Process Safety and Environmental Protection 1 0 9 ( 2 0 1 7 ) 214–223 Contents lists available at ScienceDirect Process Safety and Environmental Protection journal homepage: www.elsevier.com/locate/psep Adsorption of BTX from aqueous solutions by Na-P1 zeolite obtained from fly ash Lidia Bandura a , Dorota Kolody ´ nska b , Wojciech Franus a,∗ a Department of Geotechnical Engineering, Faculty of Civil Engineering and Architecture, Lublin University of Technology, Nadbystrzycka 40, 20-618 Lublin, Poland b Department of Inorganic Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University, Maria Curie Sklodowska Sq. 2, 20-031 Lublin, Poland a r t i c l e i n f o Article history: Received 28 November 2016 Received in revised form 28 February 2017 Accepted 28 March 2017 Available online 6 April 2017 Keywords: Synthetic zeolites Zeolite Na-P1 BTX removal Adsorption kinetics Adsorption isotherms Water treatment a b s t r a c t The adsorption of BTX (benzene, toluene, o- and p-xylene) from aqueous solution by synthetic zeolite Na-P1 obtained from fly ash was examined. The adsorbent was charac- terized by scanning electron microscope (SEM-EDS) and X-ray diffraction (XRD). Surface area and pore volume distribution were determined using a nitrogen adsorption/desorption isotherm. BTX adsorption tests, including the influence of contact time, sorption isotherms and the influence of initial concentration, were performed in a batch multicomponent sys- tem. The sorption capacity followed the order xylenes > toluene > benzene, and the removal efficiency decreased with an increase in initial BTX concentration. The process kinetics was evaluated using pseudo-first-order, pseudo-second-order and intraparticle diffusion mod- els. The adsorption equilibrium was reached within 24 h and followed pseudo-second-order kinetics. The Langmuir, Freundlich and Temkin models were used to evaluate the adsorp- tion capacity of Na-P1. The Langmuir model was found to be the most suitable for all BTX sorption from a multicomponent system. The calculated maximum adsorption capacities of Na-P1 (q max ) for benzene, toluene, o- and p-xylene were 0.032, 0.050, 0.147 and 0.129 respectively. © 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved. 1. Introduction In recent decades, water pollution has become a serious environmen- tal problem as a consequence of progressive industrialization and the development of civilization. Benzene, toluene and xylene (BTX) com- pounds are some of the most hazardous water contaminants, since they have toxic and carcinogenic properties. Even at very low concen- trations, they may adversely affect the biological functions of terrestrial and aquatic ecosystems (Standeker et al., 2009; Tang et al., 2011; Nourmoradi et al., 2012; Szarlip et al., 2014; Szala et al., 2015; Moro et al., 2015); a concentration of 0.01 mg/L may not only significantly alter the flavour of drinking water but also endanger public health. For these reasons, strict limits have been imposed all over the world on their concentrations in water and wastewater, and the removal of BTX has become necessary before water is released into the environment. ∗ Corresponding author. E-mail address: w.franus@pollub.pl (W. Franus). The most common sources of BTX water contamination appear to be petroleum leakages from underground storage tanks, pipelines or tankers. Other sources include municipal waste, the petrochemical and chemical industries, the printing and leather industries, rubber manufacture, plastics decomposition, solvent extraction, agricultural effluents, exhaust gases and petroleum leakages during car accidents (Su et al., 2010; Szala et al., 2015; Bandura et al., 2015a). Many conventional methods can be employed to remove BTX from water and wastewater, including adsorption, aeration, biological oxida- tion and chemical oxidation. Of these, adsorption processes involving porous solids are the most popular, and are widely utilized in engineer- ing practice since they permit the recovery of these compounds (Lin and Huang, 1999). Various mineral and organo-mineral sorbents have recently been regarded as alternative adsorbents which are potentially useful for the removal of BTX from water (Zytner, 1994; Sharmasarkar et al., 2000; Standeker et al., 2009; Simpson and Bowman, 2009; Torabian et al., 2010; Aivalioti et al., 2010; Moura et al., 2011; Alejandro et al., 2012; Simantiraki et al., 2012; Nourmoradi et al., 2012; Carvalho et al., 2012; Vidal et al., 2012; Aleghafouri et al., 2015; Szala et al., 2015; Muir and Bajda, 2016; Bandura et al., 2016). http://dx.doi.org/10.1016/j.psep.2017.03.036 0957-5820/© 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.