Simulation of hydrogen dissolution in pure water

[Elza MA]

Hello everyone,

I am a student and I am working on hydrogen.

I would like to test a hydrogen sensor by adding H2(g) in a pure water. The point is to find out if the sensor work by comparing with a lab test.
I am trying to do numerous simulation of the dissolution of H2 in PHREEQC but i am struggling to find a accurate answer.

I have 0.3 Liters of H2 in a IsoTube Gas Sampling, 1 liter of Pure Water (at 24 degrees). The gas is going to bubble in the pure water at a pressure of 0.1 bar during 1 hour.
In the lab test, I have a curve describing the dissolution of H2 as a function of time. the reaction stabilised at 0.2 mg/l.

Is it possible to simulate the reaction with PHREEQC step by step ? Please

Thank you in advance for any help.

[dlparkhurst]

Here is a start. The following script adds hydrogen to solution until a partial pressure of 0.1 atm (slightly different than bar) is reached. FYI, I have added the definition of the Henry's law constant and the Peng-Robinson parameters from phreeqc.dat (PHASES). These parameters define the solubility.

The script is not really a kinetic simulation. For that you would need KINETICS and RATES, where RATES defines the rate expression for dissolution of H2(g) in your system.

Code: [Select]

PHASES
H2(g)
H2 = H2
-log_k    -3.1050
-delta_h -4.184  kJ
-analytic   -9.3114    4.6473e-3   -49.335    1.4341    1.2815e5
-T_c  33.2; -P_c   12.80; -Omega -0.225

SOLUTION 1
-temp 24
EQUILIBRIUM_PHASES
H2(g) -1 0
REACTION
H2 1
100 umol in 10
USER_GRAPH 1
    -headings               Rxn H2
    -axis_titles            "H2 added, moles" "H2, mg/L" ""
  -start
10 graph_x RXN
20 graph_y MOL("H2")*GFW("H2")*1000
  -end
END


[Elza MA]

Hello,

Thank you so much for your help.
 
Have a nice day
Sincerely
Elza