Environmental Engineering Reference
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1.00
0.75
B1
B2
B3
B4
0.50
0.25
0.00
6
6.5
7
7.5
8
8.5
pH
74
64
54
44
B1
B2
B3
B4
34
24
14
6
6.5
7
7.5
8
8.5
pH
Fig. 1
Influence of pH on adsorption of fluoride (
top
) and arsenite (
bottom
)
(Fig.
2
)after180minforluorideand240minforarsenite.Inboththecases,H
2
SO
4
activatedbamboodust(B4)showedthehighestadsorption.
At low coverage, arsenite adsorption was very rapid, but as the coverage
increased, the number of available surface sites came down, and the adsorption rate
decreaseduntilequilibriumwasapproached.Atequilibrium,theuptakewascon-
trolled by the rate at which the metal ions were transported from the external surface
to the interior sites of the adsorbents (Yu et al.
2000
).
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