State of the art on the magnetic iron oxide Nanoparticles: Synthesis, Functionalization, and applications in wastewater treatment

Water pollution poses significant environmental and health challenges globally due to increasing industrialization and urbanization, which have led to a rise in wastewater discharges containing hazardous pollutants. These pollutants not only degrade aquatic ecosystems but also pose risks to human health. To address these issues, researchers have been exploring various treatment technologies, including adsorption, in which specific pollutants can be removed efficiently and selectively using adsorbents. Magnetic adsorbents, especially magnetite (Fe3O4), have emerged as a promising adsorbent material for water purification. Its high surface area, supermagnetism, and ease of functionalization make it suitable for the adsorption of many contaminants. In this Review, we highlight the recent developments in Fe3O4 nano adsorbents, including synthesis, properties, functionalization strategies, and challenges. The stability of Fe3O4 adsorbents was also discussed. A comparison of Fe3O4-based adsorbents and traditional adsorbents was then addressed. Finally, an outlook on the challenges and opportunities for the future advancement and practical application of these adsorbents is provided. Such an interdisciplinary research field is expected to stimulate further developments in nanoscience and advanced nanotechnology in water treatment.