Journal of Hazardous Materials 241–242 (2012) 73–81 Contents lists available at SciVerse ScienceDirect Journal of Hazardous Materials jou rn al h om epage: www.elsevier.com/loc ate/jhazmat Magnetic composites based on metallic nickel and molybdenum carbide: A potential material for pollutants removal Raquel V. Mambrini a , Thales L. Fonseca a , Anderson Dias b , Luiz C.A. Oliveira a , Maria Helena Araujo a , Flávia C.C. Moura a,∗ a Departamento de Química, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901, Brazil b Departamento de Química, Universidade Federal de Ouro Preto, Ouro Preto, MG 35400-000, Brazil h i g h l i g h t s ◮ New magnetic molybdenum carbide composites can be prepared by CVD from ethanol. ◮ Magnetic molybdenum carbide shows promising results for pollutants removal. ◮ The carbide composites can be easily recovered magnetically and reused. a r t i c l e i n f o Article history: Received 14 May 2012 Received in revised form 15 August 2012 Accepted 2 September 2012 Available online 7 September 2012 Keywords: Carbides Magnetic materials Vapor deposition Sulfur and nitrogen removal a b s t r a c t New magnetic composites based on metallic nickel and molybdenum carbide, Ni/Mo 2 C, have been pro- duced via catalytic chemical vapor deposition from ethanol. Scanning electron microscopy, thermal analysis, Raman spectroscopy and X-ray diffraction studies suggest that the CVD process occurs in a single step. This process involves the reduction of NiMo oxides at different temperatures (700, 800 and 900 ◦ C) with catalytic deposition of carbon from ethanol producing molybdenum carbide on Ni surface. In the absence of molybdenum the formation of Ni/C was observed. The magnetic molybdenum carbide was successfully used as pollutants removal by adsorption of sulfur and nitrogen compounds from liq- uid fuels and model dyes such as methylene blue and indigo carmine. The dibenzothiofene adsorption process over Ni/Mo 2 C reached approximately 20 mg g -1 , notably higher than other materials described in the literature and also removed almost all methylene blue dye. The great advantage of these carbide composites is that they may be easily recovered magnetically and reused. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Transition metal carbides have been widely investigated in recent years because of their good catalytic activity and selectivity for hydrogenation, hydrodesulfurization and hydrodenitrogena- tion reactions in petroleum refining [1]. Among them molybdenum carbide has been extensively studied due to its unique physical and chemical properties including mechanical hardness, thermal sta- bility, superconductivity and surface reactivity. Also, it has been reported that it possesses catalytic behavior comparable to noble metals [2–4]. The synthesis of Mo 2 C is typically carried out using Temperature Programmed Reaction (TPRe) where molybdenum oxide is heated under an atmosphere of hydrogen/hydrocarbon (e.g. CH 4 , C 2 H 6 , C 2 H 2 , etc.) [5–7]. Herein we report the preparation of the ∗ Corresponding author. Tel.: +55 31 34097556; fax: +55 31 34095700. E-mail address: flaviamoura@ufmg.br (F.C.C. Moura). magnetic composite Ni/Mo 2 C via chemical vapor deposition (CVD) using ethanol as the carbon source. Magnetic particles have many potential technological applica- tions, e.g. support for catalysts [8,9], magnetic resonance imaging [10,11], drug delivery [12], adsorption processes [13,14] and envi- ronmental remediation [8,15–17]. Magnetic particles can be coated with a protective layer of different materials to improve their sta- bility and to introduce new surface properties and functionalities. Some of these coating materials are silica [18], alumina [19], gold [20], and polymers, such as polystyrene [21], polyaniline [22], poly- methyl methacrylate [23] and polyacrylamide [24]. Carbon is a versatile coating material due to its chemical stability, biocompat- ibility, possibility of surface modification and pore creation [25], and have been used as efficient adsorbent in different applications. The use of commercial fuels and the emissions from refineries are of great environmental impact and are among the main targets of the new environmental standards that suggests the reduction of sulfur and nitrogen in fuels like gasoline and oil diesel. The removal of these compounds is a major operation in petroleum refining and 0304-3894/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jhazmat.2012.09.002