CN113603181B - Method for degrading oxytetracycline by double-chamber photoelectrocatalysis - Google Patents

Abstract

The invention discloses a method for degrading terramycin by double-chamber photoelectrocatalysis, which comprises the specific steps of constructing a double-chamber photoelectrocatalysis system, degrading terramycin by the photoelectrocatalysis system under a xenon lamp, wherein: the graphite-phase carbon nitride doped titanium dioxide nanotube array photoelectrode is prepared by a one-step method, and the high-efficiency degradation of terramycin is realized by the mode, so that the invention constructs a photoelectrocatalysis system with good stability, high photocatalytic activity, green and pollution-free properties and visible light photocatalytic activity.

Description

A double-chamber photocatalytic degradation method for oxytetracycline

technical field

The invention relates to the field of photoelectric catalysis of pollutants, in particular to a method for degrading oxytetracycline by photoelectric catalysis with two chambers.

Background technique

In recent years, semiconductor-based photocatalysis has attracted extensive attention due to its excellent properties in degrading organic pollutants.

Compared with the single photocatalytic process, the dual-chamber photocatalytic process has lower energy consumption and higher degradation efficiency in the photoanode chamber. At the same time, the removal of pollutants can also be achieved in the cathode chamber. Applying a bias voltage during the photocatalytic process can prevent the recombination of photogenerated electron-hole pairs and significantly improve the photocatalytic efficiency. The dual-chamber photocatalytic reaction system realizes simultaneous degradation of oxytetracycline, generation of hydrogen and reduction of carbon dioxide.

The degradation processes of oxytetracycline mainly include biological treatment, chlorination and advanced oxidation technology, among which advanced oxidation technology is more efficient, mainly divided into ozone method, Fenton method, photolysis method, semiconductor treatment, photoelectric treatment method, etc. The double-chamber photocatalytic treatment designed by the present invention belongs to the advanced oxidation method, and compared with the existing process, the degradation efficiency is high, and the synchronous degradation of the oxytetracycline in the light environment and the dark environment can be realized.

In the dual-chamber photocatalytic system, the degradation mechanism of oxytetracycline has not yet been discovered. The gain and loss of electrons in the photoanode and cathode chambers of the dual-chamber photocatalytic system are different, so the degradation mechanism and action mechanism of oxytetracycline in the illuminated anode chamber and the dark cathode chamber may be different. Therefore, it is of great significance to simulate the method of degrading oxytetracycline by a dual-chamber photocatalytic system under sunlight.

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a dual-chamber photocatalytic degradation method for oxytetracycline, constructs a dual-chamber photocatalytic system, and uses graphite-phase carbon nitride on a titanium dioxide nanotube array photoelectrode for dual-chamber photocatalytic system to realize simultaneous degradation of oxytetracycline on the cathode and anode, the catalytic system is cheap, good stability, high photoelectric conversion efficiency, high photocatalytic activity, green and pollution-free, and has visible light photocatalytic activity.

In order to achieve the above object, the present invention provides the following technical scheme: a kind of double-chamber photocatalytic degradation method for oxytetracycline, comprising the following specific steps:

S1: Construction of a dual-chamber photocatalytic system

Connect two quartz reactors with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the self-made graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrode as the anode and cathode of the photoelectrocatalytic system, and the anode and cathode Turn on the power supply and irradiate the anode with a xenon lamp;

S2: Degradation of Oxytetracycline by Photocatalytic System

Add a certain concentration of oxytetracycline solution into the reactor of the double-chamber photocatalytic system, turn on the xenon lamp, adjust the external bias voltage, and degrade oxytetracycline;

The titanium dioxide nanotube array photoelectrode doped with graphite phase carbon nitride is prepared by a one-step method, and the specific method is as follows: in the mixed system solution of graphite phase carbon nitride, anhydrous sodium sulfate and sodium fluoride, pretreated The titanium sheet is used as the anode, and the platinum sheet is used as the cathode. After anodic oxidation under a certain voltage condition, the oxidized titanium sheet anode is placed in a muffle furnace for high-temperature annealing, thereby obtaining self-made graphite-phase carbon nitride-doped titanium dioxide nanotubes. Array photoelectrodes.

Preferably, the power supply connected between the anode and the cathode in step S1 is a DC stabilized power supply, the distance between the xenon lamp and the anode reactor is 1-3 cm, and the power of the xenon lamp is 100-150W.

