College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China; Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, Zhejiang University of Technology, Hangzhou, 310014, China.
College of Environment, Zhejiang University of Technology, Hangzhou, 310014, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing, 100084, China; Department of Chemical Engineering, Sichuan University, Chengdu, 610065, Sichuan, China.
Chemosphere. 2022 Nov;307(Pt 4):135993. doi: 10.1016/j.chemosphere.2022.135993. Epub 2022 Aug 17.
Herein, amorphous catalysts were employed to investigate the catalytic ozonation system, revealing the degradation mechanism and influencing factors (O concentration, temperature, and humidity) for toluene catalytic ozonation. CuMnO exhibited the highest toluene oxidized and excellent stability (∼85% at 60 h) based on the suitable value of O/O and potent synergy between Cu with Mn. To explore the effect of factors, the change of fresh and post-reaction samples was compared as revealed in the relevant characterization results (SEM, XRD, BET, XPS, TGA), DRIFTS and GC-MS identified the intermediates and byproducts. The results show that appropriate temperature (100 °C) and O concentration (2100 ppm) can effectively enhance the number of reactive oxygen species. Although HO can increase the production of ·OH to promote degradation, it is easier to quench the active sites on the surface of amorphous catalysts. During the reaction, the main role of Cu in Cu-Mn bimetallic oxides is adsorption of toluene and O, formation of benzoic acid, and oxidation of short-chain products. As for the adjacent Mn, it works on the cleavage of O-O in O and the ring-opening of benzene. Then, the mainly catalytic ozonation pathway of toluene was proposed and followed the order: toluene, benzoic acid, benzene, maleic anhydride, short-chain carbon species, CO, and HO.
在此，采用无定形催化剂研究了催化臭氧化体系，揭示了甲苯催化臭氧化的降解机制和影响因素（O 浓度、温度和湿度）。基于 O/O 的合适值和 Cu 与 Mn 之间的强大协同作用，CuMnO 表现出最高的甲苯氧化活性和优异的稳定性（60 h 时约为 85%）。为了探究因素的影响，通过相关的表征结果（SEM、XRD、BET、XPS、TGA）、DRIFTS 和 GC-MS 对新鲜和反应后样品的变化进行了比较，鉴定了中间产物和副产物。结果表明，适当的温度（100°C）和 O 浓度（2100 ppm）可以有效地增加活性氧物种的数量。尽管 HO 可以增加·OH 的产生以促进降解，但它更容易猝灭无定形催化剂表面的活性位点。在反应过程中，Cu 在 Cu-Mn 双金属氧化物中的主要作用是吸附甲苯和 O，形成苯甲酸，并氧化短链产物。对于相邻的 Mn，它作用于 O 中的 O-O 的断裂和苯的开环。然后，提出了甲苯的主要催化臭氧化途径，并遵循以下顺序：甲苯、苯甲酸、苯、马来酸酐、短链碳物种、CO 和 HO。
