CN113772802B

CN113772802B - Method for degrading bisphenol A in water by using manganese oxide modified copper-manganese spinel

Info

Publication number: CN113772802B
Application number: CN202111048982.8A
Authority: CN
Inventors: 谢利娟; 朱一红; 孙紫晶; 邓芸; 阮文权
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2021-09-08
Filing date: 2021-09-08
Publication date: 2022-11-01
Anticipated expiration: 2041-09-08
Also published as: CN113772802A

Abstract

The invention discloses a method for degrading bisphenol A in water by using manganese oxide modified copper-manganese spinel, belonging to the technical field of water treatment. According to the invention, the specially prepared manganese oxide modified copper manganese spinel and persulfate are added into the water body, so that BPA in the water body is efficiently degraded in a short time, an effective and efficient BPA removing effect can be still realized in an environment with high-concentration salt, and the method has the advantages of low ion release, long service life of the catalyst and the like, and is economical and environment-friendly. The treatment method is simple, convenient, mild, short-time and efficient, is suitable for high-salinity environment, and has a very good application prospect.

Description

Method for degrading bisphenol A in water by using manganese oxide modified copper-manganese spinel

Technical Field

The invention relates to a method for degrading bisphenol A in water by using manganese oxide modified copper-manganese spinel, belonging to the technical field of water treatment.

Background

Bisphenol a is an artificially synthesized compound that does not exist under natural conditions. Bisphenol a (BPA) plays a significant role in the upper end of the chemical industry chain and is used as a raw material for synthesizing polycarbonate, epoxy resin, phenolic resin, PVC stabilizer, flame retardant, plasticizer and the like. Countries or organizations such as japan, the united states and the world wildlife foundation indicate that BPA is an environmental hormone, which is classified as one of the phenolic endocrine disruptors. BPA generally has a short half-life in the environment, can be biodegraded in the environment, and is finally converted into CO after degradation₂. But this process is slow. Researchers have studied the biodegradation of bisphenol a in rivers and found that the degradation period is about several tens of days. And the application range is wide, the demand is increasing day by day, and the worldwide demand for BPA is about several million tons every year. The industries producing or using BPA chemicals emit BPA-containing wastewater, sludge and waste residues, and BPA enters the water environment through surface runoff and rainwater washing, which is the main source of BPA in the water environment. In addition, BPA-containing plastic articles exposed to high temperature and aqueous environments can also leach out, and these BPA eventually also enter the aqueous environment. The polycarbon is generally eaten or drunk by human beingsThe acid ester is directly contacted with BPA as a food or beverage for packaging. Even at trace levels, the content of BPA can be hazardous to biological health. Most people currently consider that the harm of BPA is that the human immune system and the nervous system are damaged, the endocrine disturbance is caused by the interference of normal hormone, the healthy development of fetuses and children is influenced, the reproductive disorder is caused, and cancers are caused. BPA and active oxygen contact and then a reaction called oxidative stress occurs, and the product is considered to be possibly genotoxic and interferes with the endocrine system of the human body to cause various abnormal phenomena.

With the rapid development of industry, the demand for BPA is increasing, the concentration of BPA in environmental water is also increasing, and BPA in natural water cannot be rapidly degraded by natural biodegradation and is increasing day by day. The BPA wastewater treatment methods reported in the prior art comprise a biodegradation method, an advanced oxidation method, an adsorption method, a membrane separation technology and the like.

The high salinity organic wastewater is characterized in that the concentration of soluble salt and refractory organic compounds is higher, the high salinity organic wastewater is likely to be generated in various industrial production processes of agriculture, food, chemical industry, printing and dyeing, medical treatment and the like, and the high salinity organic wastewater has a serious inhibition effect on bacteria, so that the general biological treatment is not suitable for the high salinity wastewater. When some organic pollutants which are difficult to degrade exist in the high-salt wastewater, the general advanced oxidation process cannot efficiently degrade the organic pollutants, because the high salt has the effect of inhibiting the generation of free radicals with strong oxidizing property generated by the advanced oxidation process and can possibly react with the pollutants to generate toxic byproducts. Therefore, it is very important to provide a method which can treat common wastewater and can also be suitable for degrading and removing BPA in a high-salt environment.

