Chemical Modifications of Cassava Peel as Adsorbent Material for Metals Ions from Wastewater
Table 6
Kinetic parameters referred to linear models of pseudo-first order, pseudo-second order, and Elovich obtained by adsorbents M. H2O2, M. H2SO4, and M. NaOH in the removal of Cd(II), Pb(II), and Cr(III) from water.
Parameters/adsorbents
M. H2O2
M. H2SO4 (Line A)
M. H2SO4 (Line B)
M. NaOH
M. H2O2
M. H2SO4
M. NaOH
M. H2O2
M. H2SO4
M. NaOH
Cd(II)
Pb(II)
Cr(III)
Pseudo-first order
(min−1)
−0.0397
0.0084
0.0008
−0.0059
−0.0046
−0.0053
−0.0161
−0.0218
−0.0184
(cal.) (mg g−1)
0.3846
0.1339
0.0425
0.1757
0.2365
0.2338
0.2160
0.1404
0.3513
0.778
0.707
0.034
0.740
0.578
0.857
0.921
0.908
0.878
Pseudo-second order
(g mg−1 min−1)
0.4051
−0.0922
−1.4705
−2.3101
0.2235
0.6637
0.2546
0.5264
0.1757
(cal.) (mg g−1)
2.3833
1.7042
2.4428
2.4549
2.3867
2.3820
2.2247
1.9309
2.3540
0.999
0.990
0.999
0.999
0.997
0.998
0.999
0.999
0.996
Elovich
(mg g−1 min−1)
2.1465
2.0601
4.1905
2.5142
2.5306
2.1624
2.2250
1.8690
1.7040
1.8696
(g mg−1)
0.0454
0.0599
−0.4842
−0.0139
−0.0153
0.0211
0.0211
0.0667
0.0474
0.1019
0.639
0.883
0.712
0.610
0.687
0.768
0.709
0.982
0.850
0.949
(exp.) (mg g−1)
2.2896
1.9629
2.4556
2.4557
2.3010
2.3526
2.1296
1.8835
2.2273
: constant of pseudo-first-order velocity; : adsorbate amounts retained by adsorbent mass in equilibrium; : constant pseudo-second-order velocity; : constant indicating chemisorption initial speed; : number of suitable sites for the adsorption of the surface related to the coverage extension and the activation energy of chemisorption; : coefficient of determination.
