TITLE Example 8.--Sorption of zinc on hydrous 
                  iron oxides.
SURFACE_SPECIES
        Hfo_sOH  + H+ = Hfo_sOH2+
        log_k  7.18

        Hfo_sOH = Hfo_sO- + H+
        log_k  -8.82

        Hfo_sOH + Zn+2 = Hfo_sOZn+ + H+
        log_k  0.66

        Hfo_wOH  + H+ = Hfo_wOH2+
        log_k  7.18

        Hfo_wOH = Hfo_wO- + H+
        log_k  -8.82

        Hfo_wOH + Zn+2 = Hfo_wOZn+ + H+
        log_k  -2.32
SURFACE 1
        Hfo_sOH        5e-6    600.    0.09
        Hfo_wOH        2e-4    
SOLUTION 1
        -units  mmol/kgw
        pH      8.0
        Zn      0.0001 
        Na      100.    charge 
        N(5)    100.
SOLUTION 2
        -units  mmol/kgw
        pH      8.0
        Zn      0.1 
        Na      100.    charge 
        N(5)    100.
USE solution none
#
# Model definitions
#
PHASES
        Fix_H+
        H+ = H+
        log_k  0.0
END
#
#   Zn = 1e-7
#
SELECTED_OUTPUT
        -file ex8.sel
        -molalities     Zn+2    Hfo_wOZn+      Hfo_sOZn+
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.0   NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.25  NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.5   NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.75  NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.0   NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.25  NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.5   NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.75  NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.0   NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.25  NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.5   NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.75  NaOH    10.0
END
USE solution 1
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -8.0   NaOH    10.0
END
#
#   Zn = 1e-4
#
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.0   NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.25  NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.5   NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -5.75  NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.0   NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.25  NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.5   NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -6.75  NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.0   NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.25  NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.5   NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -7.75  NaOH    10.0
END
USE solution 2
USE surface 1
EQUILIBRIUM_PHASES 1
        Fix_H+   -8.0   NaOH    10.0
END