Synthesis of Calcium Tungstate Spherical Material by Microwave Irradiation

As an important part of metal tungstate nanomaterials, calcium tungstate nanomaterials have unique crystal structure and remarkable nano-effects, so they have important application value in the field of catalytic oxidation and photochromism.

At current stage, the main preparation method for preparing calcium tungstate nanomaterials include hydrothermal/solvothermal method, microemulsion method, ultrasonic chemical method, solid phase reaction method, etc. Most of the synthesized products are nano-particles, nanowires, and micro-blocks. or microspheres.

In recent years, the introduction of nano-materials with specific structures and dimensions to introduce specific surfactants into the chemical process has become one of the important research directions in the field of inorganic nanotechnology. There is still much room for improvement and optimization in terms of morphology design and controllable synthesis of calcium tungstate nanomaterials. In particular, a structure-directing agent-assisted microwave irradiation process is used to prepare a calcium tungstate functional nano material having a novel morphology and a regular structure.

Sodium dodecyl benzene sulfonate (SDBS) is a typical directing agent capable of efficiently adjusting the rate of nucleation and guiding the orderly growth of crystals. It also has remarkable characteristics such as good water solubility, stable structure and small environmental pollution. Therefore, the researchers used SDBS as a system stabilizer and structure-directing agent to synthesize a calcium tungstate spherical structural material assembled by one-dimensional nanowires by microwave irradiation. The synthesis process includes the following steps:

1) Dissolve 0.6597 g of sodium tungstate (NaWO4•2H2O) in 10 ml of water at room temperature to prepare a sodium tungstate solution;

2) 0.4723 g of calcium nitrate (Ca(NO3)2•4H2O) and 0.0697 g of SDBS are dissolved in 10 ml of water at room temperature to prepare a mixed solution of the two;

3) The solutions of steps 1 and 2 are rapidly mixed, and magnetically stirred for 5 minutes to obtain a reaction precursor solution;

4) Transfer the precursor solution in step three to a microwave reactor for continuous reaction for 30 minutes;

5) The obtained precipitate is cooled and rinsed with distilled water for 3 to 5 times, washed with ethanol for 2 to 3 times, and then dried at 70 to 80 ° C for 48 hours at constant temperature to prepare a spherical structure of calcium tungstate assembled by nanowires. material.

The introduction of surfactant SDBS in the reaction process can maintain the stability of the system and guide the orderly growth of the material. Secondly, the microwave irradiation process has the advantages of fast and efficient, high selectivity, strong controllability, large output, energy saving and environmental protection; The obtained calcium tungstate spherical structure material has good dispersibility, regular morphology and high crystallinity, and can significantly enhance its application value in catalytic oxidation, photoluminescence and other important functional fields. In summary, the new synthesis process has the advantages of simple operation, rapid controllability, and environmental friendliness, and is the main direction for realizing low-cost and high-efficiency control synthesis of calcium tungstate spherical structural materials in the future.

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