Supported Bismuth Tungstate Photocatalyst

Bismuth tungstate (Bi2WO6) photocatalyst is considered as a potential excellent visible light photocatalytic material because of its unique electronic structure, excellent visible light absorption ability and high organic degradation ability.

Supported bismuth tungstate photocatalyst is formed by compounding bismuth tungstate with carrier particle diatomite. It is found that soft magnetic Ni0.4Zn0.6Fe₂O₄ diatomite can greatly improve the loading properties of diatomite. The preparation process of soft magnetic Ni0.4Zn0.6Fe₂O₄ diatomite is as follows:

(1)Mixed aqueous solutions of nickel chloride, zinc chloride and ferric chloride with 0.1 *10-3 mol, 0.15 *10-3 mol, 0.5 *10-3 mol, respectively, were prepared with deionized water. The total concentration of metal ions was 0.05 mol/L. After mixing and dissolving, ammonia water was added to adjust the pH value of the solution to 10. Diatomite with a mass equal to 6 times of soft magnetic Ni0.4Zn0.6Fe₂O₄ of the above-mentioned system was added and stirred evenly and then moved to hydrothermal solution. Soft magnetic diatomite loaded with Ni0.4Zn0.6Fe₂O₄ was obtained by cooling, filtering, washing and drying in the reactor after 24 hours at 180 ℃.

(2)Ammonium tungstate solution with 0.001 mol/L concentration and bismuth nitrate solution with 0.024 mol/L concentration were prepared. Tartaric acid solution with 9 mL and 18 mL concentration of 0.1 mol/L was added to ammonium tungstate solution and bismuth nitrate solution respectively under stirring conditions to form transparent solution A and B.

(3) The transparent solution A and B were mixed to obtain a transparent mixed solution C. Under the stirring condition, the soft magnetic diatomite obtained from step 1 was added to the above mixed solution C to obtain the mixed solution D. Then the mixed solution D was kept wet for 24 hours at 80 degrees in the water bath, and the wet gel was dried at 110 degrees Celsius to dry gel.

Because the porous structure and strong adsorption of diatomite can maintain the high photocatalytic efficiency of bismuth tungstate suspension system, and magnetic technology can be used to recover the photocatalyst, simplify the separation process and reduce the operation cost, the above supported diatomite bismuth tungstate photocatalyst has a good application prospect.

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