阅读说明：本技术 一种用于降解废水污染物的重金属掺杂含氯钙铝石光催化材料及其制备方法 (Heavy metal doped chlorine-containing calcium-aluminum-containing photocatalytic material for degrading wastewater pollutants and preparation method thereof ) 是由 黄寿强 林嘉泓 吕红映 张雅珩 陈苏 樊超 于 2021-09-30 设计创作，主要内容包括：本发明涉及一种用于降解废水污染物的重金属掺杂含氯钙铝石光催化材料及其制备方法,包括如下步骤：将钙铝石作为水处理剂加入到含有氯离子与重金属离子的废水中进行搅拌反应,待所述搅拌反应结束后将分离出的固体部分于至少200℃下进行煅烧获得重金属掺杂含氯钙铝石光催化材料；所述重金属掺杂含氯钙铝石光催化材料用于光催化降解废水中的有机污染物,所述有机污染物包括氯酚类化合物、抗生素类化合物、偶氮类染料中的一种或几种,本发明方法获得的重金属掺杂含氯钙铝石光催化材料对于上述废水污染物具有非常有效的光催化降解性能,对废水有机污染物的光催化降解率可达到90％以上。(The invention relates to a heavy metal doped chlorine-containing calcium-aluminum-doped photocatalytic material for degrading wastewater pollutants and a preparation method thereof, wherein the heavy metal doped chlorine-containing calcium-aluminum-doped photocatalytic material comprises the following steps: adding mayenite serving as a water treatment agent into wastewater containing chloride ions and heavy metal ions for stirring reaction, and calcining the separated solid part at the temperature of at least 200 ℃ after the stirring reaction is finished to obtain a heavy metal doped chlorine-containing mayenite photocatalytic material; the heavy metal doped chloric calcium aluminite photocatalytic material is used for photocatalytic degradation of organic pollutants in wastewater, wherein the organic pollutants comprise one or more of chlorophenol compounds, antibiotic compounds and azo dyes, the heavy metal doped chloric calcium aluminite photocatalytic material obtained by the method has very effective photocatalytic degradation performance on the wastewater pollutants, and the photocatalytic degradation rate on the organic pollutants in the wastewater can reach over 90%.)

1. A preparation method of a heavy metal doped chlorine-containing calcium aluminate photocatalytic material for degrading wastewater pollutants is characterized by comprising the following steps: adding mayenite serving as a water treatment agent into wastewater containing chloride ions and heavy metal ions for stirring reaction, and calcining the separated solid part at the temperature of at least 200 ℃ after the stirring reaction is finished to obtain a heavy metal doped chlorine-containing mayenite photocatalytic material;

the heavy metal doped chlorine-containing calcium aluminate photocatalytic material is used for photocatalytic degradation of organic pollutants in wastewater, wherein the organic pollutants comprise one or more of chlorophenol compounds, antibiotic compounds and azo dyes.

2. The preparation method according to claim 1, wherein the mayenite is added in a mass ratio of the mayenite to the chloride ions of (9-15): 1.

3. The method of claim 1, wherein the mayenite is prepared by: uniformly mixing calcium oxide and aluminum hydroxide according to the molar ratio of Ca to Al of (1-1.3) to 1, and calcining at 1000-1700 ℃ for 1-6 hours to obtain the mayenite.

4. The method according to claim 1, wherein the heavy metal ions in the wastewater comprise Cr³⁺、Zn²⁺、Cu²⁺、Ni²⁺、Pb²⁺、Cd²⁺、Mn²⁺、Co²⁺One or more of (a).

5. The method according to claim 4, wherein the content of heavy metal ions in the wastewater is: cr (chromium) component³⁺100～2000mg/L；Cd²⁺100～5000mg/L；Zn²⁺100～400mg/L；Cu²⁺50～3500mg/L；Ni²⁺60～1000mg/L；Pb²⁺100～500mg/L；Mn²⁺50～850mg/L；

The content of chloride ions in the wastewater is as follows: 3000-50000 mg/L.

6. The method according to claim 1, wherein the stirring reaction is carried out at a temperature of 25 to 120 ℃ for 10 to 60 min.

