ORIGINAL PAPER Synthesis and characterization of MFe 2 O 4 sulfur nanoadsorbents T. Zaki • D. Saed • D. Aman • S. A. Younis • Y. M. Moustafa Received: 29 July 2012 / Accepted: 28 November 2012 / Published online: 6 December 2012 Ó Springer Science+Business Media New York 2012 Abstract Nanoparticles of ferrites (Fe 3 O 4 , NiFe 2 O 4 , CuFe 2 O 4 , and MnFe 2 O 4 ) were prepared by a reverse (water/oil) microemulsion method. The microemulsion system consisted of cetyltrimethylammonium bromide, 1-butanol, cyclohexane, and a metal salt solution. The procedure was carried out using aqueous ammonia as the coprecipitating agent. Nanosized particles were character- ized by thermal analysis, X-ray diffraction, Fourier trans- form infrared spectroscopy, transmission electron microscopy, and pyridine adsorption. The NiFe 2 O 4 sample exhibited narrow mesoporous pore size distribution and high surface area &233 m 2 /g. It achieved good adsorption activity towards the dibenzothiophene (DBT) compound (166.3 lmol/g of DBT adsorbent). The structural properties obtained were very interesting for potential applications in the desulfurization process in petroleum refining. Keywords Fe 3 O 4 Á NiFe 2 O 4 Á CuFe 2 O 4 Á MnFe 2 O 4 Á Reverse microemulsion Á Desulfurization 1 Introduction Mixed oxides in spinel and perovskite structures have long attracted interest in the field of catalysis [1, 2]. Recently, nanosized spinel ferrite particles have drawn considerable attention due to the enhancement of physical, chemical, and catalytic properties [3]. Nanoparticles of magnetite (Fe 3 O 4 ) and metal (Ni, Cu, Mn)-substituted ferrites are reported to be applicable mate- rials for use in high-density magnetic recording media [4], medical and pharmaceutical [3, 5–7], mineral separation, heat transfer [8], gas-sensing [9, 10], ceramics [11], envi- ronmental [12, 13], and catalytic applications [1, 14–17]. Different methods have been developed for the preparation of substituted ferrites, namely the sol-gel, hydrothermal synthesis, organic complexes, and combustion processes with various precursors [18]. The use of the reverse micro- emulsion technique allow for the preparation of single- phases of metal oxides at a low calcination temperatures due to the homogeneous mixing of the precursors and to the very small size of the primary particles [2]. Sulfur control in fuels is one of the most important con- cerns in environmental protection, whereas the so-called zero-sulfur fuels are required for exhaust gas-cleaning technologies introduced by automobile manufacturers. In this connection, the terms ‘‘deep desulfurization’’ and ‘‘ultralow sulfur fuels’’ have made interesting research topics [19]. Desulfurization by adsorption is based on the ability of a solid sorbent to selectively adsorb organosulfur com- pounds from refinery streams [20]. The selective adsorption for removal of sulfur compounds from liquid fuels at ambient conditions (SARS) without using hydrogen is an alternative desulfurization technique [21, 22]. In this method, physical, chemical, and adsorption features of Fe 3 O 4 , NiFe 2 O 4 , CuFe 2 O 4 , and MnFe 2 O 4 Electronic supplementary material The online version of this article (doi:10.1007/s10971-012-2933-1) contains supplementary material, which is available to authorized users. T. Zaki (&) Á D. Aman Catalysis Department, Petroleum Refining Division, Egyptian Petroleum Research Institute, P.B. 11727, Nasr, Cairo, Egypt e-mail: tamerzakisharara@yahoo.com D. Saed Á S. A. Younis Á Y. M. Moustafa Analysis and Evaluation Division, Egyptian Petroleum Research Institute, P.B. 11727, Nasr, Cairo, Egypt 123 J Sol-Gel Sci Technol (2013) 65:269–276 DOI 10.1007/s10971-012-2933-1