BIOSORPTION OF Pb2+, Cd2+, & Ni2+ FROM WATERS BY ...

Concentration (x10 -5 Concentration (x10 mol/L)
-5 mol/L)
Concentration (x10-5mol/L) Concentration (x10-5mol/L) Concentration (x10-5mol/L) Concentration (x10-4 Concentration (x10 mol/L)
-4 Concentration (x10 mol/L)
-4 mol/L)
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
Pb2+ Pb2+ PbOH + PbOH
Pb(OH) 2(aq)
+
Pb(OH) 2(aq)
0.0
1.0 3.0 5.0 7.0 9.0 11.0 13.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
(a)
(b)
Cd2+ Cd2+ pH
Cd(OH) + Cd(OH) +
- Pb(OH) 3
2+ Pb Pb3(OH) 3(OH) 4
1.0 3.0 5.0 7.0 9.0 11.0 13.0
(c)
Ni2+ Ni2+ pH
Ni(OH) + Ni(OH) +
Cd(OH) 2(aq)
Cd(OH) -
3
2- Cd(OH) 4
0.0
1.0 3.0 5.0 7.0 9.0 11.0 13.0
pH
Ni(OH) 2(aq)
- Ni(OH) 3
Figure 3.8. The speciation diagrams of (a) Pb, (b) Cd, and (c) Ni (4.83x10 -5 mol
Pb 2+ /L=10.0 mg Pb 2+ /L, 8.90x10 -5 mol Cd 2+ /L=10.0 mg Cd 2+ /L, 1.70x10 -4
mol Cd 2+ /L=10.0 mg Cd 2+ /L)
(Source:Visual Minteq Program)
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