Environmental Engineering Reference
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the probability of the occurrence of a sorption process, see Table 3 . For a removal
process to be determined as sorption, n should be in the 0.60-3.3 range, and R2
close to 1. The results presented in Table 4 show that sorption is a likely mechanism
for removal of Cd, Cu, Mo and Ni. Sorption is indicated for Pb and Zn, but more
data is needed for valid calculations.
Simulation of Species
The results from the simulation of species in the solutions with high multi-metal
concentrations, at pH 7.0 with a phosphate buffer and pH 9 without a buffer,
Table 3 Calculated Freundlich adsorption isotherm constants for metals in multi solutions in
contact with blast-furnace sludge as sorbent
Furnace sludge
Old sludge
pH 5.6
pH 7.0
pH ~9
pH ~9
n
K F
R 2
n
K F
R 2
n
K F
R 2
n
K F
R 2
Cu
0.63
1.46
0.97
-
-
-
2.24
0.53
0.7
1.5
0.96
0.96
Zn
-
-
-
-
-
-
-
-
-
1.63
0.4
0.95
Cr
1.02
0.43
0.96
-
6.48
0.90
-
-
-
-
-
-
Sn
0.3
8.43
1.00
0.25
9.68
0.95
-
-
-
0.53
5.25
1.00
Ni
0.99
0.13
0.93
0.96
0.85
0.99
0.74
2.31
0.95
1.31
0.88
0.91
V
3.34
0.01
0.98
-
-
-
-
-
-
-
-
-
Mo
0.85
0.45
1.00
-
-
-
1.04
0.2
1.00
1.67
0.02
0.99
Pb
-
-
-
-
-
-
1.02
0.35
1.00
1.31
1.82
0.74
Cd
1.25
0.09
1.00
1.52
2.36
1.00
0.87
2.44
0.89
1.02
2.08
0.99
Cs
-
-
-
-
-
-
-
-
-
-
-
-
- = No data.
Table 4 Suggested removal mechanisms for metals in solutions at
different pH values and furnace sludge as sorbent
Furnace sludge
Old sludge
Metal
pH 5.6
pH 7.0
pH ~9
pH ~ 9
Cu
Sorption
Sorption a
Sorption
Sorption
Zn
-
Other
Other
Sorption a
Cr
Sorption
Other
Other
Other
Sn
Other
Other
Other
Other
Ni
Sorption
Sorption
Sorption
Sorption
V
Other
-
Other
Other
Mo
Sorption
Sorption a
Sorption
Sorption
Pb
-
n.d.
Sorption
Sorption
Cd
Sorption
Sorption
Sorption
Sorption
Cs
-
-
Other
Other
a Data uncertain, could be sorption.
n.d = No data.
- = leaching > removal.
 
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