Preferably, in step S2, the concentration of oxytetracycline in the reactor is 10-50 mg/L, the xenon lamp is turned on simultaneously with the applied bias voltage, the range of the applied bias voltage is 0.5-1.5V, and the reaction temperature is 15-30°C.

Preferably, the titanium content in the titanium sheet is >99.9%, and the pretreatment method of the titanium sheet is as follows: wash off the surface oxide layer with hydrofluoric acid, polish with sandpaper after rinsing with water, and clean the polished titanium sheet with a cleaning agent.

Preferably, the cleaning agent is one or more of ethanol, acetone and deionized water.

Preferably, the preparation method of the graphite phase carbon nitride is as follows: melamine is calcined at a high temperature of 400° C. to 550° C., cooled naturally to room temperature after calcination, and ground and pulverized to obtain the graphite phase carbon nitride.

Preferably, the precursor of the graphitic carbon nitride in step S2 includes one or both of melamine and urea.

Preferably, the anodic oxidation voltage of the titanium sheet is 15-30V, the muffle furnace annealing temperature is 450-600°C, and the annealing time is 1-6h.

Preferably, the mixed solution system is prepared from graphite phase carbon nitride with a concentration of 0.2-1g/L, anhydrous sodium sulfate with a concentration of 0.5-1mol/L and sodium fluoride solution with a concentration of 0.2-0.6wt%. Complete, the solution is ready-to-use.

Beneficial effects of the present invention:

1. The present invention constructs an effective dual-chamber photocatalytic system for degrading oxytetracycline, realizes simultaneous degradation of oxytetracycline on the cathode and anode, and prepares electrodes with good stability, high photoelectric conversion efficiency, and high photocatalytic activity. Green and non-polluting, titanium dioxide nanotube array photoelectrode with visible light photocatalytic activity is applied in a dual-chamber photocatalytic system to achieve efficient degradation of oxytetracycline.

2. The dual-chamber photocatalytic system degrades oxytetracycline. Compared with the traditional single-chamber photocatalytic process, the dual-chamber photocatalytic system can simultaneously realize the degradation of oxytetracycline in light environment and dark environment. Under the same energy consumption, the dual-chamber photocatalytic system can increase the degradation efficiency of the cathode by 60%. Using the joint action of photocatalysis and electrocatalysis, superoxide radicals and hydroxyl radicals are generated to complete the degradation of oxytetracycline.

3. The present invention is based on an anodic oxidation synchronous deposition process, and graphite phase carbon nitride is doped on the titanium dioxide nanotube array photoelectrode by a one-step method. The conduction band of graphite carbon nitride is -1.1eV, and that of titanium dioxide The conduction band is -0.29eV. When the two are recombined, the excited electrons generated in the conduction band of graphite carbon nitride can be transferred to the conduction band of titanium dioxide, thereby promoting the separation of photogenerated carriers and holes, and generating more electron holes to degrade pollutants; relatively Compared with the traditional process, the synthesis of titanium dioxide nanotube array photoelectrode doped with graphite phase carbon nitride is divided into two processes: synthesis of titanium dioxide nanotube array photoelectrode and graphite phase carbon nitride doping, which shortens the preparation process and solves the problem of preparation The problem of high cost saves the preparation process steps and improves the photocatalytic performance.

4. Graphite carbon nitride, that is, gC ₃ N ₄ has a narrow semiconductor band gap and can absorb visible light, and the positions of the energy levels of TiO ₂ and gC ₃ N ₄ match, and the two can form a heterojunction when illuminated. At the same time, the photogenerated carriers are effectively separated, which is an effective method to broaden the light absorption range of the latter and promote charge separation. The present invention is prepared by a one-step method, and the preparation conditions are mild, simple and reliable, and greatly improves the efficiency of the titanium dioxide nanotube array photoelectrode. It has excellent quantum efficiency and photoelectric conversion ability, and has visible light photocatalytic activity, which can utilize most of the visible light energy in sunlight.

5. Compared with the graphite-phase carbon nitride-doped titania nanotube array photoelectrode prepared by the traditional method, the photoelectrode prepared by the present invention has more stable properties and good cycle performance. High degradation efficiency can still be maintained after five cycles. There is a synergistic effect between titanium dioxide and carbon nitride. Titanium dioxide can be excited by light in the ultraviolet band, and carbon nitride can be excited by light in the visible band. The synergistic effect of the two greatly improves the utilization rate of light.

