The characteristics comparison of synthetic strategies for Sch samples.
| Synthetic methods | Fe2+ oxidation | Fe3+ hydrolysis | ||
|---|---|---|---|---|
| Chemical oxidation | Biological ferrooxidation | Fast hydrolysis | Slow dialysis | |
| Fe source | Fe2+ salts (sulfate) | Fe3+ salts (sulfate, nitrate, chloride) | ||
| Temperature | 24–75 | 25–40 | 60–85 | 60 |
| pH value | 2.4–3.0 | 2.5–3.2 | 1.66–4.0 | — |
| Oxidant | H2O2 | — | — | — |
| Time | 24 h | 5–7 days | 1 h–25 days | 30 d |
| References | 20,32,34,35,38,43,78,89 | 24,38,40,41,44,51,53,83,84,90 | 1,6,52,61,62,89,92 | 20,26,35,38,45,46,53,102,103 |