---------------------------------------------------------------------------------------------------------------------------------------- Archives of Hygiene Sciences Volume 6, Number 2, Spring 2017 © 2017 Publisher: Research Center for Environmental Pollutants, Qom University of Medical Sciences. All rights reserved. • Arch Hyg Sci 2017;6(2): 214-220 • Journal Homepage: http://jhygiene.muq.ac.ir RESEARCH ARTICLE 214 Naser Tavassoli a , Reza Ansari a *, Zahra Mosayebzadeh a a Department of Chemistry, School of Science, University of Guilan, Rasht, Iran. *Correspondence should be addressed to Dr. Reza Ansari, Email: ransari271@guilan.ac.ir Water is crucial to survive all living organisms on the earth, and access to safe drinking-water is important as health and development issue at a national, regional and local levels (1). One of today's environmental challenges is the excessive use of dyes for industrial and domestic activities which it contaminates the ground and surface water; therefore, it is important to remove these dangerous organic compounds from water and wastewater prior to discharge into the environment (2-5). Water pollution by synthetic organic dyes used in textile, cosmetics, pulp and paper industries etc., is mainly regarded as environmental and ecological critical issues worldwide (4-7). These industries produce considerable unfixed dyes that in turn impart strong color, expelling of these dyes into water bodies, produce a large quantity of dyeing wastewater which needs to treatment before being discharged into waterways. Due to the aromatic structures, synthetic dyes have chemical stability; thus, they are difficult to biodegrade, oxidizing and photo degradation, giving water undesirable color, diminish light penetration and oxygen gas solubility, so, photosynthetic reactions of aquatic plants, will be decreased, having toxic effects on human health (8,9). A-R-T-I-C-L-EI-N-F-O A-B-S-T-R-A-C-T Article Notes: Received: Oct. 2, 2016 Received in revised form: Jan. 29, 2017 Accepted: Feb. 21, 2017 Available Online: Feb 28, 2017 Background & Aims of the Study: water pollution by synthetic organic dyes is mainly regarded as environmental and ecological critical issues worldwide. In this research, magnetite iron oxide/silica gel nanocomposite (termed as Fe 3 O 4 /SG) was synthesized chemically and then used as an effective adsorbent for removal of sulfur dyes from aqueous solution. Materials and Methods: The various parameters such as pH, sorbent dosage, initial dye concentration, contact time and dye solution temperature were investigated in a batch system. The equilibrium data were analyzed by Langmuir and Freundlich isotherm models. Results: The experimental data fit well with pseudo-second-order kinetic model (R 2 ≥0.998) and conformed better to Langmuir isotherm model (R 2 ≥0.997). The maximum adsorption capacity for Fe 3 O 4 /SG obtained from the Langmuir model was 11.1mg/g. Evaluation of thermodynamic parameters proved that the adsorption process was normally feasible, spontaneous and exothermic. Conclusion: It can be concluded that the Fe 3 O 4 /SG can be considered as a cost-effective and an environmental friendly adsorbent for efficient removal of sulfur dyes from aqueous solutions. Keywords: Adsorption Fe 3 O 4 coated silica Sulfur dye Isotherm Iran. Please cite this article as: Tavassoli N, Ansari R, Mosayebzadeh Z. Synthesis and Application of Iron Oxide/Silica Gel Nanocomposite for Removal of Sulfur Dyes from Aqueous Solutions. Arch Hyg Sci 2017;6(2):214-220. Synthesis and Application of Iron Oxide/Silica Gel Nanocomposite for Removal of Sulfur Dyes from Aqueous Solutions Background