SPECIFIC SURFACE-AREA AND SURFACE-CHARGES OF SOME ARGENTINEAN SOILS

The specific surface areas of nine argentinian soils obtained by adsor ption followed the order N-2 < ethylene glycol < H2O, attributed to th e presence of smectites (verified by XRD analysis) and some organic co ating. The H2O2 treatment of these soils modified the former order of surface area determined by different absorbents. This order was modifi ed because the mineral surface was evidenced and an increase of cation adsorption was produced by organic matter removal. This fact was supp orted by the decrease of PZC values of soils after H2O2 treatment. The specific surface area of initial soils obtained by water and ethylene glycol adsorptions showed a good correlation with carbon content and CEC of untreated soils and with the PZC of protonated soils.