7. The preparation method according to claim 1, wherein the calcination temperature is 200 to 1700 ℃, and the calcination time is 1 to 10 hours.

8. The preparation method according to claim 1, wherein the chlorophenols comprise one or more of 2,4, 6-trichlorophenol, 2, 3-dichlorophenol, 2-chlorophenol, 2, 4-dichlorophenol and pentachlorophenol; the antibiotic compound comprises one or more of ciprofloxacin, tetracycline, doxycycline, metacycline, oxytetracycline and aureomycin; the azo dye includes one or more of methyl orange, methyl red, acid red and Sudan red.

9. The heavy metal doped chlorine-containing calcium aluminate photocatalytic material prepared by the preparation method of any one of claims 1 to 8, wherein the heavy metal doping amount in the photocatalytic material is 0.05 to 8 wt%, and the purity of the photocatalytic material is at least 95 wt%; the photocatalytic material is used for photocatalytic degradation of wastewater containing organic pollutants, and the organic pollutants comprise one or more of chlorophenol compounds, antibiotic compounds and azo dyes.

10. The heavy metal doped chlorine-containing calc-aluminite photocatalytic material as claimed in claim 9, wherein the photocatalytic material is added to the wastewater containing organic pollutants according to a solid-liquid mass ratio of (0.005-0.02): 1.

Technical Field

The invention relates to the technical field of resource utilization of heavy metals and chloride ions in wastewater, and particularly relates to a heavy metal doped chlorine-containing calcium-aluminum-containing photocatalytic material for degrading wastewater pollutants and a preparation method thereof.

Background

Chlorophenols (CPs) are toxic, difficult to biodegrade, and difficult to remove from the environment, the half-life of pentachlorophenol in an aerobic environment can reach 3.5 months, and the half-life of some organic precipitates can reach several years. The chlorophenol has wide sources, can be found in underground water, sewage and soil, and even has trace chlorophenol in all levels of food chains. The presence of chlorophenol in drinking water at concentrations below 0.1 mug/L can produce unpleasant taste and odor and is environmentally hazardous. Chlorophenols are present in both surface and groundwater. The toxicity reference values of the 2, 4-dichlorophenol and the pentachlorophenol are respectively 36.5 mu g/L and 13.0 mu g/L; and the average maximum value is not more than 2.020mg/L, 4.380mg/L and 0.055 mg/L. And the allowable total concentration of the CPs in the drinking water cannot exceed 10 mu g/L. Various photocatalytic materials, including TiO, have been studied for the degradation of CPs in water₂CdS, ZnS and activated carbon. Due to TiO₂Has the advantages of low cost, high stability, high photosensitivity to ultraviolet radiation and the like, and is intensively researched. The use of alpha-Fe has been studied₂O₃alpha-FeOOH and TiO₂As a photocatalytic material, 2,4, 6-trichlorophenol, 2, 3-dichlorophenol, 2-chlorophenol and 2, 4-dichlorophenol in suspension are degraded. The result shows that the alpha-FeOOH can only promote the degradation of the 2, 4-dichlorophenol within a certain range, but cannot degrade other CPs.

In addition, the pollution in the wastewater also comprises the pollution of antibiotic compounds, azo dyes and the like. Although antibiotic compounds such as Ciprofloxacin (CIP) have excellent bactericidal capability and small toxic and side effects, a large amount of CIP antibiotics can cause environmental pollution of water, soil, underground water and the like, and seriously harm human health; and tetracycline antibiotics also have broad-spectrum antibacterial property and good treatment effect, but expired antibiotics discarded by hospitals, antibiotics discharged through excrement and urine of patients and antibiotics lost by pharmaceutical enterprises in the production process can be gathered into the environment to cause water pollution in the specific use process.

Along with the rapid development of industrialization in China, heavy metal pollution in wastewater is more and more serious, and high-concentration chloride ions have great harm. The invention aims to solve the technical problem of how to effectively treat and recycle wastewater containing heavy metals and chloride ions to obtain a photocatalytic material which can efficiently catalyze and degrade wastewater pollutants such as parachlorophenol compounds, antibiotic compounds, azo dyes and the like, so as to achieve the purpose of treating wastes with processes of wastes against one another.

