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.

ModelParametersC0 = 10 mg/LC0 = 20 mg/LC0 = 30 mg/LC0 = 40 mg/LC0 = 50 mg/L

Fractional powerLinear expressiony = 0.217x + 0.560y = 0.264x + 0.984y = 0.289x + 1.233y = 0.280x + 1.509y = 0.276x + 1.592
R20.970.980.970.990.97
kp1.7502.6753.4314.5224.913
Υ0.2170.2640.2890.2800.276

Pseudo-first-orderLinear expressiony = −0.035x + 1.398y = −0.030x + 1.994y = −0.025x + 2.335y = −0.023x + 2.634y = −0.025x + 2.739
R20.930.970.920.950.93
k1P (min−1)0.0250.0230.0250.0300.035
qe.1P (mg.g−1)15.47113.92910.3297.3444.047

Pseudo-second-orderLinear expressiony = 1.940x + 0.195y = 1.321x + 0.099y = 1.025x + 0.068y = 0.745x + 0.055y = 0.672x + 0.052
R20.950.980.960.940.91
k2P (g.mg−1.min−1)0.1000.0740.0660.0730.077
qe.2P (mg.g−1)5.12810.10114.70518.18119.230

ElovichLinear expressiony = 0.866x + 0.772y = 1.908x + 0,228y = 2.942x – 0.603y = 3.715x – 0.66y = 3.947x – 0.603
R20.960.990.970.970.95
αE (mg.g−1.min−1)2.1112.1502.3963.1103.387
βE (g.mg−1)1.1540.5240.3390.2690.253

Intraparticle diffusionLinear expressiony = 0.253x + 2.248y = 0.552x + 3.521y = 0.853x + 4.458y = 1.101x + 5.558y = 1.176x + 5.948
R20.960.960.950.990.98
kD (mg.g−1.min−1/2)0.2530.5520.8531.1011.176
CD (mg.g−1)2.2483.5214.4585.5585.948