Table 4.
Classes and types of filtration by biomimetic nanomembranes.
| Class | Type | Mechanism and Action |
|---|---|---|
| Pore filtration | Particle filtration | Pressure-driven filtration through >1 μm pores and above, removes large suspended particles 1 |
| Microfiltration | Pressure-driven filtration through 0.1 μm to 1 μm pores, removes bacteria and suspended organic and inorganic particles | |
| Ultrafiltration | Pressure-driven filtration through 1–100 nm pores, removes all above plus viruses | |
| Nanofiltration | Pressure-driven filtration through ~0.3–1 nm pores, removes all above plus large (polyvalent) ions | |
| Filtration by diffusion | Reverse Osmosis | An applied pressure is used to overcome osmotic pressure for separation through a semi-permeable membrane, removes all above plus small (monovalent) ions |
| Forward Osmosis | Separation driven by osmotic pressure gradient through a semi-permeable membrane | |
| Dialysis | Solute separation is induced by the difference in solute diffusion transport through the membrane | |
| Filtration assisted by liquid-gas phase transition | Pervaporation | Separation of mixtures of liquids by permeation through a membrane, followed by vaporization |
| Membrane Distillation | Thermally driven separation of liquids where only vapor molecules move through a microporous hydrophobic membrane | |
| Gas Permeation | Separation of gas mixtures permeating a membrane based on the fact that the flux of each gas is different | |
| Evapomeation | Separation of mixtures of liquids by full vaporization through a non-porous or porous membrane |
1 Only applicable if the biomimetic nanomembrane is supported by a porous substrate.