Adsorption of Arsenic, Lead, Cadmium, and Chromium Ions from Aqueous Solution Using a Protonated Chabazite: Preparation, Characterization, and Removal Mechanism
Table 3
Results of isotherm fitting using the Langmuir, Freundlich, Sips, and Liu equations for the adsorption of As(V), Pb(II), Cd(II), and Cr(III) on CH-N and CH-MS zeolites.
Ion
Zeolite
Model parameters
%D
Model
(mg/g)
(mEq/g)
As(V)
CH-N
0.024
1.954
0.984
8.473
Freundlich
1.324
0.047
1.219
0.979
14.509
Langmuir
2.226
0.079
0.330
0.701
0.973
6.539
Liu
2.226
0.079
0.460
0.685
0.982
6.166
Sips
As(V)
CH-MS
0.045
1.600
0.934
24.330
Freundlich
3.015
0.107
0.825
0.973
14.473
Langmuir
2.902
0.103
0.924
1.105
0.988
8.683
Liu
2.902
0.103
0.933
1.162
0.974
7.82
Sips
Pb(II)
CH-N
0.851
3.008
0.992
11.949
0.056
Freundlich
114.989
1.109
5.537
0.956
27.56
2.591
Langmuir
235.960
2.277
0.307
0.0407
0.992
9.656
0.048
Liu
232.429
2.244
0.635
0.410
0.989
9.778
0.049
Sips
Pb(II)
CH-MS
0.314
4.885
0.962
10.525
0.026
Freundlich
42.279
0.408
7.576
0.995
2.219
Langmuir
43.656
0.421
5.365
0.864
0.997
1.136
Liu
43.656
0.421
6.976
0.864
0.998
1.135
Sips
Cd(II)
CH-N
0.273
2.582
0.997
4.194
Freundlich
18.716
0.333
4.250
0.983
5.967
Langmuir
25.236
0.449
1.796
0.660
0.997
2.048
Liu
25.236
0.449
1.472
0.6604
0.995
2.047
Sips
Cd(II)
CH-MS
0.104
8.139
0.882
4.564
Freundlich
6.126
0.109
23.016
0.995
0.716
Langmuir
6.126
0.109
22.54
1.051
0.996
0.632
Liu
6.126
0.109
26.10
1.047
0.996
0.631
Sips
Cr(III)
CH-N
0.876
9.718
0.838
7.111
0.035
Freundlich
19.680
0.855
190.38
0.441
12.302
0.090
Langmuir
45.773
1.990
0.451
0.194
0.962
8.401
0.034
Liu
44.719
1.944
0.889
0.195
0.809
8.397
0.035
Sips
Cr(III)
CH-MS
0.455
2.457
0.986
11.058
0.078
Freundlich
17.259
0.750
2.049
0.914
20.917
0.671
Langmuir
25.495
1.108
0.629
0.544
0.966
12.965
0.075
Liu
24.434
1.062
0.842
0.559
0.941
13.310
0.0811
Sips
(,, and ) is the maximum adsorption capacities of the Langmuir, Liu, and Sips equations. (,,, and ) is the constant of the Langmuir, Liu, Sips (L/mEq), and Freundlich (mEq/g) (L/mEq)1/nF equations. (,, and ) is the dimensionless exponent of the Liu, Sips, and Freundlich equations.
