Green Cleaning Procedures Based on Titania-Doped Cotton Textiles: Effect of Titania Textural Properties

Titania-based cotton textiles have been prepared by covering the surface of the fabrics with crystalline titania anatase, which is known for its nontoxicity, low cost and for its photocatalytic activity in the degradation of many organic compounds. The coatings were prepared by using the widely used commercial P25 titania (35-65 m2/g), as reference, and an ordered mesoporous titania with high surface area (165 m2/g) prepared by soft template assisted route. In order to promote the interaction between titania and cotton textile, titania-silica nanocomposite coatings have been prepared by dispersing the titania powder into a silica sol used as binder. FE-SEM investigations revealed that the fabrics are uniformly covered by silica-titania coatings and titania particles are partially embedded into silica matrix. The presence of crystalline anatase onto cotton fabrics was confirmed by Raman and XRD measurements and it was observed that the anatase peaks were more pronounced by using mesoporous titania. The self-cleaning performances of the functionalized textiles were investigated by monitoring the discoloration of anthocyanin stains after irradiation with a solar simulator. Our findings reveal that the use of mesostructured titania leads to a more efficient discoloration with respect to the commercial P25 titania, suggesting the importance of the titania textural properties on the photocatalytic activity. The high surface area and the smaller crystallites of ordered mesoporous titania allow to gain a high number of exposed sites that can improve the self-cleaning performances of the functionalized textiles with respect to commercial P25 titania. These results appear promising to further improve the efficiency of self-cleaning cotton fabrics.