All the models were fitted to the measured loadings using nonlinear regression. Linearization of the models and the data was avoided because such manipulation affects the weights of the data points and the residuals. The parameters obtained with the three isotherm models are listed in Table 2 and the isotherm plots are shown in Figure 4.
Close modal
Table 2
Parameters of the nonlinear fitted isotherm models of MOF/LDH powder at 25 °C
| Isotherm | Parameter | R2 | ||
|---|---|---|---|---|
| Langmuir | qm (mg P/g) | KL (L/mg) | 0.9293 | |
| 60.86 | 6.10 | |||
| Freundlich | N | Kf (mg/g·(L/mg)1/n) | 0.9679 | |
| 7.67 | 45.20 | |||
| Fowler–Guggenheim | qm (mg P/g) | KFG (L/g) | χ | 0.9993 |
| 74.96 | 35.71 | −5.38 |
| Isotherm | Parameter | R2 | ||
|---|---|---|---|---|
| Langmuir | qm (mg P/g) | KL (L/mg) | 0.9293 | |
| 60.86 | 6.10 | |||
| Freundlich | N | Kf (mg/g·(L/mg)1/n) | 0.9679 | |
| 7.67 | 45.20 | |||
| Fowler–Guggenheim | qm (mg P/g) | KFG (L/g) | χ | 0.9993 |
| 74.96 | 35.71 | −5.38 |
Figure 4
Nonlinear fitted isotherm plots of MOF/LDH powder at 25 °C (batch adsorption experiments, C0 ∼50 mg P/L KH2PO4 solution, 48 h equilibrium with intermediate handshaking, and pH adjusted to 5.9−6.1, four times).
Figure 4
Nonlinear fitted isotherm plots of MOF/LDH powder at 25 °C (batch adsorption experiments, C0 ∼50 mg P/L KH2PO4 solution, 48 h equilibrium with intermediate handshaking, and pH adjusted to 5.9−6.1, four times).