Ouma, Linda ImmaculateOnani, Martin2026-07-222026-07-222022-07-22Ouma, L., & Onani, M. (2022). Sequestration of Heavy Metal Pollutants by Fe3O4-based Composites. In E. Lichtfouse, S. S. Muthu, & A. Khadir (Eds.), Inorganic-Organic Composites for Water and Wastewater Treatment (pp. 101–116). Singapore: Springer Singapore. https://doi.org/10.1007/978-981-16-5916-4_4http://erepository.kibu.ac.ke/handle/123456789/11943Book ChapterHeavy metal pollution poses a grave environmental threat. Some of the most toxic metals are highly mobile and, therefore, easily transported through ground water systems, thus, affecting large areas. Over the last decade, adsorption has been greatly focused on as a strategy for contaminated water treatment. Its versatility and relative ease of application have been a major determinant of its preference. Nanosized adsorbents have high surface areas and are size tunable and, hence, have been favored in adsorption applications. The magnetic properties of nanosized magnetite (Fe3O4) have made them particularly favorable. Magnetite composites with various materials have widely been applied in the adsorptive treatment of real and synthetic water containing heavy metal pollutants. This review outlines the application of Fe3O4 nanoparticles and Fe3O4 organic composites in the adsorption of heavy metal ions in aqueous solution. The reviewed articles indicate that the formation of Fe3O4 inorganic–organic composites improves the adsorption efficiencies of the composites and improves their applicability by providing magnetic separability. The presence of Fe3O4 nanoparticles in the composite materials also provides for improved reusability of the adsorbent. Generally, the formation of these composites tends to make adsorption a more viable alternative to conventional water treatment options for heavy metal pollutants in water.enMagnetite · Composites · Adsorption efficiency · Heavy metals · Magnetism · ReusabilityBook chapter