Functionalization of renewable bamboo charcoal to improve indoor environment quality in a sustainable way

The increasing demand for health calls for a bacteria-free environment with proper humidity content. A composite with both bactericidal and humidity control properties is promising in an environmental and economic way for this purpose. In this paper, renewable bamboo charcoal (BC) was used to prepare this multifunctional material by loading silver doped titanium dioxide (Ag/TiO2) with a sol-gel method. The synthesized composite (Ag/TiO2-BC) was characterized by X-ray diffraction (XRD) and scanning electron microscope with energy disperse spectroscope (SEM-EDS) analyses. Antibacterial performance was evaluated by bactericidal rate on both Escherichia coli and Staphylococcus aureus strains. Photocatalytic activity was studied by methylene blue (MB) removal performance. Humidity adsorption and response speed were determined to evaluate the humidity control performance. Results show that Ag promote the transformation of rutile to anatase. SEM-EDS analysis proves the successful loading of Ag/TiO2 on BC surface. Both Ag doping on TiO2 and Ag/TiO2 loading on BC show significantly promoting effects on the bactericidal rate of Ag/TiO2-BC for both strains. MB removal results indicate that TiO2 loading on BC surface increases removal ratio while Ag doping on TiO2 shows further improvement. Humidity tests show that Ag, Ag/TiO2 and calcination temperature slightly decrease the humidity adsorption of Ag/TiO2 BC due to the decreased specific surface area and pore volume determined from nitrogen adsorption tests. However, all samples present prompt humidity adsorption and desorption responses. The overall results show that this biomass deprived composite could be used as a self-control material with bactericidal and humidity control functions. (C) 2019 Elsevier Ltd. All rights reserved.