Absolute quantum yields in photocatalytic slurry reactors

• Published in: Chemical engineering science Vol. 58; no. 3; pp. 979 - 985
• Main Authors: Brandi, Rodolfo J., Citroni, Miguel A., Alfano, Orlando M., Cassano, Alberto E.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2003; Elsevier
• Subjects: Absolute quantum yield; Applied sciences; Chemical engineering; Chemistry; Exact sciences and technology; General and physical chemistry; Modeling; Photocatalysis; Photochemistry; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); Pollution; Radiation; Reaction engineering; Reactors; Remediation; Water treatment and pollution; Remediation; Absolute quantum yield; Modeling; Photocatalysis; Reaction engineering; Radiation; Water treatment; Transition metal Compounds; Theoretical study; Photochemical reactor; Particle suspension; Experimental study; Quantum yield; Liquid solid; Titanium Oxides; Heterogeneous catalysis; Pollutant; Phenol; Model compound; Physicochemical purification; Oxidation; Radiative transfer; Kinetics; Waste water purification; Mathematical model; Photochemical degradation
• ISSN: 0009-2509; 1873-4405
• DOI: 10.1016/S0009-2509(02)00638-3

Photocatalysis in slurry reactors have the particular characteristic that the reacting medium not only absorbs but also scatters photons and both phenomena occurs simultaneously. When this is the case, typical methods used in classical photochemistry such as homogeneous actinometry are useless because they cannot take into account radiation scattering. Consequently present methods in use always underestimate quantum yields calculations. A method has been developed to produce absolute values of photocatalytic quantum yields in slurry reacting systems employing titanium dioxide and near UV radiation. The new procedure resorts to the rigorous solution of the radiative transfer equation inside the reaction space in order to obtain the true value of the photonic absorption rate. Employing monochromatic light, values for the photocatalytic decomposition of phenol and 1,4-dioxane are reported under precisely defined conditions. The method can be used to compare reactivities of different catalysts or, for a given catalyst, reactivities with different compounds regardless the reactor shape, size or configuration.