Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Kinetic parameters evaluated for the process of CO2 adsorption onto the nano-CaO adsorbent at different temperatures
| Models | Parameters | Temperature | ||
|---|---|---|---|---|
| 25°C | 50°C | 75°C | ||
| Pseudo-first-order model | k1 (/min) | 0.24 | 0.58 | 0.13 |
| qmax (mmol/g) | 4.59 | 3.81 | 5.27 | |
| R2 | 0.78 | 0.58 | 0.74 | |
| Pseudo-second-order model | k2 (/min) | 3.41 | 1.4 | 0.20 |
| qmax (mmol/g) | 9.02 | 10.08 | 11.02 | |
| R2 | 0.9999 | 0.9996 | 0.9998 | |
| Elovich | α (mmol/g) | 176.8 | 122.1 | 41.2 |
| β (mmol/g) | 1.00 | 1.16 | 1.40 | |
| R2 | 0.48 | 0.50 | 0.59 | |
Intraparticle diffusion
| qe (mmol/g) | 7.56 | 8.33 | 8.53 |
| kip1 (mmol/g min1/2) | 4.36 | 4.81 | 4.92 | |
| R2 | 0.87 | 0.85 | 0.90 | |
| qe (mmol/g) | 3.38 | 3.51 | 4.64 | |
| kip2 (mmol/g min1/2) | 0.87 | 0.90 | 1.19 | |
| R2 | 0.995 | 0.94 | 0.94 | |
Summarized linear isotherm parameters for CO2 adsorption on nano-CaO adsorbent at the temperatures of 25°C, 50°C, and 75°C and at pressures of 1 atm, 5 atm, 10 atm, and 15 atm for each temperature
| Temperature (°C) | Langmuir constants | Freundlich constants | ||||
|---|---|---|---|---|---|---|
| qmax (mmol/g) | KL (/atm) | R2 | KF (mmol/g [atm]1/n) | 1/n | R2 | |
| 25 | 10.74 | 0.48 | 0.996 | 0.111 | 0.049 | 0.78 |
| 50 | 11.31 | 0.35 | 0.998 | 0.099 | 0.022 | 0.75 |
| 75 | 12.55 | 0.31 | 0.998 | 0.091 | 0.009 | 0.88 |