Comparison Of Langmuir

A laboratory experiment was conducted to evaluate the phosphate sorption potential of some representative soils of Southern Guinea savanna of Nigeria using the Langmuir, Freundlich and Temkin models. Soil samples (0 ¿ 20 cm) of different Land use types were collected from five different locations exhibiting a wide range of physico-chemical characteristics. The soils were equilibrated for six days in a solution of 30 ml of 0.01M CaCl2 containing various amounts of P (0, 25, 50, 100, 200, 400, 800 and 1000µg L-1 P) as KH2PO4 at room temperature and thereafter the amount of phosphate sorbed was determined. Results obtained revealed that, phosphate sorption was positively correlated with pH, (0.925**), clay contents (0.823**), exchangeable acidity (0.802*) of the soils when phosphate was applied at the rate of 100 µg P mL-1. The sorption curves showed more or less similar pattern of changes. Langmuir model showed best fit to the sorption data at higher P concentrations followed by the Freundlich and Temkin. Phosphate sorption was highly correlated with pH, exchangeable acidity and clay content of the soil.