title: Phosphorus sorbing materials: sorption dynamics and physicochemical characteristics.
abstract: The effectiveness of various management practices to reduce phosphorus (P) loss from soil to water can potentially be improved by using by-product materials that have the capacity to sorb phosphorus. This study evaluated the P sorption and desorption potential, and the physicochemical characteristics of various phosphorus sorbing materials. Twelve materials were selected and P sorption potentials ranged between 66 and 990 mg kg(-1). Iron, and calcium drinking water treatment residuals (DWTRs), a magnesium fertilizer by-product, aluminum, and humate materials all removed substantial amounts of P from solution and desorbed little. Humate had the highest maximum P sorption capacity (S(max)). Materials which had a low equilibrium P concentration (EPC(0)) and a high S(max) included aluminum and humate by-products. In a kinetic study, the Fe-DWTR, Ca-DWTR, aluminum, and magnesium by-product materials all removed P (to relatively low levels) from solution within 4 h. Phosphorus fractionation suggests that most materials contained little or no P that was readily available to water. Sand materials contained the greatest P fraction associated with fulvic and humic acids. In general, materials (not Ca-DWTR) and magnesium by-product were composed of sand-sized particles. There were no relationships between particle size distributions and P sorption in materials other than sands. The Ca- and Fe-DWTR, and magnesium by-product also contained plant nutrients and thus, may be desirable as soil amendments after being used to sorb P. Further, using Ca-DWTRs and Fe-DWTRs as soil amendments may also increase soil cation exchange and water holding capacity.
authors.affiliation: Wor-Wic Community College, 32000 Campus Drive, Salisbury, MD 21804, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Leader
authors.forename: E J
authors.initials: EJ
authors.lastname: Dunne
authors.forename: K R
authors.initials: KR
authors.lastname: Reddy
mesh_terms: D000327:Adsorption; D008670:Metals / Q000032:analysis / Q000737:chemistry; D010316:Particle Size; D010758:Phosphorus / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D012987:Soil; D012989:Soil Pollutants / Q000737:chemistry*; D012995:Solubility; D014866:Waste Products / Q000032:analysis; D014876:Water Pollution / Q000517:prevention & control*
chemical_list: D008670:Metals; D012987:Soil; D012989:Soil Pollutants; D014866:Waste Products; D010758:Phosphorus; D012822:Silicon Dioxide