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The feasibility of using magnetic nano-zeolite (MNZ) to remove cesium and strontium from their binary corrosive solutions was investigated by considering the multi-variant/multi-objective nature of the process. RSM (Response Surface Methodology) and ANN (Artificial Neural Network) were used to model and optimize the removal system and assess sensitive parameters that can affect the process reliability. MNZ is characterized by its high surface area and cation exchange capacity and possesses good regeneration behavior for both elements using citric acid. Its stability is comparable to other sorbents in acidic media and the stability increases in alkaline media, where dissolution rate follow first order reaction on heterogeneous sites. MNZ removes both contaminants simultaneously with small tendency toward Cs, where MNZ is suggested for application in pre-treatment of highly contaminated alkaline solutions. The percentage removal, decontamination factors, and separation factors have different dependency on the effluent/process conditions; this dependency is the same for both contaminants. Sorption kinetics is initially controlled by external mass transfer through the boundaries then intra-particle diffusion dominates the reactions. The process sensitivity to pH changes is attributed to changes in structural elements -species distribution at the solid/aqueous interface. Cs+ and Sr+2 are exchanged with Na+ and H+, regardless the effluent pH value, and with Al and Fe cations at specific pH. Isosteric heat of sorption calculations indicated that the total heat needed to complete the reaction was considerably reduced by operating the process at optimized temperature. • Cs and Sr are removed simultaneously with a small tendency toward Cs. • MNZ is recommended for pre-treatment of highly contaminated alkaline solutions. • ANN stability is important in deciding on system reliability and process sensitivity. • Altered structural element spices at solid/liquid interface cause process sensitivity. [ABSTRACT FROM AUTHOR]

The present study aims at examining the feasibility of using synthesized magnetic nano zeolite for the sorptive removal of cesium and strontium ions existing in the liquid radwaste stream. Cs + /Na + and Sr 2+ /Na + binary ion exchange experiments were performed in the batch mode at different three temperatures (298,303 and 313 K), optimized proton concentration (pH), equilibrium time and constant total normality. The thermodynamic analysis of both binary systems was performed using four types of model equations: Langmuir; Freundlich; Radlish-Peterson and thermodynamic equilibrium models. The extended Debye–Huckel relation and the Wilson equation were used to estimate the solution and the solid phase activity coefficients, respectively. The results obtained during this study demonstrated the correlation of the four examined models with the experimental equilibrium data, which proved to be satisfactory. On the other hand, the thermodynamic non-idealities was found to give the best results. Thermodynamic parameters such as enthalpy change, Gibbs free energy change and entropy change were also calculated. The obtained affirmative results demonstrated that the synthesized magnetic nano zeolite can be used as an efficient sorbent for the removal of Cs + and Sr 2+ ions from the contaminated solutions. [ABSTRACT FROM AUTHOR]