Construction of magnetic bimetallic oxide-decorated attapulgite-based adsorbents for arsenic ion adsorption

BACKGROUND

Arsenic contamination can exert severe detrimental effects on the ecological environment and human health. It can cause acute or chronic poisoning, resulting in cell distortion or cancer when humans come into contact with or consume arsenic-containing water. Adsorption technology is one of the effective methods for arsenic removal. In this study, using attapulgite (ATP) as a support for bimetallic iron–manganese oxides, a series of adsorbents (Fe-Mn/ATP) with different manganese-to-iron molar ratios were prepared via the coprecipitation method. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy mapping, X-ray diffraction and zeta potential measurements were used to analyze the structure and properties of Fe-Mn/ATP. In addition, the adsorption performance of the material for arsenic ions was investigated by static adsorption and dynamic adsorption experiments.

RESULTS

A novel Fe-Mn/ATP adsorbent was prepared using ATP as the raw material and manganese-to-iron molar ratio was 1:3 by coprecipitation at 60 °C for 1 h. The adsorption efficiency of arsenic ions was optimal at an Fe-Mn/ATP dosage of 2 g L⁻¹, pH 4 and a contact time of 10 min, reaching a maximum adsorption capacity of 38.27 mg g⁻¹ at room temperature. The adsorption process followed the pseudo-second-order kinetic model and the Langmuir isotherm adsorption model, indicating that arsenic ion adsorption by Fe-Mn/ATP was mainly monolayer chemical adsorption. Furthermore, Fe-Mn/ATP showed a removal rate for arsenic ions of over 80% after four cycles of regeneration, revealing a great potential for practical application.

CONCLUSION

This study offers a promising Fe-Mn/ATP adsorbent for removal of arsenic ions from wastewater. © 2024 Society of Chemical Industry (SCI).