Removal of methyl–ethyl ketone vapour on polyacrylonitrile-derived carbon/mesoporous silica nanocomposite adsorbents Rafał Janus a , Piotr Kus ´ trowski a,⇑ , Barbara Dudek a , Zofia Piwowarska a , Andrzej Kochanowski a , Marek Michalik b , Pegie Cool c a Faculty of Chemistry, Jagiellonian University, Ingardena 3, 30-060 Kraków, Poland b Institute of Geological Sciences, Jagiellonian University, Oleandry 2a, 30-063 Kraków, Poland c Department of Chemistry, University of Antwerpen, Universiteitsplein 1, B-2610 Wilrijk, Belgium article info Article history: Received 3 March 2011 Received in revised form 20 April 2011 Accepted 23 April 2011 Available online 30 April 2011 Keywords: Mesoporous silica sieves Polyacrylonitrile Precipitation polymerization Adsorption Volatile organic compounds abstract Mesoporous silica supports (MCM-41, SBA-15 and silica gel) were modified by the introduction of con- trolled amounts of polymer-derived carbon. Precipitation polymerization of polyacrylonitrile in the aque- ous suspension of a silica material was used as a deposition method. The samples of PAN/silica composites were studied by thermal analysis, performed in air and inert atmosphere, in order to deter- mine the amount of a deposited polymer and its thermal stability. The effect of surface area of a silica support and the monomer concentration in the mother solution on the effectiveness of deposition was revealed. The PAN/silica composites were transformed into C/SiO 2 adsorbents by carbonization carried out at 623 K. Texture (low-temperature sorption of N 2 ), surface structure (FTIR-DRIFT) and morphology (SEM) of the carbonized samples were investigated. The adsorption tests in the elimination of methyl– ethyl ketone from gas phase were performed under dynamic conditions. The MCM-41-based composites containing highly dispersed carbon layers on the surface appeared to be the most promising adsorbents for a commercial application. Moreover, these materials exhibited a high stability in the adsorption– desorption runs repeated ten times suggesting the possibility of regeneration of the adsorbent bed with- out a significant loss in the adsorption effectiveness. Ó 2011 Elsevier Inc. All rights reserved. 1. Introduction Volatile organic compounds (VOCs) are a large-number group of low-boiling liquid organic pollutants, characterized by boiling points in the range 323–533 K under normal atmospheric pressure [1], discharged into the atmosphere. This group includes aliphatic and aromatic hydrocarbons, alcohols, carbonyl compounds as well as various hydrocarbon derivatives containing other elements like halogens, nitrogen and sulphur. VOCs contribute to increasing the greenhouse effect and have negative impact on human health [2–7]. VOCs can originate from any natural sources such as volcanoes eruptions, biological processes, forest fires and geological beds [8]. However, human activities (e.g. transport, chemical and petro- chemical industry, waste utilization plants, use of organic solvents) considerably increase the level of VOCs’ emission [9–11]. Many dif- ferent methods of the VOCs’ abatement are known, for example, cryogenic condensation [12–14], biofiltration [15], wet absorption methods [16] as well as catalytic oxidation [17,18] and thermal oxidation connected with recuperation [19]. Nevertheless, adsorp- tion seems to be the most effective, cheapest and environmentally friendly technique of VOCs elimination. There is a large number of various solid adsorbents based on porous materials, e.g. zeolites [20], clays [21,22], MCM-48 [23], silicated MCM-41 and spherical ordered silicas [24,25], organomodified silica materials or organ- ic–inorganic composites [26,27] and many different activated car- bon species [28,29]. Activated carbons can be produced from carbon containing raw materials like biomass, waste polymer [30,31] and high-processed coal (hard and brown coal, charcoal). The carbon-based materials have been applied among other to cap- turing of coal mine methane [32], removal of organic solvents [33] as well as remediation of waste water. Typical activated carbons are characterized by ultramicroporosity, which causes diffusion limitations. For this reason, adsorption of high molecular adsorbate takes place only on the external surface of carbon particles result- ing in an ineffectiveness of inner surface. The accessible surface of active carbon can be extended by its deposition on a high surface, mesoporous support. Polymers (e.g. polyacrylonitrile) are the best carbon precursors in such a case. Polymer layers can be relatively easily deposited on a support sur- face and subsequently transformed into carbon by thermal 1387-1811/$ - see front matter Ó 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.micromeso.2011.04.029 ⇑ Corresponding author. Tel.: +48 12 6632006; fax: +48 12 6340515. E-mail address: kustrows@chemia.uj.edu.pl (P. Kus ´ trowski). Microporous and Mesoporous Materials 145 (2011) 65–73 Contents lists available at ScienceDirect Microporous and Mesoporous Materials journal homepage: www.elsevier.com/locate/micromeso