Adapted mode of the mechanism of the photooxidation of coomassie blue with hydrogen peroxide by ph variations in aqueous medium

Effects of variation of different parameters on decolorization of the acidic dye Coomassie Brilliant Blue R-250 has been studied in the range = 530nm by UV-Visible spectrophotometry. Effect of change in concentration of Coomassie Brilliant Blue R-250 with Hydrogen peroxide was studied in basic medium (pH = 11) as the decolorization of the dye was catalysed in the presence of NaOH. Effect of pH was studied, variations were( pH =1-11 ), it was found that high pH had enhanced the % decolorization of the Coomassie Brilliant Blue R-250. Study of Temperature was investigated in the range (313-343K) showed that temperature elevation raised the reaction rate. The activation parameters are Ea 13.33 KJ.mol-1, ∆S ≠- 0.19668KJmol-1, ∆H≠+28.53 KJmol-1 and ∆G≠ + 90.0944 KJmol-1 revealed the reaction was endothermic, nonspontaneous and strong interactions between dye molecule and oxidant take place under the assistance of NaOH as a catalyst, low value of activation energy exhibits that the reaction was fast, whereas negative entropy of activation shows that the mechanism is an associated one. Rate Law was -d[CBB]/ dt=[OH- ] [CBB ]0 [ H2O2] . Order of the reaction with respect to variation of concentration of CBB dye was zero order and with respect to hydrogen peroxide and hydroxyl ion is found to be first order. Decolorization rates were well in basic medium and unappreciable in acidic medium.