DATABASE phreeqd.dat
# diffusion of NaCl in clay membrane. Membrane opens up when DDL thickness reduces.
KNOBS; -step_size 10; -pe_step_size 5; -iterations 1000
SOLUTION 0; Na 500; Cl 500 # saline outer solution
END
SOLUTION 1-20; Na 1; Cl 1; water 0.02
SOLUTION 21;  Na 1; Cl 1
SURFACE_MASTER_SPECIES; Su Su-
SURFACE_SPECIES; Su- = Su-; log_k 0

SURFACE 1-20; Su 0.1 1.786e5 1; -equil 1
 -donnan debye_length 1 limit_DDL 0.98 viscosity 1
END
PRINT; -reset false
TRANSPORT; -cells 15; -length 1e-2; -shifts 1 0; -bcon 1 3; -time 2.592e5 1.3
 -multi_d true 1e-9 1 0 1
USER_GRAPH
 -plot_concentration_vs x
 -axis_titles "Distance / m" "mol/L" "H2O_DDL / H2O_tot"
 -chart_title "Clay Membrane Diffusion"
 -axis_scale x_axis 0 0.1501 0.05
 -axis_scale y_axis 0 0.601 0.2
 -axis_scale sy_axis 0 1
 -head dist Na Cl aq_DDL
 -start
 10 graph_x dist
 20 graph_y sys("Na"), sys("Cl")
 30 graph_sy edl("water")
 -end
END