Multi-metal oxide incorporated microcapsules for efficient As(iii) and As(v) removal from water

Abstract

Arsenic contamination in ground water is a major problem in various countries, and causes serious health issues, such as cancer and skin diseases. Among the many different methods of arsenic removal, extraction using functional adsorbents has been employed owing to its low cost, simplicity, and fast regeneration. In this paper, preparation and characterization of mixed metal oxide loaded polycaprolactone microcapsules and their application as adsorbents for both As(III) and As(V) from water is demonstrated. The presence of CeO₂ nanoparticles on microcapsules enhance the affinity towards As(III), while magnetic Fe₃O₄ nanoparticles help to bind As(V) and facilitate the removal of capsules from the medium under an applied magnetic field. Polyvinylpyrrolidone was used as a surface modifier to prepare microcapsules with high surface roughness and large surface area. Efficient removal of As(III) and As(V) can be achieved using the modified microcapsules within 15 minutes. The arsenic extraction was insensitive to changes in pH within a range of 3–11. The microcapsules were recycled using 1 M NaOH solution and reused 3 times without losing significant extraction efficiency. The microcapsules showed a maximum Langmuir adsorption capacity of 32 and 28 mg g⁻¹ for As(III) and As(V), respectively. In summary, our metal oxide incorporated polycaprolactone microcapsules can be used as efficient and readily removable adsorbents for arsenic removal from ground water.