Adsorption of Cr(vi) onto a magnetic CoFe₂O₄/MgAl-LDH composite and mechanism study

Abstract

Magnetic materials as adsorbent can provide effective remove and quickly separate of pollutant in wastewater treatment. A magnetic CoFe 2 O 4 /MgAl-LDH composite was successfully synthesized through low saturation coprecipitation method. The adsorption behaviors of Cr(VI) from aqueous solution by CoFe 2 O 4 /MgAl-LDH were investigated. The adsorbents were characterized using scanning electron microscope (SEM), N 2 adsorption/desorption isotherms, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Kinetic and equilibrium studies indicated that the experimental data of Cr(VI) adsorption were best described by pseudo-second-order kinetic and Langmuir models. The maximum adsorption capacity of CoFe 2 O 4 /MgAl-LDH for Cr(VI) was found to be 72.4 mg/g at an equilibrium time of 300 min and temperature of 283 K. Evaluation of the thermodynamics parameters ( ∆ H < 0, ∆ S < 0 and ∆ G < 0) revealed the adsorption process was exothermic and spontaneous. The mechanisms study showed that the adsorption of Cr(VI) onto CoFe 2 O 4 /MgAl-LDH likely involved adsorption/surface complexation and ion exchange interaction. This study demonstrated that the magnetic CoFe 2 O 4 /MgAl-LDH composite was an effective adsorbent for Cr(VI) removal with quick separation.

Effective and selective aerobic oxidation of primary and secondary alcohols using CoFe2O4@HT@Imine‐CuII and TEMPO in the air atmosphere

“…22-1086). [50] We can deduce that the crystal structure of CoFe 2 O 4 is retained after modification of the surface via AEPH 2 and Cu II that was also confirmed by unchanged CoFe 2 O 4 NPs' peak positions.…”

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“…In the O 1 s spectra of C@Ni-Al LDH HSS (Fig. S2b), the peaks with binding energies of 530.8, 531.7 and 533.3 eV correspond to M-O, -OH and H 2 O, respectively 45,46 .…”

Multifunctional hierarchical cabbage-like nZVI-Fe 3 O 4 /C composites for efficient chromium (VI) removal

“…However, in contrast to the traditional adsorbents, magnetic carbonaceous adsorbents have received great attention due to their superior magnetic separation performance, by which can allow rapid separation of target molecules from the samples simply by applying an external magnetic field [16] . For instances, Deng et al [17] successfully synthesized a magnetic CoFe 2 O 4 /MgAl-LDH composite through a low saturation co-precipitation method for removing Cr(VI) from aqueous solution and the adsorbent exhibited a maximum adsorption capacity of 72.4 mg g −1 . Xu and coworkers [18][19][20][21] successfully prepared nanoscale zero-valent iron (nZVI)-Fe 3 O 4 nanocomposites, Fe 3 O 4 -stabilized Fe 0 nanoparticles and nZVI@MG nanocomposites for removing Cr(VI) from aqueous solution.…”