Disclosure of Invention

The technical problem is as follows: aiming at the problem that the common wastewater and the common advanced oxidation technology under the high-salt condition are not suitable for the refractory organic matters such as BPA, the invention provides a method for degrading BPA under the high-salt background, which can efficiently decompose the target pollutant BPA in a short time.

The technical scheme is as follows:

the invention provides a method for degrading BPA in water, which comprises the steps of adding a copper manganese spinel catalyst modified by manganese oxide and persulfate into a water body for degradation treatment;

the manganese oxide modified copper manganese spinel catalyst is prepared by the following method:

dispersing soluble divalent copper salt, divalent manganese salt, polyethylene glycol and citric acid in water, and uniformly mixing to obtain a mixed system; concentrating and drying the mixed system, and calcining in a muffle furnace to obtain solid powder; and washing and drying to obtain the manganese oxide modified copper-manganese spinel catalyst.

The invention also provides a method for degrading BPA in the high-salinity water body, which is to add the copper-manganese spinel and the persulfate modified by the manganese oxide into the high-salinity water body for degradation treatment; the high salinity water generally refers to wastewater having a Total Dissolved Solids (TDS) mass fraction greater than 3.5%;

the manganese oxide modified copper-manganese spinel is prepared by the following method:

dispersing soluble divalent copper salt, divalent manganese salt, polyethylene glycol and citric acid in water, and uniformly mixing to obtain a mixed system; concentrating and drying the mixed system, and calcining in a muffle furnace to obtain solid powder; washing and drying to obtain the manganese oxide modified copper manganese spinel catalyst which is marked as Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄。

In one embodiment of the invention, the high salinity water is an aqueous environment system having a Total Dissolved Solids (TDS) mass fraction greater than 3.5%, comprising any one or more of the following cations: na (Na)⁺、K⁺(ii) a And any one or more of the following anions: cl^-、NO₃ ^-、HCO₃ ^-、CO₃ ^2-、SO₄ ^2-、HPO₄ ^3-。

In one embodiment of the invention, the adding amount of the manganese oxide modified copper manganese spinel relative to the water body or the high-salinity water body is 0.05-0.3g/L; preferably 0.15 to 0.25g/L; further preferably 0.20 to 0.25g/L.

In one embodiment of the present invention, persulfate (PS) is selected from cheap and readily available Peroxodisulfate (PDS); the peroxodisulfate can be sodium peroxodisulfate or potassium peroxodisulfate; sodium peroxodisulfate is preferred.

In one embodiment of the invention, the adding amount of the peroxydisulfate relative to the water body or the high-salt water body is 1.0-2.5mmol/L; preferably, the adding amount is 1.5-2.5mmol/L; further preferably 2.0 to 2.5mmol/L.

In one embodiment of the invention, the temperature of calcination is 550 to 750 ℃; the time is 1-3h. The specific calcining temperature can be selected as 600 ℃, and the time can be selected as 2 hours.

In one embodiment of the present invention, the temperature of the degradation treatment is not limited, and common room temperature is applicable.

In one embodiment of the invention, the experimental concentration of the target contaminant BPA is between 2 and 20ppm, and the optimum BPA concentration is preferably 10ppm, considering the possible concentration of BPA in the actual sewage plant and the degradation rate.

In one embodiment of the invention, the salt concentration in the high salinity water body is 1-100g/L.

In one embodiment of the present invention, in the preparation of the manganese oxide-modified copper manganese spinel catalyst, the cupric salt is selected from the group consisting of: copper nitrate, copper nitrate trihydrate, copper chloride dihydrate; the divalent manganese salt is selected from: manganese acetate tetrahydrate, manganese nitrate, manganese chloride.

In one embodiment of the invention, in the process of preparing the manganese oxide modified copper-manganese spinel catalyst, the concentration of the cupric salt in the mixed system is 0.01-0.04mol/L; preferably 0.03 to 0.04mol/L. Specifically, 0.0375mol/L can be selected.

In one embodiment of the invention, in the process of preparing the manganese oxide modified copper manganese spinel catalyst, the concentration of the divalent manganese salt in the mixed system is 0.1-0.4mol/L; preferably 0.3 to 0.4mol/L. Specifically, 0.3375mol/L can be selected.

