Iron shavings were modified and used as the catalyst (named as Fe-shaving-based catalyst) for the ozonation of bio-treated coking wastewater. Gel chromatography and 3DEEM were used to analyze the MW distribution and the oxidation order of organic pollutants. Almost all organic pollutants with different MW distributions could be degraded simultaneously and more thoroughly in catalytic ozonation process, while small molecular neutral species will be oxidized firstly, and then the partial large molecular organic pollutants in sole ozonation process. In the catalytic ozonation process, removal of the pollutants with MW of 5~10 kDa and 10~20 kDa was 81.5% and 85.2%, which was far better than that in sole ozonation process (31.1% and 41.8%). Organics with MW of 0.3~2 kDa and 2~5 kDa would accumulate in both two processes, while the accumulation amount in catalytic ozonation process was half of it in sole ozonation process. The removal of fluorescent substances in catalytic ozonation process experienced a procedure of lower firstly and then higher than that in sole ozonation process. The naturally fluorescent substances were removed by 70% in the ozonation process in 15 min, which was better than in catalytic ozonation process (50%). However, with the reaction time increased to 180 min, the slight residual fluorescent substances were completely removed in the catalytic ozonation process, but they remained unchanged in sole ozonation process. Hydroxyl radicals were confirmed to be the effective oxidant in catalytic ozonation process. In comparison to commonly used powder catalysts, such as FeOOH, Fe2O3, and Fe3O4, the total production of hydroxyl radicals with 200 g/L Fe-shaving-based catalyst during 180 min was 361 μmol, which was far more than others, and that’s why it could exhibit better catalytic effect. The surface hydroxyl density of Fe-shaving-based catalyst was 0.489 mmol/g, and the phosphate experiments revealed that the surface hydroxyl groups were the dominating active sites for hydroxyl radicals generation. The Fe-shaving-based catalyst had greater structural superiority with large specific surface area and could be used as fillers at the same time.

Characteristics and mechanisms of catalytic ozonation with Fe-shaving-based catalyst in industrial wastewater advanced treatment

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.