Celluphot: hybrid cellulose : bismuth oxybromide membrane for pollutant removal

The simultaneous removal of organic and inorganic pollutants from wastewater is a complex challenge and requires usually several sequential processes. Here, we demonstrate the fabrication of a hybrid material that can fulfill both tasks: i) the adsorption of metal ions due to the negative surface charge, and ii) photocatalytic decomposition of organic compounds. The bio-inorganic hybrid membrane consists of cellulose fibers to ensure mechanical stability and of Bi4O5Br2/BiOBr nanosheets. The composite is synthesized at low temperature of 115 °C directly on the cellulose membrane (CM) in order to maintain the carboxylic and hydroxyl groups on the surface that are responsible for the adsorption of metal ions. The composite can adsorb both Co(II) and Ni(II) ions and the kinetic study con- firmed a good agreement of experimental data with the pseudo-second-order equation kinetic model. CM/Bi4O5Br2/BiOBrshowed higher affinity to Co(II) ions than to Ni(II) ions from diluted aqueous solutions. The bio-inorganic composite demonstrates a synergistic effect in the photocatalytic degradation of rhodamine B by exceeding the removal efficiency of single components. The fabrication of the biologic-inorganic interface was confirmed by various analytical techniques including SEM, STEM EDX mapping, XRD, and XPS. The presented approach for controlled formation of the bio-inorganic interface between natural material (cellulose) and nanoscopic inorganic materials of tailored morphology (Bi-O-Br system) enables the significant enhancement of materials functionality