The D-Series family of proprietary thin-film nanofiltration membrane elements is characterized by an approximate molecular weight cut-off of 150-300 Dalton for uncharged organic molecules. Divalent and multivalent anions are preferentially rejected by the membrane while monovalent ion rejection is dependent upon feed concentration and composition. Since monovalent ions pass through the membrane, they do not contribute to the osmotic pressure, thus enabling D-Series nanofiltration membrane systems to operate at feed pressures below those of RO systems.
Among other applications, DK High Rejection NF Elements are used for dye brine purification, demineralization / concentration of organic solutions and metals recovery.
Typical Operating Flux: 5-20 GFD (8-34 LMH)
Maximum Operating Pressure:
600psi (4,137kPa) if T<95°F (35°C)
435psi (3,000kPa) if T>95°F (35°C)
Maximum Temperature:
Continuous Operation: 122°F (50°C)
Clean-In-Place (CIP): 122°F (50°C)
pH Range:
Continuous Operation: 3.0 – 9.0
Clean-In-Place (CIP): 2.0 -11.0
Maximum Pressure Drop:
Over an element: 15 psi (103 kPa)
Per housing: 60 psi (414 kPa)
Chlorine Tolerance: 500 ppm hours, dechlorination recommended
Feed water: NTU < 1 SDI₁₅ < 5