Fan Guijun, Guo Yacong, Chai Shaohua, Zhang Le, Guan Jian, Ma Guojun, Han Ning, Chen Yunfa
State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing 100049, China; Key Laboratory of Science and Technology on Particle Materials, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 361021, China.
Key Laboratory for Mechanics in Fluid Solid Coupling Systems, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
J Environ Sci (China). 2025 Jan;147:642-651. doi: 10.1016/j.jes.2023.04.021. Epub 2023 Apr 27.
Nowadays, it is still a challenge to prepared high efficiency and low cost formaldehyde (HCHO) removal catalysts in order to tackle the long-living indoor air pollution. Herein, δ-MnO is successfully synthesized by a facile ozonation strategy, where Mn is oxidized by ozone (O) bubble in an alkaline solution. It presents one of the best catalytic properties with a low 100% conversion temperature of 85°C for 50 ppm of HCHO under a GHSV of 48,000 mL/(g·hr). As a comparison, more than 6 times far longer oxidation time is needed if O is replaced by O. Characterizations show that ozonation process generates a different intermediate of tetragonal β-HMnO, which would favor the quick transformation into the final product δ-MnO, as compared with the relatively more thermodynamically stable monoclinic γ-HMnO in the O process. Finally, HCHO is found to be decomposed into CO via formate, dioxymethylene and carbonate species as identified by room temperature in-situ diffuse reflectance infrared fourier transform spectroscopy. All these results show great potency of this facile ozonation routine for the highly active δ-MnO synthesis in order to remove the HCHO contamination.
如今，为应对长期存在的室内空气污染问题，制备高效低成本的甲醛（HCHO）去除催化剂仍是一项挑战。在此，通过一种简便的臭氧化策略成功合成了δ-MnO，其中Mn在碱性溶液中被臭氧（O）气泡氧化。在48,000 mL/(g·hr)的气体时空速（GHSV）下，对于50 ppm的HCHO，其呈现出最佳的催化性能之一，100%转化温度低至85°C。相比之下，如果用O代替O，则需要超过6倍长的氧化时间。表征表明，臭氧化过程产生了不同的四方β-HMnO中间体，与O过程中相对热力学更稳定的单斜γ-HMnO相比，这有利于快速转化为最终产物δ-MnO。最后，通过室温原位漫反射红外傅里叶变换光谱确定，HCHO通过甲酸盐、二氧亚甲基和碳酸盐物种分解为CO。所有这些结果表明，这种简便的臭氧化方法在合成高活性δ-MnO以去除HCHO污染方面具有巨大潜力。
