Graphite phase carbon nitride photocatalyst for sewage treatment and preparation method and application thereof

文档序号：369550 发布日期：2021-12-10 浏览：23次中文

阅读说明：本技术 污水处理用石墨相氮化碳光催化剂及其制备方法和应用 (Graphite phase carbon nitride photocatalyst for sewage treatment and preparation method and application thereof ) 是由朱龙海于 2021-08-16 设计创作，主要内容包括：本发明公开了一种污水处理用石墨相氮化碳光催化剂及其制备方法和应用,该光催化剂包括乙二胺四乙酸改性石墨相氮化碳,所述乙二胺四乙酸改性石墨相氮化碳的形貌为空心管状或实心棒状,空心管状和实心棒状的直径均为1μm～10μm。本发明的石墨相氮化碳光催化剂包括乙二胺四乙酸改性石墨相氮化碳,可实现针对性的形貌调控,改善g-C-(3)N-(4)比表面积小、光生载流子复合严重等缺点,相对于传统g-C-(3)N-(4)催化剂,本发明的石墨相氮化碳光催化剂在可见光照射下分解三乙醇胺的活性提高最高可到11.5倍,具有高的光催化降解醇胺类有机污染物的特性。(The invention discloses a graphite phase carbon nitride photocatalyst for sewage treatment and a preparation method and application thereof, wherein the photocatalyst comprises ethylene diamine tetraacetic acid modified graphite phase carbon nitride, the morphology of the ethylene diamine tetraacetic acid modified graphite phase carbon nitride is hollow tubular or solid rod-shaped, and the diameters of the hollow tubular and the solid rod-shaped are both 1-10 mu m. The graphite-phase carbon nitride photocatalyst comprises ethylene diamine tetraacetic acid modified graphite-phase carbon nitride, and can realize pertinenceThe shape of the product is regulated and controlled, and g-C is improved 3 N 4 Small specific surface area, serious photon-generated carrier recombination and the like, compared with the traditional g-C 3 N 4 The activity of the graphite-phase carbon nitride photocatalyst for decomposing triethanolamine under the irradiation of visible light is improved by 11.5 times at most, and the catalyst has the characteristic of high photocatalytic degradation of organic pollutants of alcamines.)

1. A graphite phase carbon nitride photocatalyst for sewage treatment is characterized by comprising ethylene diamine tetraacetic acid modified graphite phase carbon nitride.

2. The graphite-phase carbon nitride photocatalyst for sewage treatment as claimed in claim 1, wherein the morphology of the ethylenediaminetetraacetic acid-modified graphite-phase carbon nitride is hollow tubular or solid rod-shaped, and the diameters of the hollow tubular and the solid rod-shaped are both 1 μm-10 μm.

3. A method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment as defined in claim 1, wherein the raw materials comprise a graphite-like phase carbon nitride precursor and ethylenediaminetetraacetic acid, the mass of ethylenediaminetetraacetic acid being 0.2 to 20 times that of the graphite-like phase carbon nitride precursor.

4. The method of claim 3, wherein the graphite-like phase carbon nitride precursor is melamine, dicyandiamide, or urea.

5. The method according to claim 3, comprising in particular:

step one, adding deionized water into a lining of a hydrothermal kettle filled with a graphite-like carbon nitride precursor and ethylenediamine tetraacetic acid, and stirring to uniformly mix;

secondly, placing the inner liner of the hydrothermal kettle provided with the mixed system in the first step into a stainless steel shell, sealing, and carrying out hydrothermal reaction for 1-20 h in a drying oven at 100-200 ℃;

step three, cooling the system after the hydrothermal reaction in the step two to the temperature of less than or equal to 25 ℃, centrifuging the cooled system, filtering, and washing and centrifuging the precipitate for 3 times;

fourthly, placing the solid phase washed and centrifuged in the third step in an oven at the temperature of 40-100 ℃ for drying treatment for 6-24 h to obtain a photocatalyst precursor;

and fifthly, in an air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 500-550 ℃ at the heating rate of 2-10 ℃/min, carrying out heat preservation roasting for 2-4 h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

6. The method of claim 5, wherein the cooling in step three is cooling in an air stream at 25 ℃ or cooling in a water bath at 25 ℃.

