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. 2016 Jul 26;14:11. doi: 10.1186/s40201-016-0252-0

Table 2.

The kinetic and thermodynamic and isotherm constants for the adsorption of Cr (VI) and Ni (II) by Fe3O4 NH2 and other adsorbents

Tem. Adsorbent pH Pseudo-second-order Thermodynamic parameters Ref.
(k) Cr (VI) Ni (II) K2 (g/mg−1) (min)−1 qe,cal (mg/g−1) R2 ΔGɵ (kJ mol−1) ΔHɵ (kJmol−1) ΔSɵ (J (mol K)−1)
308 EDA-NMPs 2.5 - 0.7862 - 1 −1.61 10.59 37.50 [25]
308 DETA-NMPs 2.5 - 0.3668 - 1 −1.76 9.67 34.64 [25]
308 TETA- NMPs 2.5 - 0.3219 - 1 −2.15 23.15 76.82 [25]
308 TEPA- NMPs 2.5 - 0.1042 - 1 −2.36 10.46 38.04 [25]
303 Activated Alumina 3 - - 0.0757 0.999 9.78 - - [40]
298 LewaitMP 610 5 - - - - −10.40 −2.51 35.49 [5]
298 Fe3O4 - 6 0.004 0.998 - - - [41]
298 ZnO - 6 0.002 0.998 - - - [41]
298 CuO - 6 0.019 0.995 - - - [41]
303 Bagass Fly ash 5 - - - - −1.46 14.24 49 [42]
293 Nano-HAP - 6.6 - - - −1.599 8.438 83.1 [30]
298 Superparamagnetic Iron Oxide - 5.5 - - - 27.9 7.8 110 [29]
293 Fe3O4-GS 2 - 0.055 17.29 0.999 −4.182 76.63 18.28 [28]
293 Fe3O4-GS - 6 0.0203 22.07 0.998 −3.456 31.86 5.965 [28]
323 Fe3O4-TW - 6 - - - 10.02 33.41 0.5799 [6]
298 Waste tea - 4 - - - −3.82 17.07 20.92 [43]
313 DETA-NMPs - 6 1.03 9 0.999 −13.7 8.41 72.83 [25]
298 Fe3O4-NH2 3 - 0.002 28.25 0.987 −3.2891 137.1 ΔSɵ R2 This study
26.91 0.975
298 Fe3O4-NH2 - 6 0.008 25.97 0.994 −6.8433 116.7 31.02 0.960 This study
303 Fe3O4-NH2 Cr (VI) Ni (II) - - - ΔGɵCr (VI) ΔGɵNi (II) This study
3 6 −5.5038 −8.424
308 Fe3O4-NH2 3 6 - - - −9.7477 −10.045 This study
313 Fe3O4-NH2 3 6 - - - −13.234 −12.934 This study
If: RL > 1, the adsorption is unfavorable. RL = 1, the adsorption is linear.
0 < RL < 1, the adsorption is favorable. RL = 0, the adsorption is irreversible.		 [17, 44, 45]
If: 1/n < 1, the adsorption is unfavorable. If: 0.1 < 1/n < 1, the adsorption is favorable. [46]
Tem. Adsorbent pH Freundlich constants Langmuir constants Ref.
(k) Cr (VI) Ni (II) KF (Lg−1) n R2 qmax (mg g−1) KL (Lmg−1) R2
308 EDA-NMPs 2.5 - - - - 136.98 0.1648 0.999 [25]
308 DETA-NMPs 2.5 - - - - 149.25 0.4467 0.999 [25]
308 TETA- NMPs 2.5 - - - - 204.08 0.075 0.998 [25]
308 TEPA- NMPs 2.5 - - - - 370.37 0.1233 0.999 [25]
298 Walanut 3.5 - 0.244 3.36 0.989 8.01 2.98 0.964 [2]
298 Hazelnut 3.5 - 0.386 2.38 0.992 8.28 4.42 0.976 [2]
298 Almand Shells 3 - 0.153 2.68 0.984 3.40 0.580 0.972 [2]
303 Activated Alumina 3 - 2.84 1.80 09880 25.57 0.467 0.991 [40]
298 Mag 2.5 - 4.90 2.94 0.729 20.16 0.262 0.998 [47]
298 MagDt-H 2.5 - 1.62 2.63 0.984 13.88 0.030 0.965 [47]
298 Lewait MP 610 5 - - - - .41 - 0.99 [5]
298 PAC - 8 0.02 2.85 0.708 31.08 0.27 0.98 [48]
298 Bagass - 8 1.4E-03 0.868 0.868 0.03 0.95 0.97 [48]
298 Fly ash - 8 2.03E-04 0.696 0.811 0.001 0.95 0.98 [48]
298 Fe3O4 - 6 1.550 0.996 - - - - [41]
298 ZnO - 6 0.319 0.991 - - - - [41]
298 CuO - 6 0.162 0.992 - - - - [41]
303 Bagass Fly ash 5 - 1.86 12.05 - 4.35 0.014 0.987 [42]
298 NH2−MCM-41 5 - 2.759 2.2 0.900 12.36 0.2245 0.956 [49]
293 Nano-HAP - 6.6 8.87 2.74 0.934 46.17 0.07 0.995 [30]
298 DNPH-γ-Al2O3 - 5 1.95 2.037 0.926 18.18 1.426 0.985 [26]
293 Fe3O4-GS 2 - 30.58 3.01 0.997 39.92 4.08 0.959 [28]
293 Fe3O4-GS - 6 3.801 2.56 0.993 158.5 0.2830 0.966 [28]
323 Fe3O4-TW - 6 4.85 1.78 0.975 38.30 0.085 0.996 [6]
298 Superparamagnetic Iron Oxide - 5.5 0.113 0.213 0.986 0.189 mmol/g 1.39 L/mmol 0.999 [29]
298 Waste tea - 4 0.258 0.93 0.922 15.26 0.088 0.996 [43]
333 Fe3O4 -CNTs - 2 7.23 3.05 0.981 65.96 0.42 0.997 [44]
313 DETA-NMPs - 6 1.304 2.54 09026 43.24 0.288 0.999 [25]
298 Fe3O4-NH2 3 - 1.13 2.05 0.940 222.12 KL RL 0.995 This study
0.314 0.03-0.39
298 Fe3O4-NH2 - 6 1.44 1.83 0.979 232.51 0.383 0.02-0.34 0.988 This study
If: RL > 1, the adsorption is unfavorable. RL = 1, the adsorption is linear.
0 < RL < 1, the adsorption is favorable. RL = 0, the adsorption is irreversible.		 [17, 44, 45]
If: 1/n < 1, the adsorption is unfavorable. If: 0.1 < 1/n < 1, the adsorption is favorable. [46]