Influence of Ionic Strength, pH and Cation Exchange Capacity for Different Types Clay Minerals from Libya; Regions Gharyan, Murzuq and Taourgha

Samples of clay were collected from three regions in Libya; Gharyan, Murzuq and Taourgha. Each sample has been taken regard to the place and depth. Because the natural clay is found in deep layers from the soil surface about 20 m. CaCO3 and CaSO4 are precipitated at shallower depths. Results recorded have shown high percent of calcite CaCO3 and Illite in Taourgha clay. Whilst Kaolinite is found in Gharyan clay, however, Bentonite (Na-Montmorillonite), Nontronite, Cr-Volkonskoite wre found in Murzuq. Murzuq white clay sample contained the Na-bentonite. Investigations of conductivity, pH and total dissolved of solids (T.D.S) were cried out on the collected clay samples. In particular the effect of the ionic strength, chemical composition, as well as cation exchange capacity (CEC) were elaborated. pH values for all samples tend to the alkaline media. CEC values were leached by 500 ppm Ca+2 at pH = 8 for samples of Gharyan-Quasim (GQ), Gharyan-Abughalan (GA), Murzuq-Green (MG), Murzuq-White (MW),Taourgha-Mardom (TM) and Taourgha-Temeana (TT) were 6.25, 84.5, 79, 24, 27 mmoles/kg respectively. Otherwise, at pH = 2, values were in constant range for all samples 20.5 mmoles/kg. Leaching process was measured by 500 ppm K+ using flame emission photometer. The CEC values at pH = 8 for samples Gharyan, Murzuq, and Taourgha were 5.89, 91.50, 19.73 mmoles/kg, respectively. Conductivity values of weight ratios at 1:1, 1:3, and 1:5 of the extracted solutions of Murzuq samples were 0.324, 0.302, 0.198 dSm-1, respectively.