N. Munasir - Physics Department, Faculty of Mathematics and Natural Science, Universitas Negeri Surabaya, Jl. Ketintang, Surabaya, Indonesia
R. P. Kusumawati - Physics Department, Faculty of Mathematics and Natural Science, Universitas Negeri Surabaya, Jl. Ketintang, Surabaya, Indonesia
D. H. Kusumawati - Physics Department, Faculty of Mathematics and Natural Science, Universitas Negeri Surabaya, Jl. Ketintang, Surabaya, Indonesia
Z. A. I. Supardi - Physics Department, Faculty of Mathematics and Natural Science, Universitas Negeri Surabaya, Jl. Ketintang, Surabaya, Indonesia

The magnetite (Fe3O4) nanoparticle and graphene oxide (GO) have  become interesting materials due to their advanced applications. In this work, we investigated the fabrication of Fe3O4 nanoparticles (NPs) from iron sands and reduced graphene oxide (rGO) NPs from natural graphite. The core-shell fabrication of the Fe3O4/rGO was conducted by means of ex-situ method using ethanol as the medium. The crystal structure of Fe3O4/rGO was observed using X-ray diffraction (XRD) and functional groups were examined using Fourier transform infra-red (FTIR) spectroscopy. The characteristic of the disturbance originated by carbon atoms was investigated by Raman spectroscopy. The morphological, particle sizes and formation studied with transmission electron microscopy (TEM). The magnetic properties were analyzed using vibrating sample magnetometer (VSM). Furthermore, analysis of the adsorption performance, namely: dye-removal efficiency (DRE) and degradation rate (DR), as candidate materials absorbent were performed by means of UV-Vis spectroscopy. The data analysis of structure and phase of Fe3O4/rGO presented cubic spinel structure with crystallite size of 26-38 nm. The functional group analysis presented the existence of C-OH, C=O, C-O, and Fe-O. The micrograph analysis from the TEM image showed the particle size of the sample was in the range of 10 - 30 nm. Along with the thickening shell, the saturation magnetization of Fe3O4/rGO decreased from 22.60 to 18.48 emu/g and decreased from 29.21 to 10.45 emu/g for Fe3O4. Finally, the rGO composition affects the shell wall, which encloses Fe3O4 as the core. Interestingly, an increase in absorption characteristic of natural dyes Fe3O4/rGO enhanced by the decrease of the shell thickness.

Absorptivity, Core-shell, Fe3O4, Methylene-Blue, rGO