Overlooked Adsorptive Route and Challenges in Arsenic Decontamination Using Iron Oxide Nanomaterials

Heavy metal such as arsenic in water has gained major global attention because of their carcinogenicity to a living being in the environment. By different routes, arsenic enters the water environment and decreases the water quality even at a very lower concentration (parts of billion (ppb)). Several approaches have been studied for arsenic abatement, but the adsorption process is efficient and economical to decontaminate water from arsenic. Iron oxide nanoparticles (IONPs) can act as low-cost adsorbents because of their magnetic properties, abundance, biocompatibility, and high selectivity towards arsenic. Further to increase the adsorption capacity of IONPs, a sustainable approach has been taken, and decorated with several materials such as activated carbon, biochar, chitosan, cellulose, and mining waste materials (which are environmentally friendly, low cost, number of functional groups, high reactivity, thermal stability, chemical stability and easily available everywhere). This review has outlined the overlooked adsorptive routes for arsenic removal with importance on arsenic sources, pollution, and removal strategies. A detailed influence parameter for arsenic removal by iron oxide and iron oxide-based composite and the interaction of arsenic species with the various functional groups of adsorbents were studied.