Phosphorus removal from wastewater using natural pyrrhotite

• Pyrrhotite removed P of 99.1% from wastewater with P concentration of 17.1 mg/L.
• P was removed over 90% as the initial pH of wastewater was in the range of 3.5–12.
• As P adsorbed on the surface of pyrrhotite, a new FeOP structure would be formed.

Pyrrhotite is a common mineral on the earth and is used as a raw material for sulphuric acid production. This study explored the use of natural pyrrhotite mineral for phosphorus (P) removal from wastewater. With an initial P concentration of 17.1 mg/L, pyrrhotite removed 99.1% of P from aqueous solutions. P was removed over 90% as the initial pH of wastewater was in the range of 3.5 and 12. The temperature affected P removal, and the P removal efficiency was reduced from 99.1% to 88.4% as the temperature was decreased from 29 to 11 °C. P adsorption on pyrrhotite can be expressed with the Langmuir adsorption isotherm and pseudo second-order kinetics, indicating that the major mechanism of P removal by pyrrhotite would be chemisorption. This study shows that natural pyrrhotite is a good media for P removal from wastewater.

Rapid P removal was observed in the first half an hour and 23.3%, 43.2% and 69.2% of P were removed during this period as the initial pH was 2.48, 5.81, and 10.49, respectively. Thereafter P concentration was gradually decreased to 3.36, 0.23, and 0.27 mg/L until 24 h for the initial pH of 2.48, 5.81 and 10.49, respectively.Figure optionsDownload as PowerPoint slide