As_helz.ppi

# As speciation in As-S system with revised minteq.v4.dat database
# from Couture et al., J. Hazardous Materials 189, 647-652 (2011), Fig. 3B.

SPECIATION
  jobTitle                             "As redox and speciation"
  Database                             Thio_FT_helz.dat        # contains As species
  calculationType                      ht1
  calculationMethod                    1 # 2=replot 1=recalculate
  mainSpecies                          "As"
  xmin                                 2.0                 # pH 2 to 10
  xmax                                 14.0
  ymin                                 -80.0               # redox
  ymax                                 0.0
  resolution                           1000                # initial = 200 some low-angled boundaries could
                                                           # benefit from higher resolution or more smoothing

PLOT
  plotTitle                            "As helz + S0(aq)"
  xtitle                               pH
  ytitle                               "Eh"
  labelSize                            2 # default 2 labelSize 0 removes label !
  labelEffort                          3 # default 1
  yscale                               Eh
  pymin                                -0.75
  pymax                                0.5
  pxmajor                              2
  pymajor                              0.25
  pxminor                              1
  pyminor                              0.125   # minor ticks
  domain                               t       # draw domain boundaries
  extraText                            extraTextAs_helz.dat 

CHEMISTRY

# first simulation - initial solution calculation

include 'ht1.inc' 

SOLUTION 1
   temp  25
   pH    1.8                           # start out at pH<xmin
   units mol/kgw
   As    1e-5                          # total As
   Na    1e-4
   Cl    1e-4
   S(-2) 1e-4
   S(0)  1e-5 Sulfur
END

# second simulation - equilibrate
USE solution 1
EQUILIBRIUM_PHASES 1
   Fix_H+ -<x_axis>  NaOH 10
     -force_equality true
   O2(g)  <y_axis>  0.1
#  CO2(g) -3.5      1.0

  As_native                      0 0    # possible As minerals
  Orpiment                       0 0
  Realgar                        0 0
  Sulfur                         0 0
  Arsenolite                     0 0
  Claudetite                     0 0

END