Disclosure of Invention

In order to solve the technical problems, the heavy metal doped chlorine-containing calcium aluminate photocatalytic material for degrading wastewater pollutants and the preparation method thereof are provided. The heavy metal doped chlorine-containing calcium aluminate photocatalytic material obtained by the method has very effective photocatalytic degradability on waste water pollutants such as chlorophenol compounds, antibiotic compounds, azo dyes and the like, and the degradation rate of the waste water pollutants can reach more than 90%.

In order to achieve the purpose, the invention is realized by the following technical scheme:

the invention provides a preparation method of a heavy metal doped chlorine-containing calcium-aluminum-doped photocatalytic material for degrading wastewater pollutants, which comprises the following steps: adding mayenite serving as a water treatment agent into wastewater containing chloride ions and heavy metal ions for stirring reaction, and calcining the separated solid part at the temperature of at least 200 ℃ after the stirring reaction is finished to obtain a heavy metal doped chlorine-containing mayenite photocatalytic material;

the heavy metal doped chlorine-containing calcium aluminate photocatalytic material is used for photocatalytic degradation of organic pollutants in wastewater, wherein the organic pollutants comprise one or more of chlorophenol compounds, antibiotic compounds and azo dyes.

Furthermore, the addition amount of the mayenite is added according to the mass ratio of the mayenite to the chloride ions (9-15): 1.

Further, the preparation method of the mayenite comprises the following steps: uniformly mixing calcium oxide and aluminum hydroxide according to the molar ratio of Ca to Al of (1-1.3) to 1, and calcining at 1000-1700 ℃ for 1-6 hours to obtain the mayenite.

Further, the heavy metal ions in the wastewater comprise Cr³⁺、Zn²⁺、Cu²⁺、Ni²⁺、Pb²⁺、Cd²⁺、Mn²⁺、Co²⁺One or more of (a).

Still further, the content of heavy metal ions in the wastewater is as follows: cr (chromium) component³⁺100～2000mg/L；Cd²⁺100～5000mg/L；Zn²⁺100～400mg/L；Cu²⁺50～3500mg/L；Ni²⁺60～1000mg/L；Pb²⁺100～500mg/L；Mn^{2 +}50～850mg/L；

The content of chloride ions in the wastewater is as follows: 3000-50000 mg/L.

Further, the stirring reaction temperature is 25-120 ℃, and the reaction time is 10-60 min.

Further, the calcining temperature is 200-1700 ℃, and the calcining time is 1-10 h.

Further, the chlorophenols compound comprises one or more of 2,4, 6-trichlorophenol, 2, 3-dichlorophenol, 2-chlorophenol, 2, 4-dichlorophenol and pentachlorophenol; the antibiotic compound comprises one or more of ciprofloxacin, tetracycline, doxycycline, metacycline, oxytetracycline and aureomycin; the azo dye includes one or more of methyl orange, methyl red, acid red and Sudan red.

On the other hand, the invention provides the heavy metal doped chlorine-containing calcium-aluminum-doped photocatalytic material prepared by the preparation method, the heavy metal doping amount in the photocatalytic material is 0.05-8 wt%, and the purity of the photocatalytic material is at least 95 wt%; the photocatalytic material is used for photocatalytic degradation of wastewater containing organic pollutants, and the organic pollutants comprise one or more of chlorophenol compounds, antibiotic compounds and azo dyes.

Furthermore, the photocatalytic material is added into the wastewater containing the organic pollutants according to the solid-liquid mass ratio of (0.005-0.02): 1.

The beneficial technical effects are as follows:

the method can remove chloride ions while efficiently treating the heavy metal ions in the wastewater by using the mayenite, obtain the heavy metal doped chlorine-containing mayenite material with photocatalytic activity, and can efficiently carry out photocatalytic degradation on organic pollution in the wastewater.

