Efficiency and Mechanism of Phosphorus Removal by Coagulation of Iron-manganese Composited Oxide

Iron-manganese composited oxide(FeMnO) was prepared with potassium permanganate and ferrous salt.Interface performance,charge property and structure topography of the FeMnO were investigated.Coagulation efficiency and pollution removal mechanism of the FeMnO were approached.Results show that the main compositions of the FeMnO are δ-manganese dioxide and ferric hydroxide.The specific surface area is about 146.22 m2/g.The FeMnO contains rich hydroxyl with extremely strong adsorption action and chemical adsorption activity.The zero charge point of the oxide in pure water is about 8.0 of pH value.Under neutral pH value conditions,the FeMnO particle surface carried positive charges.The FeMnO particles are quasi-spherical micro-particles with irregular sizes adjoined each other to form net construction.Phosphorus removal efficiency of the FeMnO is remarkable,the total dissoluble phosphorus of settled water can be reduced below detecting level(0.3 μg/L) at a FeMnO dosage of 6 mg/L,and total phosphorus below detecting level at a FeMnO dosage of 10 mg/L,for water samples containing total phosphorus of 1281.70 μg/L and total dissoluble phosphorus of 1187.91 μg/L.The mechanism of effective coagulation for phosphorus removal is combined results of multiple actions of adsorption,charge neutralization,adsorption/bridging and so on.