Biological and Photocatalytic Activities of Magnesium Oxide Nanoparticles Prepared from Seawater Bittern by Electrochemical Method

The present study aims to prepare magnesium oxide (MgO) nanoparticles from seawater bittern using an electrochemical method to evaluate their application as antioxidant, antimicrobial, and photocatalytic agents. The synthesis of nanomaterial was performed at room temperature, employing graphite and nickel as anode and cathode, respectively, without any pH adjustment. Spectroscopic analysis determined that the optical band gap of MgO nanoparticles was 4.814 eV. The XRD patterns show hexagonal single cubic phase MgO matched with JCPDS Card No 78-0430. Electron microscopic analysis demonstrated the appearance of MgO nanoparticles in spherical morphology with 30–50 nm in particle size. Based on the maximum inhibition concentration (MIC), it was found that the MgO nanoparticles has good antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Shigella dysenteriae bacteria (MIC values: 220−480 μg mL−1), and much stronger antifungal activity against Aspergillus flavus, Aspergillus niger, and Candida albicans (MIC values: 62.5–115 μg mL−1). Methylene blue and rhodamine B dyes were degraded by MgO nanoparticles with strong photocatalytic activity when they were exposed to visible light and achieved 97% and 95% degradation, respectively. This study demonstrates that MgO nanoparticles can be effectively applied in industries like wastewater treatment and nanomedicine.