Heterogeneous photodegradation of 2,4-dichlorophenol using FeO doped onto nano-particles of zeolite P Alireza Nezamzadeh-Ejhieh *, Zahra Ghanbari-Mobarakeh Department of Chemistry, Shahreza Branch, Islamic Azad University, PO Box 311-86145, Shahreza, Isfahan, Iran 1. Introduction Phenols and phenolic compounds are one of the important organic contaminants in industrial wastewaters, so chlorophenols are widely recognized as one them in water and wastewater [1,2]. Chlorophenols are widely generated from a number of industrial manufacturing processes such as pesticide, paint, solvent, phar- maceutical, wood preserving chemicals, coke-oven and pulp industries [3]. These compounds pose severe problems to the environment, because they are carcinogens and mutagens. For example, 2,4-dichlorophenol (2,4-DCP) may cause some patholog- ical symptoms and changes human endocrine systems. Their mode of exposure is through the skin and gastrointestinal [4,5]. Several treatment methods such as: biological and physico- chemical methods have been investigated for the degradation of chlorophenols, but they are found to be ineffective for the degradation of 2,4-DCP and have some difficulties including the slow rate and requires to control of proper pH and temperature [6]. Simple physical methods including adsorption and liquid mem- brane are not effective in reducing the toxicity of chlorophenols [7]. Chemical methods such as chlorination, permanganate oxidation etc. lead to formation of toxic intermediate due to incomplete degradation [4]. Activated carbon adsorption involves phase transfer of pollutants without decomposition, which induces another pollution problem [6]. In fact, identifying products, whose toxicity may be even higher than that of the parent compounds, is an important issue because little is known about their nature [8]. In recent decades, advanced oxidation processes (AOPs) have been widely used for degradation of various organic pollutants to carbon dioxide and water. Among the various AOPs, semiconduc- tor mediated photocatalysis has been accorded great importance over the last few years due to its potential to destroy a wide range of organic and inorganic pollutants at ambient temperatures and pressures, without the production of harmful products [9,10]. The major mechanism in the degradation is due to oxidation by hydroxyl radicals produced in this process [8]. On the other hand, the efficiency of photocatalytic reactions significantly depends on the ability of electrons excitation of semiconductive photocatalysts from valence band to conduction band in a way which sufficient input of energy be greater than its band gap energy. This excitation leads to the generation of holes that react with adsorbed hydroxyl species or water molecules thereby producing reactive hydroxyl radicals. These radicals can react with pollutant molecules and disintegrate them into CO 2 and H 2 O [11,12]. Several attempts have been made to improve the photo-efficiency of semiconductors by adding adsorbents like silica, alumina, carbon active clays, and especially zeolites [13,14]. Supporting with zeolites is found to be a better candidate as compared to other supporting materials due to advantages such as: to solid structure defines channels and cavities of molecular dimension, super adsorption capability and special ion-exchange capability of zeolites [15–17]. Different works have been reported Journal of Industrial and Engineering Chemistry xxx (2014) xxx–xxx A R T I C L E I N F O Article history: Received 31 October 2013 Received in revised form 28 February 2014 Accepted 20 March 2014 Available online xxx Keywords: Photocatalytic degradation Nano-particles Zeolite P 2,4-dichlorophenol Heterogeneous catalysis A B S T R A C T Photocatalytic degradation of 2,4-dichlorophenol was studied using FeO-doped onto nano-particles of zeolite P (FeO–NP). FeO/NP was prepared by ion exchange and calcination procedures. The samples were characterized by FT-IR, SEM and DRS. UV–vis, HPLC and COD were employed to calculate the degradation extent of the pollutant. The results confirmed that the degradation efficiency of the method strongly dependent to experimental parameters such as: pH, catalyst concentration, substrate concentration, active component value (FeO) loading, presence of H 2 O 2 and inorganic Cl  and SO 4 2 anions. The first- order kinetics model was used to study the kinetics of the method. ß 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved. * Corresponding author. Tel.: +98 321 3292515; fax: +98 321 3291018. E-mail address: arnezamzadeh@iaush.ac.ir (A. Nezamzadeh-Ejhieh). G Model JIEC-1981; No. of Pages 9 Please cite this article in press as: A. Nezamzadeh-Ejhieh, Z. Ghanbari-Mobarakeh, J. Ind. Eng. Chem. (2014), http://dx.doi.org/10.1016/ j.jiec.2014.03.035 Contents lists available at ScienceDirect Journal of Industrial and Engineering Chemistry jou r n al h o mep ag e: w ww .elsevier .co m /loc ate/jiec http://dx.doi.org/10.1016/j.jiec.2014.03.035 1226-086X/ß 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.