In one embodiment of the invention, in the process of preparing the manganese oxide modified copper manganese spinel catalyst, the molar ratio of copper ions in the cupric salt to manganese ions in the manganous salt is 1: (1-9); further preferably 1: (3-9); most preferably 1:9.

In one embodiment of the invention, in the preparation of the manganese oxide modified copper manganese spinel catalyst, the molar ratio of citric acid to copper ions in the cupric salt is (20-50): 3; preferably 30:3.

in one embodiment of the invention, in the process of preparing the manganese oxide modified copper manganese spinel catalyst, the mass ratio of polyethylene glycol to citric acid is (0.2-3) to 1; preferably (1-2): 1; 1.2 can be selected specifically.

In one embodiment of the invention, in the process of preparing the manganese oxide modified copper manganese spinel catalyst, the concentration of polyethylene glycol in a mixed system is 0.05-0.1g/mL; preferably 0.08 to 0.1mol/L. Specifically, 0.0875g/mL can be selected.

In one embodiment of the invention, in the process of preparing the manganese oxide modified copper manganese spinel catalyst, the concentration of citric acid in a mixed system is 0.1-0.4mol/L; preferably 0.3 to 0.4mol/L. Specifically, 0.375mol/L can be selected.

In one embodiment of the invention, the manganese oxide modified copper manganese spinel catalyst (Mn)₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄) The preparation method specifically comprises the following steps:

(1) Adding water to dissolve a copper source which is copper nitrate trihydrate and a manganese source which is manganese acetate tetrahydrate, adding a dispersant polyethylene glycol and a complexing agent citric acid, and magnetically stirring for 30min to form a light blue mixed system in a uniform complexing state;

(2) Transferring the mixed system into a crucible, and drying at 65 ℃ for 30min; then transferring the dried complex into a muffle furnace, heating to 600 ℃, and calcining for 2h; repeatedly washing the calcined powder with ethanol and deionized water, filtering, collecting solid, drying in a 60 deg.C oven overnight to obtain the Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄。

Has the advantages that:

(1) The method has the advantages of simple catalyst preparation process, rich and cheap materials and suitability for large-scale production and use.

(2) The copper manganese spinel modified by the manganese oxide prepared by the invention can degrade BPA under high salt (100 g/L) in a short time.

(3) The manganese oxide modified copper-manganese spinel has a stable structure and a small amount of metal elution, can achieve a degradation effect of more than 98% on BPA after being repeated for five times, and is efficient and environment-friendly.

(4) The reaction system can achieve the degradation effect of more than 95 percent on BPA within the pH range of 5-9, and is suitable for removing part of organic pollutants in actual water.

Drawings

FIG. 1 is a graph showing the effect of adsorption of BPA by pure copper manganese spinel in comparative example 1.

FIG. 2 is a graph showing the effect of pH on the reaction in example 2.

FIG. 3 is a graph showing the effect of the addition of persulfate on the treatment in example 3.

FIG. 4 is a graph showing the effect of bisphenol A concentration on treatment in example 4.

FIG. 5 shows Mn for catalyst in example 5₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The adding amount affects the treatment effect.

FIG. 6 shows Mn as a catalyst in example 6₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄And recycling the influence graph of the treatment effect.

FIG. 7 is a graph showing the effect of NaCl addition on the treatment effect in example 7 under conditions simulating high salinity wastewater conditions.

FIG. 8 shows the addition of Na in example 8₂SO₄And (3) simulating an influence graph of high-salinity wastewater conditions on treatment effect.

FIG. 9 is a graph comparing the BPA removal rates of copper manganese complex oxide catalysts synthesized by different methods in comparative example 2.

FIG. 10 shows Cu of Cu-Mn composite oxide catalyst synthesized by different methods in comparative example 2²⁺、Mn²⁺Comparative graph of ion elution。

FIG. 11 shows Mn as a catalyst obtained in example 1₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄XRD pattern of (a).

FIG. 12 is a comparison of the BPA removal results for spinel materials synthesized with different copper to manganese ratios in example 9 (one).

