Thakur, ShivaniSingh, HarminderChaudhari, UmakantMittal, SunilSahoo, Prafulla Kumar2024-01-212024-08-142024-01-212024-08-142022-12-02978111987056210.1002/9781119870562.ch6http://10.2.3.109/handle/32116/4012An occurrence of arsenic (As) in an aquatic ecosystem is a major concern because of its very toxic and carcinogenic nature. Groundwater arsenic pollution has been reported globally, notably along the large Indo-Gangetic flood plain and some major rivers of South Asia and South American nations. It comes in water both via natural and anthropogenic sources. Major processes that trigger the release of As in groundwater include reductive dissolution of Fe-oxyhydroxides, sulfide oxidation, and alkali desorption. Microbial metabolisms of arsenic also play a crucial role in its mobilization in aquifers. Ions such as HCO 3 ? and PO 4 3? also help in triggering arsenic mobility in water. Different methods are developed for As removal from water such as precipitation, coagulation, ion exchange, and membrane filtration, but none of the methods are as effective as nanomaterials. With the advancement in a study in nanotechnology during the past few years, an increase in usage of different nanomaterials as adsorbents for arsenic removal has also been observed. Among these, nano zerovalent iron (nZVI) has been proved quite effective for arsenic removal from the water by the adsorption technique. The nZVI has high reactivity, good efficiency, and fast action for As removal, and a low impact on the environment. Further, intensive research is going on to alter the properties of nZVI following specific applications as per the requirements. This chapter presents an overview of several geochemical processes aiding in As mobility from the aquifer sediments into groundwater, briefly describing its distribution pattern across global groundwater systems. It also aims to provide an overview of the effectiveness of different iron-based nanoparticles with particular reference to nZVI for the removal of different species of Arsenic from water. � 2023 John Wiley & Sons Ltd. Published 2023 by John Wiley & Sons Ltd. All rights reserved.en-USArsenicgeochemical processesgroundwateriron-oxide nanoparticlesnano zerovalent iron (nZVI)Book chapterhttps://onlinelibrary.wiley.com/doi/10.1002/9781119870562.ch6