Sorption capabilities of soils for phosphate removal

The removal of phosphorus from soils was shown to be the result of three mechanisms: ion exchange, physical adsorption and precipitation. The degree of sorption by the combination of these mechanisms was evaluated by an equilibrium-adsorption procedure. The equilibrium distribution between the soil and liquid phases were correlated using the Langmuir Isotherm Equation. The Langmuir Parameters were incorporated in the expression v? /vc = 1 + (q? ?B / ? CO) which gave an estimate of the rate of phosphorus movement in the soil. The life-time of a soil-groundwater system was then determined from the groundwater flow rate and the calculated water-to-contaminant velocity ratio.