FIG. 13 is a graph comparing the BPA removal rates of spinel materials synthesized with different concentrations of polyethylene glycol in example 9 (II).

FIG. 14 is a graph comparing the BPA removal rates of spinel materials synthesized with different concentrations of citric acid from example 9 (III).

Detailed Description

The present invention is described in further detail below with reference to specific examples, but the embodiments of the present invention are not limited to these examples.

The following relates to BPA removal = (BPA concentration after degradation-initial BPA concentration)/initial BPA concentration 100%.

Cu as described below²⁺、Mn²⁺The elution amount is the content of free Cu and Mn ions in the system.

Example 1

Preparing manganese oxide modified copper manganese spinel:

preparation of Mn by citrate complexation₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄

(1) Dissolving 0.36g (1.5 mmol) of copper nitrate trihydrate and 3.31g (13.5 mmol) of manganese acetate tetrahydrate in 40mL of deionized water, stirring uniformly, then adding 3.5g of polyethylene glycol (PEG 2000) as a structure directing agent and 2.88g (15 mmol) of citric acid as a complexing agent, and magnetically stirring for 30min at room temperature to form a light blue mixture in a uniform complexing state;

(2) Transferring the uniform mixture into a crucible, and drying in a 65 ℃ oven for 30min; then transferring the dried complex into a muffle furnace, heating to 600 ℃, and calcining for 2h; repeatedly washing calcined powder with ethanol and deionized water, filtering, collecting solid, and drying in oven at 60 deg.C overnightFinally obtaining the manganese oxide modified copper manganese spinel catalyst Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄。

Degrading bisphenol A in water:

adding a target pollutant BPA into deionized water, controlling the concentration of the BPA to be 10ppm, adding BPA into the deionized water, then adding 2mmol/L sodium peroxodisulfate into the water body with the pH =6.3 (neutral), and uniformly mixing; adding copper manganese spinel modified by manganese oxide, wherein the adding amount is 0.2g/L, adding a rotor for uniformly dispersing pollutants, an oxidant and a catalyst, stirring at the stirring speed of 200r/min, sampling and filtering at a certain time interval, adding a quenching agent ethanol, and detecting the concentration of BPA remained in the solution by using high performance liquid chromatography.

The treatment effect obtained in this example is shown in table 1:

TABLE 1

pH before reaction	6.3
		System pH after reaction	3.9
BPA removal Rate (after 120 min)	100％
		Cu²⁺Amount of elution (ppm)	1.1571
Mn²⁺Amount of elution (ppm)	2.454

Example 2

Referring to example 1, a target pollutant BPA was added to deionized water, the BPA concentration was controlled to be 10ppm, and the pH of the water body after BPA addition was =6.3 (neutral), and in order to explore the pH conditions suitable for experiments, the pH of the solution was adjusted to 4.5, 6.3 (initial pH), 7.5, 9, 10.5 with 0.1mol/L HCl and NaOH, respectively, and then 2mmol/L sodium peroxodisulfate was added, which was relatively small after the addition to the system due to the acidity of sodium peroxodisulfate; finally, adding the copper-manganese spinel modified by the manganese oxide, wherein the adding amount is 0.2g/L. In order to disperse pollutants, oxidant and catalyst uniformly, a rotor is added for stirring, the stirring speed is 200r/min, sampling and filtering are carried out at certain time intervals, a quenching agent ethanol is added, and the concentration of BPA left in the solution is detected by using high performance liquid chromatography.

The effect of the treatment with different pH without salt obtained in this example is shown in Table 2:

TABLE 2 treatment Effect in different pH environments

pH before reaction	4.5	6.3	7.5	9.0	10.5
						System pH after reaction	3.8	3.9	4	4.1	7.5
BPA removal Rate (after 120 min)	99％	100％	97％	92％	70％
						Cu²⁺Amount of elution (ppm)	1.3438	1.1571	1.1314	1.0715	0.0648
Mn²⁺Amount of elution (ppm)	2.5342	2.454	2.2949	2.1386	0.174

As can be seen from Table 2, mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄Can activate sodium peroxodisulfate to degrade BPA under wider water body pH conditions (4.5-9.0), and Cu²⁺、Mn²⁺The ion elution amount is continuously reduced along with the rising of pH, and can still reach the standard of the Water quality control project for discharging sewage into the urban sewer under the acidic state, thereby being environment-friendly and practical.

