Kurnia, Nugraheni Puspita Rini, Deska Lismawenning Puspitarum, Nurul Imani Istiqomah, Emi Kurnia Sari, Daiki Oshima, Takeshi Kato, Ari Dwi Nugraheni, Edi Suharyadi
This study aims to report the development of magnetically separable and reusable reduced graphene oxide (rGO)-modified MnFe₂O₄ nanoparticles (NPs) using an environmentally friendly synthesis method for the photo-Fenton degradation of Rhodamine B under UV. The MnFe2O4 NPs were synthesized via a green co-precipitation method using Moringa oleifera leaf extract while rGO was prepared by sonicating graphene oxide with Amaranthus viridis leaf extract. The rGO-modified MnFe2O4 was fabricated through sonication at different rGO concentrations. X-ray diffraction analysis confirmed the presence of MnFe2O4 and rGO phases with all significant MnFe2O4 peaks corresponding to a single-phase cubic spinel structure. Furthermore, morphological analysis showed that the particles were almost spherical, with sizes between 7 and 17 nm, irregular shapes, slight clustering, and strong attachment to the rGO sheets. Fourier-transform infrared spectroscopy also reported the presence of metallic functional groups such as Fe−O at 540 cm⁻¹. A red absorption shift and band gap narrowing were observed as the rGO content increased. The magnetic properties analyzed using a vibrating sample magnetometer also showed that the composite exhibited superparamagnetic behavior. The saturation magnetization values for MnFe2O, MnFe2O4/rGO (5:1), MnFe2O /rGO (5:3), and MnFe2O4/rGO (5:5) were identified to be 23.9, 19.8, 16.7, and 15 emu/g, respectively. Moreover, photocatalytic investigations showed that degradation efficiency increased with rGO concentration by reaching an estimated optimal value of 99.8% after 3 h of activity. The rGO-modified MnFe₂O₄ NPs exhibited favorable magnetic properties as observed in the efficient recovery and reuse for up to six consecutive cycles. These results reflected the significant potential of rGO-modified MnFe2O4 for efficiently removing organic dye pollutants from wastewater to maintain high degradation efficiency over multiple cycles. © 2026 Elsevier B.V.
Department of Physics, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia; Department of Physics, Universitas Halmahera, Maluku Utara, 97762, Indonesia; Department of Physics, Institut Teknologi Sumatera, Lampung, Indonesia; Department of Electronics, Nagoya University, Nagoya, 464-8603, Japan; Institute of Materials and Systems for Sustainability, Nagoya University, Nagoya, 464-8603, Japan