Adsorption of benzene and ethanol on activated carbon nanofibers prepared by electrospinning
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Adsorption of benzene and ethanol on activated carbon nanofibers prepared by electrospinning Yu Bai • Zheng-Hong Huang • Ming-Xi Wang Feiyu Kang
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Received: 17 October 2012 / Accepted: 18 February 2013 / Published online: 3 March 2013 Ó Springer Science+Business Media New York 2013
Abstract Activated carbon nanofibers (ACNFs) were prepared by electrospinning polyacrylonitrile solutions, and subsequent steam activation process. The ACNFs were characterized by scanning electron microscope, X-ray photoelectron spectroscopy and nitrogen adsorption at 77 K. The adsorption equilibrium data for benzene and ethanol were obtained by using static vapor adsorption system. As-prepared ACNFs demonstrate higher adsorption capacities for volatile organic compounds (VOCs) than activated carbon fibers (ACFs) by virtue of smaller diameter and more available adsorption sites on the surface. The adsorption performance of ACNFs increases with the burn-off, as a result of the increased microporosity. In addition, it is noteworthy that surface chemistry has an important effect on the adsorption of polar VOCs. The ACNF with higher oxygen content has a stronger adsorption tendency for ethanol. Keywords Adsorption Activated carbon nanofibers (ACNFs) VOCs Microporosity Surface chemistry
1 Introduction It has been well known that volatile organic compounds (VOCs) are harmful to both human beings and our living environment. As an effective technique to remove lowconcentration VOCs, adsorption techniques have attracted Y. Bai Z.-H. Huang (&) M.-X. Wang F. Kang (&) Lab of Advanced Materials, School of Materials Science and Engineering, Tsinghua University, 100084 Beijing, China e-mail: [email protected] F. Kang e-mail: [email protected]
more and more interests in recent years (Dwivedi et al. 2004; Lillo-Ro´denas et al. 2005; Ramos et al. 2010). Usually, porous carbon materials, such as activated carbons (ACs) and activated carbon fibers (ACFs) are common adsorbents which are widely studied (Benkhedda et al. 2000; Dolidovich et al. 1999; Yi et al. 2009; Dwivedi et al. 2004). Recently, activated carbon nanofibers (ACNFs) have showed great potential in the removal of VOCs due to their smaller diameter (sub-micrometer) and more developed micropore compared with ACFs (Ramos et al. 2010; Shim et al. 2006; Oh et al. 2008a, b; Cuervo et al. 2008; Hsieh and Chou 2006; Lee et al. 2010); Tavanai et al. (2009) found that the microporosity of ACNFs was more developed than that of ACFs. In spite of lower specific surface area, carbon nanofibers have shown higher adsorption amounts for benzene and toluene, compared to ACs (Jahangiri et al. 2011). In this context, ACNFs can be novel and effective adsorbent for VOCs. Though the surface structure and the adsorption performance for VOCs of ACNFs have been studied, few data about the difference between ACNFs and ACFs in the adsorption performance for VOCs has been reported so far. It is very important to compare the adsorption performance of ACNFs with that of ACFs, through which th
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