Environmental Engineering Reference
In-Depth Information
Figure 7.4: Effect of oxalic acid concentration on vanadium removal at 25
C.
: 0.33M;
:
0.66M;
: 1.0M [From ref.
480
. Reprinted with permission].
metal sulfides in spent catalysts to corresponding oxides
[484]
. The presence of latter is more
favorable for the formation of the water-soluble complexes with organic agents. Furthermore,
the surface area and pore volume improvement as well as the increased recovery of activity
were observed in the presence of Al(NO
3
)
3
[476]
. Similar observation was made by Farrell
and Ward
[487]
using the mixture of oxalic acid with HNO
3
and Al(NO
3
)
3
. Compared with
H
2
O
2
, Al(NO
3
)
3
was more efficient additive for the removal of Ni, whereas for V removal
Figure 7.5: Effect of temperature on vanadium removal using oxalic acid (o.66M).
:25
C; +:
50
C;
:75
C [From ref.
480
. Reprinted with permission].
