Arsenic Removal from Aqueous Solutions

The presence of arsenic in water supplies poses a profound threat to public health on a global scale. Arsenic contamination arises from natural geological sources, industrial effluents and agricultural runoff, and exists primarily in two oxidation states: arsenite (AsIII) and arsenate (AsV). AsIII is generally more mobile and toxic than AsV and is challenging to remove owing to its neutral charge at circumneutral pH. Conventional treatment technologies include coagulation–flocculation, ion exchange and membrane filtration, yet these can be costly and produce secondary waste. In recent years, research has focused on adsorption-based methods employing low-cost, sustainable materials such as modified biomass, biochar composites and functionalised nanoparticles. These materials act by binding arsenic species through surface complexation, electrostatic attraction or redox reactions. Advances in model fitting, including isotherm and kinetic analyses, have clarified removal mechanisms and guided optimisation of contact time, pH and adsorbent dose. Integrating biological and nanomaterial strategies has yielded hybrid systems with enhanced capacity and selectivity. The global significance of these developments lies in their potential to deliver affordable and efficient arsenic-removal solutions tailored to diverse water-quality challenges and resource-limited settings.

Research from Nature Portfolio

A novel biosorbent comprising dead bacterial biomass immobilised in calcium alginate beads has been shown to remove AsIII rapidly and efficiently under mild conditions. Optimisation of pH, temperature and contact time yielded a maximum capacity exceeding 20 mg g−1, with equilibrium achieved within 20 minutes. Surface analysis confirmed arsenic binding via functional groups in the immobilised biomass, while regeneration tests demonstrated stable performance over multiple cycles. Thermodynamic profiling indicated an endothermic, spontaneous process, highlighting the promise of eco-friendly biosorbents for scalable arsenic remediation.

Arsenic Removal from Aqueous Solutions publication trend

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

Technical terms

Biosorption: The passive binding of contaminants to the surface of biological materials such as microbial cells or plant biomass.

Adsorption isotherm: A mathematical relationship describing how adsorbate concentration at equilibrium varies with adsorbent loading at constant temperature.

Biochar: A carbon-rich material produced by pyrolysis of biomass, used as an adsorbent owing to its porous structure and functional groups.

Pseudo-second-order kinetics: A model that assumes the rate-limiting step involves chemisorption, often providing a good fit for adsorption rate data.

References

1. Biosorption of arsenic (III) from aqueous solution using calcium alginate immobilized dead biomass of Acinetobacter sp. strain Sp2b. Scientific Reports (2024).
2. Application of BCXZM Composite for Arsenic Removal: EPS Production, Biotransformation and Immobilization of Bacillus XZM on Corn Cobs Biochar. Biology (2023).
3. Removal of As(V) from aqueous solution using modified Fe3O4 nanoparticles. Royal Society Open Science (2023).
4. Optimization of As(V) Removal by Dried Bacterial Biomass: Nonlinear and Linear Regression Analysis for Isotherm and Kinetic Modelling. Metals (2022).