Phosphate Removal and Adsorption Techniques in Aqueous Systems

Phosphate pollution in natural and engineered water bodies drives eutrophication and degrades water quality, prompting the development of efficient removal strategies. Adsorption stands out for its capacity to lower phosphate concentrations even at trace levels, while offering opportunities for recovery and reuse. A diverse array of adsorbent materials has been explored, including metal-based sorbents, carbonaceous substrates, clays and hybrid composites. Key mechanisms encompass electrostatic attraction, ligand exchange, inner-sphere complexation and, in some cases, precipitation. Advances in material design—ranging from nanoscale tuning of pore structures to surface functionalisation—have enhanced selectivity, kinetics and regeneration potential. Practical applications extend from municipal wastewater polishing to freshwater and saline-water remediation, underlining the global relevance of adsorption-based phosphate control and resource circularity.

Research from Nature Portfolio

Iron-based metal–organic frameworks (MOFs) such as MIL-101 and its amine-functionalised derivative exhibit exceptionally high phosphate adsorption capacities and rapid uptake kinetics. These materials combine large surface areas with specific binding sites and demonstrate strong selectivity against competing anions, enabling effective treatment of both synthetic solutions and actual eutrophic waters. Modification of naturally occurring halloysite nanotubes with nano-iron oxides has yielded nanosorbents whose adsorption performance is governed by pH-dependent electrostatic attraction, ligand exchange and Lewis acid–base interactions. Such hybrids achieve fast initial removal and retain performance over multiple cycles. A low-cost tea-residue activated carbon loaded with silver nanoparticles offers another practical route, achieving chemisorption-controlled phosphate uptake through complex formation and ligand exchange; the material’s performance aligns with both Langmuir and Sips isotherm models and benefits from straightforward regeneration protocols.

Phosphate Removal and Adsorption Techniques in Aqueous Systems publication trend

The graph below shows the total number of articles in phosphate removal and adsorption techniques in aqueous systems across all publications each year (not limited to Nature Index journals).

Technical terms

Adsorption: The process by which ions or molecules adhere to the surface of a solid phase.

Adsorbent: A material with surface properties designed to capture target species from a fluid.

Adsorption isotherm: A curve describing the equilibrium relationship between adsorbate concentration in the liquid and the amount adsorbed on the solid at constant temperature.

Metal–organic framework (MOF): A porous crystalline material composed of metal ions coordinated to organic ligands, offering high surface area and tunable functionality.

Mesopores: Pore structures with diameters between 2 and 50 nm that facilitate diffusion and access to internal binding sites.

Ligand exchange: A surface reaction mechanism in which phosphate ions replace pre-existing ligands on the adsorbent surface, forming inner-sphere complexes.

References

1. Tri-functional lanthanum-based biochar for efficient phosphorus recovery, bacterial inhibition, and soil fertility enhancement. Biochar (2023).
2. Effective Adsorption and Removal of Phosphate from Aqueous Solutions and Eutrophic Water by Fe-based MOFs of MIL-101. Scientific Reports (2017).
3. Adsorption of phosphate on iron oxide doped halloysite nanotubes. Scientific Reports (2019).
4. Phosphate Adsorption by Silver Nanoparticles-Loaded Activated Carbon derived from Tea Residue. Scientific Reports (2020).
5. A review of adsorption techniques for removal of phosphates from wastewater. Water Science & Technology (2022).
6. Lanthanum modified bentonite behaviour and efficiency in adsorbing phosphate in saline waters. Chemosphere (2020).