Removal of indoor airborne bacteria by nano-Ag/TiO_2 as photocatalyst: Feasibility study in museum and nursing institutions

摘要

Deterioration of indoor air quality attributable to airborne bacterial consortia is a widespread environmental problem. The main objective of this study is to evaluate the feasibility of applying the syngetic effect of nano-Ag/TiO2 as a photocatalyst and UV light to enhance the disinfecting capability of full-scale bacterial restraining equipment on-site in the National Museum of Natural Science and a medical-nursing institute. The influence of initial counts of total airborne bacteria and volume of space on the efficiency of bacterial restraining have been studied. In the case of museum application, a higher initial total bacterial count leads to better bacterial restraining rates; Site A (initial total bacterial counts = 506 CFU/m ~3) has the best bacterial restraining rate (92%) as compared with Site B (69%, initial total bacterial counts = 158 CFU/m~3) and Site C (80%, initial total bacterial counts = 338 CFU/m~3) after 24 h of operation. Higher initial counts of total airborne bacteria lead to an increasing bacterial restraining rate. Approximately 92% (Site A) and 74% of restrained bacterial rate were observed in a museum and nursing institutions, respectively, under the similar initial total airborne bacterial counts (506, 598 CFU/m~3). The results illustrate that changes in the volume of space do not have significant inhibitory effects on the efficiency. The proposed equipment can disinfect air to restrain bacteria effectively, as demonstrated on-site in museums and nursing institutions; the results will be valuable references for designing a full-scale commercialized device for large-scale applications in the future.