Surface Modification of Activated Carbon Fibers with Fe3O4 for Enhancing Their Electromagnetic Wave Absorption Property

In this study, the porous activated carbon fiber (ACF) is prepared by viscose fiber, and Fe3O4 coating is deposited on the surface of ACF through in situ hybridization to prepare carbon/magnetic electromagnetic (EM) wave absorption materials. Compared with pure Fe3O4 and ACF, the EM wave absorption rate is improved. When the solubility of FeCl3 is 2 mol/L and the thickness of the prepared ACF–Fe3O4(3) EM wave absorption material is 3 mm, the EM wave loss at 10 GHz reaches −44.3 dB and effective EM wave absorption bandwidths ( reflection loss RL < − 10 dB and RL < − 20 dB) reached 4.8 GHz (8.8–13.6 GHz) and 1.1 GHz (9.3–10.4 GHz), respectively. The prepared ACF-based composite material has a light structure and strong absorption bandwidth. Findings can provide references for the research on other EM wave-absorbing materials.

Removal of Sulfadiazine Using 3D Interconnected Petal-Like Magnetic Reduced Graphene Oxide (MrGO) Nanocomposites

Adsorption has been regarded as one of the most efficient and economic methods for the removal of antibiotics from aqueous solutions. In this work, different graphene-based magnetic nanocomposites using a modified solvothermal method were synthesized and employed to remove sulfadiazine (SDZ) from water. The adsorption capacity of the optimal magnetic reduced graphene oxide (MrGO) was approximately 3.24 times that of pure Fe3O4. After five repeated adsorption cycles, the removal rate of SDZ (100 μg/L) by MrGO nanocomposites was still around 89.3%, which was only about a 3% decrease compared to that in the first cycle. Mechanism investigations showed that both chemical and physical adsorption contributed to the removal of SDZ. The excellent adsorption performance and recyclability of MrGO nanocomposites could be attributed to their wonderful 3D interconnected petal-like structures. The MrGO with SDZ could be easily recollected by magnetic separation. The MrGO also exhibited excellent adsorption performance in the purification of real polluted water.

APTES AND TEOS MODIFIED BINARY RECYCLABLE HYBRID FE3O4@GO NANOCOMPOSITE FOR PHOTOCATALYTIC DYE REMOVAL

Methylene blue (MB) is one of the industrial used organic dye and recalcitrant pollutant which creates a serious water pollution. Among the available techniques, photo degradation using light irradiation is one of the desirable choice to treat waste water. In this regard, we synthesized a binary nanocomposite of magnetite decorated with graphene oxide sheet (Fe3O4@GO) with modification of tetraethyl orthosilicate (TEOS) and 3-Aminopropyl triethoxysilane (APTES) by mechanical stirring method. The prepared nanocomposite was tested as a potential heterogeneous catalyst for degradation of methylene blue (MB) under UV irradiation. The synthesized nanoparticles were characterized by using X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Fourier transform infrared (FTIR), Thermogravimetric Analysis (TGA), and Energy-dispersive X-ray spectroscopy (EDX) techniques. The characterizations confirm the successful synthesis of the nanocomposite. The photocatalytic activity of the catalysts was gradually enhanced with time intervals. The maximum MB removal efficiency of 70.06 % was achieved over Fe3O4@GO composite catalyst, remarkably higher than using pure Fe3O4 (57.56 %). The newly developed materials was successfully recovered using an external magnet.

Facile Synthesis of Conducting Polypyrrole/Non-Aggregated Magnetite Nanocomposites and their Magnetorheological Characteristics

Large density of the dispersed phase in magnetorheological (MR) fluids has hindered operating MR test and their industrial application. This present work adopted Fe3O4 nanoparticles to prepare MR fluid because of their moderate density and good magnetic property. Furthermore, in order to resolve aggregation problem of Fe3O4 particles due to their nano-scaled size, conducting polypyrrole (PPY) was synthesized around naono-sized Fe3O4 particles via conventional oxidation polymerization. Weight ratio of PPY to Fe3O4 was adjusted to be 5% to avoid possible deterioration of the magnetic property of Fe3O4 particles. TEM images described the morphology for PPY-Fe3O4, and XRD pattern provided information on structural characterization and particle size. Finally, MR performances of pure Fe3O4 and PPY-Fe3O4 nanocomposites were investigated via rotational and oscillatory tests.