Adsorption Mechanisms in Graphene-Based Aerogels for Wastewater Treatment

Graphene-based aerogels combine the exceptional surface area, tunable porosity and rich surface chemistry of graphene derivatives with ultralight three-dimensional networks to capture a wide range of contaminants from water. Their high specific surface area and interconnected mesoporous architecture facilitate rapid mass transfer and a large number of active sites. Oxygen-containing functional groups on graphene oxide and reduced graphene oxide introduce sites for hydrogen bonding and electrostatic attraction of charged species, while the conjugated aromatic lattice supports π-π stacking interactions with organic molecules. Crosslinking agents or biopolymer scaffolds enhance mechanical integrity and control pore size distribution, optimising contact between pollutant molecules and the aerogel matrix. Adsorption isotherms typically follow a Langmuir model, indicating monolayer coverage on homogeneous sites, and kinetic analyses often fit a pseudo-second-order model, reflecting chemisorption as the rate-limiting step. Thermodynamic studies reveal that adsorption processes can be spontaneous and exothermic, with performance modulated by pH, temperature and ionic strength. Regeneration experiments demonstrate that many graphene-based aerogels retain high removal efficiencies over multiple cycles, underscoring their potential for sustainable wastewater treatment.

Research from Nature Portfolio

Recent studies have developed a biobased composite aerogel by crosslinking sodium carboxymethyl cellulose with nanographene oxide. This material exhibits rapid removal of a model cationic dye under neutral pH, achieving more than 90 % dye elimination in under 30 minutes. Adsorption data conform to a Langmuir isotherm with a monolayer capacity of approximately 77 mg g–1 and kinetics matching a pseudo-second-order model. Thermodynamic analysis indicates a spontaneous, exothermic process, most effective at lower temperatures. Notably, the composite retains over 85 % of its initial capacity after ten successive adsorption–desorption cycles, demonstrating excellent reusability for industrial dye remediation.

Adsorption Mechanisms in Graphene-Based Aerogels for Wastewater Treatment publication trend

The graph below shows the total number of articles in adsorption mechanisms in graphene-based aerogels for wastewater treatment across all publications each year (not limited to Nature Index journals).

Technical terms

Aerogel: A highly porous, ultralight solid network with large internal surface area.

Specific surface area: The total surface area per unit mass of a material, influencing adsorption capacity.

Langmuir adsorption isotherm: A model describing monolayer adsorption on uniform sites with no interactions between adsorbed molecules.

Pseudo-second-order kinetics: A kinetic model where adsorption rate depends on the square of the number of unoccupied sites, often indicating chemisorption.

π-π interaction: Non-covalent interaction between aromatic rings, important for binding organic pollutants to graphene surfaces.

Electrostatic attraction: The force drawing oppositely charged species together, critical for uptake of ionic contaminants.

References

1. Development of carboxymethyl cellulose-graphene oxide biobased composite for the removal of methylene blue cationic dye model contaminate from wastewater. Scientific Reports (2023).
2. Fabrication of Reusable Carboxymethyl Cellulose/Graphene Oxide Composite Aerogel with Large Surface Area for Adsorption of Methylene Blue. Nanomaterials (2021).
3. Directionally-Grown Carboxymethyl Cellulose/Reduced Graphene Oxide Aerogel with Excellent Structure Stability and Adsorption Capacity. Polymers (2020).
4. Hydrothermal Synthesis of Ultra-Light Coal-Based Graphene Oxide Aerogel for Efficient Removal of Dyes from Aqueous Solutions. Nanomaterials (2018).