Methods Used for Performance Enhancement of Iron-Based Magnetic Adsorbents in Water Systems

Magnetic adsorbents are increasingly gaining attention as a focus of research for contaminant removal from water and wastewater due to their low cost, easy synthesis and separation from aqueous medium. However, the commercial applications of zero-valent iron (ZVI) and iron oxides are limited due to particle agglomeration and low oxidation stability. The agglomeration behavior of ZVI and particle oxidative stability can be enhanced by modification of magnetic adsorbents using an appropriate stabilization procedure such as surface coating or functionalization. This chapter systematically describes the recent advances in modification methods of magnetic adsorbents for contaminant removal from water and wastewater. Various modification methods including carbon stabilization, polymer coating, inorganic oxide impregnation, functionalization, and miscellaneous stabilization procedures are summarized. These stabilization procedures can enhance the adsorption capacities of magnetic adsorbents by expanding the surface area and pore volume of the adsorbents and generating new active sites and/or functional groups on the adsorbent surface. The key process parameters and relevant published data along with the results of these studies have been discussed.