Description of drawings

Fig. 1 is the degradation effect comparison of the anode of the present invention and three control groups of independent photocatalysis, independent electrocatalysis, no bias;

Fig. 2 is the degradation effect comparison of the cathode of the present invention and three control groups of independent photocatalysis, independent electrocatalysis, no bias;

Fig. 3 is that the present invention is under different voltages, the degradation effect of anode and cathode to oxytetracycline;

Fig. 4 is the degradation effect of anode and cathode to oxytetracycline of the present invention under different pH;

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

One-step preparation of graphitic carbon nitride-doped titanium dioxide nanotube array photoelectrodes

(1) Wash the titanium sheet with hydrofluoric acid to remove the surface oxide layer, polish it with sandpaper after rinsing with clear water, and clean the polished titanium sheet with ethanol, acetone, and deionized water;

(2) Preparation of graphite phase carbon nitride

Calcining melamine at 400°C-550°C, cooling to room temperature, grinding and pulverizing to obtain graphite phase carbon nitride;

(3) preparing graphite phase carbon nitride concentration is 0.2-1g/L, anhydrous sodium sulfate concentration is 0.5-1mol/L, sodium fluoride concentration is the mixed solution system of 0.2-0.6wt%, processes with step (1) The final titanium sheet is used as the anode, and the platinum sheet is used as the cathode. It is anodized at a voltage of 15-30V for 2-4h, and then placed in a muffle furnace for annealing at 450-600°C for 1-6h to obtain graphite phase carbon nitride. Doped titania nanotube array photoelectrode.

Photocatalytic degradation of oxytetracycline using dual chambers:

S1: Construction of a dual-chamber photocatalytic system

Connect two quartz reactors with a diameter of 3 cm and a height of 10 cm with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the prepared graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrodes as photoelectrocatalysts. The anode and cathode of the system, the anode and the cathode are powered on, the anode is irradiated with a 100-150W xenon lamp, and the distance between the xenon lamp and the anode reactor is 1-3cm.

S2: Degradation of Oxytetracycline by Photocatalytic System under Xenon Lamp

Add oxytetracycline solution with a concentration of 10-50mg/L into the reactor of the dual-chamber photocatalytic system, turn on the xenon lamp, adjust the external bias voltage to 0.5-1.5V, and degrade oxytetracycline at a reaction temperature of 15-30°C , Calculate the concentration and degradation efficiency of oxytetracycline by absorbance at 356nm wavelength with a UV-Vis spectrophotometer.

Example 2

One-step preparation of graphitic carbon nitride-doped titanium dioxide nanotube array photoelectrodes

(1) Wash the titanium sheet with hydrofluoric acid to remove the surface oxide layer, polish it with sandpaper after rinsing with clear water, and clean the polished titanium sheet with ethanol, acetone, and deionized water;

(2) Preparation of graphite phase carbon nitride

Calcining melamine at 550°C, cooling to room temperature, grinding and pulverizing to obtain graphite phase carbon nitride;

(4) preparation graphite phase carbon nitride concentration is that 1g/L, anhydrous sodium sulfate concentration are 0.5mol/L, sodium fluoride concentration are the mixed solution system of 0.2wt%, make with the titanium plate after step (1) process The anode and the platinum sheet are used as the cathode, anodized at 15V for 2h, and then annealed at 450°C for 1-6h in a muffle furnace to obtain a titanium dioxide nanotube array photoelectrode doped with carbon nitride in the graphite phase.

Photocatalytic Degradation of Oxytetracycline Using Dual Chambers

S1: Construction of a dual-chamber photocatalytic system

Connect two quartz reactors with a diameter of 3 cm and a height of 10 cm with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the prepared graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrodes as photoelectrocatalysts. The anode and cathode of the system, the anode and the cathode are powered on, the anode is irradiated with a 150W xenon lamp, and the distance between the xenon lamp and the anode reactor is 3cm.

S2: Degradation of Oxytetracycline by Photocatalytic System under Xenon Lamp

Add oxytetracycline solution with a concentration of 10mg/L into the reactor of the double-chamber photocatalytic system, turn on the xenon lamp, adjust the external bias voltage to 1.5V, and degrade the oxytetracycline at a reaction temperature of 30°C, and use UV-visible spectrophotometry Calculate the concentration and degradation efficiency of oxytetracycline by calculating the absorbance at 356nm wavelength.

