An effective technique for removal and recovery of uranium(vi) from aqueous solution using cellulose–camphor soot nanofibers

Abstract

Speciation and recovery of U(VI) ions from nuclear wastewater is a heavy challenge for various nuclear centers and research organizations. In this perspective, the present research work aims at using cost effective cellulose nanofibers for the reclamation of these incurable ions. Cellulose nanofibers were synthesized by electrospinning and functionalized with carbon nanoparticles (CNPs) obtained from the camphor soot with noticeable metal sorption capacity. Sorption capability was ascertained by conducting systematic batch experiments for the optimization of parameters such as CNP dosage, pH selectivity, and dosage of nanofibers. The results indicated fast uptake of U(VI) ions, which was significantly observed at pH 6 with an adsorption percentage of 97 from mimicked solution within a period of 120 minutes. 85% of U(VI) was removed from an aqueous solution with an adsorbent dosage of 50 mg. The maximum adsorption capacity was noted to be 410 mg g⁻¹ with 96% adsorption at varying concentration within a period of 60 min. Adsorptive uptake capacity of U(VI) ions was described with adsorption isotherms (Langmuir, Freundlich, Temkin and Dubinin–Radushkevich). Pseudo first order and Elovich model defined the sorption kinetics with good correlation regression values (R² = 0.99). The cellulose–camphor soot nanofibers were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared-spectroscopy (FT-IR), X-ray diffraction (XRD) and Raman spectroscopy. Further, thermodynamic parameters such as standard free energy (ΔG⁰), standard enthalpy (ΔH⁰) and standard entropy (ΔS⁰) revealed that the adsorption process was endothermic and spontaneous for the uptake of U(VI) ions. Reusability of the fibers was effectively performed with 0.1 M CH₃COOH and HCOOH with contact duration of 30 min.