Effective adsorption of metal ions by modified clinoptilolite zeolite from simulated radioactive solution

A natural clinoptilolite zeolite was modified through high temperature and chemical process to use for adsorption Mn²⁺, Ni²⁺, Co²⁺ and Cs⁺ from simulated radioactive solution. A series of analyses techniques including SEM, XRD and FTIR were applied to characterize the modification samples. The adsorption and kinetics were finely described by Langmuir isotherms and the pseudo second-order model. The adsorption rate constants denoted the adsorption rate had the following priority: Cs⁺ > Mn²⁺ > Ni²⁺ > Co²⁺. The thermodynamic parameters denoted that the adsorption of Mn²⁺, Ni²⁺, and Co²⁺ onto the modification sample were endothermic processes, and that of Cs⁺ was an exothermic process. (author)