Novel Au-Fe3O4 NPs loaded on activated carbon as a green and high efficient adsorbent for removal of dyes from aqueous solutions: Application of ultrasound wave and optimization

Abstract

Present study is devoted on the development of the effective methodology for removal ultrasonic to simultaneous removal of Bismarck Brown (BB) and Thymol Blue (TB) onto Au-Fe3O4 nanoparticles loaded on activated carbon (Au-Fe3O4-NPs-AC) in aqueous solution. The Au-Fe3O4-NPs-AC were synthesized and characterization by different techniques such as XRD, FE-SEM and FT-IR. The process efficiency was confirmed through examination of variables like initial BB and TB concentration (X1, X2, respectively), pH (X3), adsorbent mass (X4) and sonication time (X5). The optimum operating parameters (OOP) were evaluated by Response Surface Methodology (RSM) based on central composite design (CCD) for prediction and simulation of removal of BB and TB dye, while analysis of variances (ANOVA) give the estimate of significance of experimental variables. The experimental equilibrium data were fitted to the conventional isotherm models and accordingly Langmuir isotherm has good applicability for the explanation of experimental data with maximum monolayer capacity (Qmax) of 80 and 76.38 mg g-1 in binary system for BB and TB, respectively. Kinetic evaluation of experimental data showed that the BB and TB adsorption processes followed well pseudo-second-order and intraparticle diffusion models. The results of this study will be useful for further development of magnetic nanostructures for environmental applications.