Application of response surface methodology for thorium(IV) removal using Amberlite IR-120 and IRA-400: Ion exchange equilibrium and kinetics

In this work, thorium (IV) removal from aqueous solutions was investigated in batch systems of cationic and anionic resins of Amberlite IR-120 and IRA-400. In this way, the effects of pH, initial Th(IV) concentration and the amount of adsorbent were investigated. A Central Composite Design (CCD) under Response Surface Methodology (RSM) was employed to determine the optimized condition. The results showed that the maximum removal efficiency of Th(IV) onto IR-120 and IRA-400 either discretely or in combination, albeit with equal mass fraction, was determined as follows: 98.09% , 65.70% and 72.19% at pH=3.23, 6 and 4.07, initial Th(IV) concentration of 78.2, 30 and 55.4 mg.L-1 and 2.08, 2.5 and 2.2 g.L-1 of resin, respectively. The kinetic and equilibrium data were accurately described by the pseudo-second order and Langmuir models. The results showed that IR-120 is a suitable adsorbent for thorium removal from aqueous solutions.
Highlights
•A novel PVA/TiO2/ZnO/TMPTMS nanofiber adsorbent was fabricated by the electrospinning method.
•The effects of pH, initial Th(IV) concentration and the amount of adsorbent were investigated.
•The properties of the prepared novel adsorbent were determined by SEM, FTIR and BET analyses.
•The adsorption capacity of Th(IV) in a single system was reported.
•The mechanism of Th(IV) adsorption was recognized.