← Technology WikiNF Membrane (Nanofiltration)
An NF (nanofiltration) membrane sits between UF and RO at ~0.001-micron pores — it softens water and removes most divalent ions and organics while operating at lower pressure than RO.
How it works
- Pore size around 0.001 micron: rejects most divalent ions (calcium, magnesium) and organics above ~200 Daltons.
- Partial salt rejection (typically 50–90% depending on ion type) — a middle ground between UF and RO.
- Lower operating pressure than RO (typically 70–120 PSI), so energy and pump costs are lower.
- Common uses: water softening, partial desalination, and industrial process water.
Key specifications
| Pore size | ≈0.001 micron |
| Salt rejection | 50–90% (ion-dependent) |
| Operating pressure | 70–120 PSI |
| Best for | Softening, partial desalination |
What buyers and QC should check
- NF is a niche choice for drinking water — confirm the buyer's spec actually calls for NF, not RO, before quoting.
- Rejection rates vary strongly by ion type; ask for the test report against YOUR target ions.
Free one-page QC checklist (PDF)
The buyer checks from this entry, condensed for the factory floor or the inspection. No signup needed.
Download free PDF checklistCommon questions
When would I choose NF over RO?
When you want softening and partial salt removal at lower energy cost — e.g., reducing hardness without fully demineralizing the water.
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