Tetracycline Wastewater Purification by Nano Tungsten Trioxide

Tetracycline antibiotics are a kind of broad-spectrum antibiotics produced by Streptomyces, including aureomycin, oxytetracycline, tetracycline and so on. The use and abuse of these antibiotics make most of the antibiotics not fully absorbed by animals or human body and directly discharged into the water body, which has a serious impact on the environmental system and is regarded as a typical micro-polluted organic matter. The removal of antibiotics represented by tetracyclines has become an urgent scientific research problem.

Nano-semiconductor materials have been widely used for catalytic degradation of pollutants in water due to their good photocatalytic activity. nano tungsten trioxide is an important semiconductor material with excellent optical properties and is widely used in the research of photocatalysts. There are also laboratory reports on the preparation of nano tungsten trioxide for purification of tetracycline wastewater.

Nanometer tungsten trioxide was prepared by hydrothermal synthesis. The process includes:

A.Dilute 65% concentrated nitric acid into 10% diluted nitric acid 30 mL.

B.Weighing 0.5 g Na₂WO_4·2H₂O, adding 5 mL deionized water, stirring it to mix evenly, forming Na₂WO₄·2H₂O transparent solution;

C.Add the Na₂WO₄·2H₂O transparent solution to the dilute nitric acid solution described in step A, stir for 30 minutes, and change the precipitation color from white to light yellow.

D.Transfer the mixed system obtained in step C to the PTFE lined reactor, raise the temperature to 140 ℃ and keep the temperature constant for 18 h, then cool naturally to obtain the hydrothermal products.

E.The hydrothermal products obtained in step D were separated by centrifugation and washed three times with deionized water and absolute ethanol respectively.

F. The homogeneous tungsten trioxide nanosheets can be obtained by drying the product centrifugally separated from step E in air at 60 ℃ for 6 hours.

A 10 mg/L tetracycline simulated wastewater of 100 mL was added to the photocatalytic reactor, and then the tungsten trioxide photocatalyst prepared by hydrothermal reaction was added to the reactor. The magnetic stirrer was used in the dark room for 1 hour to react. After reaching the equilibrium of reaction and adsorption, the samples were taken. During the photocatalytic reaction, the oxidation of hydroxyl radicals promoted the deamination, demethylation and so on of tetracycline. The intermediate products of macromolecule will eventually be mineralized into CO₂, H₂ and NH₄⁺, and the photocatalytic degradation efficiency can reach 98% in long enough photocatalytic reaction time.

• < Prev
• Next >