Adsorption of phosphates using transition metals-modified bentonite clay

ABSTRACT

Phosphorus is a micronutrient but when it exists in abundance, it can have detrimental environmental impact. Bentonite (Bent) modified with Fe, Co and Ni salts were synthesized and evaluated for adsorption of phosphate ions from water. Results indicated that metal-modified bentonite have lower crystallinity compared to the native bentonite. Batch adsorption experiments showed maximum adsorption capacities of 20.88, 46.95, 29.07 and 6.57 mg/g for Fe-Bent, Co-Bent, Ni-Bent and Bent, respectively. The pseudo-second-order kinetic model provided a better fit for all adsorbents. The competition effect of coexisting anions were not significant for Fe and Ni modified bentonite.

KEYWORDS:

• Modified bentonite
• phosphate
• ligand exchange process
• adsorption mechanism

Acknowledgements

This work was supported by the South African Council for Scientific and Industrial Research-NRF-PDP under 88568 and Erasmus Mundus (Aesop project) under Grant ES15DM0040. The authors acknowledge the University of the Witwatersrand and the University of Latvia for contributions to this project.

Additional information

Funding

This work was supported by the South African Council for Scientific and Industrial Research-NRF-PDP under 88568 and Erasmus Mundus (Aesop project) under Grant [ES15DM0040]. The authors acknowledge the University of the Witwatersrand and the University of Latvia for contributions to this project.