Application of polyaniline nanocomposites in the trapping of thorium ions from aqueous solutions:Adsorption equilibrium, kinetics and thermodynamics

In this study, the adsorption behavior of Th(IV) ions was investigated using polyaniline (PAni) nanocomposites. Nanocomposites were synthesized with two types of dopants (H3PO4 and H2SO4) and two oxidants ((NH4)(2)S2O8 and KIO3) in the presence of two different surfactants (sodium dodecylbenzene sulfonate (SDBS) and hydroxypropyl cellulose (HPC)). The structure of the synthesized polymers was examined using FT-IR and SEM analyses. Adsorption of Th(IV) ions onto the synthesized polymers with a supreme removal (99.98%) was obtained by the H3PO4-doped polymers, especially for the sample with KIO3 oxidant and SDBS surfactant (PAni-2-1-S). BET, TGA and DSC analyses were also employed for the adsorbent characterization. The effect of main parameters was also investigated for the removal of Th(IV) ions from aqueous solutions by PAni-2-1-S. The pseudo-second-order kinetic and Langmuir isotherm models were in full agreement with the kinetic and isotherm experimental data, respectively and the highest adsorption capacity of the PAni-2-1-S was observed to be 68.49 mg/g. Thermodynamic data demonstrated the spontaneous and endothermic behavior of this adsorption process.