Example 3

Referring to example 1, sodium peroxodisulfate was added to a water body containing BPA as a target pollutant in an amount of 0.2, 1, 1.5, 2, 3mmol/L at a BPA concentration of 10ppm, and finally an equivalent amount of manganese oxide-modified copper manganese spinel was added in an amount of 0.2g/L. In order to disperse pollutants, oxidant and catalyst uniformly, a rotor is added for stirring, the stirring speed is 200r/min, sampling and filtering are carried out at certain intervals, quenching and ethanol are added, and the concentration of BPA left in the solution is detected by high performance liquid chromatography.

The effect of adding different amounts of oxidizing agent on BPA obtained in this example is shown in table 3:

TABLE 3 Water quality parameters after addition of materials

Sodium peroxodisulfate (mmol/L)	0.2	1	1.5	2	3
						BPA removal Rate (after 120 min)	47％	81％	97％	100％	100％

As can be seen from Table 3, the effect of the oxidizing agent is saturated when it is added in a certain amount, and the excessive amount of the oxidizing agent does not significantly promote the degradation of BPAThe effect is that the pH value of the water body is reduced and Cu is generated after the sodium peroxodisulfate is excessively added (when the concentration is 3 mmol/L)²⁺、Mn²⁺Dissolution also increases, and the optimum amount of the oxidizing agent is 2mmol/L.

Example 4

Referring to example 1, sodium peroxodisulfate was added to a water body containing the target pollutant BPA at concentrations of 2, 6, 8, 10, 12, 16ppm, respectively, in an amount of 2mmol/L, and finally an equivalent amount of manganese oxide-modified copper manganese spinel was added in an amount of 0.2g/L. In order to disperse pollutants, oxidant and catalyst uniformly, a rotor is added for stirring, the stirring speed is 200r/min, sampling and filtering are carried out at certain intervals, quenching and ethanol are added, and the concentration of BPA left in the solution is detected by high performance liquid chromatography.

This example gives Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The effect of activated peroxodisulfate on the treatment of BPA at different concentrations is shown in Table 4:

TABLE 4 Effect of different concentrations of BPA

BPA concentration (ppm)	2	6	8	10	12	16
							BPA removal Rate (after 120 min)	100％	100％	100％	100％	95％	88％

As can be seen from table 4, this treatment method has excellent treatment effects on lower concentrations of the target contaminants.

Example 5

Referring to example 1, sodium peroxodisulfate was added to a water body containing the target contaminant BPA at a concentration of 10ppm and in an amount of 2mmol/L, and finally the equivalent amount of manganese oxide-modified copper manganese spinel was added in an amount of 0.05, 0.1, 0.15, 0.2, 0.3g/L, respectively. In order to disperse pollutants, oxidant and catalyst uniformly, a rotor is added for stirring, the stirring speed is 200r/min, sampling and filtering are carried out at certain intervals, quenching and ethanol are added, and the concentration of BPA left in the solution is detected by high performance liquid chromatography.

Mn obtained in example₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The effect on BPA treatment at different dosages is shown in Table 5:

TABLE 5 Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄Treatment effect of different adding amount

The adding amount of the catalyst is g/L	0.05	0.1	0.15	0.2	0.3
						BPA removal Rate (after 120 min)	87％	93％	98％	100％	100％

As can be seen from Table 5, the treatment effect was still better with the amount as low as 0.05g/L, depending on Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The more BPA is degraded due to the increase of the addition, and the removal rate is up to more than 98% when the addition is 0.15-0.3 g/L. However, mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄Excessive addition (above 0.2 g/L) can result in Cu²⁺、Mn²⁺Excessive dissolution and resulting waste of catalyst material, taking Mn into account₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The optimum dosage of (2) is 0.2g/L.

