Sorption of the long-lived radionuclides cesium-134, strontium-85 and cobalt-60 on bentonite

Abstract

The sorption of long-lived radionuclides of cesium, strontium and cobalt (¹³⁴Cs, ⁸⁵Sr and ⁶⁰Co) on bentonite under various experimental conditions, such as contact time, pH, sorbent and sorbate concentrations have been studied. The uptake of Cs and Sr was rapid and equilibrium was reached almost instantaneously in both the cases, while Co sorption was time dependent. The sorption of these nuclides increased by increasing pH. The uptake of Cs, Sr and Co increased with increasing the amount of the bentonite clay. The percentage sorption for Cs, Sr and Co decreased with increasing metal concentrations. The desorption studies with 0.01M CaCl₂ and ground water at low-metal loadings on bentonite showed that about 95% of Cs, 85-90% of Sr and 97% of Co were irreversibly sorbed. These results could be helpful for nuclear waste management, for waste water effluents containing low concentrations of cesium, strontium and cobalt.