Synthesis of three crystalline forms of Al2O3 featuring rod-like fibers and their effect on the gaseous degradation of 1-chloronaphthalene. Issue 5 (17th March 2017)

• Record Type: Journal Article
• Authors: Lu, Huijie; Li, Qianqian; Su, Guijin; Zheng, Minghui; Zhao, Yuyang; Miao, Xue; Liu, Yalu; Huang, Xinchen; Zhao, Yanhui
• Is Part Of: Environmental science. Volume 4:Issue 5(2017)
• Page Start: 994
• Page End: 1004
• Publication Date: 2017-03-17
• Subjects: Environmental sciences -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c6en00662k
• Languages: English
• ISSNs: 2051-8153

Abstract

Abstract : The effect of different crystalline forms of Al2 O3 on the degradation of CN-1 is shown where γ-Al2 O3 displays superior oxidation activity. Abstract : Three crystalline forms of Al2 O3 featuring rod-like fibers are synthesized, to perform the gaseous degradation of 1-chloronaphthalene (CN-1), a model compound. The degradation efficiency (DE) decreases as follows: micro/nano-γ-Al2 O3 > micro/nano-η-Al2 O3 > regular α-Al2 O3 . The high DE of 92.2% attained over γ-Al2 O3 is attributed to its specific defective spinel structure, resulting in its large surface area and pore volume, large amounts of surface-adsorbed oxygen species, and Brønsted and Lewis acid sites. The degradation products, naphthalene and 1, 4/1, 6-dichloronaphthalene (DiCN), with yield ratios of 7.3–13.3, are detected, indicating the occurrence of hydrodechlorination and side chlorination reactions. 1, 6-DiCN is believed to be the most favored DiCN isomer product based on the calculated Δ H r and Δ G r . However, the percentage values of intermediates formed via these two reactions, in the degradation of CN-1, are 9.1%, 4.5% and 4.4%, over α-, η- and γ-Al2 O3, respectively. The oxidative degradation pathway possibly dominantly occurs especially over micro/nano-γ-Al2 O3 with oxidative species such as O2 −, O − and O 2−, following the Mars–van Krevelen mechanism. Oxidation intermediates containing –CH2 –, –CH3, and C–O groups are produced, which can be subsequently oxidized to low-molecular-weight products, such as formic, acetic and propanoic acids, and eventually completely oxidized to CO2 .