Example 6

Referring to the degradation process of example 1, catalyst Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄Adding the BPA into a water body containing a target pollutant BPA, adding sodium peroxodisulfate, sampling at a certain time, filtering, adding a quenching agent ethanol, measuring the concentration of the residual BPA in the sample by using high performance liquid chromatography until the target pollutant BPA is completely degraded, and thenFiltering out the catalyst; and repeatedly washing with ethanol and deionized water, drying in an oven at 60 ℃ overnight, collecting, adding into water containing 10ppm of target pollutant BPA at a dosage of 0.2g/L, adding sodium peroxodisulfate, and repeating the experiment to test the recyclable times of the catalyst, wherein the results are shown in Table 6.

TABLE 6 Recycling treatment Effect of manganese oxide modified copper manganese spinel

As can be seen from Table 6, mn is present in the catalyst₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄After the catalyst is recycled for 5 times, the degradation effect of BPA can reach more than 99 percent, so that the catalyst is expected to be recycled for multiple times in the reaction system.

Example 7

Adding sodium chloride into a water body containing a target pollutant BPA, wherein the concentration of the target pollutant BPA is 10ppm, the concentration of sodium chloride salt in high-salt wastewater is 1, 50 and 100g/L as shown in Table 7, the adding amount of sodium peroxodisulfate is 2mmol/L, and finally adding 0.2g/L of manganese oxide modified copper-manganese spinel. In order to disperse the substances uniformly, a rotor is added for stirring at the stirring speed of 200/min, samples are taken at certain intervals for filtering, quenching and ethanol are added, and the concentration of the residual BPA in the solution is detected by high performance liquid chromatography.

The effect of the treatment under the different NaCl concentrations obtained in this example is shown in Table 7:

TABLE 7 BPA degradation treatment Effect in NaCl environments of different concentrations

NaCl concentration g/L	1	50	100
				BPA removal Rate (after 120 min)	100％	100％	100％

As can be seen from Table 7, the degradation treatment process can be applied to a wide NaCl concentration range. BPA degradation can also reach 100% removal at concentrations as high as 100g/L. As can be seen from FIG. 7, the addition of NaCl promotes the degradation of BPA, and the promotion is more pronounced at higher concentrations.

Example 8

Adding sodium sulfate into a water body containing a target pollutant BPA, simulating partial conditions of high-salinity wastewater by using high-concentration sulfate radicals, wherein the concentration of the target pollutant BPA is 10ppm, the adding amount of the sodium sulfate is 1, 2, 50 and 100g/L respectively, the adding amount of the sodium persulfate is 2mmol/L, and finally adding an equivalent amount of nano-grade copper-manganese spinel modified by an equivalent amount of manganese oxide, wherein the adding amount is 0.2g/L. In order to disperse the substances uniformly, a rotor is added for stirring, the stirring speed is 200r/min, sampling and filtering are carried out at certain intervals, quenching and ethanol are added, and the concentration of BPA left in the solution is detected by high performance liquid chromatography.

The treatment effect obtained in this example under different sodium sulfate concentration test conditions is shown in table 8:

TABLE 8 different concentrations of Na₂SO₄Effects of treatment

Na₂SO₄The adding amount is g/L	1	2	50	100
					BPA removal Rate (after 120 min)	99.2％	97％	76％	78％

As can be seen from Table 8, the degradation process can be applied to a wider Na₂SO₄Concentration range. When the concentration is 1-100g/L in the high salt state, the BPA removal rate is not lower than 76%.

Comparative example 1

Referring to example 1, the manganese oxide modified copper manganese spinel is directly added into a water body containing target pollutant BPA without adding persulfate and other conditions. Sampling, filtering and adding a quenching agent ethanol at a certain time, measuring the concentration of the residual BPA in the sample by using high performance liquid chromatography, and researching Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄Whether there is adsorption of the contaminant BPA.

This example gives Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The adsorption effect on BPA is shown in Table 9.

TABLE 9 Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄Adsorption Effect on BPA

Time (min)	5	15	30	60	90	120
							BPA removal rate	4.3％	6.5％	8.1％	12.9％	14.2％	15.7％

As can be seen from Table 9, mn alone is used₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The treatment process has no obvious and negligible adsorption and degradation effects on the BPA pollutants.

