Si-goethite3a.ppi

# from Hiemstra et al. (2007), J. Colloid Inteface Sci. 310, 8-17, Fig. 3(a)

SPECIATION
  calculationType                      custom
  calculationMethod                    1
  xmin                                 3.0
  xmax                                 11.0
  resolution                           81
  loopfile                             "loopSi.dat"

  numericTags                          <Goe_triOH> = 9.2 \
                                       <Goe_triONa> = -0.61 \
                                       <Goe_triOHNO3> = 8.50 \

                                       <Goe_uniOH2> = 9.2 \
                                       <Goe_uniOHNa> = -0.61 \
                                       <Goe_uniOH2NO3> = 8.50 \
                                       <area> = 100
PLOT
  plotTitle                            "Si adsorption by goethite"
  xtitle                               pH
  ytitle                               "adsorbed Si (\mmol/m<sup>2</sup>)"
  pxmin                                3
  pxmax                                11
  pymajor                              1
  customxcolumn                        pH
  lines                                calcd
  linecolor                            red
  points                               umolm2                        # observed values from fig3a.dat
  pointColor                           red
  rimColor                             gray6
  pointSize                            3
  extradat                             fig3a.dat 
  extraText                            extratext3a.dat 
  changeColor                          t
  labelSize                            0
  labels                               1 2 3 4 5
  post                                 pH -2
  postSize                             1.5

CHEMISTRY

SELECTED_OUTPUT
  -reset false

SOLUTION 1
  Temp      25
  pH        2.9                                            # just less than min pH
  units     mol/kgw

  Si        <SiT> mmol/kgw
  Na        1e-1                                           # background electrolyte
  N(5)      1e-1

include 'ecosatSi.dat'                                     # aqueous species database
include 'cdmusic_hiemstra.dat'                             # adsorbed species database

USER_PUNCH
-headings pH calcd
10 PUNCH -la("H+"), SURF("Si","Goe")*1e6/(<mass>*<area>)

PHASES ; Fix_H+; H+ = H+ ; log_k 0

SURFACE 1
  Goe_uniOHH0.5 3.45 <area> <mass>  # sites/nm2  m2/g  g
    -cap    0.92  0.92           # C1  C2  (in F/m2)
  Goe_triOH0.5  2.7
    -cd_music
    -sites_units density

EQUILIBRIUM_PHASES 1
  Fix_H+  -<x_axis> NaOH
    -force_equality true
  O2(g)  -0.7
END