Table 4. Thermodynamic Parameters for Adsorption of Zn(II), Pb(II), and Cd(II) Ions on the Prepared PSP Biosorbenta.
| metal ion | T (K) | ΔG0 (kJ/mol) | ΔS0 (kJ(K–1/mol) | ΔH0 (J/mol) | R2 |
|---|---|---|---|---|---|
| Zn(II) | 293 | –3.770 | 27.75 | 108.83 | 0.988 |
| 298 | –4.353 | ||||
| 303 | –4.798 | ||||
| 308 | –5.315 | ||||
| 313 | –6.014 | ||||
| Pb(II) | 293 | –1.398 | 19.06 | 70.01 | 0.986 |
| 298 | –1.803 | ||||
| 303 | –2.202 | ||||
| 308 | –2.520 | ||||
| 313 | –2.784 | ||||
| Cd(II) | 293 | –0.842 | 15.29 | 55.24 | 0.981 |
| 298 | –1.198 | ||||
| 303 | –1.489 | ||||
| 308 | –1.679 | ||||
| 313 | –1.979 |
a
Batch conditions: initial metal concentration: 100 mg/L; pH: 6.5; contact time: 90 min; adsorbent dose: 25 mg; solution volume: 40 mL.