free expanded metal hatch pattern for autocad

The oxidation process seemed to create expanded and leafy structures of graphite oxide layers. Graphite oxide was prepared using potassium dichromate/sulfuric acid as oxidant and acetic anhydride as intercalating agent. The major aim in the proposed method is to reduce the number of layers in the graphite material and to produce large quantities of graphene bundles to be used as catalyst support in polymer electrolyte membrane fuel cells. Finally, pseudo-second-order model was used to describe the kinetics of methylene blue over expanded graphite and the silica-carbon composites.Īn improved, safer and mild method was proposed for the exfoliation of graphene like sheets from graphite to be used in fuel cells. Both Langmuir and Frendlich models were further used to evaluate the adsorption isotherms of methylene blue over expanded graphite and SEG samples with different silica contents.

This newly synthesized SEG composite shows greatly increased adsorption capacity to methylene blue than the pristine expanded graphite in the batch tests. Results show that mesoporous silica is steadily and uniformly grown on the surface of the graphite slices and the thickness of the silica layer can be finely tuned according to the silica/C molar ratio in the initial reaction solution. Textural property and morphology of the SEG composite were characterized by the combination of X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared measurements.

Considering its non-toxicity, easy operation, low cost, suitability for large-scale industrial production, and excellent microwave absorbing performance, EG/Fe3O4 is expected to be a promising candidate for industrialized electromagnetic absorbing materials.Ī novel mesoporous silica coated carbon composite (denoted SEG) with hierarchical pore structure has been successfully prepared in an aqueous solution that contains triblock copolymer template, aluminum chloride, siliceous source and expanded graphite. When applied as a microwave absorber, the reflection loss (RL) of EG/Fe3O4 reaches −40.39 dB with a thickness of 3.0 mm (10 wt% loading), and the effective absorption bandwidth (EAB < −10 dB) with RL exceeding −10 dB is 4.76–17.66 GHz with the absorber thickness of 1.5–4.0 mm. The Fe3O4 intercalated between the layers of expanded graphite forms a sandwich-like structure which is superparamagnetic and porous. The structure and properties of as-prepared EG/Fe3O4 were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), Raman, X-ray photoelectron spectrometry (XPS), thermogravimetric (TG), and vibrating sample magnetometry (VSM) characterizations. In this study, sulfur-free expanded graphite (EG) was obtained by using flake graphite as the raw material, and EG/Fe3O4 composites with excellent microwave absorption properties were prepared by a facile one-pot co-precipitation method. The findings indicate that the CEG would be potentially applicable in water purification. Equilibrium data were fitted well with the Langmuir model with a maximum adsorption capacity of 399.08 mg g  1. The kinetic studies exhibited that the MB adsorption onto the CEG followed a pseudo-second-order kinetic model. The potential application of the as-prepared CEG in environmental clean-up was evaluated by adsorptive removal of methylene blue (MB) from the aqueous solution. Under the optimal condition, the developed room-temperature liquid-phase intercalation and expansion processes led to an expansion volume of up to 250 times.

The other optimum preparation conditions were obtained at 1.5 g of KMnO 4 and 30 mL of H 2 O 2 30%. The sulfuric acid concentration was the most effective parameter on the expansion, and the maximum expansion occurred at a sulfuric acid concentration of 77.5%. The absence of the graphite diffraction peak at 26 o in the XRD pattern of expanded graphite (EG) indicates that the intercalation and expansion processes were complete, and most of the starting graphite layers were converted into the graphene sheets. The results showed that the CEG had an interconnected and highly porous structure, and some oxygen-containing groups were grafted on the graphite layer by the oxidation-intercalation process. A facile, effective, and eco-friendly process was developed for the preparation of chemically expanded graphite (CEG) under ambient conditions using natural flake graphite as raw material, potassium permanganate (KMnO 4) as an oxidative intercalating agent, and hydrogen peroxide (H 2 O 2) as the reactive species.

Free expanded metal hatch pattern for autocad