Use of zeolite in reducing environmental risk of polonium: kinetic models

Abstract A study was conducted to understand the mechanism of adsorption kinetic that is effective in removal of 209 Po by clinoptilolite, a natural zeolite, from aquatic environments. Studies of the adsorption kinetics of 209 Po were carried out by interacting zeolite with 209 Po at different time intervals. Experimental polonium adsorption data obtained in our previous article were applied to some known kinetic models such as pseudo-first order, pseudo-second order, Elowich, Bangham, Homogeneous particle diffusion and Shell step models. The data obtained from the models revealed that the rate-limiting step is more compatible with the pseudo-second order model, which is based on the assumption that chemical sorption. According to the results obtained, the calculated the amount of 209 Po adsorbed at equilibrium (q e ) and the equilibrium rate constant of pseudo-second-order sorption (k 2 ) were found to be 0.3302 ng g −1 , − 4.4 × 10 –5 ng g −1 min −1 , respectively.