Example 4

One-step preparation of graphitic carbon nitride-doped titanium dioxide nanotube array photoelectrodes

(1) Wash the titanium sheet with hydrofluoric acid to remove the surface oxide layer, polish it with sandpaper after rinsing with clear water, and clean the polished titanium sheet with ethanol, acetone, and deionized water;

(2) Preparation of graphite phase carbon nitride

Calcining melamine at 400°C, cooling to room temperature, grinding and pulverizing to obtain graphite phase carbon nitride;

(5) preparation graphite phase carbon nitride concentration is 0.5g/L, anhydrous sodium sulfate concentration is 1mol/L, sodium fluoride concentration is the mixed solution system of 0.6wt%, makes with the titanium sheet after step (1) process The anode and the platinum sheet were used as the cathode, anodized at 30V for 2h, and then annealed at 450°C for 5h in a muffle furnace to obtain a titanium dioxide nanotube array photoelectrode doped with carbon nitride in the graphite phase.

Photocatalytic Degradation of Oxytetracycline Using Dual Chambers

S1: Construction of a dual-chamber photocatalytic system

Connect two quartz reactors with a diameter of 3 cm and a height of 10 cm with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the prepared graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrodes as photoelectrocatalysts. The anode and cathode of the system, the anode and the cathode are powered on, the anode is irradiated with a 100W xenon lamp, and the distance between the xenon lamp and the anode reactor is 2cm.

S2: Degradation of Oxytetracycline by Photocatalytic System under Xenon Lamp

Add oxytetracycline solution with a concentration of 10mg/L into the reactor of the double-chamber photocatalytic system, turn on the xenon lamp, adjust the external bias voltage to 1V, and degrade the oxytetracycline at a reaction temperature of 25°C, and use a UV-visible spectrophotometer The absorbance at 356nm wavelength was used to calculate the concentration and degradation efficiency of oxytetracycline.

Comparative example 1

Degradation of oxytetracycline by graphitic carbon nitride-doped titania nanotube array photoelectrode under photocatalysis alone:

(1) Wash the titanium sheet with hydrofluoric acid to remove the surface oxide layer, polish it with sandpaper after rinsing with clear water, and clean the polished titanium sheet with ethanol, acetone, and deionized water;

(2) Preparation of graphite phase carbon nitride

Calcining melamine at 400°C, cooling to room temperature, grinding and pulverizing to obtain graphite phase carbon nitride;

(6) preparation graphite phase carbon nitride concentration is 0.5g/L, anhydrous sodium sulfate concentration is 1mol/L, sodium fluoride concentration is the mixed solution system of 0.6wt%, makes with the titanium plate after step (1) process The anode and the platinum sheet were used as the cathode, anodized at 30V for 2h, and then annealed at 450°C for 5h in a muffle furnace to obtain a titanium dioxide nanotube array photoelectrode doped with carbon nitride in the graphite phase.

Photocatalytic Degradation of Oxytetracycline Using Dual Chambers

S1: Construction of a dual-chamber photocatalytic system

Connect two quartz reactors with a diameter of 3 cm and a height of 10 cm with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the prepared graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrodes as photoelectrocatalysts. The anode and cathode of the system, the anode is irradiated with a 100W xenon lamp, and the distance between the xenon lamp and the anode reactor is 2cm.

S2: Degradation of oxytetracycline by photocatalytic system under xenon lamp

Add oxytetracycline solution with a concentration of 10mg/L into the reactor of the dual-chamber photocatalytic system, turn on the xenon lamp, and degrade oxytetracycline at a reaction temperature of 25°C, and calculate the absorbance at 356nm wavelength with a UV-visible spectrophotometer Oxytetracycline concentration and degradation efficiency.

Comparative example 2

Degradation of oxytetracycline by graphitic carbon nitride-doped titania nanotube array photoelectrode under separate electrocatalysis

(1) Wash the titanium sheet with hydrofluoric acid to remove the surface oxide layer, polish it with sandpaper after rinsing with clear water, and clean the polished titanium sheet with ethanol, acetone, and deionized water;

(2) Preparation of graphite phase carbon nitride

Calcining melamine at 400°C, cooling to room temperature, grinding and pulverizing to obtain graphite phase carbon nitride;

(7) preparation graphite phase carbon nitride concentration is 0.2g/L, anhydrous sodium sulfate concentration is 1mol/L, sodium fluoride concentration is the mixed solution system of 0.6wt%, makes with the titanium plate after step (1) process The anode and the platinum sheet were used as the cathode, anodized at 30V for 2h, and then annealed at 500°C for 6h in a muffle furnace to obtain a titanium dioxide nanotube array photoelectrode doped with carbon nitride in the graphite phase.

