Phosphorus removal from aqueous solutions containing low concentration of phosphate using pyrite calcinate sorbent

Natural pyrite was modified by calcination under nitrogen (N-2) atmosphere to produce a novel sorbent for removing phosphorus (P) with low concentration from aqueous solutions. The crystallinity, porous texture, magnetic susceptibility and performance in P removal of pyrite calcinates depended on calcination temperatures. The sorbent obtained at calcination temperature of 500-600 A degrees C possessed the most efficient P removal. Solution pH in the range of 3.0-9.0 and anions of chloridion (Cl-), nitrate (NO3)(-) and sulfate (SO4 (2-)) had ignorable effect on P removal. The batch adsorption experiment shows that the maximum sorption capacities for P of this novel sorbent (q (m)) were up to 1.61-5.36 mg P/g at adsorption temperatures of 15-35 A degrees C. Dynamic sorption and regeneration experiments were conducted in an adsorption column filled with pyrite calcined at 600 A degrees C. The study found that oxygen was an important control factor responsible for P adsorption because the oxidization of Fe2+ to Fe3+ on the surface of the sorbent followed by P being bound to a ferric hydroxide surface film was the crucial processes. The mechanism was confirmed with surface characterization techniques including field emission scanning electron microscope and X-ray photoelectron spectroscopy. This research potentially provides a cheap, abundant sorbent for P removal from the secondary effluent of municipal wastewater treatment plant.