Remediation of Aquatic Anionic Pollutants Using Magnetic Nanocomposites

Abstract

Water contamination by anionic pollutants poses a significant threat to both public health and the environment. Effective treatment and recycling of this polluted water are essential to address the growing challenges of water scarcity and quality degradation. While conventional techniques like adsorption, ion exchange, chemical reduction, and membrane separation are employed for anion removal, they are often hindered by limitations such as high operational costs, the generation of secondary waste, and complex operational procedures. In recent years, iron oxide nanoparticles (IONPs) have emerged as a promising solution due to their remarkable adsorption capacity for anions. However, their high specific surface area leads to tendencies for agglomeration and oxidation, which subsequently reduces their reactivity and effectiveness. A key strategy to overcome these drawbacks is the incorporation of IONPs into supportive matrices such as graphene, chitosan, zeolite, polyaniline, or biochar. This process fabricates composite materials—like magnetic biochar, chitosan, or graphene—that enhance nanoparticle dispersion, prevent agglomeration, and improve stability, thereby maintaining high reactivity. Furthermore, these composites often inherit the beneficial properties of both the IONPs and the supporting matrix, leading to superior adsorption performance and easier magnetic separation from treated water. The primary aim of this review is to synthesize current knowledge and provide a comprehensive understanding of iron oxide-based composites, evaluating their potential as advanced materials for the efficient removal of anionic pollutants from water.