Hydrogen peroxide solution

[Tom]

Possibly a basic question, but does anyone have any thoughts on the coding for simulation of a 10 ml of 30% H2O2 (equates to 10.01 M) solution?

I assume using H(0) and O(0) under SOLUTION is inappropriate since this models gas phases.


The solution will be used to react with an equilibrium phase.

Any thoughts appreciated, couldn't find anything on the Q+A thread so thought this might be helpful to others.

[dlparkhurst]

H2O2 will not appear in a solution because usually, H2O2(aq) is not present in the databases, but also because it is thermodynamically unstable relative to O2(aq).

You can model the effect of a H2O2 solution, but using an equivalent amount of O2(aq). You can make a solution by using REACTION to add the H2O2 to a pure water solution, or you can simply define the appropriate amount of O2(aq) (1/2 the molality of H2O2).

[Tom]

Thanks David, that's a useful tip.

I had issues reaching convergence using the REACTION approach, but defining O2(aq) in solution seems to have done the trick.

Would you agree with the following formulation?

20 ml of water and 10 ml of 10 M H2O2 combined:

SOLUTION 1
temp 90
O(0) 3337 #default mmol/kgw, effectively three-fold dilution
-water 0.03

Which gives 1.669 mol/kgw O2
(0.05 mol O2 in the 30 g solution, i.e. half the molality of H2O2 as suggested)

Thanks

[dlparkhurst]

Looks OK to me. Here is the reaction approach. Molality is a bit different because of the H2O that is created by the reaction.

SOLUTION
REACTION
   H2O2  0.3333
   1 mol
END

[Tom]

Thanks David, very helpful.

[AntonioG]

#Hello,
# My approach is probably a bit naive but I'm trying to simulate addition of hydrogen peroxide into a surface water solution containing dissolved U(VI) to precipitate uranyl peroxide. I've been doing preliminary tests by only incrementally adding H2O2 to evaluate the potential impact on saturation indices of other uranium phases. Saturation indices don't change much but dissolved concentrations of U(VI) and U(V) have decreased.
# I have only used the reaction block to add H2O2 so where is uranium going? Any ideas? Thanks.

#DATABASE LLNL.dat
DATABASE sit.dat

SOLUTION_SPREAD
      -temp   25 #31.7
      -units    mg/l
pH   C(4)   Al   As   B   Ba   Be   Bi   Br   Ca   Cd   Cl   Co   Cr   Cs   Cu   F   Fe   Hg   K   Li   Mg   Mn   Mo   N(5)   Na   Ni   Pb   Rb   S(6)   Sb   Se   Si   Sn   Ta   Te   Th   Tl   U   V   W   Zn
8.23   349.13  as HCO3   6.553E-01   1.300E-02   5.242E-01   1.521E-01   0.000E+00   0.000E+00   5.880E-01   3.195E+01   9.510E-06   2.070E+02   1.608E-05   2.650E-03   0.000E+00   2.070E-03   0.000E+00   2.189E-03   0.000E+00   1.149E+01   2.115E-02   4.558E+01   2.109E-03   5.227E-03   7.322E+00   1.639E+02   2.273E-04   4.161E-05   0.000E+00   4.602E+01   1.119E-05   2.921E-03   8.935E+01   3.497E-06   0.000E+00   0.000E+00   0.000E+00   3.497E-07   2.958E-02   2.865E-02   0.000E+00   1.710E-02
END

REACTION 1
   H2O2  1
   0.001 0.01 0.1 1 10 100 mol
END

# Solution 2
# -temp   25 #31.7
# -units    mol/kgw
# O(0)   100
# water 1
# END

SELECTED_OUTPUT
    -file                output_temp.xls
    -reset               true
    -solution       true
   
USER_PUNCH 1
   -headings    pH C(4)  U
   -start
           1 PUNCH -LA("H+")
      2 PUNCH TOT("C(4)")*100*1000    
      72 PUNCH TOT("U")*238*1000      
   
USE SOLUTION 1
USE REACTION 1
SAVE SOLUTION 111
END