FeNi LDH/Loofah Sponge-Derived Magnetic FeNi Alloy Nanosheet Array/Porous Carbon Hybrids with Efficient Electromagnetic Wave Absorption

Confining Magnetic Response by the Surface Reorganization of Buckling Permalloy Microspheres for Boosting Microwave Absorption

Sharp corners and edges with high surface curvature provide low-dimensional nanosized materials with special static magnetic properties. However, the surface engineering of their high-frequency magnetic response remains challenging, and the underlying mechanism requires further clarification. In this study, we propose a template-aided surface reorganization strategy for integrating surfaces with different curvatures into one permalloy architecture. The high-curvature surface demonstrates a dramatic variation in localized magnetic moments and confines the coupling of magnetic flux lines owing to high anisotropy, which helps concentrate magnetic energy absorption and dissipation. In addition, the magnetic resonances of multiple surfaces were superimposed by the spin-wave interaction for enhancing magnetic loss capacity, which cooperates with amorphous/crystalline interfacial polarization to achieve a satisfactory dielectric-magnetic synergistic electromagnetic wave (EMW) absorption performance. The reflectance loss values increased from -13.4 dB for microspheres to -49.7 dB for surface-restructured ones. Remarkably, the effective absorption bandwidth can be extended to 7.68 GHz with a matching thickness of 2.0 mm. This advancement presents new possibilities for an elaborate design of magnetic EMW absorbers and establishes a basis for comprehending a complex magnetic response mechanism.

Fabrication of the Fe-Doped Corona Schiff Base for Enhanced Microwave Absorption Performance

A corolla-shaped Schiff base polymer was synthesized from terephthalaldehyde (TPAD), glutaraldehyde (GA), and p-phenylenediamine (PPD) by block copolymerization, and Schiff base iron complexes were formed by doping with FeCl3. The microscopic morphology, crystal structure, and elemental valence state were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Comparing the change of conductivity before and after Fe3+ doping, it was found that the conductivity did not break away from the category of insulator, and the doped sample is a paramagnetic material. Morphological changes were observed by adjusting the ratio of GA to TPAD, and it was found that the corolla-like structure was most complete when the ratio of GA to TPAD was 2:1, and its Schiff base iron complex absorbed waves better. At a thickness of 3 mm, the absorption effect can reach below -10 dB at 12.44-15.16 GHz, and the maximum absorption value is -45.07 dB at a thickness of 3.8 mm; it is an organic absorbing agent with excellent impedance matching and absorbing properties.

Preparation of novel Zn-Al layered double hydroxide composite as adsorbent for removal of organophosphorus insecticides from water

In this work, a new and efficient composite LDH with high adsorption power using layered double hydroxide (LDH), 2,4-toluene diisocyanate (TDI), and tris (hydroxymethyl) aminomethane (THAM) was designed and prepared, which was used as an adsorbent to adsorb diazinon from contaminated water. The chemical composition and morphology of the adsorbent were evaluated using Fourier transform infrared (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), Energy dispersive X-ray (EDX) and Field emission scanning electron microscopy (FESEM) techniques. Also, the optimal conditions for adsorption of diazinon from water were determined by LDH@TDI@THAM composite. Various parameters like the effect of adsorbent dosage, pH, concentration and contact time of diazinon were studied to determine the optimal adsorption conditions. Then, different isotherm models and kinetic adsorption were used to describe the equilibrium data and kinetic. Also, the maximum adsorption capacity is obtained when the pH of the solution is 7. The maximum adsorption capacity for LDH@TDI@THAM composite was 1000 mg/g at 65 °C and the negative values of ΔG indicate that the adsorption process is spontaneous. After that, studying the reusability of LDH@TDI@THAM composite showed that the removal of diazinon by LDH@TDI@THAM was possible for up to four periods without a significant decrease in performance.