Homogeneous CaAlg/PES hybrid ultrafiltration membranes prepared with in situ ionic crosslinking and phase inversion method

Calcium alginate hydrogel/polyethersulfone (CaAlg/PES) hybrid membranes were synthesized via combining in situ ion crosslinking with phase conversion method. Once the Sodium alginate (NaAlg) uniformly dispersed in the casting solution contacted with Ca 2+ dissolved in coagulation bath solution in the phase conversion membrane formation process, nanoscale CaAlg hydrogel was in situ formed through ion exchange and evenly dispersed in the membrane matrix. FT-IR and XPS were adopted to confirm the formation of CaAlg hydrogel distributed in PES membrane matrix. SEM, AFM, BET analysis and contact Angle analyzer were all used to characterize the surface changes of morphology, roughness and hydrophilicity in detail. Specific separation performance was also evaluated and compared by cross-flow ultrafiltration tests. Comprehensive analysis of the measured properties of all obtained membranes, when the content of NaAlg was 1.5 wt%, the CaAlg/PES hydrogel membrane M 32 had the most excellent performance. The pure water flux increased from 1967 to 2193 L/m 2 hMPa, rejection rate of BSA was up to 99.87 %, and RFR value was almost 76.83 % after 4 cycles BSA filtration. XPS characterization of the membrane after filtration for 72 hours showed that the retention rate of Ca (2 P) reached 95 %, which further proved the stability of the membrane operation.