Degradation of oxytetracycline by double-chamber electrocatalysis

S1: Construction of a dual-chamber electrocatalytic system

Connect two quartz reactors with a diameter of 3 cm and a height of 10 cm with connecting pipes at the bottom, add a cation exchange membrane in the middle, and use the prepared graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrodes as electrocatalysts. The anode and cathode of the system are connected to the power supply.

S2: Degradation of oxytetracycline by electrocatalytic system under xenon lamp

Add oxytetracycline solution with a concentration of 10mg/L into the reactor of the dual-chamber photocatalytic system, adjust the external bias voltage to 1V, and degrade oxytetracycline at a reaction temperature of 25°C. Calculate the concentration and degradation efficiency of oxytetracycline under the absorbance.

Comparative example 2

Degradation of oxytetracycline by graphitic carbon nitride-doped titania nanotube array photoelectrode under photoelectrocatalysis without external bias

One-step preparation of graphitic carbon nitride-doped titanium dioxide nanotube array photoelectrodes

(1) Wash the titanium sheet with hydrofluoric acid to remove the surface oxide layer, polish it with sandpaper after rinsing with clear water, and clean the polished titanium sheet with ethanol, acetone, and deionized water;

(2) Preparation of graphite phase carbon nitride

Calcining melamine at 400°C, cooling to room temperature, grinding and pulverizing to obtain graphite phase carbon nitride;

(8) It is 0.2g/L that the concentration of graphite phase carbon nitride is prepared, the concentration of anhydrous sodium sulfate is 1mol/L, and the mixed solution system that sodium fluoride concentration is 0.6wt% is made with the titanium plate after step (1) processing The anode and the platinum sheet were used as the cathode, anodized at 30V for 2h, and then annealed at 500°C for 6h in a muffle furnace to obtain a titanium dioxide nanotube array photoelectrode doped with carbon nitride in the graphite phase.

Photocatalytic Degradation of Oxytetracycline Using Dual Chambers

S1: Construction of a dual-chamber photocatalytic system

Connect two quartz reactors with a diameter of 3 cm and a height of 10 cm with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the prepared graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrodes as photoelectrocatalysts. The anode and cathode of the system are connected by wires, the anode is irradiated with a 150W xenon lamp, and the distance between the xenon lamp and the anode reactor is 3cm.

S2: Degradation of Oxytetracycline by Photocatalytic System under Xenon Lamp

Add oxytetracycline solution with a concentration of 10mg/L into the reactor of the double-chamber photocatalytic system, turn on the xenon lamp, and degrade oxytetracycline at a reaction temperature of 25°C, and calculate the absorbance at 356nm wavelength with a UV-visible spectrophotometer Oxytetracycline concentration and degradation efficiency.

According to Comparative Example 1-Comparative Example 3 and the comparison of the effect of the dual-chamber photocatalytic system on oxytetracycline, from Figure 1-Figure 2 (E stands for electrocatalysis alone, P stands for photocatalysis alone, PW stands for electrocatalysis without external bias voltage , PE represents the dual-chamber photocatalysis of the present invention) as can be seen, compared to Comparative Example 1, the degradation effect of the cathode has improved by 40%; compared to Comparative Example 2, the degradation effect of the anode has improved by 80%, and the degradation effect of the cathode The degradation effect was increased by 60%; compared with Comparative Example 3, the degradation effect of the cathode was increased by 40%. It can be seen from the degradation effect that the degradation efficiency of the present invention is the highest, the degradation efficiency of the anode is as high as 80%, and the degradation efficiency of the cathode is 60% within 60 minutes, realizing the simultaneous degradation of oxytetracycline in light environment and dark environment. Under light environment and dark environment, due to the joint action of photogenerated electrons and external bias voltage, the separation efficiency of photogenerated holes and electrons is improved, and more hydroxyl radicals and superoxide radicals are generated, realizing the efficient degradation of oxytetracycline . Compared with other processes, the degradation effect is significantly improved.

