Comparison of BEA, USY and ZSM-5 for the quantitative extraction of polycyclic aromatic hydrocarbons from water samples Andréia A. Costa a , Walter B. Wilson b , Huiyong Wang b , Andres D. Campiglia b,⇑ , José A. Dias a , Sílvia C.L. Dias a,⇑ a Universidade de Brasília, Campus Darcy Ribeiro, Instituto de Química, caixa postal 4478, Brasília-DF 70904-970, Brazil b University of Central Florida, 4000 Central Florida Blvd., Physical Science Building, Orlando, FL 32816-2366, USA article info Article history: Received 2 May 2011 Received in revised form 7 June 2011 Accepted 15 June 2011 Available online 22 June 2011 Keywords: Zeolite Water Extraction Polycyclic aromatic hydrocarbons Adsorption abstract The physicochemical properties of three commercial zeolites – namely BEA, USY and ZSM-5 – are com- pared for the water removal of 15 PAHs included in the US EPA priority pollutants list. The best percent- ages of extraction were obtained with BEA and varied from 85.2 ± 1.7% (benzo[g,h,i]perylene) to 99.6 ± 1.1% (pyrene). The correlation of physicochemical properties to the percentages of extraction sug- gests that the predominant factor for a successful extracting performance is the adsorption of PAHs to the external surface of the extracting material. This process is facilitated by relatively large total pore vol- umes, large average pore diameters and a homogeneous distribution of Lewis acid sites. The presence of the latter enhances extraction performance via p-electron interactions with the aromatic rings of the PAH. Ó 2011 Published by Elsevier Inc. 1. Introduction Considering the importance of water and the major environ- mental health risk that contaminated waters poses to the human- kind, the scientific international community has carried out extensive research in the past two decades on water protection and remediation. Adsorption is one of the most effective and sim- plest approaches for removing organic and inorganic pollutants from contaminated waters. Investigated materials include natural or synthetic inorganic solids [1–7], natural organic matter [8,9], bio-sorbents [10,11], polymeric adsorbents and polymer–inorganic hybrids [12–14], a variety of natural or industrial by-products [15– 18], silica-based organic–inorganic hybrid adsorbents [19–22], and more recently ordered mesoporous organosilica materials [23,24]. This article deals with the adsorption and removal of PAHs from drinking water sources. PAHs are an important class of pollutants that derives from mankind activities involving incomplete com- bustion of organic matter. Some PAHs are capable of interacting with DNA to promote mutagenic and carcinogenic responses [25]. Their omnipresence in the environment and chemical persis- tence makes PAHs a permanent threat to humans. Because a pri- mary route of potential human exposure is contaminated water, the US EPA recommends the continuous monitoring of 16 PAHs (EPA-PAHs) in water samples from municipal wells. Adsorbent materials investigated so far for removing PAHs from water sam- ples include polymerin and lignimerin [26], activated carbon [27–29], porous carbon [30] and imprinted polymers [31,32]. Activated carbon with low oxygen content appears to be more efficient for PAH adsorption [28,29]. Oxygen functionalities reduce the accessibility and affinity of PAHs to the inner pore structure of the carbon material via formation of hydration clusters. Despite the effectiveness of activated carbon, the long extraction times are often the limiting factors in large-scale applications of numerous samples. The ability of petroleum coke-derived porous carbon to ad- sorb PAHs from water was demonstrated with naphthalene, fluo- rene, phenanthrene, pyrene and fluoranthene [30]. Quantitative removal of the five PAHs took approximately 300 min of mixing and equilibrium time. Shorter extraction times were obtained with a molecular imprinting polymer (MIP) specifically synthesized for the removal of acenaphthene, benzo[a]anthracene, benzo[a]pyrene, chrysene, fluoranthene, fluorene, phenanthrene and pyrene from groundwater samples [31,32]. Extraction times depended on the volume of sample, which varied between 1 mL (60 min) and 10 mL (180 min). With the larger sample volume and longer extraction 1387-1811/$ - see front matter Ó 2011 Published by Elsevier Inc. doi:10.1016/j.micromeso.2011.06.016 Abbreviations: PAHs, polycyclic aromatic hydrocarbons; US EPA, US Environ- mental Protection Agency; SDBAC, stearyldimethylbenzylammoniumchloride; TG, thermogravimetry; DTG, derivative thermogravimetry; DTA, differential thermal analysis; TPD, temperature-programmed desorption; RTF, room-temperature fluo- rescence; LOQ, limit of quantitation; RSD, relative standard deviations; AFOM, analytical figures of merit; LDR, linear dynamic ranges; LOD, limit of detection; R, correlation coefficient. ⇑ Corresponding authors. E-mail addresses: andres.campiglia@ucf.edu (A.D. Campiglia), scdias@unb.br (S.C.L. Dias). Microporous and Mesoporous Materials 149 (2012) 186–192 Contents lists available at SciVerse ScienceDirect Microporous and Mesoporous Materials journal homepage: www.elsevier.com/locate/micromeso