Preparation method for synthesizing recyclable CdS/CoFe2O4/rGO (reduced graphene oxide) composite photocatalyst by hydrothermal process and application of composite photocatalyst

[0028] Example 1:

[0029] (1) Preparation of GO:

[0030] According to the Hummer method, GO is synthesized from natural graphite powder. Combine 1g graphite powder, 2.5g NaNO 3 Add 30ml of concentrated sulfuric acid to a 250ml three-necked flask, and put the three-necked flask in an ice bath and magnetically stir. After stirring to complete dissolution, slowly add 0.4g KMnO to the suspension 4 , Continue to stir for 2h until the mixture turns green, at this time the mixture is cooled to 0 ℃. Subsequently, it was removed from the ice bath and reacted at 35°C for 30 minutes, then 40ml of deionized water was added to the mixture, and then reacted at 98°C for 40 minutes. When the solution becomes dark brown, add 10ml 30% H to it separately 2 O 2 , 40ml deionized water to stop the reaction. Finally, the product was washed 3 to 4 times with 30% HCl, precipitated, centrifuged, and dried in vacuum at 50°C for 10 hours.

[0031] (2)CoFe 2 O 4 Preparation:

[0032] Add 0.0646g Fe(NO 3 ) 3 ·9H 2 O, 0.0233g Co(NO 3 ) 2.6H 2 Add O to 40mL ethylene glycol and stir, stir until it is completely dissolved, add 0.005g PVP, stir evenly, transfer the solution to 240℃ reactor for 24h constant temperature reaction; after the reaction, cool to room temperature, and use the solid product Wash with deionized water and ethanol, and then dry at 60℃ for 12h to obtain CoFe 2 O 4.

[0033] (3) CdS/CoFe 2 O 4 /rGO composite photocatalyst preparation:

[0034] 0.1833g CdCl 2 ·2.5H 2 O and 0.1756g L-cysteine ​​are dissolved in 40mL deionized water and stirred until completely dissolved; then use 0.1mol L -1 Sodium hydroxide solution adjusts the pH of the above solution = 7, and then add 0.05g GO and 0.05g CoFe 2 O 4 Continue to stir evenly, then add 0.045g Na 2 S·9H 2 O and stir evenly, then transfer the solution to a 180°C reactor for 2h constant temperature thermal reaction; after the reaction is over, separate the precipitate from the solution with a magnet, wash the precipitate with ethanol, and put it in a vacuum drying oven for drying. Get CdS/CoFe 2 O 4 /rGO composite photocatalyst.

[0035] (4) Take the sample in (3) for a photocatalytic degradation test in a photochemical reactor, and it is measured that the degradation rate of the photocatalyst to the tetracycline antibiotic reaches 86.3% within 90 minutes.

[0036] Example 2:

[0037] According to the steps in Example 1, the difference is (3) 0.1833g CdCl 2 ·2.5H 2 O and 0.1756g L-cysteine ​​are dissolved in 40mL deionized water and stirred until completely dissolved; then use 0.1mol L -1 Sodium hydroxide solution adjusts the pH of the above solution to 5, then add 0.05g GO and 0.05g CoFe 2 O 4 Continue to stir evenly, then add 0.045g Na 2 S·9H 2 O and stir evenly, then transfer the solution to a 180°C reactor for 2h constant temperature thermal reaction; after the reaction is over, separate the precipitate from the solution with a magnet, wash the precipitate with ethanol, and put it in a vacuum drying oven for drying. Get CdS/CoFe 2 O 4 /rGO composite photocatalyst.

[0038] Take the sample in (3) to perform a photocatalytic degradation test in a photochemical reaction apparatus, and it is measured that the degradation rate of the photocatalyst to the ciprofloxacin antibiotic reaches 40.56% within 90 minutes.

[0039] Example 3:

[0040] According to the steps in Example 1, the difference is (3) 0.1833g CdCl 2 ·2.5H 2 O and 0.1756g L-cysteine ​​are dissolved in 40mL deionized water and stirred until completely dissolved; then use 0.1mol L -1 Sodium hydroxide solution adjusts the pH of the above solution = 6, then add 0.05g GO and 0.05g CoFe 2 O 4 Continue to stir evenly, then add 0.045g Na 2 S·9H 2 O and stir evenly, then transfer the solution to a 180°C reactor for 2h constant temperature thermal reaction; after the reaction is over, separate the precipitate from the solution with a magnet, wash the precipitate with ethanol, and put it in a vacuum drying oven for drying. Get CdS/CoFe 2 O 4 /rGO composite photocatalyst.

[0041] Take the sample in (3) to perform a photocatalytic degradation test in a photochemical reactor, and it is measured that the degradation rate of the photocatalyst to the ciprofloxacin antibiotic reaches 54.26% within 90 minutes.