Nanostructured carbons for solid phase extraction A.M. Puziy a, *, O.I. Poddubnaya a , B. Gawdzik b , M. Sobiesiak b , C.A. Reinish a , M.M. Tsyba a , T.P. Segeda a , M.I. Danylenko c a Institute for Sorption and Problems of Endoecology, NAS of Ukraine, Naumov St. 13, 03164 Kiev, Ukraine b Faculty of Chemistry, Maria Curie-Sklodowska University, Pl. Marii Curie-Sklodowskiej 3, 20031 Lublin, Poland c Institute for Problems of Materials Science, NAS of Ukraine, Krzhizhanovsky St. 3, 03142 Kiev, Ukraine 1. Introduction Solid state extraction (SPE) is an extremely efficient method for isolating and concentrating analytes from relatively large volumes of liquid. This technique can be very effective, even when the solutes are present at extremely dilute concentrations (e.g. ppb). For this reason, SPE is widely used for analysis of environmental pollutants in aqueous solutions. Most popular SPE adsorbents are alkyl-bonded silica, porous copolymers and carbon adsorbents. Carbonaceous adsorbents offer major advantages over modified silica and organic sorbents due to high thermal and chemical stability over a wide pH range. Special convenience of carbon adsorbents is high adsorption capacity towards polar molecules with high solubility in water. Nanostructured carbons have attracted considerable atten- tion due to advanced properties and great potential for application ranging from catalysis, separation and adsorption to energy storage and environmental protection [1,2]. Such carbons show uniform porous structure with tunable pore size which depends on the template material [3]. There are numerous potential applications in which nanostructured carbons would be attractive, for instance, adsorption of large hydrophobic molecules such as vitamins, dyes, humic sub- stances, dextrins, etc., chromatographic separations, electro- chemical double-layer capacitors, lithium batteries and in catalysis. In this paper we describe preparation of nanostruc- tured carbons with reliable control of textural parameters such as specific surface area, pore volume, and pore size which is critical for adsorption concentration of environmental pollu- tants. 2. Experimental methods Nanostructured carbons were prepared by the hard template method using zeolite NaY and two commercial silica gels (SG60, Fluka and ZK, POCh) as a hard template and furfuryl alcohol (FA) as a carbon source. The template was impregnated with acetone solution of FA to fill 100% of total pore volume. Then the sample was heated in water bath (100 8C) for 1 h to polymerize FA, heated in the electric plate at ca. 230 8C for 1 h and then carbonized in argon atmosphere with gradual temperature rise up to 800 8C and kept for 30 min at the end temperature. Then the atmosphere was switched to argon saturated with benzene vapor and kept for 1 h at 800 8C. After that, the atmosphere was switched again to argon and the temperature was increased to 900 8C and maintained for 1 h. The carbon/silica composite thus obtained was treated with 40% HF to dissolve the silica template, washed with water and dried in air at 110 8C. Applied Surface Science 256 (2010) 5216–5220 ARTICLE INFO Article history: Available online 28 December 2009 Keywords: Nanostructured carbon Template method Porous structure Surface chemistry Solid phase extraction ABSTRACT Nanostructured carbons have been obtained by the template method using zeolite NaY and silica gels (SG60, Fluka and ZK, POCh) as structure directing agents. Texture and porous structure of carbons were characterized by TEM, XRD and nitrogen adsorption. Surface chemistry was investigated by the potentiometric titration method. It has been shown that all carbons show developed and uniform porous structure with mean size in the micropore range (1.1 nm) for zeolite derived carbon and in the mesopore range (3.4 and 4.8 nm) for silica gel derived carbons. The BET surface area of silica gel derived carbons is in the range 1230–1280 m 2 /g whereas zeolite derived carbon possesses very high BET surface area, 3000 m 2 /g. Potentiometric titration showed that carbons obtained by the template method contain significant amount of acid surface groups (carboxylic, lactone/enol and phenolic) with the total amount 1.1–1.5 mmol/g. To study adsorption–desorption properties of nanostructured carbons towards phenol and chlorophenols the solid phase extraction method was used. High recoveries of chlorophenols were obtained (80–93%) at the breakthrough volumes 1700–3000 mL. The recoveries are much higher than that obtained with commercially available carbon ACC (Supelco). ß 2009 Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +380 44 4529325; fax: +380 44 4529328. E-mail address: alexander.puziy@ispe.kiev.ua (A.M. Puziy). Contents lists available at ScienceDirect Applied Surface Science journal homepage: www.elsevier.com/locate/apsusc 0169-4332/$ – see front matter ß 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2009.12.106