Development of a superhydrophilic nanofiber membrane for oil/water emulsion separation via modification of polyacrylonitrile/polyaniline composite

In this research, polyaniline (PANI) was used to modify polyacrylonitrile (PAN) electrospun nanofibers for separating oil/water (O/W) emulsions due to its hydrophilic amino groups and simple synthesis. The fabrication of PAN/PANI membranes was carried out by two different methods: blending of PANI with PAN in pre-electrospinning solution and coating of PANI on the PAN electrospun nanofibers using in situ polymerization of aniline. The effect of PANI composition (10, 20, 30 and 40 wt% with respect to the weight of PAN) and electrospinning temperature (25 degrees C, 40 degrees C and 55 degrees C) was investigated in PAN/PANI membrane fabrication. The prepared membranes were characterized by Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), water and under water oil contact angle (WCA and UOCA) measurement and mechanical tensile test. Regarding the results, PAN/40%PANI nanofibers prepared at 40 degrees C was considered as the superhydrophilic nanofibers (WCA < 5 degrees) and the most suitable membrane among the samples for separation of O/W emulsions. Separation studies revealed a flux of 1300 Lmh (pure water) under gravity and an efficient oil rejection of about 98.8% for PAN/40%PANI@40 degrees C membrane. Hence, the PAN/40%PANI@40 degrees C membrane was subjected to additional tests including separation of different industrial oils, emulsion separation with surfactant agent, separation under harsh acidic/basic conditions and fouling test. The results confirmed an efficient performance of the obtained superhydrophilic membrane for O/W separation, which make it a potential candidate for the purification of water from industrial organic pollutant.

Automated summary

In this study, PAN/PANI membranes were prepared by modifying PAN electrospun nanofibers with PANI. The PAN/40%PANI nanofibers prepared at 40 degrees C exhibited superhydrophilicity and were found to be the most suitable membrane for separating O/W emulsions. The membrane showed high water flux and efficient oil rejection, making it a promising candidate for water purification from industrial organic pollutants.