Research Article
Metals Ions Removal by Polymer Membranes of Different Porosity
Table 4
Acidic properties of investigated adsorbents before and after filtration with 15 mg/dm3 iron solution (mmol/g).
| | Membrane | pKa | | | | | | <3 | 3–5 | 5–7 | 7–9 | 9–11 | >11 | Acidic groups | Total content of surface oxides | | A | B | A | B | A | B | A | B | A | B | A | B | A | B | A | B |
| | PES-18 PVP-1 | — | — | 3.86 | 2.05 | 1.32 | — | 0.14 | 0.15 | — | 0.78 | 1.72 | 1.63 | 7.04 | 4.61 | 8.98 | 6.88 | | PES-18 PVP-2 | — | 0.24 | 0.55 | 2.01 | — | — | 0.06 | 0.13 | 0.66 | 0.69 | 0.87 | 1.18 | 2.14 | 4.25 | 3.04 | 6.41 | | PES-18 PVP-3 | — | — | 0.58 | 1.98 | 0.98 | — | 0.21 | 0.08 | — | 0.86 | 1.54 | 0.68 | 3.31 | 3.60 | 5.19 | 5.64 | | PES-18 PVP-4 | — | — | 2.14 | 2.28 | — | — | 0.09 | 0.12 | 0.81 | 1.08 | 1.30 | 1.02 | 4.34 | 4.50 | 6.40 | 6.93 |
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A: before filtration, B: after filtration.
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