Mercury-free sources of VUV/UV radiation: application of modern excimer lamps (excilamps) for water and air treatment

Abstract

This paper reviews recent experimental results concerning the use of modern excilamps (excimer lamps) in photoscience and photochemical technology. The special characteristics of these sources of incoherent vacuum-UV (VUV)/UV radiation are presented and their applications in water and air remediation are discussed. Special attention is paid to the VUV (172 nm)-initiated oxidation and mineralization of organic water and air contaminants. For example, the VUV-initiated production of carbon dioxide and carbon monoxide during 172 nm irradiation of several saturated volatile organic substrates in the gas phase (e. g. methanol, ethanol, 2-propanol, 1,4-dioxane, cyclohexane, and n-hexane) was quantitatively verified by gas chromatography. Depending on the nature of the gaseous substrate and on the flow rate through the excimer-flow-through photoreactor different CO2/CO ratios were obtained. Key words: excimer lamps, excilamps, 172 nm irradiation, VUV oxidation, photo-mineralization, UV disinfection, excilamp flow-through photoreactor, plug-flow photoreactor, gas-phase photo-oxidation.