Fabrication of cellulose acetate–zirconia hybrid membranes for ultrafiltration applications: Performance, structure and fouling analysis

Organic–inorganic hybrid membranes were fabricated by solution casting using different ratios of cellulose acetate (CA) and zirconia (ZrO2) in N,N′-dimethylformamide (DMF). The addition of ZrO2 microparticles in the CA matrix was varied from 0 to 7 wt.%. The developed membranes were characterized for ultrafiltration (UF) performance, mechanical stability, morphology and fouling-resistant ability. It is found that the pure water flux increases from 15.6 to 46.7 lm−2 h−1 while the tensile strength decreases from 2 to 1.4 N/mm2 with addition of zirconia from 0 to 7 wt.% to pure CA, respectively. Morphological studies indicate that the CA:ZrO2 hybrid membranes possess asymmetric structure with ultra scale pores. From the pore statistics analysis, it was seen that the CA:ZrO2 (6:4 ratio) hybrid membranes have an average pore radius of 47.52 Å compared to 26.88 Å of pure CA membrane. It was found that the hybrid CA:ZrO2 membranes exhibit higher permeate flux for the separation of different molecular weight proteins compared to pure CA membrane. It has been demonstrated that the fouling-resistant ability and the recycling property of CA:ZrO2 hybrid membranes are enhanced due to the high flux recovery ratio with the addition of ZrO2 in the casting solution.

Hybrid membranes have been developed using cellulose acetate and zirconia microparticles for improving the ultrafiltration performance especially flux and fouling resistance. Recycling potential of the CA:ZrO2 hybrid membranes was analyzed by three cycles of UF of BSA solution and the results are shown in the graph. As can be seen, the water flux went up to 30 lm−2 h−1 after three runs of BSA solution for the CA:ZrO2 membrane with ZrO2 content of 7 wt.%. compared to 9.1 lm−2 h−1 for pure CA membrane. Hence, it is shown that the recyclable potential of CA:ZrO2 hybrid membranes is improved considerably.Figure optionsDownload as PowerPoint slide