63 Characterization and Application of Nanomaterials (2021) Volume 4 Issue 1 doi:10.24294/can.v4i1.1291 Original Research Article Preparation and characterization of magnetic graphene oxide nano- composite (GO-Fe 3 O 4 ) for removal of strontium and cesium from aqueous solutions Sule Aytas 1 , Sabriye Yusan 1* , Senol Sert 1 , Cem Gok 2 1 Institute of Nuclear Sciences, Ege University, 35100 Bornova, Izmir, Turkey. E-mail: sabriye.doyurum@ege.edu.tr 2 Faculty of Technology, Department of Metallurgical and Materials Engineering, Pamukkale University, 20160 Kinikli Denizli, Turkey ABSTRACT Magnetic graphene oxide nanocomposites (M-GO) were successfully synthesized by partial reduction co-precipi- tation method and used for removal of Sr(II) and Cs(I) ions from aqueous solutions. The structures and properties of the M-GO was investigated by X-ray difraction, Fourier transformed infrared spectroscopy, X-ray photoelectron spectros- copy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometer (VSM) and N 2 - BET measurements. It is found that M-GO has 2.103 mg/g and 142.070 mg/g adsorption capacities for Sr(II) and Cs(I) ions, respectively. The adsorption isotherm matches well with the Freundlich for Sr(II) and Dubinin–Radushkevich model for Cs(I) and kinetic analysis suggests that the adsorption process is pseudo-second-ordered. Keywords: Graphene Oxide; Magnetite; Nanocomposite; Strontium; Cesium, Sorption ARTICLE INFO Received: 26 January 2021 Accepted: 12 March 2021 Available online: 18 March 2021 COPYRIGHT Copyright © 2021 Sule Aytas, et al. EnPress Publisher LLC. This work is licensed under the Creative Commons Attribution- NonCommercial 4.0 International License (CC BY-NC 4.0). https://creativecommons.org/licenses/by- nc/4.0/ 1. Introduction Nuclear and Industrial Safety Agency (Japan) reported that the Fukushima Daiichi reactor meltdowns have thus far released 15,000 tera becquerels of radioactive cesium-137 into the environment [1] . Also, strontium was measured in plant samples in four others villages, with values ranging from 12 to 61 Bq/kg for Sr-89 and 1.8 to 5.9 Bq/kg for Sr-90 [2] . This accident caused a great environmental disaster for living metabolisms and plants. Furthermore, diverse anthropogenic activities like nuclear research reactors, the production and use of radioisotopes and radiopharmaceuticals bring about the spread of radioactive wastes in the environment [3] . Some radionuclides as cesium and strontium are biologically toxic and of great importance due to their long-lasting nature and high solu- bility in aqueous systems [4] . For this reason, it is a signifcant subject to fnd out efcient, economic method that can be used in the removal and recovery of cesium and strontium from contaminated environments. Diferent types of physicochemical methods as ion exchange, chemical precipitation, membrane separation and adsorption, etc. are used for removal and recovery of radionuclides. Considering many parameters, one of these techniques comes to the forefront. Adsorption is wide- ly-used technique that is fast and efective approach in eliminating pol- lutants from aqueous solutions [5] .