Adsorption Mechanisms for Bisphenol A in Aqueous Solutions

In aqueous environments, adsorption mechanisms for bisphenol A (BPA) hinge on a combination of physical and chemical interactions at the interface between adsorbent and solute. The process encompasses diffusion of BPA molecules through macropores and mesopores to the adsorbent surface, followed by retention via hydrophobic interactions, hydrogen bonding, π–π stacking and electrostatic attraction. Solution pH strongly influences the ionisation state of BPA and the surface charge of the adsorbent, thereby modulating uptake capacity. Temperature and ionic strength further direct the spontaneity and thermodynamics of the process, often yielding exothermic, spontaneous adsorption. Kinetic studies commonly fit pseudo-second-order models, suggesting chemisorption or electron-sharing mechanisms as rate-determining steps. Equilibrium data generally conform to Langmuir or Freundlich isotherms, distinguishing monolayer and heterogeneous surface adsorption. Recent advances have leveraged high-surface-area materials, functionalised surfaces and magnetic composites to enhance selectivity and facilitate regeneration. These improvements underpin scalable water treatment technologies aimed at mitigating BPA pollution in industrial and municipal effluents worldwide.

Research from Nature Portfolio

Recent studies have demonstrated the synthesis of a magnetic graphene oxide–polyaniline composite for BPA removal. The material comprises Fe₃O₄@PANI nanoparticles uniformly anchored on graphene oxide sheets, yielding high specific surface area and facile magnetic separation. Adsorption follows pseudo-second-order kinetics and conforms to a Langmuir isotherm, indicating monolayer chemisorption. Thermodynamic analysis reveals a spontaneous and endothermic uptake process, with hydrogen bonding and π–π interactions driving strong affinity for aromatic BPA molecules. The magnetic nature of the composite enables rapid recovery and reuse with minimal capacity loss, highlighting its potential for efficient removal of endocrine disruptors from contaminated water.

Adsorption Mechanisms for Bisphenol A in Aqueous Solutions publication trend

The graph below shows the total number of articles in adsorption mechanisms for bisphenol a in aqueous solutions across all publications each year (not limited to Nature Index journals).

Technical terms

Pseudo-second-order kinetics: A rate model assuming the adsorption rate is proportional to the square of the number of unoccupied sites, often indicative of chemisorption.

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

π–π interactions: Attractive forces between aromatic rings of the adsorbent and adsorbate, facilitating adsorption of aromatic compounds.

Hydrogen bonding: A dipole–dipole interaction between a hydrogen atom bound to an electronegative atom and a lone-pair electron donor.

Specific surface area: The total surface area of an adsorbent per unit mass, a determinant of adsorption capacity.

Chemisorption: Adsorption involving the formation of chemical bonds between adsorbate and surface, typically stronger and more specific than physisorption.

References

1. Fabrication and characterisation of magnetic graphene oxide incorporated Fe3O4@polyaniline for the removal of bisphenol A, t-octyl-phenol, and α-naphthol from water. Scientific Reports (2017).
2. Adsorption Characteristics and Mechanism of Bisphenol A by Magnetic Biochar. International Journal of Environmental Research and Public Health (2020).
3. Removal of Endocrine Disrupting Chemicals from Water: Adsorption of Bisphenol-A by Biobased Hydrophobic Functionalized Cellulose. International Journal of Environmental Research and Public Health (2018).
4. Adsorptive Behavior of an Activated Carbon for Bisphenol A Removal in Single and Binary (Bisphenol A—Heavy Metal) Solutions. Water (2020).