Phosphorus removal from wastewater using electric arc furnace slag aggregate

ABSTRACT

Electric arc furnace (EAF) slag aggregate, a waste by-product of the steel industry, exhibited a high potential for phosphorus (P) removal and had attracted considerable attention. The main objectives of this study were to evaluate the performance of using EAF slag aggregate as an adsorbent for P removal and identify its P removal capacity. A series of batch tests showed that P removal capacity of EAF slag increases gradually with the increase of pH with a range of 2–10, while the highest P removal capacity (1.94 mg/g) can be obtained at pH 12. The adsorption kinetics of P on EAF slag can be described by pseudo-second-order kinetic equations. Isothermal adsorption simulations showed that the best fitted model was the Freundlich model with a correlation coefficient of 0.9825. A continuous flow column experiment feeding a synthetic influent containing 15 mg P/L was operated for 60 days and the P removal efficiency was greater than 95% with a P removal capacity of 1.6 mg P/g slag. The results obtained in this study showed that EAF slag could act as an efficient adsorbent for P removal. Calcium phosphate precipitation depends on the release of Ca²⁺ and OH⁻ by the dissolution of calcium oxide in EAF slag was found to be the dominant removal mechanism for P removal.

GRAPHICAL ABSTRACT

KEYWORDS:

• Phosphorus removal
• electric arc furnace slag
• adsorption
• kinetics
• column experiment

Acknowledgements

The authors gratefully acknowledge financial support by Science and Technology Program in 13th five-year plan of Education Department of Jilin Province (JJKH20180449KJ), Science and Technology Development Program of the Jilin Province (20200301030RQ, 20180101079JC), Ph.D Scientific Research Foundation by NEEPU (bsjjxm-201329).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The authors gratefully acknowledge financial support by Science and Technology Program in 13th five-year plan of Education Department of Jilin Province (JJKH20180449KJ), Science and Technology Development Program of the Jilin Province (20200301030RQ, 20180101079JC), Ph.D Scientific Research Foundation by NEEPU (bsjjxm-201329).