Pilot study on the treatment of spent solvent cleaning rinse in metal plating

Pilot trials on a spent solvent cleaning rinse from a nickel-plating operation were conducted using polyacrylonitrile hollow-fiber UF membranes. The results indicated that the membrane pore size and operating conditions were important factors for treating the emulsified spent solvent rinse. Retention of TOC increased with a decrease in membrane pore size or product recovery. TOC retention also increased with increase of feed velocity. Flux declines of membranes of MWCO 13 K and 50 K over time showed the same trend and their stabilized fluxes were 12 and 60 L m−2 h−1 at 0.1 MPa, respectively. The results also showed that retention of TOC and oil/grease for the membrane of MWCO 13 K was above 95.1% and 72.5%, respectively. It was hypothesized that there might be a critical micellar concentration for the emulsified solvent or oil/grease.