Iron-based nanohybrids for sustainable dye removal from wastewater: A comprehensive review on adsorption mechanisms and environmental implications

Synthetic dye-contaminated industrial effluents pose a persistent environmental threat due to their toxicity, chemical stability, and resistance to conventional remediation methods. This review provides a comprehensive assessment of iron-based nanohybrids (INHs) as versatile materials for dye adsorption and catalytic degradation in wastewater treatment systems. A critical research gap is identified in the limited integration of mechanistic insights with considerations of scalability, environmental safety, and economic feasibility. The major adsorption and catalytic mechanisms, including electrostatic interactions, ion exchange, and Fenton-like oxidation, are systematically evaluated under varying operational conditions. Particular emphasis is placed on regeneration potential, magnetic recovery, long-term reusability, and the influence of pH and temperature, positioning these mechanisms within the broader framework of process optimization. The review also highlights future directions in INHs design, including predictive modeling, comprehensive environmental risk assessment, and the adoption of circular-economy strategies to facilitate the transition from laboratory-scale research to industrial implementation. Overall, INHs represent a promising class of recyclable, multifunctional, and environmentally compatible materials for next-generation dye-remediation technologies.