Synthesis, Characterization, and Adsorptive Properties of Fe3O4/GO Nanocomposites for Antimony Removal

Hindawi Journal of Analytical Methods in Chemistry Volume 2017, Article ID 3012364, 8 pages https://doi.org/10.1155/2017/3012364 Research Article Synthesis, Characterization, and Adsorptive Properties of Fe3O4/GO Nanocomposites for Antimony Removal Xiuzhen Yang,1 Tengzhi Zhou,1 Bozhi Ren,1 Zhou Shi,2,3 and Andrew Hursthouse1,4 1 College of Civil Engineering, Hunan University of Science and Technology, Xiangtan 411201, China College of Civil Engineering, Hunan University, Changsha 410082, China 3 Key Laboratory of Building Safety and Energy Efficiency, Ministry of Education, Hunan University, Changsha 410082, China 4 School of Science & Sport, University of the West of Scotland, Paisley PA1 2BE, UK 2 Correspondence should be addressed to Xiuzhen Yang; Received 28 February 2017; Revised 1 June 2017; Accepted 6 June 2017; Published 20 July 2017 Academic Editor: Ricardo Jorgensen Cassella Copyright © 2017 Xiuzhen Yang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. A magnetic Fe3 O4 /GO composite with potential for rapid solid-liquid separation through a magnetic field was synthesized using GO (graphene oxide) and Fe3 O4 (ferriferous oxide). Characterization of Fe3 O4 /GO used scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), and Vibrating Sample Magnetometer (VSM). A number of factors such as pH and coexisting ions on adsorbent dose were tested in a series of batch experiments. The results showed that GO and Fe3 O4 are strongly integrated. For pH values in the range of 3.0∼9.0, the removal efficiency of Sb(III) using the synthesized Fe3 O4 /GO remained high (95%). The adsorption showed good fit to a pseudo-second-order and Langmiur model, with the maximum adsorption capacity of 9.59 mg/g maintained across pH 3.0–9.0. Thermodynamic parameters revealed that the adsorption process was spontaneous and endothermic. Analysis by X-ray photoelectron spectroscopy (XPS) showed that the adsorption process is accompanied by a redox reaction. 1. Introduction Antimony has recently gained considerable attention as a toxic heavy metal [1]. By binding with sulfhydryl groups inside human body, antimony and antimony compounds can interfere in enzyme activity or destroy intracellular ionic equilibrium which leads to cell hypoxia, causing metabolic disorders and injury to the nervous system and other organs [2]. Antimony has been classified as a priority pollutant by European Union (EU) and United States Environmental Protection Agency (EPA) in 1976 and 1979, respectively [3, 4]. The Environmental Protection Department of Japan also listed it as a pollutant of concern and stipulated a maximum acceptable concentration of 2 ug/L [5]. In China, the maximum concentration of antimony limited by GHZBl and Drinking Water Health Standards is 5 ug/L [6], which is consistent with the standards of World Health Organization [7]. China has the largest reserve and capacity for production of antimony in the world [8]. Over 80% of total world antimony production is in China in the past several decades, and use is wide spread as a catalyst in cPET production, in flame retardants, in alloys, and in the electronics industry. The main production areas are in Hunan in the southwest of China, where the 100-year-old mine, Xikuangshan, is known as the World Antimony Capital. The region has a history of nearly 200 years of antimony ore production and, therefore, antimony pollution in this region is of concern. Research shows that the antimony content of water in the mining area can exceed 7,000 ug/L [9]. The severity of antimony pollution has threatened the health of residents surrounding the mine. Therefore, cost effective methods to control antimony pollution in China, especially in the southwest, have become an imperative. Toxicity of antimony is mainly affected by its valence state and the nature of compounds with the toxicity of trivalent antimony being ten times higher than that of pentavalent 2 Journal of Analytical Methods in Chemistry Fe3 O4 /GO N Sb(III) solution S Magnetic separation Adsorption Sb(III) Figure 1: The adsorption experiment process. antimony [10–12]. Hence, trivalent antimony is chosen as the target oxidation state of this pollutant. A variety of methods have been developed to remove antimony from solution, of which approaches using adsorption are popular due to the effectiveness and availability of of reactive solid phases. Due to the huge specific surface area (2,630 m2 /g) [13], Graphene Oxide (GO) has been widely applied in water treatment; however, its strong sorption makes it difficult to desorb after reaction. The preparation of Fe3 O4 /GO nano composites for effective pollutant removal has been demonstrated [14] showing strong affinity and reversibility for a number of pollutants and was prepared in this experiment to evaluate removal of antimony from water. 2. Materials and Methods 2.1. Reagent and Instrument Raw Material and Reagent. Graphene Oxide (prepared by modified Hummers’ method) and the regents (antimony potassium tartrate, sodium hydroxide, hydrochloric acid, etc.) were analytically pure. Key Instruments. The key instruments are Scanning electron microscope (JSM-6700F, Japan, JEOL); X-ray diffractometer (D8/ADVANCE, Germany, BRUKER); Fourier transform infrared spectrometer (IRAffinity-1, Japan Shimadzu); magnetometer (MPMS-XL-7, the United States, Quantum Design Company); atomic absorption spectrophotometer (AA-7000, Japan, JEOL). 2.2. Preparation of Fe3 O4 /GO. Fe3 O4 particles were prepared by coprecipitation method. The successful in situ growth of Fe3 O4 nanoparticles on GO surface during the synthetic process of Fe3 O4 /GO composites was ascribed to the oxygencontaining functional groups of GO. The as-synthesized composites in this study not only have the excellent adsorption properties of GO, but also possess the superparamagnetism of Fe3 O4 nanoparticles. Hence, the proportion of Fe3 O4 to GO needed optimization during the preparation of composites to take advantage of the strong adsorption properties of GO and the magnetism of Fe3 O4 . GO (15 mg) was dispersed into DI water (30 ml) by ultrasonication for 30 min. To this suspension, 50 ml solution of FeCl3 (110 mg) and FeCl2 (43 mg) in DI water was added at room temperature. Then the temperature was raised to 85∘ C and a 30% ammonia solution was added increasing the pH to 10.0. After being rapidly stirred for 1 h the solution was cooled to room temperature. The resulting black precipitate was centrifuged at 4500 rpm for 10 min and washed three times with DI water and finally dried in a vacuum oven at 60∘ C for overnight to yield the Fe3 O4 /GO composite. 2.3. Adsorption Experiments. The model wastewater with varying concentration of Sb(III) was prepared using antimo (...truncated)