Characterization and adsorption of arsenate and selenite onto Kemiron

Abstract

Kemiron, a commercially available, porous iron oxide sorbent was evaluated in batch systems for arsenate (As(V)) and selenite (Se(IV)) removal from aqueous solutions as a function of pH, ionic strength, and particle size (< 38 μ m and between 250 and 425 μ m). BET surface area of Kemiron is 39.8 m²/g and Electron dispersive spectroscopy (EDS) studies found Kemiron to be 40.37% iron and 42.25% oxygen by mass. Langmuir isotherms best described the As(V) and Se(IV) removal at pH 7 with maximum adsorption capacity of 82 mg/g and 52 mg/g respectively. As(V) and Se(IV) sorption decreased as pH increased and both anions were unaffected by sodium nitrate (NaNO₃) background electrolyte. As(V) sorption was not affected in surface water samples from the Hillsborough River. Batch kinetic models of the experimental data on the 250 to 425 μ m particle size yielded mass transfer coefficients of 0.0008 min⁻¹ and 0.009 min⁻¹ for As(V) and Se(IV) respectively.

Keywords:

• Kemiron
• arsenate
• selenite
• Langmiur
• Freundlich model

Acknowledgments

This work was supported by Florida Center for Solid and Hazardous Waste. Grant No. 1933-082. We thank Paula Lowe, the laboratory supervisor of the City of Tampa Water Department for granting permission to use the Department's equipment for the water sampling. Joniqua Howard, Erlande Omisca and Ken Thomas also assisted with laboratory experiments and insights.

Notes

*Analyzed by GFAA using standard additions method at USF.

*Multipoint nitrogen gas intrusion result.

*The unit is (L/μ g)^1/n .