In this study, novel nanofiltration membranes were prepared with acrylonitrile–butadiene–styrene (ABS)–poly(ethylene glycol)–N,N-dimethylacetamide–[tetrahydrofuran (THF)–acetone] as a cosolvent. All of the membranes were prepared by the phase inversion method and a casting solution technique. The effects of the cosolvent concentration in the casting solution and the evaporation time before the immersion/precipitation step on the membrane performance and properties were investigated. The prepared membranes were characterized through their permeation flux, salt rejection, and phase-inversion time values. The salt rejection was increased from 53% for the bare ABS membrane to 73% for the membrane prepared with 40 wt % THF as a cosolvent. The water flux was decreased from 4345 to 1121 cc m22 h21 with the addition of THF to the casting solution. The addition of acetone to the casting solution improved the water flux from 4345 to 5607 cc m22 h21 and reduced the salt rejection from 53 to 36%. The evaporation time of THF and acetone led to similar effects on flux and rejection. However, with evaporation time, membranes prepared with acetone were denser than those prepared with THF; this was due to the lower boiling point and higher boiling rate of acetone at the same temperatures. This resulted in greater effects on the ABS performance and structure.
