RESUMO
The present study devoted to description of efficient removal of radioactive UO22+ ions (U(IV)) via complexation with Arsenazo III (ARS III) accelerated by ultrasound-assisted adsorption onto the Au-NPs supported on carbon nanotubes (Au-NPs-CNTs), which were characterized by conventional techniques such as FESEM, EDS and XRD. Central composite design (CCD) employed to model contribution of parameters viz. pH (2.5-8.5), adsorbent mass (5-25mg), UO22+ concentration (5-25mgL-1) and sonication time (1-5min) onto response. The predicted results optimum conditions corresponding achievement of maximum UO22+ removal efficiency are pH 5.5, 20mg of Au-NPs-CNTs, is highly applicability for removal of more than 98% of 25mgL-1 of UO22+ following 5min sonication. Through analysis of corresponding results based on evaluation according to UO22+ concentration were found significantly affect responds. ANOVA analysis revealed a high R2 (0.9950) & AP (51.79) and low SD (0.6078) & CV% (0.6703) values of regression model equation which completely ensure accuracy of the quadratic model. Langmuir isotherm model was applicable for description of adsorption data with maximum monolayer adsorption capacity of 133.3mgg-1 at 25°C and pH 5.5. Dubinin-Radushkevich (D-R) isotherm model based on mean sorption energy (E) reveal high contribution of physisorption (1.17-3.78kJmol-1) on adsorption process. Moreover, Pseudo-second-order kinetic model delivered a better correlation for the experimental data in comparison to the pseudo-first-order kinetic model and intraparticle diffusion mechanism.
