Adsorptive removal of cesium from aqueous solution using oxidized bamboo charcoal

In this study, the air oxidized bamboo charcoal (BC) was investigated for cesium (Cs) adsorption from aqueous solution. The physicochemical properties of the adsorbent were evaluated systematically using the different techniques including BET, FESEM, FTIR, XPS and also the pHpzc value. Batch adsorption experiments were conducted to determine the effect of contact time, solution pH, initial Cs concentrations, temperature and also the presence of competitive ions on adsorption. The adsorption kinetic parameters confirmed the better fitting of pseudo-second order kinetic model. The isotherm data could be well described by the Langmuir isotherm model and the maximum monolayer adsorption capacity was 55.25 mg g−1. The high specific surface area and the porous structure with some acidic functional groups on the surface were obviously responsible for high Cs adsorption onto oxidized-BC. Thermodynamic parameters such as standard enthalpy, entropy, and Gibbs free energy were evaluated and it had been found that the adsorption process was favorable, spontaneous and endothermic in nature. In the competitive ions study, the presence of Na and K with their concentrations up to 12 mM did not strongly affect the removal of Cs by oxidized-BC. Therefore, the experimental results suggested that the oxidized-BC could be used as an effective adsorbent for significant Cs removal from aqueous solution considering the high adsorption capacity, short adsorption time and selective removal of Cs ions.