School of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China; State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China.
State Key Laboratory of Clean Energy Utilization, Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China.
Chemosphere. 2018 May;199:502-509. doi: 10.1016/j.chemosphere.2018.01.169. Epub 2018 Feb 3.
Ozone assisted carbon nanotubes (CNTs) supported vanadium oxide/titanium dioxide (V/Ti-CNTs) or vanadium oxide-manganese oxide/titanium dioxide (V-Mn/Ti-CNTs) catalysts towards gaseous PCDD/Fs (polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans) catalytic oxidations at low temperature (150 °C) were investigated. The removal efficiency (RE) and decomposition efficiency (DE) of PCDD/Fs achieved with V-Mn/Ti-CNTs alone were 95% and 45% at 150 °C under a space velocity (SV) of 14000 h; yet, these values reached 99% and 91% when catalyst and low concentration (50 ppm) ozone were used in combined. The ozone promotion effect on catalytic activity was further enhanced with the addition of manganese oxide (MnO) and CNTs. Adding MnO and CNTs in V/Ti catalysts facilitated the ozone decomposition (creating more active species on catalyst surface), thus, improved ozone utilization (demanding relatively lower ozone addition concentration). On the other hand, this study threw light upon ozone promotion mechanism based on the comparison of catalyst properties (i.e. components, surface area, surface acidity, redox ability and oxidation state) before and after ozone treatment. The experimental results indicate that a synergistic effect exists between catalyst and ozone: ozone is captured and decomposed on catalyst surface; meanwhile, the catalyst properties are changed by ozone in return. Reactive oxygen species from ozone decomposition and the accompanied catalyst properties optimization are crucial reasons for catalyst activation at low temperature.
臭氧辅助碳纳米管（CNTs）负载的氧化钒/二氧化钛（V/Ti-CNTs）或氧化钒-氧化锰/二氧化钛（V-Mn/Ti-CNTs）催化剂在低温（150°C）下对气态 PCDD/Fs（多氯二苯并对二恶英和多氯二苯并呋喃）的催化氧化进行了研究。在 SV 为 14000 h 的条件下，V-Mn/Ti-CNTs 单独使用时，PCDD/Fs 的去除效率（RE）和分解效率（DE）分别达到 95%和 45%，但当催化剂与低浓度（50ppm）臭氧结合使用时，这些值分别达到 99%和 91%。添加氧化锰（MnO）和 CNTs 进一步增强了臭氧对催化活性的促进作用。在 V/Ti 催化剂中添加 MnO 和 CNTs 有助于臭氧分解（在催化剂表面产生更多活性物种），从而提高臭氧利用率（需要相对较低的臭氧添加浓度）。另一方面，通过比较臭氧处理前后催化剂的性质（即成分、表面积、表面酸度、氧化还原能力和氧化态），本研究揭示了臭氧促进机制。实验结果表明，催化剂和臭氧之间存在协同效应：臭氧在催化剂表面被捕获和分解；同时，臭氧反过来改变催化剂的性质。臭氧分解产生的活性氧物种和伴随的催化剂性质优化是催化剂在低温下活化的关键原因。
