A Thermocatalytic Ceramic Membrane by Perovskite Incorporation in the Alumina Framework

Access to clean water is limited by the increasing amount of persistent organic pollutants (POPs), since current methods fail to remove POPs completely. Therefore, new treatment technologies of surface water and wastewater are needed. In this study, two treatment methods are combined in one step, i.e., membrane filtration and thermocatalytic chemical oxidation of POPs. A perovskite-type catalyst with formula Sr_0.85Ce_0.15FeO_3-δ (SCF) is incorporated into an alumina membrane using a simple two-step heat treatment to minimize any chemical reaction of the catalytic active perovskite with alumina. First, a sintering process under inert atmosphere, then, a heat-treatment under oxidative conditions to oxidize the iron species in the perovskite structure. The well-known thermocatalytic properties of SCF make the membrane thermocatalytic and thus able to degrade pollutants under dark conditions without addition of oxidants. The SCF content in the membrane is varied between 0 and 15 wt% to explore the change in membrane properties. Results demonstrate that the thermocatalytic membranes have great potential for continuous membrane filtration and simultaneous degradation of POPs. When considering methyl orange, up to 100% removal is obtained at room temperature, whereas up to 93% of bisphenol A is removed at temperatures approaching 60 °C.