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Silane modification and characterization of activated carbon Qing He · Yingbo Xu · Chenghui Wang · Shike She · Shun Zhou · Ran Wang

Received: 20 May 2010 / Accepted: 14 September 2011 / Published online: 27 October 2011 © Springer Science+Business Media, LLC 2011

Abstract Activated carbons have been wildly used as adsorbents for various purpose. When used in a cigarette filter activated carbon can selectively remove a number of the vapor phase compounds to varying degrees of efficiency. To improve the wet-feeling of cigarette smoke with AC in the filter, a new method is developed to chemically functionalize a coal-based activated carbon (AC) based on silanization reaction. Silanization using 3-glycidoxypropyltrimethoxy silane was performed after the oxidized AC was reduced by lithium aluminum hydride. N2 and water adsorption, FTIR, and XPS were employed to characterize the changes in the surface morphology, chemistry and physical conditions at different processing stages. Water content analysis in cigarette mainstream smoke (MSS) showed a positive result in the application of modified AC. Keywords Activated carbon · Silanization · Functional groups · Modification

1 Introduction Activated carbons (ACs) have been proven to be useful catalyst (Nevskaia and Martin-Aranda 2003; Heinen et al. 2001) as supports for the active phase, or effective adsorbents for the removal of a wide variety of organic and inorganic pollutants dissolved in aqueous media, or from gaseous environments (Streat and Horner 2000; Suffet et al. 1978; Saha et al. 2001; Biniak et al. 1999). Due to their porous Q. He () · Y. Xu · C. Wang · S. She · S. Zhou · R. Wang Group Research & Development, China Tobacco Anhui Industrial Corporation, Hefei, 230088 China e-mail: [email protected]

texture and high surface area (>1000 m2 /g), activated carbons are finding an increase application in cigarettes filter to remove smoke compounds. Their performance is thought to be determined by their texture and surface chemistry (Rodriguez-Reinoso 1998). However, a major disadvantage by application of ACs in cigarettes filter is agreed to be the dry-feeling of smoke caused by significant water adsorption. The texture of ACs was proved to be controlled by activation procedure and it’s possible to prepare carbons with different proportions of micro, meso and macropores (Wigmans 1986). Carboxyl, carbonyl, phenol, quinone, and lactone groups have been identified in ACs surface (Donnet 1968; Hsieh and Teng 2000; Laszlo and Nagy 1997), meanwhile, a variety of methods have been used to modify the surface groups (Chingombe et al. 2005; Shim et al. 2001; Jia et al. 2002). However, these methods were limited in either chemical/thermal oxidation or reduction by heating under inert gas, however, no evidence was proved to decrease the water adsorption ability. Organosilanes have been extensively used as coupling agents on hydroxylated surfaces (SiO2 on Si, Al2 O3 on Al, glass etc.) (Sagiv 1998; Duchet et al. 1997; Wasserman et al. 1989). Recently, works have mainly been perfo