author：Broujeni, B. R., and A. Nilchi
journal：Desalination And Water Treatment
In this study, novel polyacrylonitrile (PAN) nanofiber adsorbent modified with 6-amino-1-hexanethiol hydrochloride (Ahh) was synthesized by electrospinning method and evaluated as an adsorbent for removing thorium (IV) (Th4+) ion from aqueous solution. The PAN/Ahh was characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). Response surface methodology (RSM) was utilized in the optimization of Th4+ adsorption in terms of (i.e., initial Ahh concentration, pH, the initial metal ion concentration, and contact time). To ensure the validity of the model, the statistical measures were investigated, thus to specify that the developed model is proper. In addition, the adsorption kinetics was well defined by the pseudo-second-order equation, while the Langmuir model better fit the adsorption isotherms. The adsorption capacity of PAN/Ahh was 499 mg Th4+ g(-1) composite, leads to 98.5% removal at 25 degrees C. Moreover, thermodynamic parameters were determined which point out the natural and endothermic nature of the reactions. The loaded Th4+ can be easily regenerated with HNO3/HCl and the PAN/Ahh could be used repeatedly without any significant reduction in its adsorption capacity. The desorption level of Th4+ from the PAN/Ahh was more than 94%.