Recent trends in the application of magnetic nanocomposites for heavy metals removal from water: A review

Intensive urbanization and industrialization has led to increasing water pollution by heavy metals, adversely affecting human health and the environment. Among the different technologies available for heavy metals removal from water, adsorption is regarded as the most effective approach. Nanomaterials, especially magnetic nanoparticles, have emerged as promising tools for heavy metals removal because of their unique properties. One of the main drawbacks with magnetic nanoparticles is their tendency to form aggregates in solution, decreasing their efficacy and limiting their applications in water treatment. In order to stabilize magnetic nanoparticles, researchers have therefore begun modifying their surfaces with a variety of support media. In addition to carbon-based materials, natural and synthetic polymers and other molecules, metal organic frameworks and layered double hydroxides have all been employed as carriers in novel magnetic nanocomposites. This review summarizes the most recent developments in this field, focussing on the potential application of magnetic nanocomposites as adsorbents for removing heavy metals from water. Critical gaps in the current literature are also identified, as much work is still required before magnetic nanocomposites may be readily applied in real world applications, including scale up of production and subsequent pilot investigations of water treatment in dynamic flow conditions.