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.