Synthesis and characterization of Au-NPs supported on carbon nanotubes: Application for the ultrasound assisted removal of radioactive UO22+ ions following complexation with Arsenazo III: Spectrophotometric detection, optimization, isotherm and kinetic study

The present study devoted to description of efficient removal of radioactive lie ions (U(IV)) via cornplexation 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 (5-25 mg), UO22+ concentration (5-25 mg L-1) and sonication time (1-5 min) onto response. The predicted results optimum conditions corresponding achievement of maximum UO22+ removal efficiency are pH 5.5, 20 mg of Au-NPs-CNTs, is highly applicability for removal of more-than 98% of 2-5 mg L-1 of UO22+ following 5 min sonication. Through analysis of corresponding results based on evaluation according to UO3. concentration were found significantly affect responds. ANOVA analysis revealed a high R-2 (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 133.3 mg g(-1) at 25 degrees C and pH 5.5. Dubinin-Radushkevich (D-R) isotherm model based on mean sorption energy (E) reveal high contribution of physisorption (1.17-3.78 kJ morl) 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. (C) 2017 Elsevier Inc. All rights reserved.