Adsorption Mechanisms for Antimony Contamination Removal

Antimony enters aquatic and terrestrial environments through mining, smelting and various industrial processes, posing a risk to human health and ecosystems. Adsorption has emerged as a versatile and cost-effective approach for its remediation, relying on the affinity of Sb species—trivalent antimonite (Sb(III)) and pentavalent antimonate (Sb(V))—for engineered surfaces. Key mechanisms include electrostatic attraction, inner-sphere complexation, ion exchange, surface precipitation and, in some biochar-based systems, simultaneous oxidation of Sb(III) to the less toxic Sb(V). The performance of an adsorbent is governed by its surface area, pore structure and the nature of functional groups (hydroxyl, carboxyl, amino, π-electron systems) capable of bonding with Sb oxyanions. Solution pH critically influences the dominant sorption pathway by altering both Sb speciation and the surface charge of the adsorbent. Advanced composites—combining metal oxides, carbonaceous matrices or biopolymers—exploit synergistic effects to enhance capacity, selectivity and reusability. Modelling with adsorption isotherms and kinetic expressions provides insight into thermodynamic favourability and rate-limiting steps, informing the design of point-of-use filters and large-scale treatment units. Continued innovation centres on sustainable feedstocks, waste-derived materials and hybrid systems that integrate adsorption with oxidation or magnetic separation for efficient antimony removal worldwide.

Research from Nature Portfolio

A novel magnetic composite was fabricated by co-precipitating ferriferrous oxide with ceric hydroxide derived from industrial polishing sludge. This sorbent achieves rapid antimonite uptake within two hours over a broad pH range (3–7), fitting a Langmuir isotherm with a maximum capacity around 23 mg g⁻¹. Kinetic analysis indicates a pseudo-second-order rate law dominated by chemical adsorption. Thermodynamic parameters reveal the process to be spontaneous and endothermic. Spectroscopic and microscopic evidence attributes removal to synergistic interactions on Fe₃O₄, FeCe₂O₄ and hydrous ceric oxide phases, demonstrating an environmentally friendly route to valorise waste sludge while effectively eliminating Sb(III) from wastewater.

Adsorption Mechanisms for Antimony Contamination Removal publication trend

The graph below shows the total number of articles in adsorption mechanisms for antimony contamination removal across all publications each year (not limited to Nature Index journals).

Technical terms

Adsorption: Accumulation of dissolved species at the surface of a solid phase.

Inner-sphere complexation: Direct chemical bonding between a contaminant ion and functional groups on the adsorbent surface.

Langmuir isotherm: A model describing monolayer adsorption onto a uniform surface with a finite number of sites.

Pseudo-second-order kinetics: A rate expression where the adsorption rate is proportional to the square of the number of unoccupied sites, often indicating chemisorption.

Sb(III)/Sb(V): Trivalent (antimonite) and pentavalent (antimonate) oxidation states of antimony, differing in charge and affinity for surfaces.

Biochar: Carbon-rich solid produced by pyrolysis of biomass, used as an adsorbent owing to its porous structure and surface functional groups.

References

1. The Potential for the Treatment of Antimony-Containing Wastewater by Iron-Based Adsorbents. Water (2017).
2. Preparation of a novel Fe3O4/HCO composite adsorbent and the mechanism for the removal of antimony (III) from aqueous solution. Scientific Reports (2019).
3. Insights into simultaneous adsorption and oxidation of antimonite [Sb(III)] by crawfish shell-derived biochar: spectroscopic investigation and theoretical calculations. Biochar (2022).
4. Frontier Materials for Adsorption of Antimony and Arsenic in Aqueous Environments: A Review. International Journal of Environmental Research and Public Health (2022).