256 страниц. 2012 год. LAP Lambert Academic Publishing The photo-reduction of methylene green with EDTA was investigated spectrophotometrically. The apparent rate of decoloration was calculated from observed absorption data on the kinetics of bleaching of dye, showed that reaction follows pseudo first order kinetics. The effects of different reaction parameters such as initial MG+ concentration, EDTA concentration, pH value of solution and the presence of KNO3 on the reduction of methylene green were investigated. The results show that the dye degrade efficiently in the presence of NaOH. Lastly, we used HPLC analysis to show that degradation of dye followed with reduction lead to suggest many side reaction.