Environmental Engineering Reference
In-Depth Information
FIGURE 38.5
(See color insert.) Al 13 -PACl plant established using the electrochemical method.
50
50
6 kD
3 kD
1 kD
45
45
40
40
35
35
30
30
25
25
20
20
15
15
10
10
5
5
0 0 0 0 0 0 0
40
50
60
70
80
90
100
Al a (%)
Al b (%)
FIGURE 38.6
Relation between Al a or Al b by UF on various MWCO membranes.
increases somewhat, and the 1-3 kD MWCO fraction enhances greatly. If the content of
Al a enhances, the fraction with an MWCO >1 kD decreases and that with an MWCO <1 kD
increases. It also indicates that the particle size of Al b is close to the pore diameter of a
1-kD membrane. The experimental results show that the PSD of PACls varies markedly
with the B value and total aluminum concentration with a 3-6 kD MWCO membrane. The
interception rate differs signiicantly with the Al a , Al b , and Al c species (hydrolyzed specia-
tion according to chemical ferron assay). By choosing the combination of 3 kD and 1 kD
UF membrane, it is possible to separate and purify Al 13 . The operation pressure exhibits
little effect on the selective separation of Al 13 with other species, while it does decrease
the separation time needed. High concentrations of Al 13 (about 0.5 mol Al/L) could be
obtained with a purity of >95%.
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