Determination of Cation Exchange Capacity of Clayey Soils by the Methylene Blue Test

The methylene blue adsorption test (MBAT) for determining the cation exchange capacity (CEC) of clays is described. An attempt has been made to respond to previously expressed uncertainties in the MBAT itself and then to apply this test to determine the CEC values of the three geologically different soil types encountered in Ankara (alluvial soils, terrace deposits, and residual soils). Experiments with Na-montmorillonite, Ca-montmorillonite, illite, and kaolinite clays revealed that the MBAT method for determining the CEC of clays was simple and rapid and that the results were reasonable.