A comparison of the Langmuir, Freundlich and Temkin equations to describe phosphate sorption characteristics of some representative soils of Bangladesh.

摘要

To study the phosphate sorption potential of soils, an experiment was conducted with eight different soil series of Bangladesh. The soils were equilibrated with 0.01 M calcium chloride solution containing 0, 1, 2, 4, 8, 16, 25, 50, 100 and 150 micro g phosphorus mL-1 and the amount of phosphate sorbed was determined. Calcareous soils sorbed more phosphorus than non-calcareous soils. The sorption curves showed more or less similar pattern of changes. Langmuir model showed better fit to sorption data at higher P concentrations. Phosphate sorption was highly correlated with Fe oxide and clay content of the soils. Freundlich constant k_f and n, Phosphorus Sorption Maximum (S_max) and EPC₀ values were positively correlated with both the above soil properties. On the contrary, phosphate binding strength (b) was negatively correlated. It is suggested that Langmuir equation might be more suitable for commercial soil-testing laboratories for routine determination of phosphate sorption characteristics of soils.CAS Registry Numbers 7723-14-0 7440-70-2 10043-52-4 7439-89-6 14265-44-2