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a fundamental question!



Dear David,

Thank you for the contact with Vincent Post. He helps me to use
"USER_GRAPH" in an easy way. There were a synthatic problem concerning the
outpout of pe (30 GRAPH_SY -LA("e-") was to be tape).

Now I couldn't progress in modelling uranium-rollfront. The idea was to
create a redox front such that inflooding U(VI) will precipitate at it.
What I've yet done is to reduce to pe and uranium concentration trough
sucessive equilibria with selected uranium phases. Although these are
relevant for similating real life, it was not the aim (not a "real front").

I've found in the literature (Merkel & Planer-Friedrich: Abbau_10000Tage;)
an example where the degradation of organic carbon induces the
pricipitation of soluble uranium. but incooporate this kinetic step in the
transport could not produces the same result (Roll-front122;). What is your
comment?

Thank you for the answer, I'll be absent for the rest of the week.

Have a nice time, 

Chicgoua
TITLE Abbau organischer Substanz im Grundwasserleiter unter Reduktion redoxsensitiver Elemente (Fe, As, U, Cu, Mn, S) (10000 Tage)
SOLUTION 1 Leaching-Lösung 
 	units   	ppm
     pe      	4	O2(g)  -0.7
     temp    	10
     pH 	     2.3
S(6)	5000      as  SO4  charge
Cl	450
F	1
N(5)	100    as NO3
U	40
Fe	600
Zn	100
As	2
Mn	20
Pb	0.2
Ni	5
Cu	3
C     1       			# ergänzt wegen calcite
Cd	1
Li	0.1
Na	500
K	4
Mg	50
Ca	400	
Al    200
Si    50

save solution 1
end

use solution 1

KINETICS 1
	 Calcite 
	-tol 1e-8
	-m0 	1e-2
	-m	1e-2
	-parms	50  	0.6
	
	Organic_C
       	-formula  CH2O
		-tol	1e-8
		-m0	1				# mol/kgw
		-m	1
	-steps 864000000 in 100 steps  	# 10.000 Tage
		-step_divide 1000000
		Pyrite  
		-tol    1e-8
		-m0 	1
		-m	1
		-parms -5.0 	0.1 	.5 	-0.11 

RATES
	Calcite
  	-start
   	1 rem	parm(1) = A/V, 1/dm	parm(2) = exponent for m/m0
	5  if time > 8640000 then goto 200
   	10  si_cc = si("Calcite")
   	20 if (m <= 0  and si_cc < 0) then goto 200
   	30  k1 = 10^(0.198 - 444.0 / (273.16 + tc) )
   	40  k2 = 10^(2.84 - 2177.0 / (273.16 + tc) )
   	50  if tc <= 25 then k3 = 10^(-5.86 - 317.0 / (273.16 + tc) )
   	60  if tc > 25 then k3 = 10^(-1.1 - 1737.0 / (273.16 + tc) )
   	70   t = 1
   	80  if m0 > 0 then t = m/m0
   	90  if t = 0 then t = 1
   	100   moles = parm(1) * 0.1 * (t)^parm(2)
   	110   moles = moles * (k1 * act("H+") + k2 * act("CO2") + k3 * act("H2O"))
   	120   moles = moles * (1 - 10^(2/3*si_cc))
   	130   moles = moles * time
   	140 if (moles > m) then moles = m
   	150 if (moles >= 0) then goto 200
   	160   temp = tot("Ca")
   	170   mc  = tot("C(4)")
   	180 if mc < temp then temp = mc
   	190 if -moles > temp then moles = -temp
   	200 save moles
  	-end

 	Organic_C
  	-start
   	10 if (m <= 0) then goto 200
   	20  mO2 = mol("O2")
   	30  mNO3 = tot("N(5)")
   	40  mSO4 = tot("S(6)")
#   	50   rate = 1.57e-9*mO2/(2.94e-4 + mO2) + 1.67e-11*mNO3/(1.55e-4 + mNO3)
   	50   rate = 1.57e-7*mO2/(2.94e-4 + mO2) 
# 	60   rate = rate + 1.e-13*mSO4/(1.e-4 + mSO4)
   	60   rate = rate + 1.e-10*mSO4/(1.e-4 + mSO4)
   	70  moles = rate * m * (m/m0) * time
   	80 if (moles > m) then moles = m
   	200 save moles
  	-end

	Pyrite
  	-start
   	1 rem	parm(1) = log10(A/V, 1/dm)	parm(2) = exp for (m/m0)
   	2 rem	parm(3) = exp for O2		parm(4) = exp for H+
      
