Research Article
Eco-Friendly Adsorbent from Waste of Mint: Application for the Removal of Hexavalent Chromium
Table 2
Adsorption kinetic model parameters at pH 2 for Cr(VI) removal.
| Model | Parameters | C0 = 10 mg/L | C0 = 20 mg/L | C0 = 30 mg/L | C0 = 40 mg/L | C0 = 50 mg/L |
| Fractional power | Linear expression | y = 0.217x + 0.560 | y = 0.264x + 0.984 | y = 0.289x + 1.233 | y = 0.280x + 1.509 | y = 0.276x + 1.592 | R2 | 0.97 | 0.98 | 0.97 | 0.99 | 0.97 | kp | 1.750 | 2.675 | 3.431 | 4.522 | 4.913 | Υ | 0.217 | 0.264 | 0.289 | 0.280 | 0.276 |
| Pseudo-first-order | Linear expression | y = −0.035x + 1.398 | y = −0.030x + 1.994 | y = −0.025x + 2.335 | y = −0.023x + 2.634 | y = −0.025x + 2.739 | R2 | 0.93 | 0.97 | 0.92 | 0.95 | 0.93 | k1P (min−1) | 0.025 | 0.023 | 0.025 | 0.030 | 0.035 | qe.1P (mg.g−1) | 15.471 | 13.929 | 10.329 | 7.344 | 4.047 |
| Pseudo-second-order | Linear expression | y = 1.940x + 0.195 | y = 1.321x + 0.099 | y = 1.025x + 0.068 | y = 0.745x + 0.055 | y = 0.672x + 0.052 | R2 | 0.95 | 0.98 | 0.96 | 0.94 | 0.91 | k2P (g.mg−1.min−1) | 0.100 | 0.074 | 0.066 | 0.073 | 0.077 | qe.2P (mg.g−1) | 5.128 | 10.101 | 14.705 | 18.181 | 19.230 |
| Elovich | Linear expression | y = 0.866x + 0.772 | y = 1.908x + 0,228 | y = 2.942x – 0.603 | y = 3.715x – 0.66 | y = 3.947x – 0.603 | R2 | 0.96 | 0.99 | 0.97 | 0.97 | 0.95 | αE (mg.g−1.min−1) | 2.111 | 2.150 | 2.396 | 3.110 | 3.387 | βE (g.mg−1) | 1.154 | 0.524 | 0.339 | 0.269 | 0.253 |
| Intraparticle diffusion | Linear expression | y = 0.253x + 2.248 | y = 0.552x + 3.521 | y = 0.853x + 4.458 | y = 1.101x + 5.558 | y = 1.176x + 5.948 | R2 | 0.96 | 0.96 | 0.95 | 0.99 | 0.98 | kD (mg.g−1.min−1/2) | 0.253 | 0.552 | 0.853 | 1.101 | 1.176 | CD (mg.g−1) | 2.248 | 3.521 | 4.458 | 5.558 | 5.948 |
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