Influence of TiO₂ Immobilization Strategy on BC-TiO₂ Nanocomposite Photocatalytic Performance

Bacterial cellulose (BC) has been used as a renewable support for the development of photocatalytic nanocomposites due to its three-dimensional nanofibrillar network and large surface area. BC-based photocatalytic systems have been investigated for environmental applications, including the degradation of organic pollutants in wastewater. BC is commonly considered a passive scaffold. However, there is evidence suggesting that the strategy used to immobilize photocatalysts may influence the physicochemical characteristics of the resulting nanocomposites and their photocatalytic performance. This work investigates the effect of the TiO₂ immobilization strategy on the photocatalytic performance of BC/TiO₂ nanocomposites. Two simple immobilization approaches, namely agitation-assisted deposition and vacuum filtration-assisted deposition, were compared to evaluate how catalyst loading and immobilization routes influence the photocatalytic degradation of tartrazine as a model organic pollutant. The materials were characterized by FTIR, XRD, and UV-Vis, and their photocatalytic activity was evaluated through degradation kinetics. The results showed that photocatalytic performance is not only dependent on the amount of immobilized TiO₂ but also on the immobilization strategy employed. FTIR tests revealed differences in the O-H stretching region, suggesting changes in the local chemical environment of cellulose surface hydroxyl groups, whereas XRD and UV-Vis analyses indicated that the crystalline structure and optical band gap of TiO₂ remained essentially unchanged. These findings indicate that controlling the TiO₂ immobilization strategy provides a simple strategy for tailoring the photocatalytic performance of BC-based nanocomposites.