Sorption behavior of cesium on Ain Oussera soil under different physicochemical conditions

In the present study, the sorption behavior of cesium was investigated in Ain Oussera soil around the Es-Salam reactor facility. This study was conducted using batch method under different physicochemical conditions including contact time, ionic strength, pH, solid/liquid ratio and temperature. The results showed that sorption followed pseudo-second-order kinetics with a good regression coefficients (R(2)=0.999). The activation energies were 11.26 and 15.21 kJ mol(-1) which correspond to ion-exchange-type sorption mechanism. The adsorption was favored at low temperature and it was exothermic (ΔH(0)<0, with average value of -1.97 kJ mol(-1)) and spontaneous (ΔG(0)<0, with average value of -11.97 kJ mol(-1) at 23°C and -13.2 kJ mol(-1) at 60°C). The presence of competing cations such as K(+) and Ca(2+) ions in groundwater can significantly reduce the Cs adsorption onto soil. Desorption reaction was also investigated using three reagents with different ionic strengths (deionized water, groundwater and 0.1M KCl solution). The results showed that Cs ions were preferentially distributed onto high affinity sorption sites.