Bismuth Tungstate Synthesis by Microwave Hydrothermal Method

Tungstate, as a new photocatalyst, has good optical properties and few electron recombination centers. Among them, bismuth tungstate Bi₀WO₆ photocatalyst is the most popular. Bismuth tungstate photocatalyst has good ultraviolet and visible photocatalytic properties. It can utilize both ultraviolet and visible light in sunlight. It has a good application prospect in environmental purification.

Among the preparation methods of bismuth tungstate, microwave hydrothermal method is a novel method, which uses microwave as heating method and combines traditional hydrothermal method to prepare nanometer or ceramic powders. The preparation of bismuth tungstate by microwave hydrothermal method needs the following processes:

Step 1: Weigh Bi (NO₃)_3·5H₂O and Na₂WO₄·2H₂O in beaker, add appropriate deionized water to beaker to make the concentration of Bi (NO₃)_3·5H₂O 0.05mol/L and Na₂WO₄·2H₂O 0.025 mol/L.

Step 2: Adjust the pH = 1.6, magnetic stirring at room temperature for 1 hour to make the raw materials mix evenly, and get the precursor of microwave hydrothermal reaction.

Step 3: The precursor solution obtained in step 2 was put into the PTFE lined reactor, and then the reactor was put into the microwave hydrothermal reactor MDS 8. The power was set at 300W, and the reaction temperature was 220 ℃ for 60 minutes, and the pressure was 3.0Mpa.

Step 4: After the reaction temperature drops to room temperature, the precipitate in the reactor is removed; the precipitate is washed to neutral with water and absolute ethanol; the bismuth tungstate powder is obtained by drying at 80 for 10 hours.

High-temperature microwave hydrothermal method for preparing high-photocatalytic activity of barium tungstate powder, the reaction time is short, and the photocatalytic activity of barium tungstate powder can be synthesized at a relatively high temperature of 220 °C and a high pressure of 3.0 Mpa. The degradation rate of rhodamine B solution with a concentration of 5mg/L after degradation was over 97% after being irradiated with a 350W xenon lamp for 40 minutes. It is higher than the traditional hydrothermal method for preparing doped barium tungstate powder, which is a simple process and high efficiency. Low energy consumption, low cost and environmentally friendly preparation method.

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