Preparation Of Nanometer Materialwith Emulsion Precipitation Method

With the development of science and technology, the demand of high performance material is increased, and nanometer material as the Important component of high performance material is also in short supply. At present, the methods of preparing nanometer materialare mainly by precipitation method, sol-gel method, micro-emulsion method, gas phase method and so on. But some problems limittheir industrial production or product quality. Therefore, improving the existing technology and research and development of new production technology are the focus of the present study.In this paper, thenano-silica and nano-MgOwere prepared by direct precipitation method in paraffin emulsion.FT-IR, XRD, BET, FESEM and TEM were used to characterize and analyze the performance of the products.Precursor P/AMC was prepared by MgCl2·6H2O and Na2CO3, and the nano-MgO was prepared by roasting P/AMC. At 500℃, nano-MgO has cubic crystal and lamellar structure, with the rising of calcine temperature, the lamellar structure gradually destroyed, the MgO turn to granular. When the molar ratio of reactants was 1:1, the product specific surface area was the largest and the particle size was smallest, and the increase of the concentration of the reactants would make the sheet pile more closely. The MgO’shas highly adsorption rate of Congo red.Results show the preparednano-silica was amorphous structure.It has uniform particles, good morphology,and its particle size is about 120 nm, specific surface area of 490 m2·g-1, and there are large amounts of microporous in the particles, themicroporousareuniform, orderly arrangement, and its diameter is about 1.5 nm.Through experiment, the best experimental conditions were studied. The TG-DTA diagram of the silica precursor shows that the optimum calcination temperature is 600℃. The reaction temperature, reaction temperature, pH value, paraffin content and surfactant use level were analyzed in the experiment. The best experimental conditions were: reaction temperature 70℃, sodium silicate concentration 0.6 mol·L-1, hydrochloric acid concentration 1.2 mol·L-1, paraffin content 4 g, reaction system pH=5, the amount of surfactant 3.2%. Under this condition, the nano-silica has the largest surface area and the best morphology.