Investigation of thorium(IV) removal utilizing reduced graphene oxide-zinc oxide nanofibers via response surface methodology

Abstract This study examines the removal of Th(IV) ions from aqueous solutions using reduced graphene oxide-zinc oxide (rGO-ZnO) nanofibers synthesized via electrospinning. The nanofibers were characterized using XRD, SEM, FTIR, XPS, and zeta potential measurements. Response surface methodology optimized adsorption parameters, including pH, temperature, Th(IV) concentration, and adsorbent dosage. The Freundlich isotherm indicated heterogeneous adsorption, and thermodynamic analysis revealed an endothermic process with enhanced efficiency at higher temperatures. The maximum adsorption capacity was 99.73 mg/g, demonstrating the high performance of rGO-ZnO nanofibers. Competitive adsorption studies demonstrated high selectivity for Th(IV), demonstrating the potential of rGO-ZnO nanofibers for radioactive wastewater treatment.