A Bench-Scale Photoreactor For Performing Photocatalytic Degradation Studies

Abstract

Several investigations have been published across the globe and also discussing more on the applicability of
photocatalytic activity for the treatment of industrial dye effluents. Photocatalytic process involves the removal of
contaminants and organic waste from effluent streams that are chemically stable and resistent to biodegradation. This
process has shown a great potential being cost effective, ecofriendly and complete mineralisation, use of low cost catalyst
system and in the field of sustainable treatment with zero waste discharge. The principle of photocatalysis relies on insitu generation of hydroxyl radicals under ambient conditions which are capable of generating a wide spectrum of toxic
organic compounds including non-biodegrdables into relatively less toxic end products. Photocatalytic process of removal
of colour from aqueous solutions also indicated the better removal of methylene blue compared to methyl orange. It was
interestingly to note that, photocatalytic degradation of both the colours by all nanoparticles studies is more effective than
the removal by batch studies. Further the adsorbent dosage required for photocatalysis was found to be very less compared
to batch studies. The removal percentage of methylene blue by using ZnO was
99.6%, TiO2 was 96.3% and MgO was 93.4% respectively under optimum experimental conditions. Accordingly, these
values for methyl orange were found to be 96.2% for ZnO, 91.1% for TiO2 and 85.8% for MgO respectively. In the
present research work, the combination of different nanoparticles are used to remove the colour from aqueous solutions
of industrial dye effluents by using photocatalytic process are also presented.