Fenton's Reagent Parameters

Effect of Fenton’s Reagent Parameters: Photo-Fenton’s process is highly sensitive to the initial H2O2, iron catalyst concentration and pH value. This reagent is extremely producer of .OH radicals and the reaction rate is limited by the .OH generation. Traditionally, hydroxyl radical has been viewed as the workhorse of hydrogen peroxide oxidation systems. Thus, the main source of OH radicals and oxygen depends on the hydrogen peroxide. Fig. 6 (a) shows the effect of hydrogen peroxide increase on the MB removal at constant pH 3 and Fe3+ of 40 mg/L. The results show that the degradation rate of MB increases with an increase in initial H2O2 concentration from 100 to 400 mg/L, but in excess of about 400 mg/L; the H2O2 dose of 1000 mg/L, plot of the reaction rate curve is almost horizontal. This could be illustrated that the presence of H2O2 beyond the ratio with Fe3+ does not improve the MB degradation. According to Murry and Parson (2004) hydrogen

8. The results in the figure reveals that the reduction efficiency decreases with increasing in the flow rate of the dye solution. Almost 13% of MB was removed at flow rate 15 mL/min, then it is increased to 75% for flow rate 25 mL/min, where as 33% and 20% of MB was removed at flow rate 40 and 70 mL/min, respectively. The role of increasing the degradation rate of pollutant with increasing the flow rate is valid up to a certain limit then the reaction becomes slower. These phenomena could be illustrated by the fact that once the flow rate was slow MB in the sample solution got more contact time with UV radiation induced. However, the flow rate of 25 mL/min was chosen to be the optimum because it makes the removal process higher. These results accord with the findings of Coelho et al. (2006), who investigated the photo-Fenton treatment of a petroleum refinery