Blended Polysulfone/Polyethersulfone (PSF/PES) Membrane with Enhanced Antifouling Property for Separation of Succinate from Organic Acids from Fermentation Broth

Biofouling is a serious challenge in the separation of succinic acid from fermentation broth because of its complex mixture containing substantial amount of dissociated and nondissociated forms of dissolved organics, metabolites, residual mineral salts, and bacteria. A robust blended polysulfone/polyethersulfone (PSF/PES) membrane was fabricated and presented in this study for alleviating the challenges encountered during biobased succinic acid separation. PSF/PES membranes were fabricated at varying compositions of polymers via the phase inversion technique and coated with poly(vinyl) alcohol (PVA) to enhance its antifouling properties. The synthesized membranes were characterized for surface morphology, surface functionalities, thermal stability, surface hydrophilicity, and mechanical properties by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis, contact angle measurement, and nanotensile tests, respectively. The performances of PSF/PES membranes for succinic recovery were evaluated from a synthetic fermentation broth, consisting of succinate, formate, and acetate. Influence of different process conditions such as polymer compositions, feed concentrations, and filtration pressures were investigated on the fabricated membranes. From the SEM results, the fabricated membranes showed the formation of pores with a dense outer surface. The membranes also displayed exceptional thermal stability based on the consistent FTIR and contact angle analysis. A notable higher pure water flux of 114.60 Lm–2 h–1 was observed for 100% PES/PVA and 128.40 Lm–2 h–1 pure water flux for the 75% PSF/PES-blended membrane coated with PVA. The rejection performance improved with decreasing pressure and low feed concentration. The PSF/PES-blended membrane exhibited a high succinate rejection of 99.9% from synthetic broth. It can be concluded that the PSF/PES/PVA-coated membrane has a great potential in applications for succinic acid separation from synthetic fermentation broth.