7. The method of claim 5, wherein the washing centrifugation in step three comprises washing the retentate with deionized water, then centrifuging, and filtering off the supernatant.

8. A method for catalytically treating alcohol amine-containing pollutants by using the graphite-phase carbon nitride photocatalyst for sewage treatment as defined in claim 1.

Technical Field

The invention belongs to the technical field of organic pollution treatment, and particularly relates to a graphite-phase carbon nitride photocatalyst for sewage treatment as well as a preparation method and application thereof.

Background

The ethanolamine compound is a chemical raw material with wide application, is used as a surfactant, a humidifier of textiles and cosmetics, a dispersing agent of resin and rubber and the like, and has wide application in modern industrial production. At present, the waste water similar to the alcohol amine organic pollutants is mostly treated biochemically, and a method combining chemical pretreatment and biochemistry is adopted. The alcohol amine wastewater is used as a sacrificial agent for photocatalytic reaction, is degraded by a cavity reaction generated by a photocatalyst, and is used for generating hydrogen in a synergistic manner, so that the method is an economic and effective method for treating the alcohol amine wastewater.

Graphite-like phase carbon nitride (g-C)₃N₄) Is a novel organic photocatalyst. The catalyst has the advantages of low cost, simple synthesis process and narrow band gap (E)_g2.70eV, which can respond to visible light), strong chemical stability, easy modification, etc., and is considered as a very promising photocatalyst. Nevertheless, there are many disadvantages that limit the photocatalytic reactivity and restrict the wider application, such as easy recombination of photo-generated electrons and holes, small specific surface area, etc. Therefore, in order to overcome the defects, researchers propose a series of modification schemes such as morphology regulation, doping modification, copolymerization modification and the like for improving g-C₃N₄The photocatalytic performance of (a).

In the existing modification method and process, for example, Chinese patent CN105478153A, named as' a CeV0₄/Ag/g-C₃N₄The patent is technically characterized in that g-C is added₃N₄Powder and CeV0₄Dissolving in ethanol respectively, ultrasonic dispersing, mixing, and adding AgNO₃Mixing the solution, heating to evaporate, oven drying, and grinding to obtain CeV0₄/Ag/g-C₃N₄The method has the advantages of simple synthesis process, low raw material requirement, lack of morphology regulation and limited application range. Further, as shown in Chinese patent CN109046422A, the name is' lamellar graphite-like carbon nitride g-C₃N₄Materials and methods for their preparation "g-C prepared in this patent₃N₄The method has the advantages of lamellar structure, simple flow, wide raw material source, easy preparation of products, good repeatability, lack of regulation and control on electronic structures and limited application range.

Disclosure of Invention

The invention aims to solve the technical problem of providing a graphite-phase carbon nitride photocatalyst for sewage treatment and a preparation method and application thereof aiming at the defects of the prior art. The graphite-phase carbon nitride photocatalyst comprises ethylene diamine tetraacetic acid modified graphite-phase carbon nitride, can realize targeted morphology control, and improves g-C₃N₄Small specific surface area, serious photon-generated carrier recombination and the like, compared with the traditional g-C₃N₄The activity of the graphite-phase carbon nitride photocatalyst for decomposing triethanolamine under the irradiation of visible light is improved by 11.5 times at most, and the catalyst has the characteristic of high photocatalytic degradation of organic pollutants of alcamines.

In order to solve the technical problems, the invention adopts the technical scheme that: a graphite phase carbon nitride photocatalyst for sewage treatment is characterized by comprising ethylene diamine tetraacetic acid modified graphite phase carbon nitride.

The graphite-phase carbon nitride photocatalyst for sewage treatment is characterized in that the morphology of the ethylenediaminetetraacetic acid modified graphite-phase carbon nitride is hollow tubular or solid rod-shaped, and the diameters of the hollow tubular and the solid rod-shaped are both 1-10 mu m.

