Preparation and benchmarking of highly hydrophilic polyaniline poly(2-acrylamido-2-methyl-1-propanesulfonic acid) PANI PAMPSA membranes in the separation of sterols and proteins from fruit juice

A straightforward approach is presented to prepare highly hydrophilic ultrafiltration polyaniline poly(2-acrylamido-2-methyl-1-propanesulfonic acid (PANI PAMPSA) membranes. Their application in the fractionation of phytosterols and proteins from fruit juice is described. Poly(2-acrylamido-2-methyl-1-propanesulfonic (PAMPSA) is added to aniline during the polymer synthesis and the membrane is prepared via phase inversion forming a highly hydrophilic and mechanically stable ultrafiltration membrane of 200 µm thickness and pure water flux of 126 LMH at 1 bar. The membrane so produced is benchmarked against a hydrophilic commercial regenerated cellulose acetate membrane (RCA) for the separation of phytosterols and proteins from orange juice. Cross-flow filtration experiments show comparable protein separation efficiency of the membranes, but better rejection of phytosterols for the commercial RCA membrane. Both commercial and lab prepared membranes are subject to fouling, with the PANI PAMPSA membrane showing higher irreversible fouling. Nevertheless, the PANI PAMPSA membrane showed a good cleaning efficiency of 74% after three fouling-cleaning cycles. Overall, this work has demonstrated the possibility of use PANI PAMPSA for ultrafiltration application and provided a better understanding of its fouling ability when compared to a commercial membrane in a multicomponent system.</p