PCE degradation and transport

[phuongthanh.hd.1993]

Hello,

I am a beginner PHREEQC user.
I wrote code for PCE degradation and transport following some references.
However, this code is wrong. I don't know where is wrong, chemical reaction part or transport part?

Could you please give me some suggestions.
Thank you

Melinda.




TITLE PCE->TCE->DCE->VC->Ethene

SOLUTION_MASTER_SPECIES
    Pce       Pce       0.0          Pce         1
   Tce       Tce       0.0          Tce         1
    Dcecis       Dcecis       0.0          Dcecis       1
    Dcetrans    Dcetrans    0.0          Dcetrans    1
    Dceee       Dceee       0.0          Dceee       1
   Vc          Vc          0.0          Vc          1
   Ethe        Ethe        0.0         Ethe        1

SOLUTION_SPECIES
    H+ = H+
      log_k   0.0
      -gamma   9.0    0.0
   e- = e-
      log_k   0.0
   H2O = H2O
      log_k   0.0
   Na+ = Na+
      log_k   0.0
      Cl- = Cl-
      log_k   0.0
   Pce = Pce
       log_k   0.0
    Tce = Tce
        log_k   0.0
   Dcecis = Dcecis
        log_k   0.0
    Dcetrans = Dcetrans
        log_k   0.0
     Dceee = Dceee
        log_k   0.0
   Vc = Vc
        log_k   0.0
   Ethe = Ethe
      log_k   0.0
   H2O = OH- + H+
        log_k   -14.000
      delta_h 13.362 kcal
      -analytic -283.971 -0.05069842 13323.0 102.24447 -1119669.0
      -gamma    3.5000 0.0000
   2 H2O = O2 + 4 H+ + 4 e-
      log_k   -86.08
      delta_h 134.79 kcal
   2 H+ + 2 e- = H2
      log_k   -3.15
      delta_h -1.759 kcal
   Na+ + H2O = NaOH + H+
      log_k   -14.180

SOLUTION 0
   Temp    25
   water   0.5
   pH      6.0
   pe      13.0
   Pce     1E-20

END

PHASES
   Pce_lq
      Pce = Pce
      log_k -2.769405544
      analytical_expression -125.5965344 0 5531.053038 42.14129445 0

RATES

    Pce

   -start
   10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Pce")
   30 moles = - rate * TIME
   40 SAVE moles
   -end

   Tce
      -start
        10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Tce")
   30 moles = - rate * TIME
   40 SAVE moles

      -end

   Dcecis
      -start
        10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Dcecis")
   30 moles = - rate * TIME
   40 SAVE moles
      -end

      Dcetrans
      -start
        10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Dcetrans")
   30 moles = - rate * TIME
   40 SAVE moles
      -end

     Dceee
      -start
        10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Dceee")
   30 moles = - rate * TIME
   40 SAVE moles
      -end
   Vc
      -start
       10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Vc")
   30 moles = - rate * TIME
   40 SAVE moles
      -end
   Ethe
      -start
        10 REM par1 = k
   20 rate = parm(1)*TOT("water")*MOL("Ethe")
   30 moles = - rate * TIME
   40 SAVE moles
      -end
END

Equilibrium_phases 1-101
   Pce_lq 0 0.01

SOLUTION 1-101
   Temp    25
   water   0.5
   pH      6.0
   pe      13.0


KINETICS

   Pce
      -formula Pce 1.0 Tce -0.79
        -parms 0.075

   Tce
      -formula Tce 1.0 Dcecis -0.5328 Dcetrans -0.111 Dceee -0.0962
      -parms 0.070

   Dcecis
      -formula Dcecis 1.0 Vc -0.64
      -parms 0.020

   Dcetrans
      -formula Dcetrans 1.0 Vc -0.64
      -parms 0.035

   Dceee
      -formula Dceee 1.0 Vc -0.64
      -parms 0.055

   Vc
      -formula Vc 1.00 Ethe -0.45
      -parms 0.030

   Ethe
      -formula Ethe 1.00
      -parms 0.000001

PRINT
   reset false

TRANSPORT
   -cells  20
   -shifts  6
   -timest 8640
   -bcon   constant closed
   -diffc  0.0e-9
   -length 0.2
   -disp   0.015
    -stag   5
END

SOLUTION 0  # Original solution reenters
   Temp    25
   water   0.5
   pH      6.0
   pe      13.0

END

#SELECTED_OUTPUT
   #-file  Pce.prn
   #-sim false; -state false; -soln false; -time false; -step false
   #-pH false;  -pe    false;
   #-totals Pce Tce Dcecis Dcetrans Dceee Vc Ethe

TRANSPORT
   -shifts  10  1
   -se    10
   -punch 1   2   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17   18   19   20

USER_GRAPH
   -headings Distance Pce Tce Dcecis Dcetrans Dceee Vc Ethe
   -chart_title "Pce series"
   -axis_titles "Distance (m)" "mmol/L"
   -axis_scale x_axis 0 4 0.4 0.2
   -axis_scale y_axis 0 0.022 0.001
   -initial_solutions false
   -plot_concentration_vs x
   -start
   10 GRAPH_X DIST
   20 GRAPH_Y TOT("Pce")*1000 TOT("Tce")*1000 TOT("Dcecis")*1000 TOT("Dcetrans")*1000 TOT("Dceee")*1000 TOT("Vc")*1000
   -end
END

[dlparkhurst]

Think about how to debug your simulation. May I suggest:

(1) Do not turn off the printing (remove -reset false).

(2) Do not use stagnant zones.

(3) Run only one transport simulation for 2 steps.

(4) Look carefully at the results.