Zirconium preconcentration from zircon raffinate using gamma radiation–induced polymerization of reduced graphene oxide composite

Abstract

Zirconium is commonly used as a cladding material for nuclear reactors. The purity of the zirconium material seeks to control reactor efficiency. A novel composite of reduced graphene oxide–grafted polyacrylic acid, malic acid, and trioctylamine (rGO-g-PAA-MA/TOA) was prepared using in situ radical polymerization with gamma radiation at a dose of 25 KGy from a 60Co cell to preconcentrate zirconium Zr(IV) from zircon raffinate. Five distinct rGO-g-PAA-MA/TOA composite compositions were created and evaluated. The best composite composition was 62.95% acrylic acid, 15.8% malic acid, and 15.8% trioctylamine. After 60 min, the sorption reaction reached equilibrium at pH 0.35 and 20 °C. The pseudo nth order indicated that the order of the sorption reaction was 1.8476. The Elovich model and Dubinin-Radushkevich model controlled the kinetic mechanism and adsorption isotherm of the sorption reaction, respectively; based on estimated regression plots and quantitatively with three different error functions: coefficient of determination (R2), chi-square statistic (χ2), and corrected Akaike information (AICc). The adsorption capacity of rGO-g-PAA-MA/TOA was 75.06 mg g−1. Exothermic reaction and spontaneous sorption took place. Using 2 M H2SO4, 98% of the zirconium was efficiently desorbed. The separation of contaminated Ti(IV) from desorbed Zr(IV) by raising pH to 2.5 through hydrolysis and ZrO2 formation.