Characteristics of heavy MONPs assessed in radish, cucumber, tomato, and alfalfa plants.
| Particulars | Al2O3-NPs | CuO-NPs | TiO2-NPs | ZnO-NPs |
|---|---|---|---|---|
| Size on packing (nm) | 20–30 | ≈40 | ≈7 | ≈30 |
| Assay, min (%) | 99.9 | 99 | 95 | 99.9 |
| Elemental% in EDX spectrum | Al (50.61), O (49.39) | Cu (76.7), O (23.3) | Ti (53.19), O (46.81) | Zn (78.92), O (21.08) |
| Morphology by SEM, AFM, and TEM | Spherical to lobular to short rods of variable length and diameter | Irregular individuals and aggregates with rough surface | Spherical with uniform size distribution | Pleomorphic, smaller to larger sized aggregates with some small thin sheets |
| Crystal size by XRD (nm) | 28 | 18 | 4 | 24 |
| Primary size by TEM (nm) | 21.8 ± 8.7 | 18.4 ± 5.5 | 3.9 ± 0.9 | 34 ± 10 |
| Secondary size by QLS (nm) | 238 ± 4.6 | 194 ± 5.8 | 148 ± 8.4 | 248 ± 11.7 |
| Zeta potential (mV) | +26.1 ± 1.7 | −29.8 ± 2.1 | +19.2 ± 2.3 | −21 ± 0.9 |
| Signal in IR spectrum (cm−1) | 466 | 533 | 541 | 482 |