Purification of landfill biogases from siloxanes by adsorption: A study of silica and 13X zeolite adsorbents on hexamethylcyclotrisiloxane separation

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• 作者：Tania Montanari ; Elisabetta Finocchio ; Irene Bozzano ; Gilberto Garuti ; Andrea Giordano ; Chiara Pistarino ; Guido Busca
• 关键词：Biogases cleaning ; Hexamethylcyclotrisiloxane ; Activated carbon ; Regeneration of adsorbents ; 13X zeolite ; Silica
• 刊名：Chemical Engineering Journal
• 出版年：2010
• 出版时间：15 December 2010
• 年：2010
• 卷：165
• 期：3
• 页码：859-863
• 全文大小：2566 K

文摘

The adsorption capacity on and the desorption from pure activated carbons, silica and NaX zeolite, of hexamethylcyclotrisiloxane (HMCTS or D₃, a common siloxane impurity in biogases) has been evaluated in laboratory experiments using synthetic biogas. The adsorption mode of this molecule has also been investigated by FT-IR spectroscopy. HMCTS adsorbs on silica by hydrogen bonding on the surface hydroxyl groups. However, its desorption up to 200 °C by purging with nitrogen as well as by vacuum treatment, is incomplete, leaving surface hydroxyl groups partially affected. Limited desorption is observed also from activated carbons at temperatures between 20 and 200 °C. On zeolite NaX molecular adsorption as well as reactive adsorption occurs, partial desorption being obtained by purging with nitrogen already at room temperature. In the three adsorbents, polymerization of HMCTS to silicone is found during adsorption in dynamic conditions. This is supposed to be the common cause of the only partial regenerability of all these solids after HMCTS adsorption.