The principle of removing heavy metal ions and chloride ions in wastewater simultaneously by mayenite is as follows: the calcined mayenite has a plurality of sub-nanometer cage-shaped structures in the crystal structure, the structure can efficiently contain high-concentration heavy metal ions, in addition, the cage-shaped structures of the crystal structure contain hydroxide ions which can exchange ions with chloride ions in wastewater, heavy metal doped chlorine-containing mayenite is formed through an intermediate product of a precipitation reaction in the calcining and stirring processes, and after calcination, the heavy metal ions are doped into the crystal structure of the mayenite, so that the photocatalytic activity of the mayenite is improved. In the process of removing heavy metal and chloride ions from the wastewater, in order to enable the precipitation reaction to be carried out quickly and effectively, the appropriate reaction temperature is adjusted, and stirring is carried out to enable the reaction to be sufficient. The product obtained by the invention has better photocatalytic activity, because the heavy metal ions comprise Cr after calcination³⁺、Zn^{2 +}、Cu²⁺、Ni²⁺、Pb²⁺、Cd²⁺、Mn²⁺、Co²⁺The catalytic performance of the original mayenite with low photocatalytic activity is improved to a great extent by one or more of the doping effects on the chlorine-containing mayenite, and the photocatalysis degradability of organic pollutants in the wastewater, including chlorophenol compounds, antibiotic compounds and azo dyes, can reach more than 90%.

Drawings

FIG. 1 is SEM topography of the Cr-doped chloric-containing perovskite photocatalytic material of the example

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention and the accompanying drawings, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Unless specifically stated otherwise, the numerical values set forth in these examples do not limit the scope of the invention. Techniques, methods known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.

The experimental methods of the following examples, which are not specified under specific conditions, are generally determined according to national standards; if no corresponding national standard exists, the method is carried out according to the universal international standard or the standard requirement proposed by related enterprises. Unless otherwise indicated, all parts are parts by weight and all percentages are percentages by weight.

Example 1

(1) Removing Cr in wastewater³⁺And chloride ions to prepare a photocatalytic material:

calcium oxide and aluminum hydroxide are uniformly mixed according to the molar ratio of Ca to Al of 1:1, and then calcined at 1700 ℃ for 1h to obtain the mayenite.

For Cr³⁺1L of wastewater with the ion content of 2000mg/L and the chloride ion content of 10000mg/L, adding mayenite according to the mass ratio of 9:1 of the mayenite to the chloride ions, stirring for 60min at 25 ℃ to perform precipitation reaction, performing solid-liquid separation after the reaction is finished, performing chloride ion content determination on a liquid part by adopting ion chromatography, and obtaining a solidAnd calcining part of the material at 1700 ℃ for 1h to obtain the Cr-doped chloric calcium-containing aluminite photocatalytic material, wherein the SEM appearance of the material is shown in figure 1, and the material is of a sheet structure.

The chlorine removal efficiency of the embodiment for the above wastewater is 90%, heavy metal Cr³⁺The removal efficiency reached more than 99.9%, and XRD and SEM-EDS analysis of the final product photocatalytic material of this example were performed to obtain a chloric mayenite with a Cr-doped main phase, wherein the Cr-doped amount was 1.8 wt%, and the overall purity of the Cr-doped chloric mayenite was 97.3 wt%.

(2) The Cr-doped chlorine-containing mayenite is used as a photocatalytic material for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing a 50 mg/L2, 4-dichlorophenol aqueous solution;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four kinds of wastewater A, B, C, D, respectively adding the Cr-doped chloric mayenite according to the solid-liquid mass ratio of 0.02:1 to perform a dark reaction for 2h to achieve adsorption and analysis balance, then performing a photocatalytic reaction for 3h under a sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled sample through full spectrum, converting through a standard curve to obtain the residual concentration of organic pollutants in the wastewater, and calculating the degradation efficiency. See table 1 for details.

TABLE 1 Cr-doped chloric mayenite on removal of organic pollutants in wastewater

The effect in table 1 can still be achieved by repeating the experiment (2) after the Cr-doped chloric mayenite of this example is left for one year, which shows that the photocatalytic material of this example has better stability.

Example 2

(1) Removing Cd in wastewater²⁺And chloride ions to prepare a photocatalytic material:

calcium oxide and aluminum hydroxide are uniformly mixed according to the molar ratio of Ca to Al of 1.2:1, and then calcined at 1200 ℃ for 4 hours to obtain the mayenite.

