Table 1. Linear regression equations and coefficient of determination (R2) for Freundlich, Langmuir and Dubinin-Radushkevich isotherm models for the metal ions adsorption on unmodified and modified maize husk of 450 µm and 850 µm particle sizes. |
Metal |
Unmodified |
Modified |
|||
450 µm |
850 µm |
450 µm |
850 µm |
||
Freundlich Isotherm |
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Cd |
Y = 2.6421 x -5.3968 |
Y = 1.6218 - 2.5328 |
Y = 0.2926 x +2.0573 |
Y = 0.9686 x +0.0876 |
|
Pb |
Y = 1.8178 x -3.178 |
Y = 2.1734 x -4.3554 |
Y = 0.2506 x +2.0689 |
Y = 1.0631 x +0.4862 |
|
Zn |
Y = 1.1595 x -0.3138 |
Y = 1.3107 x -0.7849 |
Y = 0.0245 x +2.7883 |
Y = 0.312 x +1.977 |
|
Langmuir Isotherm |
|||||
Cd |
Y = -0.0066 x +9.593 |
Y = -0.003 x +7.7867 |
Y = 0.0012 x +0.1344 |
Y = 0.00008 x +0.9488 |
|
Pb |
Y = -0.0046 x +10.038 |
Y = -0.007 x +14.646 |
Y = 0.0014 x +0.1902 |
Y = 0.00008 x +2.0808 |
|
Zn |
Y = -0.0003 x +0.9212 |
Y = -0.0006 x +1.208 |
Y = 0.0013 x +0.0339 |
Y = 0.0012 x +0.1655 |
|
Dubinin-Radushkevich Isotherm |
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Cd |
Y = -0.9121 x +8.138 |
Y = -0.6514 x +7.0375 |
Y = -0.022 x +6.6179 |
Y = -0.1654 x +7.079 |
|
Pb |
Y = -0.7767 x +7.2452 |
Y = -0.9387 x +7.3686 |
Y = -0.029 x +6.473 |
Y = -0.2879 x +6.9124 |
|
Zn |
Y = -0.185 x +7.4298 |
Y = -0.249 x +7.6253 |
Y = -0.0051 x +6.6113 |
Y = -0.0267 x +6.5972 |
|