Evaluation of single and simultaneous thorium and uranium sorption from water systems by an electrospun PVA/SA/PEO/HZSM5 nanofiber

The performance of poly vinyl alcohol/sodium alginate/poly(ethylene oxide)/HZSM5 (PVA/SA/PEO/HZSM5) nanofiber adsorbent synthesized by electrospinning method for sorption of Th(IV) and U(VI) ions from aqueous systems was investigated in a batch system. The predicted optimum sorption conditions were determined as HZSM5 content of 10 wt%, adsorbent dosage of 1 g/L and initial pH 5.5 by response surface methodology (RSM). The results of experimental confirmation test showed that the predicted model agreed reasonably well with the experimental data. The prepared nanofiber adsorbents were characterized by SEM, FTIR, TGA, BET and BJH analyses. Also, the effects of contact time, initial concentration and temperature were evaluated. The kinetic data of metal ions were well described by the double-exponential model. The maximum sorption capacity of Th(IV) and U(VI) ions were estimated to be 274.6 and 144.7 mg/g, respectively in the single system. Thermodynamic modeling indicated that the nature of both Th(IV) and U(VI) sorption was endothermic and spontaneous and was favored at higher temperature. In binary system, the sorption capacity decreased with increasing another metal ion concentration. The combined effect of metal ions onto the nanofiber was found to be antagonistic. The selectivity order of metal ions sorption onto the adsorbent was Th(IV) > U(VI).