Photochemical treatment of simulated dyehouse effluents by novel TiO2 photocatalysts:: experience with the thin film fixed bed (TFFB) and double skin sheet (DSS) reactor

This study has been undertaken to provide a rather practical assessment of the heterogeneous photocatalytic treatment of two simulated reactive dye-bath effluents via three commercial TiO2 types (Degussa P25, Millennium PC 500 and Sachtleben Mikroanatas), which were employed in fixed film and suspended photochemical reactor configurations. The obtained results have clearly revealed that the inherent advantage of eliminating a proceeding photocatalyst separation step did not justify the significantly lower treatment performance of the thin film fixed bed (TFFB) reactor, which is directly reflected in the values obtained for percent photonic efficiencies (% zeta), first-order decolourisation rate constants (k(d)) and the collector area requirements per unit of mineralisation rate (CA/M), as compared to the more recently developed suspended double skin sheet (DSS) photoreactor. Generally speaking, Degussa P25 was found to be most efficient among the investigated TiO2 photocatalyst types.