Models/parameters | ASC400 | Ch-ASC400 | ASC500 | Ch-ASC500 | |
---|---|---|---|---|---|
Freundlich | |||||
KF | 2.8728 | 7.3672 | 3.3620 | 23.659 | |
N | 3.0826 | 2.4643 | 2.7518 | 1.7646 | |
R2 | 0.9582 | 0.9935 | 0.8840 | 0.9248 | |
Langmuir | |||||
Kb | 4306.2 | 1182.8 | 2374.0 | 538.00 | |
As (mmol g−1) | 0.4644 | 1.0569 | 0.5265 | 1.6898 | |
R2 | 0.9979 | 0.9857 | 0.9978 | 0.9955 | |
Scatchard | |||||
Ks | 21242 | 3144.9 | 4331.9 | 500.60 | |
Qs (mmol g−1) | 0.3883 | 0.8839 | 0.4865 | 1.7466 | |
R2 | 0.7930 | 0.6841 | 0.9543 | 0.8604 | |
D-R | |||||
Xm | 0.7955 | 1.7727 | 1.0010 | 4.1421 | |
K | 0.0030 | 0.0043 | 0.0040 | 0.0071 | |
E (kJ mol−1) | 12.910 | 10.783 | 11.180 | 8.3918 | |
R2 | 0.9877 | 0.9932 | 0.9468 | 0.9626 | |
Temkin | |||||
b (J mol−1) | 827.27 | 299.91 | 628.68 | 146.56 | |
AT (L g−1) | 68.106 | 7.3666 | 17.103 | 1.5026 | |
R2 | 0.9832 | 0.9473 | 0.9883 | 0.9814 | |
Pseudo-first-order model | |||||
K | 0.0113 | 0.0334 | 0.0154 | 0.0180 | |
q (mmol g−1) | 0.0289 | 0.4362 | 0.0275 | 0.3178 | |
R2 | 0.9221 | 0.9734 | 0.9820 | 0.9903 | |
Pseudo-second-order model | |||||
H | 0.0701 | 0.0917 | 0.0864 | 0.0745 | |
K | 1.3511 | 0.1612 | 1.6474 | 0.1245 | |
q (mmol g−1) | 0.2278 | 0.7541 | 0.2291 | 0.7735 | |
R2 | 0.9997 | 0.9995 | 0.9999 | 0.9996 | |
Intra-particle diffusion model | |||||
Step 1 | Ki | 0.0041 | 0.0480 | 0.0026 | 0.0385 |
R2 | 0.8035 | 0.9979 | 0.8866 | 0.9562 | |
Step 2 | Ki | 0.0018 | 0.0107 | 0.0009 | 0.0088 |
R2 | 0.9996 | 0.7222 | 0.9994 | 0.9782 | |
Film diffusion model | |||||
kfd | 0.0112 | 0.0334 | 0.0155 | 0.0179 | |
R2 | 0.9221 | 0.9734 | 0.9820 | 0.9903 | |
Thermodynamic parameters | |||||
ΔH (kJ mol−1) | 25.421 | 36.009 | 6.939 | − 1.143 | |
ΔS (J K−1mol−1) | 109.71 | 149.52 | 52.64 | 23.73 | |
ΔG (kJ mol−1) | 298.15 K | − 7.288 | − 8.569 | − 8.756 | − 8.219 |
308.15 K | − 8.385 | − 10.064 | − 9.282 | − 8.456 | |
318.15 K | − 9.482 | − 11.559 | − 9.809 | − 8.635 | |
328.15 K | − 10.579 | − 13.054 | − 10.335 | − 8.930 | |
Temperature range in which adsorption is spontaneous | > − 41.4 °C | > − 32.3 °C | > − 141.3 °C | All temperatures |