Advances in iron-based nanomaterials for mercury removal from water: trends and mechanisms

Abstract

Mercury (Hg) contamination remains a global concern due to its chemical complexity, environmental mobility, and threat to human health. The limitations of traditional clean-up methods have driven increased interest in iron-based nanomaterials (IBNMs) as versatile and effective options for mercury removal. This review combines a scientometric analysis of 332 publications (1995–2025) with a critical examination of material design strategies and the primary mechanisms involved in Hg capture by IBNMs. Scientometric trends reveal a rapidly expanding research landscape dominated by iron oxides, zero-valent iron nanoparticles, and diverse composite materials incorporating graphene, biopolymers, silica frameworks, and doped structures. Mechanistic evidence highlights the importance of Fe(0)/Fe(II)/Fe(III) cycling, surface hydroxyl coordination, sulphur-based soft–soft interactions, and cooperative binding environments in controlling Hg uptake, transformation, and stability. By connecting research evolution with mechanistic understanding, this review identifies persistent challenges (such as material aging, matrix effects, and limited pilot-scale validation) while outlining opportunities in hierarchical supports and multi-contaminant treatment. Overall, the consolidated findings demonstrate that rationally engineering IBNMs holds strong potential to advance next-generation Hg-removal technologies.