Two step and one step preparation of porous nanocomposite cellulose membranes doped with TiO2

Abstract

Cellulose–TiO₂ nanocomposites have been successfully prepared by non-solvent induced phase separation from cellulose acetate solutions in classical organic solvents followed by deacetylation (“regeneration”). The cellulose deacetylation has been performed either sequentially, i.e. after the completion of the phase separation process, or simultaneously, i.e. during the phase separation process. Commercially available titania nanoparticles from gas phase synthesis processes have been used and processed as a dispersion in the respective polymer solutions. The resulting nanocomposites have been characterized by means of scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) spectroscopy. Special attention has been given to the complex relation between the conditions of the deacetylation process, the structure of the resulting TiO₂ doped cellulose membranes and their corresponding catalytic activities. Two catalytic activity tests, based on the photocatalytic degradation of model organic dyes under UV irradiation, have been used for the functional characterization of the TiO₂ doped nanocomposites. The performed experiments demonstrated the successful photocatalyst immobilization in porous cellulose acetate together with good catalytic activity of this nanocomposite intermediate. By simply varying the conditions of the cellulose deacetylation, nanocomposite cellulose membranes with different structures and properties have been obtained. However after the regeneration of cellulose a partial decrease of the catalytic activity was observed.