In addition, the invention also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, which is characterized in that raw materials comprise a graphite-like carbon nitride precursor and ethylene diamine tetraacetic acid, wherein the mass of the ethylene diamine tetraacetic acid is 0.2-20 times of that of the graphite-like carbon nitride precursor.

The method is characterized in that the graphite-like phase carbon nitride precursor is melamine, dicyandiamide or urea.

The method is characterized by specifically comprising the following steps:

step one, adding deionized water into a lining of a hydrothermal kettle filled with a graphite-like carbon nitride precursor and ethylenediamine tetraacetic acid, and stirring to uniformly mix;

fourthly, placing the solid phase washed and centrifuged in the third step in an oven at the temperature of 40-100 ℃ for drying treatment for 6-24 h to obtain a photocatalyst precursor;

The method as described above, wherein the cooling in step three is cooling in an air stream at 25 ℃ or cooling in a water bath at 25 ℃.

The method is characterized in that the washing centrifugation in the third step comprises washing the retentate with deionized water, then centrifuging, and filtering out the supernatant.

Furthermore, the invention also provides a method for catalytically treating alcohol amine pollutants by using the graphite-phase carbon nitride photocatalyst for sewage treatment.

Compared with the prior art, the invention has the following advantages:

1. the graphite-phase carbon nitride photocatalyst comprises ethylene diamine tetraacetic acid modified graphite-phase carbon nitride, can realize targeted morphology control, and improves g-C₃N₄Small specific surface area, serious photon-generated carrier recombination and the like, compared with the traditional g-C₃N₄The activity of the graphite-phase carbon nitride photocatalyst for decomposing triethanolamine under the irradiation of visible light is improved by 11.5 times at most, and the catalyst has the characteristic of high photocatalytic degradation of organic pollutants of alcamines.

2. Preferably, the ethylene diamine tetraacetic acid modified graphite-phase carbon nitride is in a hollow tubular shape or a solid rod shape, and has lower photon-generated carrier recombination rate and higher efficient electron transmission efficiency.

3. According to the method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, raw materials comprise melamine, dicyandiamide or urea and other graphite-phase carbon nitride precursors and ethylenediamine tetraacetic acid, the method comprises the steps of hydrothermal treatment and introduction of chelating agent ethylenediamine tetraacetic acid in the hydrothermal treatment process, the shape of the photocatalyst is controlled by controlling the hydrothermal reaction temperature to be 100-200 ℃ for 1-20 h and cooling to the temperature of less than or equal to 25 ℃, and the photocatalyst with high photocatalytic activity is prepared by using the chelating effect of the ethylenediamine tetraacetic acid.

4. The preparation method comprises the step of raising the temperature of the photocatalyst precursor in the step four to 500-550 ℃ at the heating rate of 2-10 ℃/min in the air atmosphere, and carrying out heat preservation roasting for 2-4 h, so that the regulation and control of the catalyst element proportion, the carried groups, the crystallinity, the energy band position, the forbidden band width, the micro morphology, the specific surface area, the pore characteristics and the like are realized, the lower photon-generated carrier recombination rate is realized, and the more efficient electron transmission efficiency is realized.

5. Preferably, in the preparation method of the invention, the modified graphite-phase carbon nitride with a special hollow tubular or solid rod-like structure is prepared by cooling in 25 ℃ air flow or in 25 ℃ water bath, and the modified graphite-phase carbon nitride is endowed with the modified performance.

The technical solution of the present invention is further described in detail with reference to the accompanying drawings and embodiments.

Drawings

FIG. 1 is a schematic flow chart of the preparation process of example 1.

FIG. 2 is an XRD spectrum of the graphite phase carbon nitride photocatalyst of examples 1-2 and comparative example 1.

FIG. 3 is an SEM image of the graphite phase carbon nitride photocatalysts of examples 1-2 and comparative example 1.

Fig. 4 is a TEM image of the graphite phase carbon nitride photocatalyst of example 1.

Fig. 5 is a steady state and transient PL spectrum for the graphite phase carbon nitride photocatalyst of example 1 and comparative example 1.

