Optimization of Congo-Red Photo-Catalytic Degradation by Central Composite Design

Abstract

The photo catalytic degradation of Congo red by oxidant’s and semiconductors in suspension aqueous solution of ZnO, H2O2 has been studied. This work has been done by assist of RSM (surface response methodology) for design of experiments and statistical calculations. All photochemical experiments have been carried out in quartz photo cell and the solvent used for all experiment was distilled water (D. W). The influence of hydrogen peroxide H2O2, zinc oxide and dye concentration has been studied by statistical analysis. The instrument used for experiments in this work is spectrophotometer in order to find the calculated and then predicted percentage of degradation, ANOVA analysis and other statistical parameters also has been measured. The result shows that the P-values are higher than 0.05 confidence level in all experiments this means that the parameter of this work does not make a sense on percentage of degradation. This is may be due to that the hydrogen peroxide (H2O2) may work as oxygen provider to accelerate the photo degradation process. Meanwhile, Excess amount of H2O2, Could act as hydroxyl radical capture in the mineralization system. On the other hand; the best result was 19% degradation in case of 10ppm Congo red concentration, 5% H2O2 and 0.1g/L ZnO.