International Journal of Composite Materials 2014, 4(2): 135-145 DOI: 10.5923/j.cmaterials.20140402.13 Synthesis and Characterization of Silica Coated Iron-Oxide Composites of Different Ratios Rafique Ullah 1 , Biplob Kumer Deb 2,* , Mohammad Yousuf Ali Mollah 3 1 Department of Chemistry, Bangladesh University of Engineering and Technology, BUET, Dhaka-1000, Bangladesh 2 Department of Chemistry, Notre Dame College, Dhaka-1000, Bangladesh 3 Department of Chemistry, University of Dhaka, Dhaka-1000, Bangladesh Abstract Silica coated Iron-oxide composites of different ratios (iron oxide / SiO 2 = 3:7, 1:1 and 7:3) have been synthesized. Iron oxyhydroxide, as the precursor of iron oxide, has been prepared by electrochemical method .The Iron oxide and tetraethylorthosilicate (TEOS), as precursor of silica, have been used at different ratios to synthesize silica coated Iron-oxide composite of different ratio. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Differential thermal analysis (DTA) , Thermogravometric analysis (TG), Scanning electron microscopy (SEM), and Energy dispersed X-ray spectroscopy (EDS) technique have been employed to characterize the precursors as well as the prepared composite materials. The results reveal that well dispersed silica coated iron-oxide composites of different ratios were formed. The prepared silica coated iron-oxide composite material can be used for treatment of wastewater to remove heavy metal. Keywords Silica coated composite material, Electrochemical and mesoporous 1. Introduction In the last decades, composites are playing a vital role in synthesizing new materials. Composites provides high quality mechanical and physical properties because it combines the most desirable properties of its constituents while suppressing their least desirable properties [1]. The attractive properties shown by the composites are high thermal or electrical conductivity [2a], a low coefficient of thermal expansion [2b], adsorbent [2c, d, e], surfactant [2f], catalytic [2g], photo catalytic [2h] and elastic properties [2h]. The properties shown by the composites could not be achieved by either of the constituent materials alone. In recent years, Silica coated Iron oxide composites have attracted a great deal of attention in the field of chemistry and applied sciences. As a result extensive study have been carried in the last few years globally on it [3, 4]. In the Silica coated Iron oxide composite, usually SiO 2 matrix structure plays the role of host for Iron oxide fine particles, which nucleates in the Silica pores, conveniently. High performance technological and scientific and operational applications such as magnetic technology [5-7], catalysis [8], sensors [9-11], optics [12], adsorbent [13] properties has widen the research on the Silica coated Iron oxide composite. Hence Silica-coated composite nanoparticles (Fe 3 O 4 @SiO 2 / core-shell) have been synthesized and studied by many * Corresponding author: biplob_deb@hotmail.com (Biplob Kumer Deb) Published online at http://journal.sapub.org/cmaterials Copyright © 2014 Scientific & Academic Publishing. All Rights Reserved groups [14-17]. Recently, Silica coated magnetite composite have been successfully applied to extract some heavy metals, like Cd 2+ , Cu 2+ , Hg 2+ , and Pb 2+ from water in a wide pH range [18]. Different physical methods, chemical methods and electro-chemical methods have been using to synthesize the Silica-Coated composite materials [19]. In the present investigation, we focused our attention on the preparation of Silica coated Iron-oxide composites by Sol-Gel method because it offers wide range of advantages over other techniques [20-21]. Despite of all these, scientists all over the world are still trying to develop a technologically simple, cost effective and the most versatile sol-gel synthetic route for preparation of specific type of composite materials with desired chemical composition. In this work, the Silica coated Iron-oxide composite particles of different ratios were synthesized through two steps. At first, the hematite particles were prepared by electrochemical method [22] and then the composite material were synthesized through the modified sol-gel method using the prepared hematite and tetraethylorthosilicate (TEOS). TEOS was used as the precursor of Silicon (IV) oxide. The precursors and composite materials were characterized with Fourier-transform infrared spectroscope, Simultaneous Thermal Analyzer (TGA/DTA) and X-Ray Diffractiometer (XRD). The compatibility and morphology of the materials were investigated by using the scanning electron microscope. Composite materials prepared by different method can be used for the removal of different heavy metals from wastewater. Thus we can use composite materials for environmental applications.