Influence of pH, concentration and ionic strength during batch and flow-through continuous stirred reactor experiments of Sr2+-adsorption onto montmorillonite

Abstract

Sorption/desorption experiments in batch and continous flow-through stirred reactor under different experimental conditions were carried out using montmorillonite (<2 μm clay fractions). The Sr2+ amount desorbed at pH 4 is only half of the amount desorbed at pH 8, revealing that the retention of Sr2+ onto montmorillonite was enhanced at pH 4. The largest adsorption value was obtained at pH 8.0 ([KNO3] = 10−3 mol/L) with q m = 41.49 mg Sr2+/g from the Langmuir isotherm. The gradient of concentration acted as an increasing driving force since the amount of Sr2+ adsorbed increased as increasing of Sr2+ concentration during the flow-through experiments.