Kinetics of Sulphate Desorption In Some Low Activity Clay Soils of Nigeria

The kinetics of SO₄ desorption in 20 low activity clay soils of Nigeria was investigated from samples incubated for 3 months. Desorption study was carried out under varying desorption times and water soil ratio, Results showed that SO4sorption and desorption reactions are not absolutely reversible. The kinetics of desorption conformed to the power function kinetic equation of the type S_d = S₀Kt^αW^β. Where K, α and β are constants for a given soil. In these soils, K, α and β values ranged from 0.006 to 0.065, 0.360 to 0.622 and 0.256 to 0.543, respectively. Although the kinetic constants were related to many of the soil properties, total free Fe₂O₃ was the most important predictor variable, contributing 88.4% to K, 70.6% to ex and 84.6% to β. It was concluded that the power function equation provides an excellent description of S04 desorption kinetics in low activity clay soils.