| Sample name | Average size | Elementary analysis by EDX (%) |
| S1 (pH 3) | 40 ± 10 µm | Si-66.67, O2-33.33 |
| S2 (pH 5) | 1.5 ± 0.5 µm | Si-66.67, O2-33.33 |
| S3 (pH 8) | 15 ± 5 nm | Si-66.67, O2-33.33 |
| S4 (pH 10) | 3 ± 0.5 µm | Si-66.67, O2-33.33 |
| S5 (pH 12) | 10 ± 2 µm | Si-66.67, O2-33.33 |