FIG. 6 is a graph showing photocurrent density curves of the graphite phase carbon nitride photocatalysts of examples 1-2 and comparative example 1.

Detailed Description

Example 1

The embodiment provides a graphite phase carbon nitride photocatalyst for sewage treatment, which comprises ethylene diamine tetraacetic acid modified graphite phase carbon nitride, wherein the ethylene diamine tetraacetic acid modified graphite phase carbon nitride is in a hollow tubular shape, and the diameter of the hollow tubular shape is 1-10 mu m.

As shown in fig. 1, this example also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method include a graphite-like phase carbon nitride precursor and ethylenediaminetetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 0.2 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is melamine.

The method comprises the following steps:

step one, adding 30mL of deionized water into a 100mL hydrothermal kettle lining filled with 5g of graphite-like carbon nitride precursor and 1g of ethylenediamine tetraacetic acid, and stirring to uniformly mix; the stirring time can be 30 min;

step two, putting the inner liner of the hydrothermal kettle provided with the mixed system in the step one into a stainless steel shell, sealing, and carrying out hydrothermal reaction in an oven at 180 ℃ for 20 hours;

step three, cooling the system after the hydrothermal reaction in the step two to the temperature of less than or equal to 25 ℃, centrifuging the cooled system, filtering to remove supernatant, and washing and centrifuging the precipitate for 3 times; the cooling is in a 25 ℃ air stream; washing and centrifuging, namely washing the retentate with deionized water, centrifuging at the speed of 5000r/min, and filtering the supernatant;

step four, placing the solid phase washed and centrifuged in the step three in a 60 ℃ drying oven for drying treatment for 24 hours to obtain a photocatalyst precursor;

and step five, under the air atmosphere, raising the temperature of the photocatalyst precursor in the step four to 520 ℃ at the heating rate of 5 ℃/min, preserving heat, roasting for 4h, and grinding to obtain the graphite phase carbon nitride photocatalyst for sewage treatment, which is named as MEH-10.

Example 2

The embodiment provides a graphite phase carbon nitride photocatalyst for sewage treatment, and the graphite phase carbon nitride photocatalyst for sewage treatment comprises ethylene diamine tetraacetic acid modified graphite phase carbon nitride, wherein the ethylene diamine tetraacetic acid modified graphite phase carbon nitride is in a solid rod shape, and the diameter of the solid rod shape is 1-10 mu m.

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 2 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is melamine.

The method comprises the following steps:

step one, adding 30mL of deionized water into a hydrothermal kettle lining filled with 5g of graphite-like carbon nitride precursor and 10g of ethylenediamine tetraacetic acid, and stirring to uniformly mix; the stirring time can be 30 min;

step four, placing the solid phase washed and centrifuged in the step three in a 60 ℃ drying oven for drying treatment for 24 hours to obtain a photocatalyst precursor;

Example 3

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 20 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is melamine.

The method comprises the following steps:

step one, adding 30mL of deionized water into a hydrothermal kettle lining filled with 5g of graphite-like carbon nitride precursor and 100g of ethylenediamine tetraacetic acid, and stirring to uniformly mix; the stirring time can be 30 min;

step three, cooling the system after the hydrothermal reaction in the step two to the temperature of less than or equal to 25 ℃, centrifuging the cooled system, filtering to remove supernatant, and washing and centrifuging the precipitate for 3 times; the cooling is carried out under the condition of water bath at 25 ℃; washing and centrifuging, namely washing the retentate with deionized water, centrifuging at the speed of 5000r/min, and filtering the supernatant;

fourthly, drying the solid phase washed and centrifuged in the third step in a drying oven at 100 ℃ for 10 hours to obtain a photocatalyst precursor;

and fifthly, under the air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 500 ℃ at the heating rate of 2 ℃/min, preserving heat, roasting for 2h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

Example 4

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 0.2 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is dicyandiamide.

