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 DSeries 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 removal/concentration, sodium chloride diafiltration and metals recovery.
Typical Operating Flux: 5 – 20 GFD (8 – 34 LMH)
Maximum Operating Pressure: 600 psi (4,137 kPa) if T<95°F (35°C) 435 psi (3,000 kPa) 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 – 9
Clean-In-Place (CIP): 2 – 11 (1)
Maximum Pressure Drop Over an element: 15 psi (103 kPa)
Per housing: 60 psi (414 kPa)
Chlorine Tolerance 500 ppm hours,
Feedwater NTU < 1 SDI 15 < 5