Australian dump-site leachate treated in annular bubble column photoreactor

The photocatalytic mineralization of industrial dump-site leachate was evaluated using an internallyirradiated 18-Litre photoreactor. The study includes evaluating effect of catalyst loading, leachate initial concentration, initial solution pH, light intensity and oxygen partial pressure. The reaction runs were performed over a 48-hours period at room temperature and atmospheric pressure. Titanium catalyst loading was optimized to be 3 gL-1 where the reaction rate constant 20x10-6 mol L-1 min- 1.Beyond this dosage, the effect of light scattering by the catalyst particles were noticed on dropping the degradation rate. Moreover, at high catalyst loading, particles aggregates reduce the interfacial area between the reaction solution and the photocatalyst resulting in significant reduction in the number of active sites on the catalyst surface. The plot of the apparent reaction rate constant versus the initial leachate concentration exhibits almost a quadratic behaviour which has an optimum value at concentration of 50 mM.