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Silver nanoparticles have been prepared by reducing a silver nitrate precursor and loaded on the surface of bacterial cellulose (BC)in situto form Ag/BC composite membrane. The membrane microstructure was characterized by using scanning electron microscope (SEM). The SEM images showed that the number of the silver nanoparticles with diameters in the range of 50–80 nm increases with higher silver nitrate concentration. X-ray diffraction spectra results indicated that the silver nanoparticles are with face-centered cubic structure. X-ray fluorescence spectrum showed that Ag element was incorporated into the bacterial cellulose. UV-Vis results showed characteristic silver absorption peak at 424 nm. Both antimicrobial activity and biocompatibility of the Ag/BC nanocomposites have been evaluated. The silver nanoparticles exhibited good antimicrobial activities againstE. coliandS. aureus.The antibacterial ratio againstE. coliandS. aureusreached 99.4% and 98.4%, respectively. The Ag/BC composite membrane also showed better biocompatibility. The results suggest that our Ag/BC membrane may find applications for antimicrobial purposes, for example, antibacterial wound dressings. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) was chosen as a support for nanometer titanium dioxide (TiO2) particles due to its superfine network structure. The composite membrane of TiO2/BC doped with rare earth elements was prepared by a sol-gel method using tetraisopropyl titanate as starting material. Photocatalysis properties of this composite membrane were estimated by using methyl orange as a degradation agent. X-ray fluorescence (XRF) spectra showed that rare earth ions were incorporated into TiO2/BC membrane. X-ray diffraction (XRD) spectra showed that the resulting titanium dioxide was anatase type, which didn't change after doping. Compared with a pure TiO2/BC membrane, photocatalysis efficiency was significantly enhanced for the doped one. The degradation rate of methyl orange solution for a composite membrane doped with Ce4+ was up to 100%, while with La3+ it was was up to 79.7%. The optimal dosage of Ce4+ was 2 mmol/L, while the most suitable concentration of La3+ was 5 mmol/L within the experimental range. [ABSTRACT FROM AUTHOR]