Selective Adsorption of Metal Ions from Aqueous Solutions

The selective adsorption of metal ions from aqueous solutions encompasses the design and implementation of materials that preferentially bind target ions in the presence of competing species. This process exploits surface active sites, tailored pore structures and specific functional groups—such as thiol, amine or phosphine moieties—to achieve high affinity and capacity. Beyond conventional physisorption, many modern sorbents employ chelation, redox interactions and ion-exchange mechanisms to improve selectivity, kinetics and recyclability. Advances in nanomaterials, composite hydrogels and metal-oxide matrices have delivered platforms with fine-tuned surface chemistry, enabling rapid uptake at trace concentrations. Owing to escalating concerns over water pollution, resource scarcity and critical metal recovery, this field addresses both environmental remediation and secondary resource extraction. The integration of theoretical modelling with in situ characterisation has further clarified adsorption thermodynamics and pathways, paving the way for scalable applications in wastewater treatment, mining leachate purification and circular-economy strategies.

Research from Nature Portfolio

Recent studies have introduced a mixed-valence molybdenum oxide sorbent that combines Mo(V) and Mo(VI) sites to achieve exceptional silver selectivity in complex wastewaters. Density functional theory elucidated how Mo(V) reduces Ag⁺ to metallic silver, lowering the barrier for subsequent uptake and enabling recovery efficiencies above 97 % over multiple cycles. In parallel, a thiourea-branched polyethylene glycol diacrylate hydrogel has demonstrated near-complete sorption of Ag(I) and Pd(II) at low pH. This polymer network leverages simultaneous chelation and electrostatic attraction to achieve sorption capacities exceeding 150 mg g⁻¹, and its chromic response aids monitoring of saturation. Both materials can be regenerated readily, illustrating the potential of recyclable sorbents that marry high specificity with operational simplicity.

Selective Adsorption of Metal Ions from Aqueous Solutions publication trend

The graph below shows the total number of articles in selective adsorption of metal ions from aqueous solutions across all publications each year (not limited to Nature Index journals).

Technical terms

Adsorption: Accumulation of ions or molecules at the interface between a fluid and a solid surface.

Sorbent: A solid material that removes substances from a liquid or gas phase by adsorption or absorption.

Cheation: Formation of coordinate bonds between a metal ion and a multidentate ligand, enhancing selectivity.

Distribution coefficient (Kd): Ratio of metal concentration on the sorbent to that in solution at equilibrium, indicating affinity.

Langmuir isotherm: Model describing monolayer adsorption on a homogeneous surface with finite binding sites.

Pseudo-second-order kinetic model: Rate equation assuming chemisorption as the rate-limiting step, dependent on sorbate–sorbent interactions.

References

1. Mixed-valence molybdenum oxide as a recyclable sorbent for silver removal and recovery from wastewater. Nature Communications (2023).
2. Novel reusable hydrogel adsorbents for precious metal recycle. Scientific Reports (2021).
3. Silver adsorption on biochar produced from spent coffee grounds: validation by kinetic and isothermal modelling. Biomass Conversion and Biorefinery (2022).
4. A facile method to synthesize nZVI-doped polypyrrole-based carbon nanotube for Ag(i) removal. Nanotechnology Reviews (2023).
5. Gamma radiation synthesis of hydroxyethyl cellulose/acrylic acid/CYANEX 471X hydrogel for silver ions capture from acidic nitrate medium. Cellulose (2024).