1 Introduction
2 Materials and Methods
2.1 Resin
Matrix | Polystyrene-divinylbenzene (PS-DVB) |
---|---|
Structure | gel |
Functional groups | diphosphonic, sulfonic, carboxylic |
Ionic form | H+ |
Total capacity (meq/g) | 5.6 |
Particle size range (mm) | 0.074–0.150 |
Density (g/mL) | 1.05–1.11 |
Moisture content (%) | 60–70 |
Max temperature range (K) | 313 |
Operating pH range | 0–12 |
2.2 Reagents and solutions
2.3 Apparatus
2.4 Adsorption studies
2.5 Desorption studies
2.6 Data analysis
2.6.1 Basic parameters characterizing adsorption process
2.6.2 Kinetic studies
2.6.3 Equilibrium studies
2.6.4 Thermodynamic studies
3 Results and discussion
3.1 Resin characteristics
3.1.1 SEM, EDF and AFM studies
3.1.2 ASAP studies
3.1.3 pHpzc studies and water contents determination
3.1.4 FTIR studies
3.2 Effect of HNO3 concentration
3.3 Effect of phase contact time and kinetic studies
Kinetic model | Parameter | La(III) | Ni(II) | ||||
---|---|---|---|---|---|---|---|
50 | 100 | 200 | 50 | 100 | 200 | ||
qexp (mg/g) | 5.30 | 11.25 | 20.50 | 2.91 | 5.03 | 9.91 | |
Pseudo-first order | q1 (mg/g) | 0.01 | 0.02 | 0.03 | 0.21 | 0.30 | 0.14 |
k1 (1/min) | 0.02 | 0.06 | 0.08 | 0.09 | 0.09 | 0.01 | |
R
2
| 0.452 | 0.855 | 0.993 | 0.849 | 0.979 | 0.404 | |
Pseudo-second order | q2 (mg/g) | 5.30 | 11.25 | 20.50 | 2.91 | 5.04 | 9.91 |
k2 (g/mg min) | 20.11 | 17.30 | 10.75 | 1.43 | 1.08 | 0.88 | |
R
2
| 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | 1.000 | |
Intraparticle diffusion | ki1 (mg/g min1/2) | 0.01 | 0.01 | 0.01 | 0.16 | 0.03 | 0.14 |
C
1
| 5.29 | 11.22 | 20.45 | 2.38 | 4.75 | 9.51 | |
R
2
| 0.906 | 0.952 | 0.840 | 0.802 | 0.848 | 0.841 | |
ki2 (mg/g min1/2) | – | – | – | 0.01 | 0.02 | 0.04 | |
C
2
| – | – | – | 2.87 | 4.83 | 9.76 | |
R
2
| – | – | – | 0.792 | 0.809 | 0.875 | |
Boyd |
Bt
| 0.0070 | 0.0072 | 0.0079 | 0.0057 | 0.0059 | 0.0033 |
R
2
| 0.849 | 0.979 | 0.805 | 0.842 | 0.855 | 0.994 |
3.4 Effect of initial concentration and equilibrium studies
Concentration (mg/L) | Adsorbed amount (mg/g) | |
---|---|---|
La(III) | Ni(II) | |
25 | 2.67 ± 0.13 | 1.54 ± 0.08 |
50 | 5.30 ± 0.27 | 2.91 ± 0.15 |
100 | 11.25 ± 0.56 | 5.03 ± 0.25 |
150 | 16.20 ± 0.81 | 7.47 ± 0.37 |
200 | 20.50 ± 1.02 | 9.91 ± 0.49 |
300 | 30.03 ± 1.50 | 15.13 ± 0.76 |
400 | 39.51 ± 1.98 | 19.01 ± 0.95 |
600 | 59.41 ± 2.97 | 26.69 ± 1.33 |
Isotherm model | Parameter | La(III) | Ni(II) |
---|---|---|---|
Langmuir | qm (mg/g) | 98.73 | 45.75 |
KL (L/mg) | 0.88 | 0.01 | |
R
2
| 0.989 | 0.945 | |
Freundlich | KF [(mg/g)(L/mg)1/n] | 41.57 | 2.23 |
1/n | 0.76 | 0.71 | |
R
2
| 0.989 | 0.996 | |
Temkin | AT (J/mol) | 16.27 | 7.17 |
KT (L/g) | 11.99 | 14.79 | |
R
2
| 0.932 | 0.905 |
3.5 Effect of temperature and thermodynamic studies
Parameter | La(III) | Ni(II) | |
---|---|---|---|
ΔH° (kJ/mol) | − 6.98 | − 11.71 | |
ΔS° (J/mol K) | 12.14 | − 43.92 | |
ΔG° (kJ/mol) | 293 K | − 26.81 | − 12.79 |
303 K | − 27.46 | − 13.15 | |
313 K | − 28.17 | − 13.27 |
3.6 Distribution coefficient comparison for REE and HM ions
3.7 Desorption studies
3.8 Metal ions mixture adsorption/desorption
3.9 Comparison of adsorption capacity of REEs and HMs with various materials
Material | Optimal pH | Initial concentration (mg/L) | Element recovered | Adsorption capacity (mg/g) | Refs. | |
---|---|---|---|---|---|---|
Magnetic nanoparticles CuFe2O4 | 7–8 | 3–20 | La, Ce | 42.02 (La) 40.16 (Ce) | Tu and Johnston (2018) | |
Calcium alginate | 5 | 50–200 | La, Cu | 37.59 (La) 15.09 (Cu) | Kolodynska and Fila (2018) | |
Cyanex 272 impregnated Amberlite XAD-7 resin | 2.5 | 751 (La) 113 (Nd) | La, Nd | 11.1 (La) 1.69 (Nd) | İnan et al. (2018) | |
Synthetic alumosilicate zeolite | – | – | Ni, Cu, Fe | 140 (Ni) 160 (Cu) 560 (Fe) | Shilina et al. (2017) | |
Oxidized ordered mesoporous carbons | 5 | – | Ni, Co | 126–145 (Ni) 135–148 (Co) | Marciniak et al. (2018) | |
Chelating resin 1,8-(3,6-dithiaoctyl)-4-polyvinylbenzenesuphonate (dpvbs) | 5.5 | 150 | Cu | 46.07 (Cu) | Khalil et al. (2018) | |
6 | Fe, Co, Ni | 44.68 (Fe) 30.94 (Co) 28.47 (Ni) | ||||
Diphonix resin | 2 | 25–600 | La, Ni | 59.41 (La) 26.69 (Ni) | This study | |
4.55 (Nd) 6.45 (Ce) 35.6 (La) 58.75 (Fe) 16.30 (Co) 134.40 (Ni) 4.7 (Cu) 4.5 (Zn) | Nd, Ce, La, Fe, Co, Ni, Cu, Zn | 0.65 (Nd) 1.00 (Ce) 6.65 (La) 3.48 (Fe) 1.74 (Co) 14.86 (Ni) 0.15 (Cu) 0.41 (Zn) |