   	10 if (m <= 0) then goto 200
   	20 if (si("Pyrite") >= 0) then goto 200
   	20  rate = -10.19 + parm(1) + parm(3)*lm("O2") + parm(4)*lm("H+") + parm(2)*log10(m/m0)
   	30  moles = 10^rate * time
   	40 if (moles > m) then moles = m
   	50 if (moles >= (mol("O2")/3.5)) then moles = mol("O2")/3.5
   	200 save moles
  	-end

EQUILIBRIUM_PHASES
Al(OH)3(a)	 	0  0
Calcite   		0  0
Coffinite		0  0
Jurbanite		0  0
Kaolinite		0  0
Pyrite		0  0
Uraninite(c)	0  0

SELECTED_OUTPUT
-file    Abbau_10000Tage.csv
-totals  Fe(2) Fe(3) U(6) As(3) As(5) Cu(1) Cu(2) Mn(2) Mn(3) Mn(6) Mn(7)
-molalities SO4-2 CaSO4 UO2+2  UO2SO4  CuCl2- Cu+ CuCl3-2  CuHCO3+ Cu+2 CuSO4 CuCO3 
-saturation_indices Al(OH)3(a) Calcite Coffinite Jurbanite	Kaolinite	Pyrite  Uraninite(c)
-kinetic_reactants Organic_C  Pyrite Calcite
	   -pH				true
  	   -pe				true

END
TITLE  Rollfront


SOLUTION 0 Rainwater
        units            mmol/kgw
        temp           25.0
        pH              7.0     charge
        pe               4.0
EQUILIBRIUM_PHASES 0
	CO2(g)	-3	10
	O2(g)		-0.7	10
Save	Solution 0
END

SOLUTION 12-21
SOLUTION 1-10

USE solution 0
EQUILIBRIUM_PHASES 1-2
	Calcite 	0.0	0.1
	Goethite	0.0	0.1
SAVE solution 1-2
END

USE solution 1
EQUILIBRIUM_PHASES 3
	Schoepite	0.0	0.1
	Calcite 	0.0	0.1
	Goethite	0.0	0.1
SAVE solution 3
END

USE solution 3
EQUILIBRIUM_PHASES 4-7
	Schoepite		0.0	0.1
	Calcite 		0.0	0.1
	Pyrite		0.0	0.1
SAVE solution 4
END


USE solution 4
KINETICS 7-10
      Organic_C
       	-formula  CH2O
		-tol	1e-8
		-m0	1	
		-m	1
	-steps 51840000 in 100 steps  	

RATES
 	Organic_C
  	-start
   	10 if (m <= 0) then goto 200
   	20  mO2 = mol("O2")
   	30  mNO3 = tot("N(5)")
   	40  mSO4 = tot("S(6)")
   	50   rate = 1.57e-7*mO2/(2.94e-4 + mO2) 
   	60   rate = rate + 1.e-10*mSO4/(1.e-4 + mSO4)
   	70  moles = rate * m * (m/m0) * time
   	80 if (moles > m) then moles = m
   	200 save moles
  	-end
END

KNOBS
      -pe   2
      -step       2
      -iterations 200
SOLUTION_SPECIES
      H2O + .01e- = H2O-0.01
      log_k -9


TRANSPORT				
        -cells  			10
        -shifts  		100	  
        -time_step 		86400 
	  -flow_direction  	forward
        -length 			1	  
        -dispersivities   	2.0 
	   -punch_cells 		1-10
        -punch_frequency  	100
        -stagnant          1      1.056e-10  0.05          0.15
	  -print_cells 		1-10
	  -print_frequency	100

PRINT
        -reset 				false
SELECTED_OUTPUT
        -file   			Roll-front122.csv
        -reset  			false
        -time			false
	  -distance  		true
        -totals 			U
	   -pH				true
  	   -pe				true

USER_GRAPH
-headings x U pe
-chart_title Uranrollfront
-axis_titles "Distance[m]"  "Konzentration [Mol]" "pe-Wert"
-axis_scale y_axis 0.6 30  
-axis_scale secondary_y_axis -6.0  12.0 
-initial_solutions false
-plot_concentration_vs x
10 GRAPH_X DIST
20 GRAPH_Y tot("U")
30 GRAPH_SY -LA("e-")


END






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Last modified: $Date: 2005-09-13 21:04:21 -0600 (Tue, 13 Sep 2005) $
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