Thermal activation, characterization and performance evaluation of Ethiopian bentonite for sodium removal.

Bentonite is one of the clay materials that have important characteristics and is applicable to construction and for different industrial uses. Treatment of this material to enhance some of its physicochemical properties to suit the desired applicability has been a focus research area. In this work, natural bentonite from Warseisso, Afar region, Ethiopia was activated with thermal treatment. The raw and treated bentonites were then characterized using SEM, FTIR, XRD, BET, and cation exchange capacity. The effects of activation parameters (time and temperature) on its physiochemical properties and its performance for the removal of sodium ions from water were investigated. Bentonite activated for 6 h at 300 °C showed a maximum specific surface area of 81.74 m/g while the raw one showed 57.6 m/g. However, the cation exchange capacity value of the raw bentonite was found to be 82.1 meq/100 g while the value was reduced to 67.2 meq/100 g for treated bentonite with high specific surface area. To check the performance of the activated bentonite for desalination application, batch adsorption of sodium from synthetically produced sodium chloride solution was made. A sodium removal performance of 10% was achieved with treated bentonite at the maximum specific surface area.