Study on the control of pore sizes of membranes using chemical methods Part IV. The role of organic acids Original Research Article

In this paper, polyacrylonitrile (PAN) porous membranes were prepared via combination of phase inversion and chemical reaction method with different organic acids (glacial acetic acid, fumaric acid and citric acid) as additive. The experimental results showed that pure water flux of the membrane decreased with increase in polymer concentration and membrane prepared with moderate polymer concentration presented better performance. The influence of different organic acids on the properties of the casting solution was examined by viscosity, and the relationship between viscosity and membrane performance was analyzed. The prepared membranes were characterized in terms of pure water flux, retention, pore size distribution and scanning electron microscopy (SEM) observation. It was found that the membrane, prepared with glacial acetic acid, has the typical asymmetric membrane morphology with optimal combination of narrow pore size distribution and better permeability. The contribution of different organic acids in casting solution to membrane performance during chemical reaction was quantitatively analyzed, and the effects of different organic acids on membrane structures were discussed. Meantime, compaction analysis demonstrated that the membranes prepared with glacial acetic acid had improvement in resistance against compaction compared to that prepared with other acids.