From Figure 3-Figure 4, it can be seen that the degradation effect of the dual-chamber photocatalytic system on oxytetracycline under different pH and different voltages is quite different, and the degradation of oxytetracycline is more conducive to the degradation of oxytetracycline in alkaline environment, and its main active species are hydroxyl radicals and superoxide radicals. When the applied bias voltage is a positive voltage, the degradation effect of the cathode is greatly improved, because when the applied bias voltage is positive, the external power supply can promote the separation of photogenerated electrons and holes, and inhibit the recombination of electron-hole pairs, thereby improving degradation efficiency.

In summary, the present invention constructs an effective dual-chamber photocatalytic system for degrading oxytetracycline, realizes simultaneous degradation of oxytetracycline on the cathode and anode, and prepares electrodes with good stability, high photoelectric conversion efficiency, and high photocatalytic activity , green and pollution-free, titanium dioxide nanotube array photoelectrode with visible light photocatalytic activity, which is applied in a dual-chamber photocatalytic system to achieve efficient degradation of oxytetracycline

Finally, it should be noted that: the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, it still The technical solutions recorded in the foregoing embodiments may be modified, or some technical features thereof may be equivalently replaced. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (8)

1. a method for photocatalytic degradation of oxytetracycline with two chambers, is characterized in that, comprises following specific steps: S1: Construction of a dual-chamber photocatalytic system Connect two quartz reactors with connecting tubes at the bottom, add a cation exchange membrane in the middle, and use the self-made graphite-phase carbon nitride-doped titanium dioxide nanotube array photoelectrode as the anode and cathode of the photoelectrocatalytic system, and the anode and cathode Turn on the power supply and irradiate the anode with a xenon lamp; S2: Degradation of Oxytetracycline by Photocatalytic System Add a certain concentration of oxytetracycline solution into the reactor of the double-chamber photocatalytic system, turn on the xenon lamp, adjust the external bias voltage, and degrade oxytetracycline; The titanium dioxide nanotube array photoelectrode doped with graphite phase carbon nitride is prepared by a one-step method, and the specific method is as follows: in the mixed system solution of graphite phase carbon nitride, anhydrous sodium sulfate and sodium fluoride, pretreated The titanium sheet is used as the anode, and the platinum sheet is used as the cathode. After anodic oxidation under a certain voltage condition, the oxidized titanium sheet anode is placed in a muffle furnace for high-temperature annealing, thereby obtaining self-made graphite-phase carbon nitride-doped titanium dioxide nanotubes. array photoelectrodes; In step S1, the power supply connected between the anode and the cathode is a DC stabilized power supply, the distance between the xenon lamp and the anode reactor is 1-3 cm, and the power of the xenon lamp is 100-150 W. 2. The method according to claim 1, wherein the concentration of oxytetracycline in the reactor in step S2 is 10-50 mg/L, the xenon lamp is opened simultaneously with the applied bias voltage, and the range of the applied bias voltage is 0.5-1.5 V, the reaction temperature is 15-30°C. 3. The method according to claim 1, wherein the titanium content in the titanium sheet is >99.9%, and the pretreatment method of the titanium sheet is as follows: wash off the surface oxide layer with hydrofluoric acid, rinse with water Grind with sandpaper, and clean the polished titanium sheet with cleaning agent. 4. The method according to claim 3, wherein the cleaning agent is one or more of ethanol, acetone, and deionized water. 5. The method according to claim 1, characterized in that, the preparation method of the graphite phase carbon nitride is as follows: melamine is calcined at a high temperature of 400°C-550°C, naturally cooled to room temperature after calcined, ground and pulverized to obtain graphite phase carbon nitride. 6. The method according to claim 1, characterized in that, the precursor of graphite phase carbon nitride in step S2 comprises one or two of melamine and urea. 7. The method according to claim 1, wherein the anodic oxidation voltage of the titanium sheet is 15-30 V, the muffle furnace annealing temperature is 450-600° C., and the annealing time is 1-6 h. 8. method as claimed in claim 1, is characterized in that, described mixed system solution is the anhydrous sodium sulfate and the graphite phase carbon nitride that concentration is 0.2-1 g/L, concentration is 0.5-1 mol/L and It is prepared from sodium fluoride solution with a concentration of 0.2-0.6wt%, and the solution is prepared and used immediately.

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