Comparative example 2 comparison of degradation effects of different copper-manganese composite oxides on BPA

Referring to example 1, a different catalyst was used instead:

adding peroxodisulfate into a water body containing a target pollutant BPA, wherein the concentration of the target pollutant BPA is 10ppm, and the adding amount of sodium peroxodisulfate is 2mmol/L; the copper-manganese composite oxides (including the manganese oxide-modified copper-manganese spinel in the method) prepared by three different preparation methods shown in table 10 were added, respectively, and in order to disperse the substances uniformly, a rotor was added and stirred at a stirring speed of 200r/min, samples were taken at certain intervals and filtered, and then quenching and ethanol were added, and the concentration of BPA remaining in the solution was detected by high performance liquid chromatography.

Wherein the copper-manganese composite oxide prepared by the gel sol method is Mn₃O₄-Cu_1.5Mn_1.5O₄The preparation process comprises the following steps: dissolving 0.005mol of copper acetate and 0.015mol of manganese acetate tetrahydrate in 200mL of ethanol solution, and magnetically stirring for 10min; adding a certain amount of polyvinylpyrrolidone into the mixed solution, and magnetically stirring again to obtain a uniform and transparent solution; transferring the obtained mixed solution into an ultra-constant temperature water bath kettle at 85 ℃ to prepare gel, and calcining at 400 ℃ for 4h to obtain Mn₃O₄-Cu_1.5Mn_1.5O₄And (3) sampling.

The copper-manganese composite oxide prepared by the solvothermal method is Mn₂O₃-Cu_1.5Mn_1.5O₄The preparation process comprises the following steps: dissolving 1mmol of copper acetate and 2mmol of manganese acetate tetrahydrate in a proper amount of ethylene glycol by magnetic stirring to form a clear solution; then 30mmol ammonium carbonate is added at room temperature, and stirring is carried out vigorously for 30min; the resultant mixture was transferred to 50cm³Carrying out hydrothermal reaction in a stainless steel high-pressure reaction kettle at the temperature of 200 ℃ for 20 hours; centrifuging to collect residue, repeatedly cleaning with ethanol and deionized water, and oven drying at 60 deg.C overnight to obtain CuMn₂CO₃A precursor; calcining the collected precursor in air at 800 ℃ for 10h to obtain Mn₂O₃-Cu_1.5Mn_1.5O₄And (3) sampling.

The results of treatment of BPA-containing water bodies with different manganese oxide-modified copper manganese spinels are shown in table 10.

TABLE 10 treatment Effect of different manganese oxide-modified copper manganese spinels

Preparation method	Gel sol process	Citrate complexation method	Solvothermal process
				Catalyst and process for preparing same	Mn₃O₄-Cu_1.5Mn_1.5O₄	Mn₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄	Mn₂O₃-Cu_1.5Mn_1.5O₄
BPA removal Rate (after 120 min)	100％	100％	95.8％
				Cu²⁺Amount of elution (ppm)	3.82	1.01	5.75
Mn²⁺Amount of elution (ppm)	7.60	2.45	5.38

As can be seen from Table 10, several different preparation methods were usedWhen the obtained manganese oxide modified copper manganese spinel is used for treating salt-free water body, mn synthesized by a gel sol method₃O₄-Cu_1.5Mn_1.5O₄Mn synthesized by citrate complexation₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The best treatment effect, but Mn synthesized by citrate complexation method₂O₃/Mn₃O₄-Cu_1.5Mn_1.5O₄The ion elution amount is minimum, so that the method is more favorable for recycling, and is more practical and environment-friendly.

Example 9: degradation comparison of manganese oxide modified copper manganese spinel obtained in preparation processes of different citrate complexation methods

(I) optimizing the dosage conditions of Cu and Mn

Referring to the procedure for preparing the catalyst of example 1, only the molar ratio of Cu to Mn was changed, and the others were not changed, to obtain a corresponding spinel product. BPA was then degraded following the procedure of example 1, with the results shown in the following table.

TABLE 11 degradation efficiency and ion elution of catalysts prepared with different Cu and Mn contents

And (4) analyzing results: as can be seen from Table 11, when the Cu content in the material was increased, cu was present in the solution²⁺Since the elution amount is also increased and the efficiency of removing BPA is also decreased, the spinel material synthesized after the comparison preferably has a Cu: mn =1:9 with the best effect and is environmentally friendly.