The method comprises the following steps:

step one, adding 30mL of deionized water into a hydrothermal kettle lining filled with 5g of graphite-like carbon nitride precursor and 1g of ethylenediamine tetraacetic acid, and stirring to uniformly mix; the stirring time can be 30 min;

step three, cooling the system after the hydrothermal reaction in the step two to the temperature of less than or equal to 25 ℃, centrifuging the cooled system, filtering to remove supernatant, and washing and centrifuging the precipitate for 3 times; the cooling is carried out under the condition of water bath at 25 ℃; washing and centrifuging, namely washing the retentate with deionized water, centrifuging at the speed of 5000r/min, and filtering the supernatant;

fourthly, drying the solid phase washed and centrifuged in the third step in a drying oven at 40 ℃ for 20 hours to obtain a photocatalyst precursor;

Example 5

The graphite-like phase carbon nitride precursor is dicyandiamide.

The method comprises the following steps:

step three, cooling the system after the hydrothermal reaction in the step two to the temperature of less than or equal to 25 ℃, centrifuging the cooled system, filtering to remove supernatant, and washing and centrifuging the precipitate for 3 times; the cooling is carried out under the condition of water bath at 25 ℃; washing and centrifuging, namely washing the retentate with deionized water, centrifuging at the speed of 5000r/min, and filtering the supernatant;

step four, placing the solid phase washed and centrifuged in the step three in a drying oven at 100 ℃ for drying treatment for 6 hours to obtain a photocatalyst precursor;

and fifthly, under the air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 520 ℃ at the heating rate of 5 ℃/min, preserving heat, roasting for 3h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

Example 6

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 20 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is dicyandiamide.

The method comprises the following steps:

step three, cooling the system after the hydrothermal reaction in the step two to the temperature of less than or equal to 25 ℃, centrifuging the cooled system, filtering to remove supernatant, and washing and centrifuging the precipitate for 3 times; the cooling is carried out under the condition of water bath at 25 ℃; washing and centrifuging, namely washing the retentate with deionized water, centrifuging at the speed of 5000r/min, and filtering the supernatant;

step four, placing the solid phase washed and centrifuged in the step three in a 60 ℃ drying oven for drying treatment for 24 hours to obtain a photocatalyst precursor;

and fifthly, under the air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 550 ℃ at the heating rate of 10 ℃/min, preserving heat, roasting for 4h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

Example 7

The diameter of the hollow pipe is 1 μm.

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 10 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is urea.

The method comprises the following steps:

step one, adding 30mL of deionized water into a hydrothermal kettle lining filled with 5g of graphite-like carbon nitride precursor and 50g of ethylene diamine tetraacetic acid, and stirring to uniformly mix; the stirring time can be 30 min;

step four, placing the solid phase washed and centrifuged in the step three in a drying oven at 100 ℃ for drying treatment for 6 hours to obtain a photocatalyst precursor;

and fifthly, under the air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 550 ℃ at the heating rate of 10 ℃/min, preserving heat, roasting for 3h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

Example 8

The diameter of the hollow pipe is 1 μm.

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 0.2 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is urea.

The method comprises the following steps:

fourthly, drying the solid phase washed and centrifuged in the third step in a drying oven at 40 ℃ for 10 hours to obtain a photocatalyst precursor;

and fifthly, under the air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 500 ℃ at the heating rate of 2 ℃/min, preserving heat, roasting for 4h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

Example 9

The diameter of the hollow pipe is 1 μm.

The embodiment also provides a method for preparing the graphite-phase carbon nitride photocatalyst for sewage treatment, wherein the raw materials of the method comprise a graphite-like phase carbon nitride precursor and ethylene diamine tetraacetic acid; the mass of the ethylene diamine tetraacetic acid is 20 times of that of the graphite-like phase carbon nitride precursor.

The graphite-like phase carbon nitride precursor is urea.

The method comprises the following steps:

step four, placing the solid phase washed and centrifuged in the step three in a 60 ℃ drying oven for drying treatment for 24 hours to obtain a photocatalyst precursor;

and fifthly, under the air atmosphere, raising the temperature of the photocatalyst precursor in the fourth step to 520 ℃ at the heating rate of 5 ℃/min, carrying out heat preservation roasting for 2h, and grinding to obtain the graphite-phase carbon nitride photocatalyst for sewage treatment.

