Enhanced photocatalytic degradation of methylene blue under vacuum ultraviolet irradiation

• Published in: Catalysis today 2013-03, Vol.201, p.189-194
• Main Authors: Huang, Haibao, Leung, Dennis Y.C., Kwong, Philip C.W., Xiong, Jing, Zhang, Lu
• Format: Article
• Language: English
• Subjects: Catalysis; catalytic activity; Chemistry; Exact sciences and technology; General and physical chemistry; irradiation; Methylene blue; Mineralization; Photocatalytic degradation; Photochemistry; Photolysis; photooxidation; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; ultraviolet radiation; Vacuum ultraviolet irradiation
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2012.06.022

[Display omitted] ► Photocatalytic oxidation of methylene blue was conducted under VUV irradiation. ► VUV/TiO2 obtains much higher degradation and mineralization rate than UV/TiO2. ► Multiple advanced oxidation processes coexist to produce highly reactive species. A vacuum ultraviolet (VUV) lamp was used as the irradiation of photocatalysis to enhance the degradation of methylene blue (MB), a model dye compound. In contrast to photocatalysis under 254nm UV irradiation (UV/TiO2), photocatalysis under VUV irradiation (VUV/TiO2) exhibited much higher efficiency in MB degradation and mineralization and needed less TiO2 dosage. The rate constant of MB degradation in VUV/TiO2 (0.0793min−1) is about 4 times of that of UV/TiO2 (0.0205min−1). The MB mineralization rate is also greatly increased from 12.5% in UV/TiO2 to 47.7% in VUV/TiO2 after 60min of irradiation. Multiple advanced oxidation processes including photocatalytic oxidation and VUV photo-oxidation coexist in VUV/TiO2 to substantially produce highly reactive species (such as OH and energetic photons), which is responsible for efficient degradation and mineralization of MB.