Synthesis, characterization and evaluation of carbon nanofiber modified-polymer for ultra-removal of thorium ions from aquatic media

Removal of thorium ions from aquatic media using high effective adsorbents is a very convenient viewpoint for the management of environmental pollutants. With this respect, this study is aimed to facile synthesize carbon nanofiber modified-(ethylene triamine- trimesoyl chloride) polymer (CNF-ETA-TMC) as a novel material for ultra-adsorption of thorium (Th(IV)) from aquatic media. The prepared CNF-ETA-TMC composite polymer adsorbent was characterized by FTIR and SEM/EDX techniques. The effective experimental parameters on the adsorption performance were optimized with factorial design analysis. The Langmuir modeling results showed that the CNF-ETA-TMC ultra-removal adsorption capacity of 867.9 mg g⁻¹ at optimized batch conditions; pH 5, 30 min contact time, and 20 °C. Thermodynamic evaluations exhibited that the ΔG° function was decreased from -18.96 to -14.84 kJ/mol as the ΔH° parameter was calculated as -47.88 kJ.mol⁻¹, confirming the spontaneous and exothermic nature of Th(IV) adsorption with increasing temperature from 303 to 333 K. The kinetic findings indicated that the adsorption mechanism was in an agreement with the pseudo-second-order model. Additionally, the regeneration performance of the adsorbent was increased in the range of 55-98% using HCl solvent at different concentrations, 0.25–1.0 mol.L⁻¹. The cycling results that the composite polymer adsorbent revealed about 80% regeneration performance after five replications while the adsorption/desorption efficiencies decreased to 20/25% after 10th cycle. This research suggested that the synthesized CNF-ETA-TMC could be evaluated as a beneficial adsorbent for the infiltration of thorium from aquatic media due to its ultra-removal capacity.