Kinetics of Photochemical Reactions of M.G with Organic Reductants

Present research work is focused on the decoloration / reduction abilities of different cations and anions at various important operational parameters in the treatment of methylene green with urea and diethyl thiourea (DETU), which are important chemicals of textile dye industry. Urea and DETU are routinely used in textile industry as a strong reducing agent. Dye can cause environmental problems unless it is properly treated before disposal. The kinetics and mechanistic study for reduction of methylene green (MG) with urea and DETU in acidic and alkaline medium were studied at 652.8 nm by monitoring the depletion in MG concentration using spectrophotometer. Reduction of MG was followed spectrophotometrically by alone UV radiation / solar radiation. Influence of addition of dye into reaction mixture retarded the bleaching processes which enhanced by the addition of DETU and urea. The reduction followed pseudo first order kinetics with urea whereas th order with DETU, whereas with the variation of dye concentration, reduction followed order kinetics with respect to DETU and unity with respect to urea. Also solar light induced treatment may be helpful in cleaning the environment.