Adsorption Mechanisms of Carbon Nanomaterials in Aqueous Systems

Carbon nanomaterials such as graphene, graphene oxide, reduced graphene oxide and carbon nanotubes have emerged as versatile adsorbents in water treatment owing to their exceptional surface area, tunable surface chemistry and unique electronic properties. Adsorption at the solid–liquid interface is governed by a combination of hydrophobic effects, π–π stacking interactions, electrostatic attraction, hydrogen bonding and van der Waals forces. Surface functionalisation introduces oxygen-containing groups, nitrogen moieties or metal nanoparticles, which modulate affinity toward organic pollutants, metals and dyes. Porous architectures—from interlayer galleries in graphene composites to mesoporous networks in carbon nanotube bundles—further enhance uptake by providing abundant adsorption sites. Environmental conditions such as pH, ionic strength, temperature and the presence of dissolved organic matter influence both capacity and kinetics, often leading to multi-step adsorption processes. The interplay between experimental characterisation, theoretical modelling and field-scale testing is rapidly advancing our understanding of how to optimise nanomaterial design for selective, high-efficiency removal of contaminants and for resource recovery in sustainable water treatment technologies.

Research from Nature Portfolio

Graphene-coated silica particles have been shown to maintain expanded interlayer spacing and expose hydrophobic graphene sites, delivering a hundred-fold increase in aromatic pollutant uptake through enhanced π–π stacking and displacement of water nanodroplets. A one-pot hydrothermal synthesis of a graphene foam–TiO₂ nanosheet hybrid demonstrated strong synergistic removal of both chromium(VI) and organic dyes, combining the photocatalytic properties of TiO₂ with the adsorption capacity of graphene and offering facile recyclability. Investigations into organics recovery from ultra-short solids retention time effluent have revealed that single-walled and multi-walled carbon nanotubes achieve near-complete adsorption of humic substances and mixed organics, highlighting the potential for carbon recovery and energy reclamation in advanced wastewater processes.

Adsorption Mechanisms of Carbon Nanomaterials in Aqueous Systems publication trend

The graph below shows the total number of articles in adsorption mechanisms of carbon nanomaterials in aqueous systems across all publications each year (not limited to Nature Index journals).

Technical terms

Adsorption capacity: maximum mass of adsorbate per unit mass of adsorbent at equilibrium.

Hydrophobic effect: tendency of non-polar surfaces to associate in water, displacing solvent molecules.

π–π interactions: non-covalent stacking between aromatic rings on adsorbent and adsorbate.

Langmuir isotherm: model describing monolayer adsorption on a homogeneous surface with finite identical sites.

Pseudo-second-order kinetics: rate model assuming adsorption rate is proportional to the square of available sites.

Graphene oxide (GO): oxidised form of graphene bearing oxygen-functional groups that enhance dispersibility and reactivity.

Reduced graphene oxide (rGO): partially deoxygenated form of GO with restored graphitic structure and altered electronic properties.

References

1. Surface interaction of tetrabromobisphenol A, bisphenol A and phenol with graphene-based materials in water: Adsorption mechanism and thermodynamic effects. Journal of Hazardous Materials Advances (2023).
2. Graphene-coated materials using silica particles as a framework for highly efficient removal of aromatic pollutants in water. Scientific Reports (2015).
3. Single-step One-pot Synthesis of Graphene Foam/TiO2 Nanosheet Hybrids for Effective Water Treatment. Scientific Reports (2017).
4. Adsorption characteristics of organics in the effluent of ultra-short SRT wastewater treatment by single-walled, multi-walled, and graphitized multi-walled carbon nanotubes. Scientific Reports (2018).
5. Predicting the effect of dissolved humic acid on sorption of benzotriazole to biochar. Biochar (2022).
6. Modern Carbon–Based Materials for Adsorptive Removal of Organic and Inorganic Pollutants from Water and Wastewater. Molecules (2021).