Degradation of azo dye (direct red 89) using H(2)O(2)/periodate process-parameter optimization and mixture composition evaluation

Abstract

As a fast and efficient process, a periodate (PI)-based advanced oxidation process was used to degrade direct red 89 (DR89), wherein hydrogen peroxide (H(2)O(2)) was employed to activate PI (H(2)O(2)/PI process) to investigate the effect of operating parameters and mixture composition. The PI was efficiently activated by H(2)O(2) to degrade 67 of DR89 within 1 min. Acidic pH was more favorable to high-efficiency degradation than the basic pH; at pH 3 degradation rate was 94.31, while it was only 20.92 at pH 11. The degradation rates were further enhanced with increasing H(2)O(2) and PI dose up to certain optimum values, later it decreased which was dependent upon the amount of hydroxyl ((●)OH) and iodyl (IO(3)(●)) radicals produced. The quenching experiments suggested that IO(3)(●), (●)OH, (1)O(2,) and O(2)(●-) are the predominant reactive species during H(2)O(2)/PI process, while O(2)(●-) radicals are the primary precursor of other reactive oxygen species. The results of this study suggested that H(2)O(2)/PI is the efficient and rapid treatment method to degrade persistent organic pollutants (POPs) from polluted wastewater sources.