For Cd²⁺1L of wastewater with the ion content of 5000mg/L and the chloride ion content of 20000mg/L, adding mayenite according to the mass ratio of the mayenite to the chloride ions of 12:1, stirring for 10min at 120 ℃ for precipitation reaction, performing solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 1000 ℃ for 6h to obtain the Cd-doped chloric mayenite-containing photocatalytic material.

In this embodiment, the dechlorination efficiency of the wastewater is 99%, and heavy metal Cd²⁺The removal efficiency reaches more than 99.9%, and the final product photocatalytic material of the embodiment is analyzed by XRD and SEM-EDS, so that the main phase of the material is Cd-doped chloric mayenite, wherein the doping amount of Cd is 2.2 wt%, and the overall purity of the Cd-doped chloric mayenite is 96.5 wt%.

(2) The Cd-doped chlorine-containing mayenite is used as a photocatalytic material for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing an aqueous solution containing 50mg/L of 2,4, 6-trichlorophenol;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four kinds of wastewater A, B, C, D, respectively adding the Cd-doped chloric mayenite according to the solid-liquid mass ratio of 0.005:1 to perform a dark reaction for 2h to achieve adsorption and analysis balance, then performing a photocatalytic reaction for 3h under the sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled sample through full spectrum, converting through a standard curve to obtain the residual concentration of organic pollutants in the wastewater, and calculating the degradation efficiency. See table 2 for details.

TABLE 2 Cd-doped chloric mayenite on removal of organic pollutants in wastewater

The effect in table 2 can still be achieved by repeating the experiment (2) after placing the Cd-doped chlorine-containing mayenite for one year, which shows that the photocatalytic material of the embodiment has better stability.

Example 3

(1) Removing Zn in wastewater²⁺And chloride ions to prepare a photocatalytic material:

calcium oxide and aluminum hydroxide are uniformly mixed according to the molar ratio of Ca to Al of 1.3:1, and then calcined at 1000 ℃ for 1h to obtain the mayenite.

For Zn²⁺1L of wastewater with the ion content of 400mg/L and the chloride ion content of 3000mg/L, adding mayenite according to the mass ratio of the mayenite to the chloride ions of 10:1, stirring for 30min at 75 ℃ for precipitation reaction, performing solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 200 ℃ for 10h to obtain the Zn-doped chlorine-containing mayenite photocatalytic material.

In this example, the dechlorination efficiency of the wastewater was 94.3%, and the heavy metal Zn was²⁺The removal efficiency reaches more than 99.9%, and XRD and SEM-EDS analysis of the final product photocatalytic material of this example were performed to obtain a chloric mayenite with Zn-doped main phase, wherein the Zn-doped amount was 1.3 wt%, and the overall purity of the Zn-doped chloric mayenite was 98 wt%.

(2) Zn-doped chlorine-containing mayenite is used as a photocatalytic material for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing a 50 mg/L2, 3-dichlorophenol aqueous solution;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four kinds of wastewater A, B, C, D, respectively adding the Zn-doped chloric mayenite according to the solid-liquid mass ratio of 0.01:1 to perform a dark reaction for 2h to achieve adsorption and analysis balance, then performing a photocatalytic reaction for 3h under a sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled sample through full spectrum, converting through a standard curve to obtain the residual concentration of organic pollutants in the wastewater, and calculating the degradation efficiency. See table 3 for details.

TABLE 3 effect of Zn-doped chloric mayenite on removal of organic pollutants in wastewater

Waste water	Efficiency of catalytic degradation (%)
		Waste water A (containing 50mg/L of 2, 3-dichlorophenol)	95.4
Waste water B (ciprofloxacin containing 40 mg/L)	98.8
		Waste water C (tetracycline 30 mg/L)	97.9
Wastewater D (containing 40 m)g/L methyl orange)	92.6

The effect in table 3 can still be achieved by repeating the experiment (2) after the Zn-doped chloric mayenite of this example is left for one year, which shows that the photocatalytic material of this example has better stability.

Example 4

(1) Removing Ni in wastewater²⁺、Mn²⁺And chloride ions to prepare a photocatalytic material:

calcium oxide and aluminum hydroxide are uniformly mixed according to the molar ratio of Ca to Al of 1.1:1, and then calcined at 1300 ℃ for 1h to obtain the mayenite.

