The Visible-Light Photocatalytic Activity and Antibacterial Performance of Ag/AgBr/TiO₂ Immobilized on Activated...

Visible-light-driven Ag/AgBr/TiO₂ /activated carbon (AC) composite was prepared by solgel method coupled with photoreduction method. For comparison, TiO₂ , TiO₂ /AC, and Ag/AgBr/TiO₂ were also synthesized. Their characteristics were analyzed by XRD, SEM-EDS, TG-DSC and UV-vis techniques. Photocatalytic activity and antibacterial performance under visible-light irradiation were investigated by ICP-AES, ATR-FT-IR and spectrophotometry methods using methylene blue and Escherichia coli as target systems, respectively. The results showed that Ag/AgBr was successfully deposited on anatase TiO₂ /AC surface, and exhibited a distinct light absorption in the visible region. Ag/AgBr/TiO₂ /AC displayed excellent antibacterial performance both in dark and under visible-light illumination. The growth of E. coli cell was inhibited in the presence of Ag/AgBr/TiO₂ /AC in dark. Moreover, upon visible-light illumination, a significant damage of cell membrane was noticed. Ag/AgBr/TiO₂ /AC was also shown higher photocatalytic efficiency for methylene blue degradation than those of TiO₂ , TiO₂ /AC, and Ag/AgBr/TiO₂ . This is attributed to the synergetic effect between AC and Ag/AgBr/TiO₂ , of which AC acts as the role of increasing reaction areas, continuous enriching, and transferring the adsorbed MB molecules to the surface of supported photocatalysts, and the Ag/AgBr/TiO₂ acts as a highly active photocatalyst for degrading MB molecules under visible-light irradiation.