Preparation and characterization of Fe3O4/MWCNTs nanocomposite. Application for the removal of organic dyes from aqueous solution.
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Date
2022-01-17
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University of 20 août 1955 Skikda
Abstract
Water purification technology is growing every day along with the developing of new
nanomaterials in search of effective techniques to eliminate recalcitrant pollutants. This study
investigated the efficiency of synthesized magnetic nanocomposite Fe3O4/MWCNTs in
wastewater treatment against organic dyes contaminants. This nanomaterial was successfully
synthesized via coprecipitation method. The characterization of Fe3O4/MWCNTs with X-ray
diffraction (XRD); Fourier transform infrared spectroscopy (FTIR); Brunauer-Emmett-Teller
(BET) and scanning electron microscopy (SEM) were carried out, which confirmed the
presence of magnetite in the nanocomposite with good dispersion. The adsorption of
Bromocresol Purple (BCP) anionic dye from aqueous medium was investigated in order to
evaluate the adsorption capacity of the nanocomposite, which was around 296.52 mg.g-1.
Kinetic study indicates that the equilibrium time was estimated to 90 minutes and the pseudo
second order best suited this process. Isotherm modeling shows that the adsorption was fitted
well by the Langmuir model. Thermodynamic study revealed that the sorption mechanism
exhibits a spontaneous, exothermic and physisorption nature. The evaluation of the efficiency
of Fe3O4/MWCNTs as a catalyst was studied for the removal of Crystal Violet dye (CV).
According to the results obtained by rate constants and kinetic studies, the 3:1 weight ratio;
the H2O2 concentration of 0.14 mol.L-1 and temperature of 318 K were the optimum
conditions for the heterogeneous Fenton degradation of CV. Furthermore, the catalyst
exhibited high stability because it can be reused for five successive cycles without any loss in
its efficiency since the degradation rate remains almost complete. We also investigated the
efficiency of Fe3O4/MWCNTs as a catalyst to eliminate CV in aqueous solution under
polychromatic light (300-450 nm). The influence of certain systems on the degradation of CV
was verified and compared, by calculating the degradation rate and rate constant. The
degradation effect of the different systems is classified in the following order:
CV+Fe3O4/MWCNTs+H2O2 > CV+H2O2 > CV+Fe3O4/MWCNTs > CV > CV+Fe3O4+H2O2
The Fe3O4/MWCNT+H2O2 system showed a very high degradation rate (over 90%) compared
to the other systems. These results indicate the importance of Fe3O4/MWCNTs catalyst in
water treatment, and show the possibility of its use at large scale.