Integrated adsorption and electrochemical sensing of Th(IV) ions using graphene oxide and chitosan decorated magnetite-based adsorbent

Nuclear waste management is a crucial aspect as the most significant threat to the ecosystem is caused by radioactive waste in which thorium contamination remains a prominent issue. This work represents an integrated approach for the elimination of thorium through the adsorption technique and subsequent electrochemical sensing using Magnetite@Graphene Oxide@Chitosan (M@GO@Cs). Moreover, the sorption of Th(IV) ions is optimized through batch studies, which are consistent with the results derived from ANOVA using the Box-Behnken Design model, and the ideal parameters resulted in 95.79% removal efficiency of Th(IV) ions using 6 mg of adsorbent in 10 mL of 50 mg/L Th(IV) ions solution at a pH of 5 within 20 min. Maximum adsorption capacity (833.33 mg/g) is obtained from Langmuir adsorption isotherm and process was aligned with the pseudo-second-order kinetic model. M@GO@Cs exhibited high recyclability sustaining high performance across nine consecutive adsorption-desorption cycles while maintaining excellent removal efficiency upto 85%. Furthermore, the electrochemical characterization of the synthesized M@GO@Cs nanoadsorbent was studied using the Cyclic Voltammetry, and Electron Impedance Spectroscopy techniques and quantification of Th(IV) ions was done utilizing the Differential Pulse Voltammetry method with the Limit of Detection (LOD) of 0.2 mg/L within a linear range of 10-100 mg/L.