Table 2.
Adsorption isotherm parameters for MR and MO dye adsorption onto AC and ZnO@AC composite estimated from the non-linear models.
| Isotherm model | Parameter | AC | ZnO@AC composite | ||
|---|---|---|---|---|---|
| MR | MO | MR | MO | ||
| Langmuir | qm (mg/g) | 38.408 ± 1.659 | 42.508 ± 1.919 | 45.992 ± 2.316 | 44.500 ± 2.356 |
| KL (L/mg) | 0.112 ± 0.020 | 0.210 ± 0.021 | 0.208 ± 0.048 | 0.261 ± 0.039 | |
| Adj. R2 | 0.968 | 0.990 | 0.953 | 0.951 | |
| X2 | 4.202 | 1.069 | 10.161 | 9.001 | |
| Freundlich | Kf (L/g) | 9.828 ± 1.502 | 3.417 ± 0.743 | 15.649 ± 2.109 | 13.601 ± 1.377 |
| N | 3.45 ± 0.039 | 2.101 ± 0.051 | 4.082 ± 0.0368 | 3.77 ± 0.027 | |
| Adj. R2 | 0.914 | 0.940 | 0.896 | 0.933 | |
| X2 | 11.308 | 6.151 | 22.397 | 9.262 | |
pH = 3; temperature = 20 °C; initial dye concentration = 10–200 mg/L; adsorbent dose = 1.2 g/L; contact time = 45 min.