Effective Adsorption of Methylene Blue dye onto Magnetic Nanocomposites. Modeling and Reuse Studies

Abstract

In the present study, new adsorbent beads of alginate (A)/maghemite nanoparticles (γ-Fe2O3)/functionalized multiwalled carbon nanotubes (f-CNT) were prepared and characterized by several techniques, e.g., N2 adsorption-desorption isotherms, Fourier transformed infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM) and further tested for the adsorption of the dye methylene blue (MB) from water. The beads (A/γ-Fe2O3/f-CNT) presented a relatively low BET specific surface area value of 59 m2g−1. The magnetization saturation values of A/γ-Fe2O3/f-CNT beads determined at 295 K was equal to 27.16 emu g−1, indicating a magnetic character. The time needed to attain the equilibrium of MB adsorption onto the beads was estimated within 48 h. Thus, several kinetic and isotherm equation models were used to fit the kinetic and equilibrium experimental results. The number of adsorbed MB molecules per active site, the anchorage number, the receptor sites density, the adsorbed quantity at saturation, the concentration at half saturation and the molar adsorption energy were quantified using the monolayer model. The calculated negative ΔG0 and positive ΔH0 values suggested the spontaneous and endothermic nature of the adsorption process. In addition, A/γ-Fe2O3/f-CNT composites can be used at least for six times maintaining their significant adsorptive performance and could be easily separated by using a magnet from water after treatment.

Fabrication of UiO-66/MIL-101(Fe) binary MOF/carboxylated-GO composite for adsorptive removal of methylene blue dye from aqueous solutions

“…2E) demonstrated that the variation of peaks intensity and appearance of new peaks which strongly suggested that the removal mechanism of MB dye onto UiO-66/ MIL-101(Fe)-GOCOOH composite involves electrostatic interactions between the MB dye and adsorbent functional groups which is a good agreement with pH results. 63 Moreover, Zr-O and Fe-O centers represent good possibilities for n-p conjugation. This conjugation is conrmed by variation in intensity and the shi of the peaks in the range 440-530 cm À1 .…”

Synthesis, Characterization, and Analysis of Hybrid Carbon Nanotubes by Chemical Vapor Deposition: Application for Aluminum Removal

“…The hybrid CNTs’ adsorbent reaction behavior could be examined through kinetic behavior. For this experimental data, three kinetic models were used, including pseudo-first-order, pseudo-second-order, and the intraparticle diffusion model [ 57 , 58 ]. To conduct the kinetic study, the Al 3+ that was included varied in concentrations from 3, 5, and 10 mg/L, while the absorption dosage value was fixed at a 13.5 mg and pH of 7 at various time intervals awaiting for the equilibrium state to be attained.…”

Eggshell-supported Catalysts for the Advanced Oxidation Treatment of Humic Acid Polluted Wastewaters

“…Besides, in the case of the iron supported catalysts, peaks at 18.1 (111), 33.9 (310), 35.6 (311), 43.1 (400), 48.5(420), 62.6 (440), and 64.5 (530), which were attributed to maghemite (-Fe2O3), were identified [35]. It should be noted that these peaks are overlapped with the ones of Ca(OH)2 or CaCO3.…”