208 Int. J. Environmental Technology and Management, Vol. 15, Nos. 3/4/5/6, 2012 Copyright © 2012 Inderscience Enterprises Ltd. Photocatalytic degradation of supra black-T dye on charcoal under sunlight Reena Amatya Shrestha Department of Civil and Environmental Engineering, Lehigh University, Bethlehem, PA, USA Email: reenashrestha@yahoo.com Mika Sillanpää Department of Environmental Sciences, University of Eastern Finland, Patteristonkatu 1, FI-50100 Mikkeli, Finland and Faculty of Technology, Lappeenranta University of Technology, Patteristonkatu 1, FI-50100 Mikkeli, Finland Email: mika.sillanpaa@uef.fi Jarina Joshi Department of Biotechnology, Tribhuwan University, Kirtipur, Kathmandu, Nepal Email: jarinarjoshi@yahoo.com Ackmez Mudhoo* Department of Chemical and Environmental Engineering, University of Mauritius, Réduit, Mauritius Email: ackmezchem@yahoo.co.uk *Corresponding author Abstract: Azo dyes are used in many industries such as carpet manufacturing, textiles, paint, ink, plastics and cosmetics production processes. The coloured industrial effluent can pose serious problems in the aquatic environment. It is possible to get complete mineralisation of organic pollutants in water by photocatalysts. This study was carried out to examine the feasibility to remove supra black-T dye from carpet dyeing wastewater by photocatalytic degradation on Oak charcoal under sunlight. Adsorption efficiency of dye on charcoal at various pH values and photodegradation with ZnO and TiO 2 catalysts were studied. The removal efficiency of charcoal alone was 28 mg dye/g charcoal at pH 8 and 25C in 60 min which was half that of activated charcoal. Photocatalytic degradation and adsorption with TiO 2 and ZnO under sunlight was faster and almost complete removal was observed in shorter times.