Chapter 4
values are 2.86×10^8 mol∕m3, 3.33×10^1° mol∕m3 and 1.85×10^7 mol∕m2,
respectively. For amphoteric alumina sites, kaolinite has the same magnitude of
dissociation equilibrium constants and site density as alumina. This indicates
kaolinite has similar amphoteric alumina sites to alumina and validates the
assumption in section 4.3.2.
Table 4.9 Alumina site densities and dissociation constants
|
Reaction |
K (mol∕m3) |
Λ∕( W8 mol∕m2) |
|
-aioh; -aioh+h+ |
4.21×10^8 |
10.9 |
|
-AlOH -AlO +H+ |
3.58×10^1° |
1
0.9
0.8
0.7
O 0.6
о
≡ 0.5
U)
±s 0.4
V)
0.3
0.2
0.1
0
6 7 8 9 10 11
Bulk pH
Figure 4.22 Alumina sites fraction at different bulk pH in 0.05 M NaCI
129