Bacterial cellulose–SiO2@TiO2 organic–inorganic hybrid membranes with self-cleaning properties

This work reports the preparation of bacterial cellulose (BC) membranes with self-cleaning properties. SiO2@TiO2 (anatase) spherical nanocomposites (around 50 nm in diameter) were prepared by sol–gel process and were successfully immobilized into the BC membrane, in wet and dry states, by post-grafting method, following two different methodologies: dip-coating and spin-coating. Characterization techniques included Raman scattering, energy-dispersive X-ray spectroscopies (EDS), thermogravimetric analyses (TGA), and scanning electron microscopy (SEM). The photocatalytic activity was higher in the BC membrane in the wet state, presenting a good self-cleaning performance (fast methyl violet 2B dye decomposition in 30 min). The functional BC membranes with self-cleaning properties also presented high resistance to washing, high chemical stability, and the original features (color and texture) were maintained.