Mesoporous anatase coatings for coupling membrane separation and photocatalyzed reactions

The main goal of the present study is the coupling of membrane separation and photocatalyzed reactions based on the use of anatase mesoporous coatings. The first type of coupled device deals with the preparation of separative photoactive anatase membranes on ceramic asymmetric supports. The intrinsic photocatalytic properties of the separative layer could be in this instance used for antifouling purposes or in photocatalytic reactors. The water permeability and the molecular weight cut-off of the prepared membranes are determined. Their photocatalytic activity is evaluated from photodegradation experiments of an organic dye in aqueous solution. A second type of configuration, based on the deposition of a photoactive anatase layer on the grains of a conventional asymmetric ceramic support, is discussed. The separative function is provided by the non-photoactive top layer, whereas the opposite side is irradiated with UV light. An example of a potential application of such a membrane involves water treatment by ultrafiltration. The retention of colloids and macromolecules would be ensured by the separative top layer whereas photodegradation of smaller organic molecules remaining in the permeate is performed by UV irradiation of the opposite side. A preliminary experiment is carried out to validate this concept.