements of the conservative fluorescent tracer Uranine (C20H10N2O5) are impelemented in the phreeqc.dat. So maybe I can also use the keyword "Phases"?

Phases
Uranine #Name of Phase
C20H10Na2O5 = 20 C + 10 H+ + 2 Na+ + 5 O
log_k
delta_h

Problem now: What are the values of log_K and dehlta_h? And where get I information of the dissolution reaction?

So this is the first step formodelling my tracer test.

Maybe you can help me?

BR Hydroman

[dlparkhurst]

I do not think you want to define uranine in terms of C,N, etc. That would define it as part of the mole balances of all of these elements, and more importantly, if you do find a log K, it will show uranine to be unstable relative to CO2, CH4, NO3, and other aqueous species. Thus, it will decompose in the first reaction calculation and be essentially absent from solution.

I think you want to define Uranine as a new "element" by using SOLUTION_MASTER_SPECIES and SOLUTION_SPECIES. If Uranine is a conservative tracer, you may need only one aqueous species. If Uranine reacts in some way you may need to consider hydrolysis reactions or aqueous complexes.

If Uranine is not conservative, then you need to use KINETICS (or REACTION) to remove it from solution as a function of time or solution composition. The KINETICS formula may simply remove Uranine, but if necessary, you could remove Uranine and simultaneously introduce C20H10Na2O5 to solution to account for mole balance and redox reactions.

[Hydroman]

Thank you for your advice. You are right, it's better to define uranine as an element. I think this is the right code:

Title Tracertest
SOLUTION_MASTER_SPECIES
    Uranine       Uranine          0     C20H10Na2O5     376.2816

SOLUTION_SPECIES
Uranine = Uranine
    log_k     0

Solution 1
units mg/l
temp 25
Uranine 10


end


In the next step I model advection and transport. I will tell if i'm succesfull :)


BR Christoph