Mineralization of Ionic Liquids by Catalytic Ozonation over ZnO/Ca2Fe2O5

• Published in: Industrial & engineering chemistry research 2025-01, Vol.64 (1), p.301-312
• Main Authors: Zhang, Heng, Zheng, Man, Cao, Xuepu, Li, Huiyang, Tian, Heli, Zhou, Lilong, Liu, Runjing, Yun, Jimmy
• Format: Article
• Language: English
• Subjects: Kinetics, Catalysis, and Reaction Engineering
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/acs.iecr.4c03902

Imidazolyl-based ionic liquids (ILs) have been widely used in many fields, leading to potential environmental problems due to the toxicity of ILs. In this work, ZnO/Ca2Fe2O5 was prepared and used as an efficient catalyst to mineralize 1-butyl-3-methylimidazolium chloride ([BMIM]­Cl) ILs using the catalytic ozonation process. [BMIM]­Cl was mineralized to CO2, H2O, NH4 +, and Cl– in a short time. The mineralization efficiency of [BMIM]Cl can reach up to >92% in 120 min with a catalyst dosage of 3.3 g/L, an ozone flow rate of 72 mg/min, an initial pH of 10.5, and an initial [BMIM]Cl concentration of 175 mg/L. Meanwhile, the degradation pathway of [BMIM]Cl was also proposed. The physical and chemical properties of the catalysts were characterized by XRD, FTIR, N2 physical adsorption–desorption profiles, TEM, and XPS. The results showed that the ZnO/Ca2Fe2O5 catalyst had good stability, and the presence of Zn2+ promoted the decomposition of ozone and the production of •OH, which increased the degradation efficiency of [BMIM]­Cl. The catalytic mechanism was also discussed. This research showed a promising way to prepare efficient catalysts for the treatment of [BMIM]Cl using the catalytic ozonation process.