Introduction: Prof. Dennis Y.C. Leung received his BEng (1982) and PhD (1988) from the Department of Mechanical Engineering at the University of Hong Kong. He had worked with the Hongkong Electric Co., Ltd. for five years heading the air pollution section of the company before joining the University of Hong Kong in 1993. Professor Leung is now a full professor and ex-Head of the Department of Mechanical Engineering specializing in environmental engineering and renewable & clean energy. He has published more than 500 articles in these two areas including 360+ peer reviewed SCI journal papers. His current h-index is 88 and total citations are 42,000+. He is one of the top 1% highly cited scientists in the world in energy field since 2010 (Essential Science Indicators) and named as Highly Cited Researcher by Clarivate Analytics for the past six years consecutively from 2017 to 2022. Prof. Leung has delivered more than 80 keynote and invited lectures in many international conferences.
Prof. Leung is a chartered engineer, a fellow of the IMechE, Energy Institute and HKIE. He was also the Past Chairman of the Institute of Energy (HK Branch), and currently serves as an editorial board member of a number of journals including Applied Energy, Energy Conversion and Management, and Applied Sciences. Prof. Leung also serves as a board member of the Hong Kong Institution of Science, chairman and member of a few committees of the HKSAR government and government’s appeal board panels related to sustainable energy and environment.

This speech will focus on the various applications of UV light in environmental protection, with particular emphasis on vacuum UV (VUV) light. VUV light, with a wavelength of 185 nm, has strong ionizing power and can generate high-concentration ozone, making it a powerful tool in advanced oxidation processes. Through a series of reactions, including VUV photolysis, UV photocatalytic oxidation (UV-PCO), and ozone catalytic oxidation, VUV irradiation can activate photocatalysts and generate active oxidants such as O and OH radicals, as well as ozone, to enhance the oxidation of air and water pollutants. Furthermore, VUV technology can effectively kill microbes and common environmental pathogens in air, water, and on surfaces, making it a promising disinfectant. The talk will present and discuss the results of VUV-enhanced photocatalytic degradation of common organic gases and water pollutants, such as antibiotics, together with its disinfection effect on common pathogens. A novel and efficient process of degrading volatile organic compounds (VOCs) by combining VUV photolysis and photocatalytic oxidation in a wet scrubber will also be introduced.