Study On The Sorption Of Europium (â…¢) Onto Peat And Ca-bentonite

Peat and bentonite are the meterials which disposaled the radioactive waste water.It isimportant to research the sorption behaviour of nuclides onto them. In this paper, thesorption behavior of Eu(Ⅲ) ions on peat and Ca-bentonite had been studied， as two kindsof different absorbent, the sorption behaviour of peat and bentonite have similarities anddifferences, the behaviour between the two absorbent are compared.The sorption behavior of Eu(Ⅲ) ions on peat and Ca-bentonite had been studiedadopting batch technique. In the batch technique, the influence of function of time,solid-to-liquid ratio (m/V), pH value, ionic strength and HA on the sorption were studied,and the sorption isotherm at different temperature was determined.The result of batch technique indicated that the sorption equilibrium time of Eu(Ⅲ)ions on peat and Ca-bentonite was shorter and only about four hours to reach theequilibrium state, which showed that the affinity of Eu(Ⅲ) ions on this two adsorbent wasstronger. The solid-to-liquid ratio (m/V) was confirmed at0.5g/L. The influence of pHvalue on the absorption of Eu(Ⅲ) ions was stronger, in the low pH vaule, with theincreasing of pH, the absorptive capacity was increase, when the pH at about4, thesorption attain equilibrium. In the process of sorption of peat, when pH greater than8, withthe increasing of pH, the absorptive capacity was decrease. The influence of ionic strengthin the sortion process is different, compare to peat, the influence is greater in bentonite. Inthe low pH value the HA will promote the sorption, and in high pH value, HA will restrainthe sorption. The influence of HA on peat is low.The property of peat and bentonite specimen had been illustrated by using ScanningElectron Microscope, X-ray Diffraction, Element Analysis, Infrared Spectroscopy, SpecificSurface Area, Electron Probe Micro-Analyzer, separately separately. The adsorptionisotherm was studied, the result show that the sorption process can be modled byFreundlich modle, and the pseudo-second-order model can describe the sorption kinetics.The thermodynamic parameter was calculated.