In situ One-pot Electrochemical Synthesis of Aluminum Oxide/polyaniline Nanocomposite; Characterization and Its Adsorption Properties towards Some Heavy Metal Ions Somayyeh Piri, a Farideh Piri, a Bahare Rajabi, a Sahar Ebrahimi, a Abbasali Zamani b and Mohammad Reza Yaftian a * a Department of Chemistry, Faculty of Science, University of Zanjan, 45371-38791, Zanjan, Iran b Department of Environmental Science, Faculty of Science, University of Zanjan, 45371-38791, Zanjan, Iran (Received: Jun. 13, 2015; Accepted: Sept. 21, 2015; Published Online: Oct. 30, 2015; DOI: 10.1002/jccs.201500230) Aluminum oxide/polyaniline nanocomposite is prepared by a new and one-pot method including in situ electrooxidation of aluminum and electropolymerization of aniline. The product has been characterized by elemental analysis, FT-IR spectroscopy, X-ray diffraction (XRD), Field Emission Scanning Electron Micrographs (FESEM), and Transmission Electron Micrographs (TEM) techniques. ICP-OES was used for determination of aluminum in the prepared nanocomposite. A porous structure of the prepared com- posite has been shown by FESEM images. TEM of the product confirms the presence of exfoliated alumi- num oxide nanofibers. The adsorption potentials of the prepared nanocomposite towards Cu 2+ , Pb 2+ , Zn 2+ , Cd 2+ , Ni 2+ and Co 2+ ions were evaluated in batch adsorption experiments. The results show that the ad- sorption efficiency is controlled by aqueous phase pH. The experimental data was well interpreted by con- sidering the Langmuir model. The kinetics of the adsorption processes can be well interpreted by pseudo-second-order equation. Keywords: Aluminum oxide nanofiber; Polyaniline nanocomposite; Exfoliation; Heavy metal; Water decontamination. INTRODUCTION Aluminum oxide nanoparticles and nanocomposites have wide applications in various arrays of products and processes such as preparation of catalysts, 1-4 in medical sci- ences, 5-7 fabrication of sensors, 8-10 production of semicon- ductors, 11,12 batteries 13-15 and also as adsorbent for a wide variety of chemical species. 16-18 Nanoparticles have been synthesized by a variety of techniques and methods including ball milling, 19 sol-gel, 20 pyrolysis 21 and hydrothermal 22 methods. Application of electrochemical method for generating metal oxide nano- particles has been also reported. 23 Synthesis by electro- chemical method can be performed by passing an electric current between two electrodes in an electrolyte, in which the anode can be oxidized to metal ion species in the electrolyte. The polyaniline family (PANI) is a group of conju- gated conducting polymers which gain much interest be- cause their unique conduction mechanism, bearing rela- tively high conductance, good stability in the presence of oxygen and water, and exhibiting chemical sensitivity. 24 It is shown that, the conductivity, thermal stability and mor- phological properties of conducting polymers can be sig- nificantly improved or altered by application of metallic compounds in their structure. 25-27 Several reports have been published on the synthesis of polyaniline nanocomposites with the inorganic nano- scale materials such as TiO 2 , 28 CdS, 29 graphene, 30 Fe 3 O 4 , 31 graphene oxide, 32 silica 33 and MnO 2 . 34 These nanocom- posites exhibit many new characteristics, such as electrical, optical, catalytic and mechanical properties which are not presented by their single materials. In this paper, we propose a new approach to the syn- thesis of aluminum oxide/polyaniline Al 2 O 3 /PANI nano- composite by simultaneous exfoliation of aluminum nano- fibers and electropolymerization of aniline. The mecha- nism of multiple electrochemical exfoliation of aluminum nanofibers was discussed in detail. Preliminary adsorption experiments for the removal of heavy metal ions (Cu 2+ , Pb 2+ , Zn 2+ , Cd 2+ , Ni 2+ and Co 2+ ) from aqueous solutions by the alumina/polyaniline nanocomposite are performed to elucidate the adsorption potential of the prepared nano- composite. The effect of parameters influencing the ad- sorption process such as; the aqueous solution pH, the ini- tial ion concentration and the amount of sorbent was stu- died and discussed. The adsorption isotherms and kinetics J. Chin. Chem. Soc. 2015, 62, 1045-1052 © 2015 The Chemical Society Located in Taipei & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 1045 JOURNAL OF THE CHINESE CHEMICAL SOCIETY Article * Corresponding author. Tel: + 98 (0) 24 3305 2519; Fax: +98 (0) 24 3228 3080; Email: yaftian@znu.ac.ir