Preparation of graphene oxide/chitosan/ferrite nanocomposite for Chromium(VI) removal from aqueous solution Melvin S. Samuel a , Sk. Sheriff Shah b , Vasudevan Subramaniyan b , Tanvir Qureshi c , Jayanta Bhattacharya a , N.D. Pradeep Singh b, ⁎ a School of Environmental Science and Engineering, Indian Institute of Technology, Kharagpur, West Bengal 721302, India b Department of Chemistry, Indian Institute of Technology, Kharagpur, West Bengal 721302, India c Department of Civil Engineering, The University of Toronto, Toronto M5S 1A4, Ontario, Canada abstract article info Article history: Received 4 May 2018 Received in revised form 28 June 2018 Accepted 11 July 2018 Available online xxxx A magnetically modified graphene oxide/chitosan/ferrite (GCF) nanocomposite material was synthesized and exploited for removal of Chromium(VI) from aqueous solution. The GCF nanocomposite material was character- ized by powder-X-ray diffraction (powder-XRD), Fourier transform infrared spectroscopy (FT-IR), scanning elec- tron microscope- energy dispersive X-ray (SEM-EDX) analysis, transmission electron microscopy (TEM) thermogravimetric analysis (TGA), UV–vis diffusive reflectance spectra and Brunauer–Emmett–Teller (BET) analysis. The effect of pH, adsorbent dose, contact time and initial Cr(VI) metal ion concentration were studied in batch process. The GCF nanocomposite material showed an adsorption capacity of 270.27 mg g -1 for Cr(VI) at pH 2.0. The adsorption mechanism of GCF adsorbent material was well described by Langmuir isotherm and pseudo second order kinetic model, with a high regression coefficient (b0.99). The results have shown that GCF nanocomposite material can be used as a suitable adsorbent for removal of Cr(VI) from wastewater. © 2018 Elsevier B.V. All rights reserved. Keywords: GCF nanocomposite material Isotherms Kinetics Chromium(VI) 1. Introduction In recent years the rapid growth of industrialization has resulted in a serious shortage of water supply [1]. The heavy metals and organic dyes are widely used in the synthesis of textile, pharmaceuticals, leathers and other industries [2]. It has to be noted that 10%–15% of the heavy metals and dyes released into water table is due to the incomplete exhaustion during the treatment process. The major concerns related to these pol- lutants are their chemical stability and low biodegradability in water systems [3, 4]. Chromium is the seventh most abundant element on earth and its prevalence in aquatic and terrestrial ecosystems has in- creased beyond limit in the present decades. The two major types of chromium in industries are trivalent chromium Cr(III) and hexavalent Cr(VI). However, Cr(VI) is more toxic than Cr(III) and has been classified as Group “A” carcinogen because of it's mutagenic, teratogenic and car- cinogenic nature. Cr(VI) is highly mobile and hence most prevalent in wastewater being released from the industrial processes such as leather tanning, metal finishing, electroplating, metallurgy, dye, battery manufacturing and wood preservation industries [5–8]. The permissible limit for Cr(VI) in drinking water is recommended to be 0.05 mg L -1 in 2008 by the World Health Organization (WHO) [9] and the US Environ- mental Protection Agency (EPA) has set a maximum contaminant level of 100 μgL -1 for total chromium in drinking water [10, 11]. As a conse- quence, an effective and economical technique must be developed to re- move these heavy metals before releasing into the aquatic environment [12, 13]. In order to stick to the guidelines, various technologies such as ion exchange [14], coagulation and flocculation [15, 16], complexation, membrane separation [17, 18], biosorption and adsorption techniques [19, 20], are adopted for the removal of Cr(VI) from the aqueous solu- tion. Among the reported techniques, adsorption technique is advanta- geous due to its effectiveness, easy in operation and time constraint. This has opened a gateway to explore adsorbents with abundant avail- ability and economy. In the current trend, nanotechnology provides op- portunity in engineering or functionalizing the materials to develop new products for the treatment of polluted water. Recently, graphene oxide (GO), a two dimensional monolayer of car- bon atoms containing functional groups on its surface, has wide applica- tions in the areas of energy storage, sensors, optical, thermal and composites. The carbon and carbon based materials play a crucial role as an effective adsorbent for the removal of heavy metals from aqueous medium and it is being applied for the remediation of industrial efflu- ents, ground water, surface water and drinking water [21–24]. How- ever, GO has a tendency to aggregate in water, thereby resulting in the reduced surface area and will lead to decreased adsorption capacity. Formation of GO composites with other active adsorbents will reduce the aggregation of GO and eventually result in better adsorption capac- ity [25–27]. Chitosan is a biopolymer used as an adsorbent for the International Journal of Biological Macromolecules 119 (2018) 540–547 ⁎ Corresponding author. E-mail address: ndpradeep@chem.iitkgp.ernet.in (N.D. Pradeep Singh). https://doi.org/10.1016/j.ijbiomac.2018.07.052 0141-8130/© 2018 Elsevier B.V. All rights reserved. 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