DEGRADATION OF REACTIVE RED 198 DYE BY CATALYTIC OZONATION USING PUMICE AND COPPER COATED PUMICE

摘要

Due to environmental and aesthetical problems of dyes, in this study, we tried to use catalytic ozonation by focusing on a different aspect of pumice stone as a catalyst and a media for immobilization of metal catalyst to remove reactive red 198 dye. The heterogeneous catalytic ozonation experiments were carried out in a semi-batch reactor to determine the effect of pH, contact time, initial concentration of dye, catalyst dosage, radical scavenger and COD removal. The pumice granules were modified by CuSO_4. X-ray Diffraction, X-ray Fluorescence and Scanning Electron Microscope analyzes were used to investigate the structural and morphological character of pumice and copper coated pumice. Also, pH_(ZPC) of both catalysts were determined. The results showed that the removal efficiency of dye has been increased by increasing pH, contact time and catalyst dosages. The optimum conditions with both processes were determined at reaction time 15 min, pH 8, copper coated pumice dosages 10 g/L and pumice 20 g/L. Furthermore, the presence of radical scavenger in catalytic ozonation process didn't have noticeable effect on oxidation efficiency in comparison with single ozonation. Compared with single ozonation, catalytic ozonation with both pumice and copper coated pumice have shown higher efficiency but the modified pumice was more efficient than raw pumice. These results suggest that copper coated pumice is an effective catalyst in ozonation and may be used to develop a simple and efficient method in dye removal from aqueous solution.