Preparation, characterization, acid stability and organic fouling of poly(acrylonitrile-co-methacrylic acid) ultrafiltration membranes

Poly(acrylonitrile-co-methacrylic acid) (PANMA) ultrafiltration membranes were prepared according to phase-inversion method using a semi-automatic mechanical casting unit. Membranes were made using casting dopes containing PANMA (16–22%) and polyvinylpyrrolidone (0–2%) in dimethylformamide or the mixture of dimethylformamide (DMF) and tetrahydrofuran (THF). SEM micrographs showed the presence of finger-like macrovoids and tear drop shape-like cavities under the dense skin layer for the membranes prepared using the casting dope containing 16–18% and 20–22% PANMA, respectively. The pure water fluxes were in the range of 756–78 and 246–52 L/m2.h at 3 kg/cm2, and the molecular weight cut off values were found to be in the range of 96–112 kDa and 92–102 kDa, respectively, for the membranes prepared using the casting dope in DMF and DMF + THF. Fouling tendency of the membranes was studied by permeating aqueous solution of PEO-100 kDa and measuring the trend in the flux with time. The flux recovery ratio values were in the range of 93–99%, thus indicating that the membranes have excellent fouling resistant nature. Acid stability measurements have shown that the flux was decreased by 13–16% while, there was no significant change in the rejections of the membranes which were immersed in 5–20% sulphuric acid solution for 12 months.

► Poly(acrylonitrile-co-methacrylic acid) ultrafiltration membrane preparation.
► Effect of the presence of tetrahydrofuran in the casting dope on membrane morphology.
► SEM micrographs with macrovoids or tear drop shape-like voids.
► Acid stability, fouling resistant and high flux recovery efficiency.