Recent progress in silver (Ag) adsorption technologies: mechanisms, challenges, and opportunities: a review

The adsorption of silver (Ag) from aqueous solutions is a critical research area due to its environmental, industrial, and economic significance. Silver, a valuable metal widely used in various industries, poses ecological and health risks when released into wastewater. Adsorption is an effective, cost-efficient method for silver removal, offering high efficiency and operational simplicity. Recent advancements have led to the development of advanced adsorbents with enhanced capacity and selectivity for silver ions. This review examines the mechanisms of silver adsorption, including electrostatic interactions, ion exchange, surface complexation, and redox reactions, and evaluates adsorbent performance through isotherms, kinetics, and thermodynamics. Key factors influencing adsorption, such as pH and competing ions, are analyzed, alongside emerging trends like sustainable adsorbents and hybrid technologies. Challenges, including adsorbent regeneration and scalability, are discussed, as are opportunities for resource recovery and circular economy approaches. This review aims to guide the development of efficient, sustainable silver adsorption technologies for environmental remediation and industrial applications.