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Kinetics of photocatalytic decolorization of paramagenta at buffer solutions using nanotitanium dioxide under aerobic condition



The photocatalytic degradation of paramagenta (PM) using nanotitanium dioxide (99.9% anatase, 70–100 nm) as photocatalyst in aqueous buffer solutions under 400 W high pressure mercury lamp irradiation under aerobic condition is presented. Some effectual parameters such as amount of photocatalyst, irradiation time of mercury lamp and pH of buffer solution are investigated. Kinetics of phocatalytic decolorization process with optimum amount of nanotitanium dioxide at various buffer pHs under air bubbling conditions was studied. The observed rate constant (kobs), photodegradation rate (kr) and adsorption constant KA based on Langmuir–Hinshelwood model were found to have spans 1.5 × 10−3 to 9.0 × 10−3 min−1, 1.37–212.76 mg min−1 L−1 and 3.41 × 10−5 to 4.11 × 10−3, respectively at buffer pHs of 2, 5, 7, and 9. © 2012 American Institute of Chemical Engineers Environ Prog, 32: 1061–1065, 2013