Silver Tungstate Composite Silver Phosphate Photocatalyst

In the field of pollutant degradation and energy production, semiconductor photocatalysis is one of the most promising methods. In 2010, researchers at the Material Research Institute found that silver phosphate had photocatalytic effects, and the photocatalytic oxidation effect was more than tens of times that of the known photocatalysts. 

However, due to the instability of silver phosphate, it is easy to self-corrode in photocatalysis, which leads to the rapid degradation of the catalyst. Therefore, nanoparticles need to be loaded on some carriers. The carriers need high compatibility and photocatalytic performance. Therefore, tungsten oxide materials were first used in this research and achieved results.

A preparation method of silver tungstate composite silver phosphate photocatalyst has been proposed. The method is to form a catalyst on the surface of the carrier, and the catalyst and the carrier are closely combined.

1)Weighing 12-16 mmol silver nitrate, configuring 18 mmol/L silver nitrate solution, weighing 6.6-8 mmol sodium tungstate, configuring 18 mmol/L sodium tungstate solution;

2)The above two solutions were mixed at a rotational speed of 350-400 rpm to form colloidal substances. The colloidal substances were stirred continuously for 3-4 h. During the stirring process, sodium tungstate reacted with silver nitrate to form silver tungstate colloids.

3)Silver tungstate colloid was placed in a semi-permeable membrane bag, washed 3-4 times with distilled water to remove free ions, and then added to 60-80 mL sodium phosphate solution with a concentration of 3-4 mol/L. After soaking for 2-4 days, silver phosphate nanoparticles were formed on the surface of silver tungstate particles, separated by solid and liquid, and washed by deionized water for 2-3 days. The silver tungstate silver phosphate photocatalyst was prepared by drying at 75~105 degrees.

The combination of silver tungstate and silver phosphate can make silver tungstate play a better catalytic role in visible light and obtain a good catalytic effect. Silver tungstate composite silver phosphate photocatalyst 0.5g was added into acid red wastewater with 400 mL concentration of 40 mg/L. The decolorization rate was 95.1% after irradiation with 300 W metal halide lamp for 30 min. The catalyst could be reused after separation.

• < Prev
• Next >