Photocatalytic Degradation of Congored on Silica Supported Ag Impregnated TiO₂

Advanced oxidation process using nano sized silver impregnated titania-silica composite catalysts for the degradation of carcinogenic dye has been investigated. x% Silver/y% Titania/Silica. (x = 1%, 4%, 7% and 10%; and y = 10%, 15%, 20% and 25%), composite photocatalysts were synthesized by a three step process and characterized by using various physicochemical analytical techniques and evaluated for their photocatalytic activities towards decolourization/degradation of Congo red. The photodecolourisation and the photodegradation were monitored by using UV-Visible spectrophotometer and Total Organic Carbon analyzer respectively. The effects of various operating variables such as percentage loading of titania and silver on the decolourization/degradation of Congo red dye were studied, optimized and compared. Impregnation of silver increased the photocatalytic activity. 1% Silver/Titania/Silica composite catalyst showed better photocatalytic activity than titania-silica composite catalysts. However further increase of silver to 4%, 7% and 10% did not show any significant improvement in photocatalytic activity. Among the catalysts synthesized 1% silver/25% titania/silica composite catalyst was found to show the best decolourization and degradation of Congo red.