Improved antifouling characteristics of acrylonitrile co-polymer membrane by low temperature pulsed ammonia plasma in the treatment of oil–water emulsion

• Ammonia plasma enhances hydrophilicity of PAN co-polymer membrane.
• O2 and N2 functional groups were imparted on membrane surface.
• Contact angle was reduced by 24% after 100 days.
• 32% enhancement of permeate flux was effected for oily water.

Flat sheet polyacrylonitrile co-polymer membrane was treated by low temperature direct current ammonia plasma to enhance its antifouling characteristics. The surface properties, like, morphology, functional groups and wettability of the membrane were investigated by scanning electron microscopy, fourier transform infrared, X-ray photoelectron spectroscopy and contact angle. Enhancement in membrane hydrophilicity was monitored as function of plasma operating conditions, i.e., duty cycle and treatment time. Nitrogen and oxygen functional groups were identified to be responsible for surface hydrophilicity. The plasma treated membranes were used for separation of oil–water emulsion. It was found that the anti-fouling property of membrane improved remarkably after plasma treatment by enhancement of permeate flux without significant changes in oil rejection.