| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 73170 | Microporous and Mesoporous Materials | 2014 | 10 Pages |
•Synthesis of stable large particles (>70 μm) of SOD, LTA, FAU-X zeolites (without binders) suitable for stirring process.•Remarkable increase of Total Organic Carbon removal by adding zeolites in ozonation process for wastewater treatment.•Na-LTA more active > K-LTA = K-SOD > K-FAU-X.•Na-LTA promotes hydroxyl radicals generation most probably by interaction of ozone with hydroxyl groups of the zeolite.•Three time more mineralization reached with Na-LTA in comparison to single ozonation.
Advanced oxidation processes (AOP) as ozonation coupled with inorganic materials have been recently demonstrated to be highly suitable for wastewater treatment. In petrochemical wastewaters, pollutants as alkylphenols are often detected. In this paper, we highlight the efficiency to couple ozone with zeolites as SOD, LTA and FAU-X for the degradation of 2,4-dimethylphenol (2,4-DMP). For process requirement the 3 zeolites were prepared as particles of 70 μm and 1 mm thanks to pseudomorphic transformation without binders. The zeolites were synthesized under their sodium (Na) form and potassium (K) ion-exchange was performed to enhance their basicity. By single ozonation (without zeolite) 100% of 2,4-DMP removal occurred in 25 min, but the pollutant is transformed into oxidized by-products corresponding to only 14% of the Total Organic Carbon (TOC) removal after 5 h. Adding zeolites to the ozonation process increased very slightly the kinetic of disappearance of the pollutant but increased the removal of its oxidation by-products, with 34% of TOC removal after 5 h. Among the zeolites, the best solid catalyst for ozonation was Na-LTA. Experiments with tert-butanol (t-BuOH) put in evidence that Na-LTA generates hydroxyl radicals from ozone, which increased the degradation of the by-products. No adsorption of 2,4-DMP and of the resulting oxidation by-products was detected by thermogravimetric analysis (TGA) on the materials after 5 h of ozonation. The TOC removal is consequently equivalent to the total mineralization of the organics into CO2.
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