(II) Structure directing agent optimization

Referring to the procedure for preparing the catalyst of example 1, only the amount of polyethylene glycol (PEG 2000) was changed, and the others were not changed, to obtain the corresponding spinel product. BPA was then degraded following the procedure of example 1, with the results shown in the following table.

TABLE 12 catalyst degradation efficiency and ion elution for different concentrations of polyethylene glycol participating in synthesis

The amount of polyethylene glycol used	0.7g	3.5g	7.0g
				m (polyethylene glycol) m (citric acid)	0.24:1	1.2:1	2.4:1
BPA removal Rate (after 120 min)	100％	100％	100％
				Cu²⁺Amount of elution (ppm)	2.25	1.01	1.11
Mn²⁺Amount of elution (ppm)	2.52	2.45	3.04

And (4) analyzing results: from Table 12, it can be seen that the change of the concentration of the participating structure-directing agent polyethylene glycol does not affect the degradation effect on BPA, but the addition of polyethylene glycol under the condition that m (polyethylene glycol): m (citric acid) is 1.2.

(III) optimization of complexing Agents

Referring to the procedure for preparing the catalyst of example 1, only the amount of Citric Acid (CA) was changed, and the others were not changed, to obtain the corresponding spinel product. BPA was then degraded following the procedure of example 1, with the results shown in the following table.

TABLE 13 catalyst degradation efficiency and ion elution for different concentrations of citric acid involved in synthesis

Amount of citric acid	10mmol	15mmol	25mmol
				n (citric acid): n (Cu)²⁺)	20:3	30:3	50:3
BPA removal Rate (after 120 min)	99.28％	100％	100％
				Cu²⁺Amount of elution (ppm)	1.18	1.01	2.97
Mn²⁺Amount of elution (ppm)	2.46	2.45	3.07

And (4) analyzing results: as can be seen from table 13, varying the concentration of the participating complexing agent citric acid, the degradation of BPA was slightly inhibited at low concentrations, and the resulting catalyst material was more efficient and environmentally friendly when citric acid was added at a dosage of 30.

Claims

1. A method for degrading BPA in water is characterized in that a copper manganese spinel catalyst modified by manganese oxide and persulfate are added into a water body for degradation treatment; the persulfate is a peroxydisulfate salt; the pH value of the water body is 4.5 or 6.3; the adding amount of the peroxydisulfate relative to the water body is 2-2.5mmol/L or 3mmol/L; the concentration of the BPA is 2-10ppm; the adding amount of the manganese oxide modified copper manganese spinel relative to a water body is 0.15-0.3 g/L;

2. A method for degrading BPA in a high-salinity water body is characterized in that copper-manganese spinel and persulfate modified by manganese oxide are added into the high-salinity water body for degradation treatment; the high-salinity water body is a water body with the mass fraction of total soluble solids more than 3.5%; the persulfate is a peroxydisulfate salt; the concentration of the BPA is 2-10ppm; the adding amount of the manganese oxide modified copper manganese spinel relative to a high-salt water body is 0.15-0.3 g/L;

the manganese oxide modified copper manganese spinel is prepared by the following method:

3. The process according to claim 1 or 2, wherein the molar ratio of copper ions in the cupric salt to manganese ions in the manganous salt is 1:1-9.

4. The process according to claim 1 or 2, wherein the molar ratio of citric acid to copper ions in the copper (ll) salt is 20 to 50:3.

5. the method of claim 1 or 2, wherein the mass ratio of polyethylene glycol to citric acid is 0.2 to 3:1.

6. The method of claim 2, comprising any one or more of the following cations: na (Na)⁺、K⁺(ii) a And any one or more of the following anions: cl^-、NO₃ ^-、HCO₃ ^-、CO₃ ^2-、SO₄ ^2-、HPO₄ ^3-。

7. The method according to claim 1 or 2, wherein the concentration of the divalent copper salt in the mixed system is 0.01 to 0.04mol/L.

8. The method according to claim 1 or 2, wherein the concentration of the divalent manganese salt in the mixed system is 0.1 to 0.4mol/L.