For Ni²⁺The ion content is 1000mg/L, Mn²⁺1L of wastewater with the ion content of 850mg/L and the chloride ion content of 8000mg/L, adding mayenite according to the mass ratio of the mayenite to the chloride ions of 10:1, stirring at 50 ℃ for 55min for precipitation reaction, performing solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 700 ℃ for 5h to obtain the Ni and Mn doped chlorine-containing mayenite photocatalytic material.

In this example, the dechlorination efficiency of the wastewater was 97.5%, and heavy metal Ni was used²⁺、Mn²⁺The removal efficiency reaches over 99.9 percent, and the final product photocatalytic material of the embodiment is analyzed by XRD and SEM-EDS, so that the chloric mayenite with the main phases of Ni and Mn doped, wherein the total doping amount of Ni and Mn is 2 wt%, and the overall purity of the Ni and Mn doped chloric mayenite is 97.8 wt%.

(2) Ni and Mn are doped with chlorine-containing mayenite as a photocatalytic material for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing a 2-chlorophenol aqueous solution containing 50 mg/L;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four kinds of wastewater A, B, C, D, respectively adding Ni and Mn doped chlorine-containing mayenite into the wastewater according to the solid-liquid mass ratio of 0.01:1 to perform a dark reaction for 2h to achieve adsorption and desorption balance, then performing a photocatalytic reaction for 3h under the sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled sample through full spectrum, converting the sample through a standard curve to obtain the residual concentration of organic pollutants in the wastewater, and calculating the degradation efficiency. See table 4 for details.

TABLE 4 effect of Ni and Mn doping of chlorine-containing mayenite on removal of organic pollutants in wastewater

Waste water	Efficiency of catalytic degradation (%)
		Waste water A (2-chlorophenol containing 50 mg/L)	91.8
Waste water B (ciprofloxacin containing 40 mg/L)	96.2
		Waste water C (tetracycline 30 mg/L)	94.3
Wastewater D (methyl orange 40 mg/L)	92.1

The effect in table 4 can still be achieved by repeating the experiment (2) after the Ni and Mn doped chlorine-containing mayenite material of this embodiment is left for one year, which shows that the photocatalytic material of this embodiment has better stability.

Example 5

(1) Removing Cd in wastewater²⁺、Cu²⁺And chloride ions to prepare a photocatalytic material:

calcium oxide and aluminum hydroxide are uniformly mixed according to the molar ratio of Ca to Al of 1.3:1, and then calcined at 800 ℃ for 4 hours to obtain the mayenite.

For Cd²⁺The ion content is 5000mg/L, Cu²⁺1L of wastewater with ion content of 3500mg/L and chloride ion content of 50000mg/L, adding mayenite according to the mass ratio of the mayenite to the chloride ions of 15:1, stirring for 50min at 55 ℃ for precipitation reaction, performing solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 900 ℃ for 4h to obtain the Cd and Cu doped chlorine-containing mayenite photocatalytic material.

In this embodiment, the dechlorination efficiency of the wastewater is 98%, and heavy metal Cd is²⁺、Cu²⁺The removal efficiency reaches over 99.8 percent, and the final product photocatalytic material of the embodiment is analyzed by XRD and SEM-EDS to obtain the chloric mayenite with the main phase of Cd and Cu being doped, wherein the total doping amount of Cd and Cu is 1.6 wt%, and the overall purity of Cd and Cu doped chloric mayenite is 97.6 wt%.

(2) The Cd and Cu doped chlorine-containing mayenite are used as a photocatalytic material for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing an aqueous solution containing pentachlorophenol at 50 mg/L;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four kinds of wastewater A, B, C, D, respectively adding Cd and Cu doped chlorine-containing mayenite according to the solid-liquid mass ratio of 0.015:1 to perform a dark reaction for 2h to achieve adsorption and analysis balance, then performing a photocatalytic reaction for 3h under the sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled product through full spectrum, converting through a standard curve to obtain the residual concentration of organic pollutants in the wastewater, and calculating the degradation efficiency. See table 5 for details.

