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Tuning the Acidity of Pt/ CNTs Catalysts for Hydrodeoxygenation of Diphenyl Ether
Published on: August 17, 2019
A combined effect of polybrominated diphenyl ether and aquaculture effluent on growth and antioxidative response of
Shazia Farzana1, Nora Fung Yee Tam1
1Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China; State Key Laboratory in Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China.
Abstract:
Mangrove wetland receives nutrient-rich aquaculture effluent (AE) from nearby farming activities and polybrominated diphenyl ethers (PBDEs) from the production and usage of flame retardants. The effects of BDE-209 (the most common PBDE congener), AE and their combination on two true mangrove species, namely Kandelia obovata and Avicennia marina, were compared in a 6-month microcosm study. Results showed that K. obovata was more sensitive to these contaminants than A. marina, as reflected by its enhanced production of leaf superoxide (O2-∗) by BDE-209 and root malondialdehyde (MDA) by the combined BDE-209 and AE treatment. The hormesis model showed that the combined effects of BDE-209 and AE on the production of MDA, O2-∗ and catalase (CAT) activity in K. obovata and A. marina were antagonistic except root O2-∗ in A. marina, but the effects on leaf superoxide dismutase (SOD) activity in K. obovata, and root SOD and peroxidase (POD) activities in A. marina were synergistic. The defense mechanisms differed between treatment and species. The activities of SOD and POD were the main mechanisms to defend K. obovata and A. marina against BDE-209, but CAT in K. obovata and POD in A. marina were more important in defending the combined BDE-209 and AE treatment.
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Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Crown Ethers

