Porous composites based on cellulose acetate and alfa-hematite with optical and antimicrobial properties

•α-Fe2O3 NPs were produced without surfactants.•α-Fe2O3 NPs showed good physicochemical properties.•CA/α-Fe2O3 composite membranes were produced by NIPS methodology.•The composite membranes showed better properties than CA membrane.•Antibacterial activity is explained by electrostatic interactions. Polymer nanoparticles (NPs) composites are rapidly gaining attention due to their high potential for application in several technological fields. On one hand, polymers contribute to balance the attractive magnetic and van der Waals forces that act on NPs and thus reduce their agglomeration. On the other hand, NPs can bring into the composites their inherent properties as nanosized objects. In this work, hematite NPs were blended with cellulose acetate (CA) polymer and thin nanocomposite films were produced by the non-solvent induced phase separation technique. A full physicochemical characterization of these composite materials confirmed its superior character in terms of structure, thermal stability, electronic/optical and antibacterial properties when compared to the polymer on its own and opens the door to its further validation in adsorptive and photocatalytic applications.