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Investigation of Catalytic Ozonation of Recalcitrant Organic Chemicals in Aqueous Solution over Various ZSM-5 Zeolites

State Key Laboratory of Petroleum Pollution Control, China University of Petroleum, Beijing 102249, China
Hawaii Natural Energy Institute, University of Hawaii at Manoa, Honolulu, HI 96822, USA
Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA
College of Chemical and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266590, China
Author to whom correspondence should be addressed.
These authors contributed equally to this work.
Catalysts 2018, 8(4), 128;
Received: 31 January 2018 / Revised: 9 March 2018 / Accepted: 20 March 2018 / Published: 22 March 2018
PDF [33788 KB, uploaded 3 May 2018]


Catalytic ozonation processes (COPs) are an emerging technology for wastewater treatments. NaZSM-5 zeolites in three different SiO2/Al2O3 ratios (31, 45, and 120) and their metallic oxides loaded samples were compared for COP of nitrobenzene solution. NaZSM-5(120) showed high total organic carbon (TOC) removals (70.2–74.0%) by adsorption relative to NaZSM-5(45) (0.4–0.6%) at various initial pH conditions. NaZSM-5(31) was obtained by NaOH treatment of NaZSM-5(45) and displayed 20.9–23.8% of TOC removals by adsorption. In COPs, the different ZSM-5 zeolites exhibited various TOC removals and different reaction pathways. COP-NaZSM-5(120) showed high TOC removals compared to COP-NaZSM-5(45) and COP-NaZSM-5(31). The repeated uses of zeolites in COPs were performed to understand the reaction pathways and contribution of adsorption versus ozonation (i.e., catalytic oxidation and/or direct ozonation). Both adsorption and direct ozonation in COP-NaZSM-5(120) contributed TOC removal for the first use, whereas direct ozonation and •OH mediated oxidation dominated the process for eight repeated uses. Direct ozonation and •OH-mediated oxidation controlled the COP-NaZSM-5(45) process for the first and eight repeated uses. Adsorption and direct ozonation governed the COP-NaZSM-5(31) process for the first use, whereas the direct ozonation dominated it for eight repeated uses. In COPs, NaZSM-5(120) and NaZSM-5(45) showed the catalytic activity, whereas NaZSM-5(31) displayed negligible catalytic activity. The high catalytic activity of NaZSM-5(120) may be due to more Si-O bonds on zeolite surfaces. The results revealed that loading of Mg oxide on ZSM-5 zeolites can increase catalytic activity in COPs. These results show the application potential of ZSM-5 zeolites in ozonation of recalcitrant chemical wastewaters. View Full-Text
Keywords: ozonation; ZSM-5 zeolites; SiO2/Al2O3 ratios; nitrobenzene; adsorption ozonation; ZSM-5 zeolites; SiO2/Al2O3 ratios; nitrobenzene; adsorption

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Wang, Y.; Ma, W.; Yoza, B.A.; Xu, Y.; Li, Q.X.; Chen, C.; Wang, Q.; Gao, Y.; Guo, S.; Zhan, Y. Investigation of Catalytic Ozonation of Recalcitrant Organic Chemicals in Aqueous Solution over Various ZSM-5 Zeolites. Catalysts 2018, 8, 128.

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