Effects of the addition of iron and aluminum salt on phosphorus adsorption in wetland sediment.

Adsorption and removal of phosphorus (P) in wetland sediment from aqueous solutions were investigated by using four kinds of iron (Fe) and aluminum (Al) salt (FeCl3, AlCl3, poly FeCl3, and poly AlCl3). Under optimal temperature of 25 °C, P concentration of 50 mg/L, and mole concentration ratio of 4:1 (Fe(3+)/PO4 (3-) or Al(3+)/PO4 (3-)), the P sorption capacities of wetland sediments by FeCl3, poly FeCl3, AlCl3, and poly AlCl3treatments were 296.03, 371.41, 276.3, and 357.85 μg/g, respectively, and were enhanced by 83.36, 158.74, 63.63, and 145.18 μg/g, respectively. The P sorption capacities based on different additives were in the order of poly FeCl3 > poly AlCl3 > FeCl3 > AlCl3. The EPC0 values, K values, and maximum adsorption capacities indicated that poly FeCl3 was good reagent to restore P pollution in aqueous solution by wetland sediment in the consideration of both P treatment efficiency and potential environmental impact. These findings, obviously, are useful basis to develop new effective methods for P removal in waters.