Biosorption Techniques for Heavy Metal Ion Removal from Aqueous Solutions

Biosorption harnesses the natural affinity of biological materials for binding and concentrating heavy metal ions from water. It employs dead or living biomass—ranging from bacterial and fungal cells to agricultural by-products such as feathers, hair and plant residues—that present functional groups (for example hydroxyl, carboxyl, amino and phosphate moieties) capable of chelation, ion exchange and electrostatic attraction. Chemical or physical modifications (phosphorylation, alkali treatment, grafting of ligands) can enhance surface charge, porosity and metal-binding capacity. Batch and continuous modes, including packed-bed columns, have been demonstrated at laboratory and pilot scales, achieving rapid kinetics and high removal efficiencies under optimised pH, temperature and contact time. Adsorption isotherms (Langmuir, Freundlich, Dubinin–Radushkevich) and kinetic models (pseudo-first-order, pseudo-second-order, intra-particle diffusion) govern design and scale-up. Desorption cycles with mild acids enable regeneration of biosorbents, promoting circularity. This eco-friendly approach addresses global water pollution by providing low-cost, sustainable solutions for industrial effluents, mining waters and agricultural runoff, with particular promise in regions lacking advanced treatment infrastructure.

Research from Nature Portfolio

Recent studies have demonstrated that phosphorylation of baker’s yeast biomass markedly enhances its heavy metal uptake. Cyclo-triphosphate treatment introduces abundant phosphate groups, increasing negative surface charge and zeta potential. The modified cells achieved adsorption capacities near 1.0 mmol g–1 dry weight for divalent ions such as Cd2+, Cu2+, Pb2+ and Zn2+, outperforming non-modified biomass. Desorption in dilute acid permitted efficient recovery of both metals and biomass. Moreover, the phosphorylated system displayed selective uptake of trivalent over divalent ions, suggesting tailored separation of mixed metal streams. This work establishes a versatile platform for functionalising microbial biomass to combine high capacity, rapid kinetics and facile regeneration.

Biosorption Techniques for Heavy Metal Ion Removal from Aqueous Solutions publication trend

The graph below shows the total number of articles in biosorption techniques for heavy metal ion removal from aqueous solutions across all publications each year (not limited to Nature Index journals).

Technical terms

Biosorption: Passive binding of metal ions to functional groups on biological materials.

Langmuir isotherm: Model assuming monolayer adsorption onto a uniform surface with finite binding sites.

Pseudo-second-order kinetics: Rate model indicating chemisorption as the rate-limiting step, dependent on available binding sites.

Zeta potential: Electrical potential at the slipping plane of a particle, reflecting surface charge and colloidal stability.

Desorption: Process of releasing adsorbed ions from a sorbent, often using chemical eluents for sorbent regeneration.

References

1. Recovering metals from aqueous solutions by biosorption onto phosphorylated dry baker’s yeast. Scientific Reports (2019).
2. Application of Saccharomyces cerevisiae in the Biosorption of Co(II), Zn(II) and Cu(II) Ions from Aqueous Media. Water (2022).
3. Adsorption process and mechanism of heavy metal ions by different components of cells, using yeast ( Pichia pastoris ) and Cu 2+ as biosorption models. RSC Advances (2021).