Invited Speaker
Prof. Yao-Tung Lin
Lifetime Distinguished Professor, Department of Soil and Environmental Sciences, National Chung Hsiung UniversitySpeech Title: Sustainable Photocatalytic Disinfection Using Visible Light-Responsive NTiO2/ PMMA Composite: Performance Enhancement and Kinetic Analysis
Abstract: Photocatalysis is a highly efficient method for degrading organic pollutants through reactive oxygen species (ROS). In this study, we developed an eco-friendly photocatalyst using a dipcoating technique to immobilize nitrogen-doped TiO2 (N-TiO2) on polymethyl methacrylate (PMMA). This 5 g/L N-TiO2-coated PMMA demonstrated an impressive transmittance of 92%, surpassing previous methods that utilized sprinkling. Under visible light irradiation, this photocatalyst efficiently disinfected bacterial pathogens. At a visible light intensity of 0.54 mW/m², the 5 g/L N-TiO2-coated PMMA it achieved complete inactivation (5-log reduction) of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) within 24 hours. This underscores the effectiveness of our photocatalyst for indoor environmental disinfection. The immobilized N-TiO2 on PMMA showed higher disinfection efficiency compared to N-TiO2 in suspension, which can be attributed to the increased ROS generation and improved contact between the photocatalyst and bacterial cells. The 24-hour disinfection efficiency was influenced by the dose of the photocatalyst coating solution and the visible light intensity, as modeled by the modified Hom model. Additionally, reusability experiments indicated that the N-TiO2-coated PMMA maintained a 99.99% disinfection rate against S. aureus even after five cycles of photo-oxidation, suggesting its potential for long-term and sustainable disinfection applications. Atomic force microscopy revealed changes in the biophysical properties of inactivated bacterial cells, such as alterations in height and surface roughness due to photooxidation. In conclusion, the eco-friendly N-TiO2-coated PMMA developed using the dip-coating method is an effective and economical solution for indoor pathogen control under visible light. This photocatalyst shows excellent promise for various indoor disinfection applications, including use in hospitals, schools, and other public spaces.