Investigation of Catalytic Ozonation of Recalcitrant Organic Chemicals in Aqueous Solution over Various ZSM-5 Zeolites
AbstractCatalytic 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
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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.
Wang Y, Ma W, Yoza BA, Xu Y, Li QX, 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(4):128.Chicago/Turabian Style
Wang, Yandan; Ma, Wenfeng; Yoza, Brandon A.; Xu, Yingying; Li, Qing X.; Chen, Chunmao; Wang, Qinghong; Gao, Yu; Guo, Shaohui; Zhan, Yali. 2018. "Investigation of Catalytic Ozonation of Recalcitrant Organic Chemicals in Aqueous Solution over Various ZSM-5 Zeolites." Catalysts 8, no. 4: 128.
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