TABLE 5Cd and Cu doped chloric mayenite effect on removal of organic pollutants in wastewater

Waste water	Efficiency of catalytic degradation (%)
		Waste water A (pentachlorophenol containing 50 mg/L)	90.5
Waste water B (ciprofloxacin containing 40 mg/L)	98.4
		Waste water C (tetracycline 30 mg/L)	97.3
Wastewater D (methyl orange 40 mg/L)	95.2

The effect in table 5 can still be achieved by repeating the experiment (2) after placing the Cd and Cu doped chlorine-containing mayenite for one year, which shows that the photocatalytic material of the embodiment has better stability.

Example 6

(1) Removing Pb in wastewater²⁺、Ni²⁺And chloride ions to prepare a photocatalytic material:

calcium oxide and aluminum hydroxide are uniformly mixed according to the molar ratio of Ca to Al of 1.2:1, and then calcined at 1500 ℃ for 2 hours to obtain the mayenite.

For Pb²⁺The ion content is 500mg/L, Ni²⁺1L of wastewater with the ion content of 1000mg/L and the chloride ion content of 6000mg/L, adding mayenite according to the mass ratio of 11:1 of the mayenite to the chloride ions, stirring for 25min at 80 ℃ to perform precipitation reaction, performing solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 1000 ℃ for 3h to obtain the Pb and Ni doped chloroaluminate-containing photocatalytic material.

In this example, the dechlorination efficiency of the wastewater was 96.7%, and the heavy metal Pb was²⁺、Ni²⁺The removal efficiency was 99.9% or more, and XRD and SEM-EDS analysis of the final product photocatalytic material of this example was performed to obtain a chloric mayenite with Pb and Ni doped as the main phases, wherein the total doping amount of Pb and Ni was 2.3 wt%, and the overall purity of Pb and Ni doped chloric mayenite was 97.4 wt%.

(2) Pb and Ni are doped with chlorine-containing mayenite as a photocatalytic material for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing a 50 mg/L2, 4-dichlorophenol aqueous solution;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four kinds of wastewater A, B, C, D, respectively adding Pb and Ni-doped chloric mayenite according to the solid-liquid mass ratio of 0.015:1 to perform a dark reaction for 2h to achieve adsorption and analysis balance, then performing a photocatalytic reaction for 3h under the sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled product through full spectrum, converting through a standard curve to obtain the residual concentration of organic pollutants in the wastewater, and calculating the degradation efficiency. See table 6 for details.

TABLE 6 Pb and Ni doped chlorine-containing mayenite effect on removing organic pollutants in wastewater

Waste water	Efficiency of catalytic degradation (%)
		Waste water A (containing 50mg/L of 2, 4-dichlorophenol)	92.7
Waste water B (ciprofloxacin containing 40 mg/L)	98.5
		Waste water C (tetracycline 30 mg/L)	93.8
Wastewater D (methyl orange 40 mg/L)	94.4

The effect in table 6 can still be achieved by repeating the experiment (2) after the Pb and Ni doped chlorine-containing mayenite of this example is left for one year, which shows that the photocatalytic material of this example has better stability.

Comparative example 1

The product of this comparative example was mayenite, which was prepared in the same manner as mayenite in example 1.

Comparative example 2

The product of the comparative example is chlorine-containing mayenite, and the preparation method comprises the following steps: preparing 1L of wastewater with the chloride ion content of 10000mg/L, adding mayenite (the preparation method is the same as the preparation method of the mayenite in the embodiment 1) according to the mass ratio of the mayenite to the chloride ions of 9:1, stirring for 60min at 25 ℃ for precipitation reaction, carrying out solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 1700 ℃ for 1h to obtain the chlorine-containing mayenite material.

The dechlorination efficiency of the wastewater in this comparative example was 90%.

Comparative example 3

Preparation of the comparative product: preparing 1L of wastewater with chloride ion content of 10000mg/L, adding calcium oxide and aluminum hydroxide with the same amount as that in example 1, stirring for 60min at 25 ℃ for precipitation reaction, carrying out solid-liquid separation after the reaction is finished, measuring the chloride ion content of a liquid part by adopting ion chromatography, and calcining the obtained solid part at 1700 ℃ for 1h to obtain the product of the comparative example. That is, compared to example 1, mayenite was not prepared first, but dechlorination was performed by using raw materials of calcium oxide and aluminum hydroxide as water treatment agents.

