Bismuth Cobalt Tungstate Composite Photocatalyst

Global environmental pollution restricts the progress of human civilization, and the elimination of environmental organic pollutants requires a lot of energy, which poses a serious challenge to the increasingly depleted energy. Research shows that almost all organic pollutants can be effectively degraded, decolored and detoxified by semiconductor photocatalysis. Mineralization into inorganic small molecular substances, thereby eliminating environmental pollution and hazards.

Bismuth tungstate is a new kind of visible light photocatalyst with small band gap, strong light absorption and easy modification. Some scholars combined Co₃O₄ and Bi₂WO₆ into bismuth cobalt tungstate composite photocatalyst by hydrothermal synthesis, which greatly improved the photocatalytic performance. The synthetic process includes:

1.Bismuth nitrate was added into nitric acid solution with 1 mol/L concentration and stirred for 30 minutes according to the mass ratio of bismuth nitrate to nitric acid of 3:1. Bismuth nitrate solution was obtained. Then sodium tungstate was added into deionized water and stirred evenly according to the ratio of 30:1 between sodium tungstate and deionized water to obtain sodium tungstate solution.

2.Cetyltrimethylammonium bromide was added to sodium tungstate solution at a mass ratio of 14:1 and stirred evenly to obtain a mixed solution. Bismuth nitrate solution was added to the mixed solution to obtain the precursor solution, which was kept at 160 ~℃ for 24 hours. After natural cooling to room temperature, bismuth tungstate powder was obtained by centrifugation, washing and drying.

3.Bismuth tungstate powder was mixed into cobalt salt solution with 0.05 mol/L concentration according to the mass ratio of cobalt oxide to bismuth tungstate of 0.01:1, and the intermediate product was obtained. Cobalt oxide was cobalt chloride and the solvent in cobalt salt solution was water.

4.The Cobalt-Modified bismuth-cobalt tungstate composite photocatalyst was prepared by grinding the intermediate product at 50 ℃ for 24 hours and calcining the powder-like intermediate product at 300 ℃ for 4 hours.

Bismuth cobalt tungstate composite photocatalyst can effectively treat wastewater polluted by herbicide 2,4 D, or phenol, methylene blue, rhodamine B, methyl orange, chromium, lead and mercury ions, which has realistic environmental significance. Moreover, the preparation method has raw materials that can be purchased from the market or made by conventional methods, and the preparation process is relatively easy and the relative cost is low.

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