Removal of thorium(IV) ions from aqueous solution by polyacrylamide-based monoliths: equilibrium, kinetic and thermodynamic studies

In this study, a series of macroporous polyacrylamide-based monoliths bearing negatively charged interaction sites were synthesized as adsorbents for effective removal of Th4+ from aqueous solutions. The effects of solution pH, contact time, monolith dosage, initial concentration, and temperature on adsorption process was studied. The Langmuir, Freundlich, and Dubinin–Raduskevich adsorption isotherms were applied to describe the adsorption data. The equilibrium data were best fitted with both Freundlich and Langmuir models. The experimental kinetic data were well described by the pseudo-second order kinetic. Thermodynamic studies revealed that the adsorption of Th4+ onto the synthesized monolith was an endothermic and spontaneous process.