Preparation And Properties Of Alumina/Carbon Composite Materials

Al₂O₃/C composite material is a very important inorganic materials with high hardness and strength, while the presence of acidic and basic centers, porosity, large surface area and other properties. Compared to other nanomaterials, Al₂O₃/C composite material have excellent advantages, such as a wide source and its raw materials are more cheaper, environmentally friendly. It is widely used for catalytic fields, water treatment, ceramics, reinforced biomedical composites, semiconductor materials, paint and other fields. There are some common preparation methods of Al₂O₃/C composite material, such as vapor deposition method, dipping method, stirring method, and so on. For different application areas, we need to develop different targeted synthetic methods. So how to obtain Al₂O₃/C composites by environmental protection, green chemistry, high efficient use of resources become a focus of study. At the same time, it is an important question to enlarge application field. Thus, in this paper, we develop different methods to prepare Al₂O₃/C nanomaterials with controlling the morphology, size, composition, surface area and hierarchical structure. What’s more, the adsorption properties of the as-prepared Al₂O₃/C products were also investigated, and the heavy metal ions and Congo red（CR） are used as target pollutants.Firstly, based on the "waste to treat waste" and "waste to resources" ideas, alkaline wastewater of oil refining（Dushanzi petrochemical company） are disposed by a simple process. Under certain conditions, neutralization reaction happens when the waste acid（Zhonghe aluminum business limited company） is mixed with waste alkali alkaline wastewater in accordance with a certain proportion. Nearly neutral solution was concentrated and dried, and finally it is calcined under certain conditions. Meanwhile, the aluminum waste acid with a large amount of aluminum ions can be used as a source of aluminum, and the sodium sulfate produced by neutralization reaction can be used as a molten salt medium, which cab prevent the agglomeration of the alumina nanoparticles. Organic matter in alkaline wastewater can be used as a carbon source at high temperature conditions, which make the Al₂O₃/C composite materials have excellent mechanical properties. This synthetic method not only achieve the purpose of treatment two kinds of wastewater pollution which are extremely difficult to deal with, but also get the Al₂O₃/C composite material, and this way does not require additional reagent, low cost, simple process. The structure and morphology of products were characterized by several techniques, such as X-ray diffraction（XRD）, transmission electron microscopy（TEM） and N2 adsorption-desorption technique.The result shows that the product with a large surface area, and the morphology is multi-level and multi-dimensional. The structure are good for adsorption process, heavy metal ions and CR are used as wastewater. The as-prepared Al₂O₃/C composite material showed a superior adsorption property of CR and heavy metal ions Cd2+ in 5 min, CR2+ removal percent reached 90%. The maximum adsorption capacity is as high as 350 mg/g at the Cd2+ concentration of 600 mg/L, and the adsorption obeyed well to Langmuir isotherm model.Secondly, the Al₂O₃/C nanomaterials with various morphology have been synthesized by molten salt method, with aluminum nitrate, sodium oleate, sodium hydroxide as reacting reagent. The as-prepared products were applied to the dye and heavy metal ions adsorption. In this process, we researched the effect of different calcination temperature on the morphology and adsorption properties. The product’s structure and morphology were characterized by several techniques, such as X-ray diffraction（XRD）, and so on. The results show that the product with a length of about 200 nm. The size is more homogeneous, and the performance in trials adsorption of heavy metal ions and dye is more excellent. And the maximum adsorption capacity is as high as 250 mg/g at the Cd2+ concentration of 1000 mg/L. The maximum adsorption capacity is as high as 228 mg/g at the Pb2+ concentration of 1000 mg/L, and the adsorption obeyed well to Langmuir isotherm model.Finally, aluminum nitrate, sodium oleate, sodium hydroxide, nickel nitrate are used as raw materials to prepare the Ni/Al₂O₃/C composite material by a hydrothermal-calcining method, The product’s structure and morphology were characterized by several techniques, such as X-ray diffraction（XRD）, and so on. The catalyst performance was evaluated CO methanation. CH4 yield is 45%.