Table 6 Isotherm constants of methylene blue and congo red adsorption by activated carbons.
Activated carbon | TAC1 | TAC2 | TAC3 | TAC4 | TAC5 | TAC6 |
---|---|---|---|---|---|---|
Methylene blue | ||||||
Qe,exp (mg/g) | 16.9 | 401 | 413 | 130 | 264 | 221 |
Qe,exp (mmol/g) | 0.053 | 1.25 | 1.29 | 0.406 | 0.825 | 0.692 |
Langmuir model | ||||||
Qm (mg/g) | 15.7 | 425 | 438 | 137 | 249 | 217 |
Qm (mmol/g) | 0.049 | 1.33 | 1.37 | 0.429 | 0.779 | 0.678 |
b (L/mg) | 0.521 | 0.053 | 0.052 | 0.016 | 0.152 | 0.079 |
SSE | 16.5 | 2,162 | 2,265 | 1,790 | 888 | 282 |
R2 | 0.9031 | 0.9937 | 0.9937 | 0.9616 | 0.9929 | 0.9978 |
Freundlich model | ||||||
Kf ((mg/g)(L/mg)1/n) | 7.70 | 77.6 | 81.5 | 21.5 | 58.1 | 48.7 |
n | 8.44 | 3.62 | 3.63 | 3.63 | 4.25 | 4.23 |
SSE | 15.35 | 28,557 | 32,063 | 606 | 7,044 | 4,789 |
R2 | 0.9087 | 0.9210 | 0.9152 | 0.9777 | 0.9450 | 0.9476 |
Redlich–Peterson model | ||||||
K | 15.5 | 22.7 | 22.9 | 66.1 | 54.3 | 19.5 |
a | 1.47 | 0.053 | 0.052 | 2.44 | 0.331 | 0.11 |
g | 0.932 | 1.00 | 1.00 | 0.761 | 0.932 | 0.969 |
SSE | 2.59 | 2,162 | 2,265 | 463 | 146 | 214 |
R2 | 0.9845 | 0.9937 | 0.9937 | 0.9825 | 0.9988 | 0.9982 |
Congo red | ||||||
Qe,exp (mg/g) | 90.3 | 161 | 176 | 119 | 214 | 190 |
Qe,exp (mmol/g) | 0.13 | 0.231 | 0.253 | 0.171 | 0.307 | 0.273 |
Langmuir model | ||||||
Qm (mg/g) | 92.4 | 165 | 180 | 123 | 217 | 194 |
Qm (mmol/g) | 0.133 | 0.236 | 0.258 | 0.176 | 0.312 | 0.278 |
b (L/mg) | 0.025 | 0.037 | 0.036 | 0.051 | 0.035 | 0.038 |
SSE | 19.9 | 30.1 | 38.0 | 99.0 | 371 | 97.5 |
R2 | 0.9984 | 0.9994 | 0.9996 | 0.9960 | 0.9972 | 0.9991 |
Freundlich model | ||||||
Kf ((mg/g)(L/mg)1/n) | 13.1 | 26.6 | 28.7 | 24.6 | 34.2 | 31.4 |
N | 3.41 | 3.58 | 3.53 | 4.04 | 3.49 | 3.56 |
SSE | 931 | 2,958 | 3,087 | 2,662 | 2,731 | 3,151 |
R2 | 0.9313 | 0.9387 | 0.9474 | 0.8967 | 0.9694 | 0.9547 |
Redlich–Peterson model | ||||||
K | 2.31 | 6.02 | 6.94 | 6.27 | 11.0 | 8.72 |
A | 0.025 | 0.037 | 0.043 | 0.051 | 0.089 | 0.06 |
G | 1.00 | 1.00 | 0.98 | 1.00 | 0.91 | 0.95 |
SSE | 19.9 | 30.1 | 30.5 | 99.0 | 143 | 39.4 |
R2 | 0.9984 | 0.9994 | 0.9996 | 0.9960 | 0.9987 | 0.9996 |