Mass Dependent Photocatalytic Degradation of Methylene Blue using Green Synthesized Fe3O4/rGO Nanocomposites Utilizing Moringa Oleifera and Amaranthus Viridis Leaf Extracts Larasati Hayu Regita Salma (a), Larrisa Jestha Mahardhika (a), Hanif Yoma Khoiri (a), Hafil Perdana Kusumah (a), Rivaldo Marsel Tumbelaka (a), Nurul Imani Istiqomah (a), Nining Sumawati Asri (b), and Edi Suharyadi (a*)
(a) Department of Physics, Universitas Gadjah Mada, Yogyakarta, Indonesia
(b) Research Center for Quantum Physics, National Research and Innovation Agency (BRIN), Tangerang Selatan, Indonesia
*Corresponding author: esuharyadi[at]ugm.ac.id
Abstract
Methylene Blue (MB) has gained popularity as one of the most used dyes in the textile industry. This dye is non biodegradable and difficult to degrade aromatic molecular structures therefore making this organic dye waste harmful to the environment. Photocatalysis is considered as a promising and cost effective method for separating organic compounds from wastewater by light induction on a specific wavelength. It is a process where the catalyst enhances oxidation rate and reduction reactions. rGO is a graphene based material that is involved in the development of photocatalyst nanocomposite to treat polluted wastewater with boosted photocatalytic activity. The disadvantage of this material is the difficulty to remove from the treated water. Magnetite (Fe3O4) is known as a superparamagnetic material and is highly responsive under external magnetic fields. Incorporating rGO in the photocatalysis process with the addition of metals offers the possibility for the separation of the catalyst while giving maximum pollutant removal from the wastewater. In this study, Fe3O4/rGO nanocomposite was successfully synthesized using a green synthesis method with Moringa oleifera and Amaranthus viridis leaf extracts to obtain a nanomaterial with the ability to be magnetically separated and performs adequate photocatalytic activity. The activity of photodegradation of MB was investigated using Fe3O4/rGO photocatalyst with various mass of catalyst. The Fe3O4 and rGO samples were composited, resulting in Fe3O4/rGO nanocomposite with the concentration ratio of 5:1 and then characterized using XRD, SEM/EDX, Uv Vis, and VSM to investigate the crystal structure, elemental composition, optical and magnetic properties, respectively. The crystallite size for Fe3O4 is calculated from XRD characterization resulting in the structure of inverse cubic. SEM/EDX result shows that the sample of Fe3O4/rGO is predominantly Fe, with few segments of O and rGO sheets. Uv Vis characterization using Tauc plot yields Fe3O4/rGO, Fe3O4, and rGO bandgaps as 3.16 eV, 3.20 eV, and 4,19 eV respectively. The sample of Fe3O4/rGO gives a photodegradation rate up to 77.1 percent, thus showing the material has notable potential in photocatalysis.
Keywords: Fe3O4/rGO nanoparticles- Green synthesis- Magnetic- Methylene blue- Photocatalysis
