38
2 Thermodynamics, Kinetics and Desorption Studies …
Table 2.2
Thermodynamic parameters for the adsorption of metal ions onto the absorbent at an initial concentration of 40 mg/L
Metal ions
S o
(kJ/mol/k)
H o
(kJ/mol)
G o
(kJ/mol)
R 2
Rate constant
T
= 298 K
T
= 303 K
T
= 318 K
T
= 328 K
K
c (mg/g min)
E
ad (KJ/mol)
Pb(II)
55.572
0.761
−1.232
−3.231
−3.990
−4.783
0.998
2.12
× 10 9
3.322
Cu(II)
45.653
0.644
−2.232
−3.181
−3.452
−4.122
0.994
1.54
× 10 7
3.873
Ni(II)
42.441
0.603
−1.631
−1.963
−2.433
−3.563
0.998
3.13
× 10 4
2.454
Zn(II)
50.454
0.432
−2.323
−3.132
−4.642
−6.692
0.999
4.32
× 10 8
2.403
Cd(II)
53.622
0.413
−3.542
−3.994
−5.451
−7.763
0.989
2.45
× 10 3
3.182