The use of ultrafiltration for treatment of spent solvent cleaning rinses from nickel-plating operations: membrane material selection study

Solvent-resistant hollow-fiber UF membranes were selected by measurement of fiber swelling and treatability studies on spent solvent cleaning rinse. The experimental results indicated that the membranes made of both cellulose acetate (CA) and polyacrylonitrile (PAN) materials could tolerate the solvent present and were suitable for treating the spent solvent rinses, whereas polyethersulfone and polysulfone membranes were not suitable. The CA membrane had the lowest fouling tendency when treating the spent solvent rinse. The results also showed that retentions of the emulsified solvent and oil–grease for the CA membrane were above 96% and 80%, respectively, and the PAN membrane had better retention than the CA membrane. It was hypothesized that there might be a critical micellar concentration for oil–grease for the PAN membrane.

1. The membranes made of CA and PAN could tolerate the solvent(s) present in the cleaner and were suitable for treating the spent solvent rinses, whereas PES and PSf membranes were not suitable. 2. Among CA, PAN and PES membranes, the CA membrane showed the lowest fouling tendency when treating spent solvent rinse. 3. Retention of the CA membrane for emulsified solvent and oil–grease was above 96% and 80%, respectively, and the PAN membrane had better retention than the CA membrane. 4. There might be a critical micellar concentration of oil–grease corresponding to the PAN membrane with a MWCO of 13,000 Da.