L1 /
11
CH1012
3) Effect of charge Z of counterions (10-3 M)
eg. Na+, Ba2+, Al3+
DOUBLE LAYER
EFFECTS
1 10-3 M
2 10-2 M
3 10-1 M
1 Z =
1
2 Z =
2
3 Z =
3
distance
Y
distance
Y
distance
Y
1
1
2
2
3
3
Graph
1 Graph 2 Graph 3
Diffuse Double Layer Model (Gouy
& Chapman)
1) Exponential decay
of electric pot. Y with
distance of an ion from the charged surface.
distance of an ion from the charged surface.
2) Effect of
concentration of univalent
counter- and co-ions eg. Na+Cl-
counter- and co-ions eg. Na+Cl-
For
this reason
Al3+ is chosen to coagulate blood.
Al3+ is chosen to coagulate blood.