Comparative example 1

The present comparative example provides a method of preparing a graphite phase carbon nitride photocatalyst, comprising:

weighing 5g of powdery melamine, placing the powdery melamine in a 20mL crucible, covering the crucible with the melamine, placing the crucible in an air atmosphere, heating to 520 ℃ at the heating rate of 5 ℃/min, carrying out heat preservation reaction for 4 hours, and grinding to obtain the graphite-phase carbon nitride photocatalyst, which is named as ME-0.

Performance evaluation;

FIG. 2 is an XRD spectrum of the graphite phase carbon nitride photocatalyst of examples 1-2 and comparative example 1. According to FIG. 2, the diffraction patterns of the three samples all have a g-C corresponding to the graphite phase carbon nitride₃N₄(100) Characteristic diffraction peaks of a crystal face and a (002) crystal face, and the positions of the characteristic peaks of the samples corresponding to the examples do not obviously move, which shows that the finally obtained g-C is not caused by adding the ethylene diamine tetraacetic acid in the hydrothermal process₃N₄A change in the crystal structure.

FIG. 3 is an SEM image of the graphite phase carbon nitride photocatalyst of examples 1-2 and comparative example 1, and FIG. 4 is a TEM image of the graphite phase carbon nitride photocatalyst of example 1. According to fig. 3, the sample in comparative example 1 has a large block shape with a small specific surface area, and it can be seen from fig. 3 and fig. 4 that the corresponding sample in example 1 has a hollow tubular structure with a diameter of about 1 μm and the wall of the hollow tubular structure is a porous structure, and the corresponding sample in example 2 has a porous solid rod-like structure with a diameter of about 10 μm.

FIG. 5 is a steady state and transient PL spectrum (photoluminescence spectrum) of the graphite phase carbon nitride photocatalyst of example 1 and comparative example 1, and from the steady state PL spectrum (a), it can be seen that pure g-C of comparative example 1₃N₄The method has a strong PL characteristic peak, while the strength of the characteristic peak in the embodiment 1 is obviously weakened, which shows that the change of the morphology effectively inhibits the recombination of photon-generated carriers, and the electronic structure is effectively regulated and controlled. From the transient PL spectrum (b), it can be seen that the graphite-phase carbon nitride photocatalyst carrier of example 1 has a short lifetime, indicating that electrons can rapidly transfer surface recombination, and that the modification promotes the separation of the photo-generated carriers, and also indicating that the electronic structure is effectively regulated.

Fig. 6 is a graph showing the photocurrent density curves of the graphite-phase carbon nitride photocatalysts of examples 1 to 2 and comparative example 1, and it can be seen that the photocurrent density of the graphite-phase carbon nitride photocatalyst corresponding to the examples is significantly improved.

FIG. 7 is a graph showing a comparison of the decomposition activity of triethanolamine by the graphite-phase carbon nitride photocatalysts of examples 1-2 and comparative example 1 under visible light irradiation. The activity test process comprises the following steps: 20mg of catalyst was weighed out and dispersed in 160mLAdding a cocatalyst of 3% wtPt into a 10% triethanolamine solution, purging with argon for 30min before illumination to remove oxygen, adding a 420nm cut-off filter into a xenon lamp, and controlling the temperature of the whole reaction system by using circulating water at 35 ℃. It can be seen that the activity of photocatalytic decomposition of triethanolamine is significantly enhanced by the graphite-phase carbon nitride photocatalyst of examples 1-2, wherein the amount of pure g-C is compared to that of comparative example 1₃N₄(ME-0), the MEH-100 activity of example 2 increased 11.5 fold, probably due to: the appearance of a sample is changed by adding ethylene diamine tetraacetic acid in the hydrothermal process, the generated loose porous structure has higher specific surface area, the recombination of photon-generated carriers is inhibited, the separation and the transmission of the photon-generated carriers are promoted, and the photocatalytic activity is finally improved.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still fall within the protection scope of the technical solution of the present invention.

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Graphite phase carbon nitride photocatalyst for sewage treatment and preparation method and application thereof

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