State Key Laboratory of Heavy Oil Processing, State Key Laboratory of Petroleum Pollution Control, China University of Petroleum, Beijing 102249, China; Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, USA.
State Key Laboratory of Heavy Oil Processing, State Key Laboratory of Petroleum Pollution Control, China University of Petroleum, Beijing 102249, China.
Sci Total Environ. 2018 Jan 15;612:1424-1432. doi: 10.1016/j.scitotenv.2017.09.019. Epub 2017 Sep 25.
Discharge of industrial wastewater causes water pollution. It is therefore necessary to treat wastewater prior to discharge. Catalytic ozonation processes (COP) using ZSM5 zeolites loaded with metallic (Ce, Fe, or Mn) oxides to remove nitrobenzene from water were investigated. The total organic carbon (TOC) removal by the COP treatment with NaZSM5-38, HZSM5-38, and NaZSM5-100 were increased by 6.7%, 23.1%, and 19.8%, respectively, in comparison with single ozonation efficiency (39.2%). The loadings of Ce, Fe, or Mn oxides increased the catalytic activity relative to ZSM5 zeolites alone. The Ce loaded material (Ce/NaZSM5-38) had the highest TOC removal (86.3%). The different-metallic-oxides loaded zeolites exhibited different chemical processes during the removal of nitrobenzene from water. During COP treatment, NaZSM5-38 zeolites removed nitrobenzene mainly via OH mediated oxidation. HZSM5-38 and NaZSM5-100 zeolites showed powerful adsorption toward nitrobenzene. Both adsorption and direct ozonation contribute the TOC removal in their early uses. The OH mediated oxidation dominates the TOC removal process as the adsorption became saturated after multiple uses. Surface SiO bonds and/or SiO(H)Al structures are the active sites for ZSM5 zeolites. Efficient surface dispersion of the metallic oxides enhances the catalytic activity. This study shows the high potentials of ZSM5 zeolites as catalysts in COP to efficiently treat refractory wastewaters.
工业废水排放会造成水污染。因此，有必要在排放之前对废水进行处理。本研究采用负载金属（Ce、Fe 或 Mn）氧化物的 ZSM-5 沸石的催化臭氧化工艺（COP）去除水中的硝基苯。与单独臭氧化效率（39.2%）相比，NaZSM-5-38、HZSM-5-38 和 NaZSM-5-100 的 COP 处理的总有机碳（TOC）去除率分别提高了 6.7%、23.1%和 19.8%。Ce、Fe 或 Mn 氧化物的负载增加了相对于单独 ZSM-5 沸石的催化活性。负载 Ce 的材料（Ce/NaZSM-5-38）具有最高的 TOC 去除率（86.3%）。不同金属氧化物负载的沸石在从水中去除硝基苯的过程中表现出不同的化学过程。在 COP 处理过程中，NaZSM-5-38 沸石主要通过 OH 介导的氧化去除硝基苯。HZSM-5-38 和 NaZSM-5-100 沸石对硝基苯表现出很强的吸附能力。在早期使用过程中，吸附和直接臭氧化都有助于 TOC 的去除。随着吸附在多次使用后达到饱和，OH 介导的氧化主导 TOC 去除过程。表面 SiO 键和/或 SiO(H)Al 结构是 ZSM-5 沸石的活性位。金属氧化物的高效表面分散增强了催化活性。本研究表明 ZSM-5 沸石作为催化剂在 COP 中具有高效处理难处理废水的巨大潜力。
