Chemical Engineering Journal 171 (2011) 951–957 Contents lists available at ScienceDirect Chemical Engineering Journal j ourna l ho mepage: www.elsevier.com/locate/cej Equilibria and kinetics of phenol adsorption on a toluene-modified hyper-cross-linked poly(styrene-co-divinylbenzene) resin Jianhan Huang a,b,∗ , Ruijie Deng a,b , Kelong Huang a,b a School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China b Key Laboratory of Resources Chemistry of Nonferrous Metals, Ministry of Education (Central South University), Changsha 410083, China a r t i c l e i n f o Article history: Received 14 March 2011 Received in revised form 14 April 2011 Accepted 20 April 2011 Keywords: Hyper-cross-linked Poly(styrene-co-divinylbenzene) resin Adsorption Absorption Isothermal Kinetics a b s t r a c t A series of novel toluene-modified hyper-cross-linked poly(styrene-co-divinylbenzene) resins were syn- thesized and the adsorption behaviors of the synthesized resins toward phenol were investigated from aqueous solution. Among the synthesized five resins, HJ-L15 possessed the largest adsorption capacity toward phenol. The phenol adsorption onto HJ-L15 is combination of the surface adsorption and the absorption due to skeleton swelling. The molecular form of phenol was favorable for the adsorption. The isotherms could be fitted by Freundlich model and the adsorption was shown to be an exothermic process. The kinetic curves could be characterized by pseudo-second-order rate equation and the intra-particle diffusion was the rate-limiting step at the initial stage. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Macroporous cross-linked poly(styrene-co-divinylbenzene) (PS) or polymethacrylate resins have displayed excellent adsorp- tion behaviors toward aromatic compounds [1–4], and hence these resins are increasingly applied for the efficient removal and recycling of aromatic compounds [5]. In the 1970s, Davankov developed a hyper-cross-linking technique, and a type of novel hyper-cross-linked PS resin was prepared from linear PS or low cross-linked PS through the use of bifunctional cross-linking agents and Friedel–Crafts catalysts [6,7]. The specific surface area of the prepared resin was shown to be relatively high with the pore diameter distribution being dominated by mesopores [8]. Adsorption experiments indicated that the prepared resin displayed excellent adsorption behaviors toward nonpolar or weakly polar aromatic compounds [9–11], whereas its adsorption capacity toward polar aromatic compounds was relatively small. In order to improve the adsorption capacity of the hyper-cross- linked resin toward polar aromatic compounds, various techniques such as the introduction of polar units into the copolymers, the employment of polar compounds as the cross-linking reagent and the introduction of polar aromatic compounds have been exam- ined [12,13]. The results indicated that the introduction of the polar groups into such resins increased their retention toward polar ∗ Corresponding author. Tel.: +86 831 8879850; fax: +86 731 88879616. E-mail address: xiaomeijiangou@yahoo.com.cn (J. Huang). aromatic compounds [14,15]. In addition, study of the adsorption mechanism revealed that the improved polarity of the hyper-cross- linked resin plays an important role in the enhanced adsorption of the hyper-cross-linked resin toward polar aromatic compounds [16,17]. If low cross-linked chloromethylated PS is applied as the reac- tant, some non-polar aromatic compound like toluene is also added in the Friedel–Crafts reaction, the Friedel–Crafts reaction between the chloromethylated PS and toluene will also occur in addition to the Friedel–Crafts reaction of the chloromethylated PS itself. Will the adsorption of the obtained toluene-modified hyper-cross- linked resin toward polar aromatic compounds like phenol be enhanced? In addition, because of the addition of a different quan- tity of toluene in the reaction, the pore structure and the chemical structure of the prepared hyper-cross-linked resin will be differ- ent and which will determine the adsorption selectivity of the synthesized resin. To the best of our knowledge, there is few report focusing on synthesis and adsorption behaviors of toluene- modified hyper-cross-linked PS resin so far [18]. In this study, a series of novel hyper-cross-linked PS resins are prepared from macroporous cross-linked chloromethylated PS by adding a different quantity of toluene in the Friedel–Crafts reaction, the pore structures, chemical structures and adsorption capaci- ties of the prepared resins toward phenol are compared. After investigating the adsorption mechanism for the phenol adsorp- tion onto the hyper-cross-linked PS resins, HJ-L15 is selected as the polymeric adsorbent, phenol is chosen as the adsorbate, and the adsorption behaviors of HJ-L15 toward phenol are investigated 1385-8947/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.cej.2011.04.045