Table 3.
Non-linear parameters of Langmuir, Freundlich, Redlich-Peterson, Temkin, and Dubinin–Radushkevich isotherms, along with partition coefficient for methylthioninium chloride sorption onto date palm waste-derived biochar (DBC), date palm waste-derived carbon nanodots (nCD-DBC), and date palm waste-derived biochar composited with nano zero-valent iron (nZVI-DBC).
| Isotherms | Parameters | nCD-DBC | nZVI-DBC | DBC | |
|---|---|---|---|---|---|
| Langmuir | QL | (mg g− 1) | 1558.66 | 1182.90 | 851.67 |
| KL | (L g− 1) | 0.13 | 0.02 | 0.03 | |
| R2 | 0.96 | 0.99 | 0.94 | ||
| Freundlich | KF | (L g− 1) | 378.00 | 156.67 | 144.65 |
| 1/n | 0.27 | 0.26 | 0.32 | ||
| R2 | 0.95 | 0.96 | 0.95 | ||
| Redlich-Peterson | A | (L g− 1) | 282.59 | 39.79 | 19.29 |
| B | (L mg− 1)g | 0.33 | 0.10 | 0.02 | |
| g | 0.86 | 0.92 | 0.82 | ||
| R2 | 0.98 | 0.99 | 0.96 | ||
| Temkin | b | (J mol−1) | 263.70 | 217.86 | 146.83 |
| A | (L g−1) | 1.99 | 0.44 | 0. 22 | |
| R2 | 0.97 | 0.98 | 0.94 | ||
| Dubinin–Radushkevich | QD | (mg g−1) | 1283.40 | 972.97 | 755.04 |
| E | (kJ g−1) | 0.01 | 0.27 | 0.66 | |
| R2 | 0.81 | 0.89 | 0.75 | ||
| Partition coefficient | KP (mL g−1) | 7067 | 1460 | 930 | |