Sorption of rhenium on alumina under dynamic conditions

The sorption of perrhenate anion on alumina from aqueous solutions of sodium chloride was investigated under dynamic conditions. The initial concentrations of rhenium were in the range of 2.7 x 10(-2)-2.7 mmol/dM(3). The breakthrough curves as the function of Re and NaCl concentrations (0. 12-0.20 mol/dm(3)), pH 2-6 and flow rate 3-10 ml/min were determined. According to the experimental results, it was concluded that the breakthrough capacities, the capacities at c/c(0) = 0.5, the total column capacities and the utilization degrees (column efficiency) increase with increasing Re and NaCl concentrations and decreasing pH. The optimal flow rate was found to be 3 ml/min. At pH 2 and c(0) = 2.7 mmol Re/dm(3), the total capacity was found to be Q(0.9) (max) = 2.1 x 10(-2) mmol Re/g Al2O3. The data for perrhenate anions fit with a Henry-type isotherm. It was found that, under the above mentioned conditions, the value of the Henry constant K-H was 7.8 x 10(-3) dm(3)/g and the Gibbs energy change, Delta G was -0.5 kJ/mol.