Ethylenediamine grafted to graphene oxide@Fe3O4 for chromium(VI) decontamination: Performance, modelling, and fractional factorial design

Abstract

A method for grafting ethylenediamine to a magnetic graphene oxide composite (EDA-GO@Fe3O4) was developed for Cr(VI) decontamination. The physicochemical properties of EDA-GO@Fe3O4 were characterized using HRTEM, EDS, FT-IR, TG-DSC, and XPS. The effects of pH, sorbent dose, foreign anions, time, Cr(VI) concentration, and temperature on decontamination process were studied. The solution pH can largely affect the decontamination process. The pseudo-second-order model is suitable for being applied to fit the adsorption processes of Cr(VI) with GO@Fe3O4 and EDA-GO@Fe3O4. The intra-particle diffusion is not the rate-controlling step. Isotherm experimental data can be described using the Freundlich model. The effects of multiple factors on the Cr(VI) decontamination was investigated by a 25−1 fractional factorial design (FFD). The adsorption process can significantly be affected by the main effects of A (pH), B (Cr(VI) concentration), and E (Adsorbent dose). The combined factors of AB (pH × Cr(VI) concentration), AE (pH × Adsorbent dose), and BC (Cr(VI) concentration × Temperature) had larger effects than other factors on Cr(VI) removal. These results indicated that EDA-GO@Fe3O4 is a potential and suitable candidate for treatment of heavy metal wastewater.

Coupling of kenaf Biochar and Magnetic BiFeO3 onto Cross-Linked Chitosan for Enhancing Separation Performance and Cr(VI) Ions Removal Efficiency

“…Solution pH is a decisive factor for adsorption in many relevant studies [6,20,37]. Figure 4b demonstrates that rise in pH value causes a dramatic decrease in adsorption capacity, which is similar as the results of the latest literatures [38] Specifically, adsorption percentage is 96.06%…”

“…On the other hand, the electrostatic repulsion between both negatively charged CrO 4 2− and CKB weakens Cr(VI) removal. In addition, OH − may compete with CrO 4 2− for adsorption sites, further reducing the adsorption capacity [37].…”

“…The lines in cell AC show largest angle, indicating that solution pH (A) and initial concentration of Cr(VI) (C) could significantly affect each other. Overlapped lines in row D (NaCl) indicates the neglectable influence of NaCl on Cr(VI) removal [37]. Figure 6 shows three-dimensional (3D) surface response plot and two-dimensional (2D) contour curves for AC interactive effects on the adsorption of Cr(VI).…”

Reduced Graphene Oxide/TEMPO-Nanocellulose Nanohybrid-Based Electrochemical Biosensor for the Determination ofMycobacterium tuberculosis

“…While in Figure 2(c), FTIR spectra for NH 2 -rGO show a new medium peak at 875 cm -1 representing N-H wag (1°a mine) due to amidation reaction after GO treated with an amine. Moreover, double peaks also appeared at 2890 cm −1 and 3354 cm −1 , corresponding to the -CH 2 stretching vibration and N-H stretch of primary amine groups that originated from the ethylenediamine [38,44]. Furthermore, Figure 2(d) shows the FTIR spectra of NH 2 -rGO/TNCC with a small peak observed at 1690 cm -1 which is assigned to the C=O stretching vibration of -NHCO-(amide I) [45].…”

Optimization of Cadmium Adsorption by Magnetic Graphene Oxide Using a Fractional Factorial Design

“…FFD enables people to obtain the same information as a full-factorial experiment through a small number of experiments, thus improving research efficiency [ 40 , 41 ]. The 2 5−1 FFD with a resolution of V is conducted to analyze the combined influence of five factors (including pH value, temperature, time, initial concentration of cadmium ion, and NaCl concentration) on the adsorption of cadmium ions by MGO.…”