Nanofiltration NF Membrane Technology — ExcellNano™
Available from SnowPure Water Technologies
Nanofiltration (NF) is a membrane separation process. NF membranes pass water and reject ionic and non-ionic species based on both size and charge.
Nanofiltration is not simply “loose RO”, and does more than “pass more ions than an RO” (as the phrase implies).
Nanofiltration membranes are tuned to perform the specific separation the customer needs. Each NF manufacturer chooses specific ranges of species rejection and water flux/pressure for their markets.
SnowPure’s targets process separations with its specialty NF membranes.
NF Separation Mechanism:
NF membrane chemistry is an aliphatic-aromatic polyamide thin-film composite formed on top of a porous substrate, typically a polysulfone ultrafiltration membrane. It can be flat sheet (for spiral assembly) or hollow fiber in form. The NF chemistry and thin film formation process varies to control the ionic separation. Ionic separation is based on the negative (-) charge of the membrane at normal pH. NF rejects 100% of divalent anions like SO4-2, and to maintain neutrality then holds back first divalent cations like Ca+2 then singly-charged monovalent cations like Na+.
Because of the NF rejection mechanisms, the separation performance depends highly on the composition of the feedwater to be filtered.
SnowPure NF models predict ionic separations in different feedwaters.