Room-temperature adsorption behavior of cesium onto calcium silicate insulation

A calcium silicate insulator material was investigated for its interaction with non-radioactive cesium at room temperature by batch-type adsorption experiments. An industrial-grade calcium silicate was weighted and ground into powder with an average size of 15.4 +/- 0.1 mu m, which was then placed into the polypropylene (PP) tubes containing cesium chloride aqueous solution. Cesium concentrations were range between 1.3 x 10(-6)-3.5 x10(-3) M. Adsorption kinetics of cesium was evaluated based on pseudo-first order and pseudo-second order models, while the adsorption isotherm was modeled using the Langmuir model and modified BET model. Physicochemical properties of calcium silicate before and after the adsorption was investigated using XRD, SEM/EDS, and FT-IR. Chemisorption was found as the underlying sorption process between calcium silicate insulator material and cesium.