The dechlorination efficiency of the wastewater in the comparative example was 10.5%.

The products of comparative example 1, comparative example 2 and comparative example 3 are used as photocatalytic materials for photocatalytic degradation of wastewater containing organic pollutants:

wastewater A: preparing a 50 mg/L2, 4-dichlorophenol aqueous solution;

wastewater B: preparing a ciprofloxacin aqueous solution containing 40 mg/L;

wastewater C: preparing a tetracycline aqueous solution containing 30 mg/L;

wastewater D: preparing a methyl orange aqueous solution containing 40 mg/L;

respectively measuring 50mL of the four waste water A, B, C, D, respectively adding the products of the comparative example 1, the comparative example 2 and the comparative example 3 according to the solid-liquid mass ratio of 0.02:1 to perform a dark reaction for 2h to achieve adsorption and desorption balance, then performing a photocatalytic reaction for 3h under the sunlight condition (such as a full-spectrum LED lamp), sampling every 0.5h in the 3h, measuring the absorbance of the sampled product through full spectrum, converting through a standard curve to obtain the residual concentration of organic pollutants in the waste water, and calculating the degradation efficiency. See table 7 for details.

TABLE 7 Effect of the products of comparative examples 1 to 3 on the removal of organic contaminants from wastewater

As can be seen from table 7, mayenite has a good photocatalytic degradation efficiency of 75% for chlorophenols, but has a poor photocatalytic degradation efficiency of only about 30% for antibiotic compounds and azo dyes. The chlorine-containing mayenite obtained after the treatment of the chlorine-containing wastewater can improve the photocatalytic degradation efficiency of mayenite parachlorophenol compounds, antibiotic compounds and azo dyes to a certain extent, but the efficiency is still poor. According to the invention, the wastewater containing heavy metal ions and chloride ions is subjected to resource treatment by adopting mayenite to obtain a heavy metal-doped chlorine-containing mayenite product with a high added value, the photocatalytic degradation efficiency of the chlorophenol compound, the antibiotic compound and the azo dye can reach more than 90%, and the waste is treated by waste while the high added value product subjected to resource treatment is obtained.

The reason why the calcined mayenite is used for treating wastewater containing heavy metal ions and chloride ions is that the mayenite obtained by calcination has a better crystal structure and has a better adsorption effect and exchange efficiency on the heavy metal ions and the chloride ions, the mayenite after adsorption-exchange is calcined again, and the heavy metal ions are doped into the crystal structure containing the mayenite, so that the photocatalytic activity of the mayenite on organic pollutants in the wastewater is improved, and the organic pollutants can be effectively degraded by photocatalysis. If calcium oxide and aluminum hydroxide are directly added into wastewater containing chloride ions (the method of comparative example 3), not only can the chloride ions be efficiently removed, but also the photocatalytic degradation efficiency of the calcined dechlorinated product on organic pollutants in the wastewater is very limited. In the prior art, calcium oxide and sodium metaaluminate are usually directly added into wastewater containing chloride ions for treatment, although the higher dechlorination efficiency of more than 80 percent can be obtained, the cost of the sodium metaaluminate is higher than that of aluminum hydroxide in the application, and sodium ions are also introduced into the wastewater, and the sodium ions in the wastewater are very difficult to treat, so the calcium oxide and the aluminum hydroxide are selected as raw materials in consideration of comprehensive cost and treatment difficulty, the cost is reduced by taking the calcium oxide and the aluminum hydroxide as the raw materials, but the corresponding dechlorination efficiency is also obviously reduced, in order to improve the dechlorination efficiency, the calcium oxide and the aluminum hydroxide are firstly uniformly mixed and then calcined to obtain the mayenite with a plurality of subnanometer cage-shaped crystal structures, the crystallinity is improved by calcination to form a special crystal structure, and the calcium oxide and the aluminum hydroxide are used as a water treatment agent to treat the wastewater containing heavy metal ions and chloride ions, so that the wastewater can have a high-efficiency removal effect, not only has low cost but also has good effect.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.