Metal oxide supported copper hydroxide catalyst system and use thereof

Abstract

The application belongs to the field of organic pollutant degradation, and relates to a metal oxide supported copper hydroxide catalyst system and application thereof. The metal oxide supported copper hydroxide system comprises a surface hydroxyl-containing metal oxide and copper hydroxide, and the molar ratio of the surface hydroxyl-containing metal oxide to the copper hydroxide is (1-200):1. The metal oxide supported copper hydroxide catalyst system is obtained by mixing the surface hydroxyl-containing metal oxide and a divalent copper salt solution, adjusting the pH to 7-10, and then reacting. 1 In the catalyst system, the interaction between the metal oxide carrier and Cu(OH)2 promotes electron transfer, and the two synergistically promote the reaction of Cu(OH)2 and peroxymonosulfate to generate active species Cu(III) and O2, and further deeply oxidize and degrade bromophenol and other organic pollutants.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic pollutant degradation, and more particularly relates to a metal oxide supported copper hydroxide catalyst system and application thereof. BACKGROUND

[0002] Advanced oxidation processes (AOPs) use active oxygen species with higher oxidation efficiency to degrade organic matter, and have a deeper degree of mineralization of organic matter, and are considered the best choice for removing organic pollutants in water. Common oxidants include hydrogen peroxide, persulfate (PMS, HSO5 - ) and peroxymonosulfate (PDS, S2O8 2- ) and the like. Among them, the molecular formula of PMS is KHSO5, the O-O structure is asymmetric, the bond length of O-O bond is and the bond energy is about 140-213.3 kJ / mol. The oxidation-reduction potential of PMS is 1.82 V, which is a thermodynamic strong oxidant, but the rate of direct oxidation of organic pollutants is slow, and generally requires the introduction of external energy or catalyst to activate and decompose active oxygen, which then rapidly oxidizes organic pollutants. PMS can be activated by various transition metal ions, such as Co 2+ , Mn 2+ , Ni 2+ , Fe 2+ , V 3+ , Ru 3+ . Among them, Co 2+ / PMS system shows the best performance, even better than the traditional Fenton reaction under neutral pH conditions, but Co 2+ has potential toxicity, and dissolution under acidic conditions is inevitable, so it is rarely applied in practice.

[0003] Compared with cobalt catalyst, copper catalyst has low price, low toxicity, wide applicable pH range, and good application prospect in transition metal activated PMS. Copper / PMS homogeneous system has high oxidation efficiency and simple operation, but has problems such as secondary pollution of metal ions, instability and difficulty in recovery of catalyst. Copper-based heterogeneous catalyst has high stability, low toxicity and good recyclability, and the catalyst can be easily separated from the reaction system and recycled, which can effectively avoid the secondary pollution caused by the loss of catalyst. It is gradually developed for the activation of PMS.

[0004] The existing, for example, nano zero-valent copper has attracted extensive attention due to high surface reactivity and unique redox performance, however, nano zero-valent copper is easy to aggregate, resulting in a decrease in active surface area, and generally needs to be modified. For example, copper oxide is the most studied, which has the advantages of fast reaction rate, high oxidant utilization rate and low metal ion dissolution, and is often used to activate PMS, but has problems such as difficult preparation. In addition to directly using copper compounds to activate PMS, copper species can also be fixed on various materials to form supported copper-based composite catalysts. The supported copper catalysts not only can significantly inhibit the dissolution of copper ions, but also can improve the physical and chemical properties of copper species through the interaction between copper species and the carrier, increase the number of active sites, and improve the activity and stability of the catalyst, which has attracted widespread attention.

[0005] Among the numerous copper-based catalysts, copper hydroxide sol has poor thermal stability in aqueous solution and will be converted into low-activity copper oxide above 25℃, and is easy to aggregate; in addition, the settling speed of the sol is slow, and it is difficult to separate and recover, which seriously limits the actual application effect. SUMMARY

[0006] In view of the above defects or improvement needs of the prior art, the present application provides a metal oxide supported copper hydroxide catalyst system and its application in activating peroxymonosulfate to degrade bromophenol organic matter. The metal oxide supported copper hydroxide catalyst system comprises a metal oxide containing hydroxyl groups on the surface and copper hydroxide. In the application of the catalyst system, the metal oxide is used as a carrier, and the interaction between the hydroxyl groups on the surface of the carrier and Cu(OH)2 is utilized to establish a hydrolysis loading method for efficiently activating PMS to degrade bromophenol organic matter.

[0007] To achieve the object of the present application, in the first aspect of the present application, a metal oxide supported copper hydroxide catalyst system is provided, comprising: a metal oxide containing hydroxyl groups on the surface and copper hydroxide, the molar ratio of the metal oxide containing hydroxyl groups on the surface to the copper hydroxide is (1-200):1.

[0008] The metal oxide supported copper hydroxide catalyst system is obtained by mixing the metal oxide containing hydroxyl groups on the surface and a divalent copper salt solution, adjusting the pH to 7-10, and then reacting.

[0009] As a preferred embodiment of the present application, the metal oxide containing hydroxyl groups on the surface is one of aluminum oxide, iron oxide, titanium dioxide, zinc oxide and magnesium oxide; preferably, the aluminum oxide is gamma aluminum oxide and the iron oxide is magnetite.

[0010] As a preferred embodiment of the present application, the molar ratio of the metal oxide to the copper hydroxide is preferably (20-150):1.

[0011] As a preferred embodiment of the present application, the divalent copper salt is copper sulfate, copper nitrate or copper chloride.

[0012] As a preferred embodiment of the present application, the time for the surface hydroxyl-containing metal oxide and the divalent copper salt solution to react after being mixed is 2-30 min.

[0013] In the second aspect of the present application, the use of the metal oxide supported copper hydroxide catalyst system to activate peroxymonosulfate to degrade bromophenol organic matter is provided.

[0014] As a preferred embodiment of the present application, the degradation of bromophenol organic matter specifically includes: adding the metal oxide supported copper hydroxide catalyst system to the bromophenol organic matter solution, mixing uniformly to form a solution to be degraded, and then adding a peroxymonosulfate solution.

[0015] As a preferred embodiment of the present application, the molar ratio of the copper hydroxide to the bromophenol organic matter is (0.001-0.5):1, and the molar ratio of the copper hydroxide to the peroxymonosulfate is (0.01-1):1.

[0016] As a preferred embodiment of the present application, after the solution to be degraded is formed, the pH of the solution to be degraded is adjusted to 7-12.

[0017] As a preferred embodiment of the present application, the temperature for degrading bromophenol organic matter is 5°C-55°C.

[0018] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0019] (1) The present application designs a system containing metal oxide supported copper hydroxide, uses the metal oxide supported copper hydroxide to efficiently activate peroxymonosulfate, and the generated trivalent copper and singlet oxygen can efficiently and quickly degrade effective organic pollutants. The selected metal oxide carrier is rich in surface hydroxyl groups, which not only can improve the stability of Cu(OH)2 through hydrogen bond combination, fixation and dispersion, but also can promote electron transfer through the interaction between the carrier and Cu(OH)2, and both of them can synergistically promote the reaction of Cu(OH)2 and PMS to generate active species Cu(III) and O2, and then deeply oxidize and degrade organic matter. Especially, the catalytic performance of the carrier γ-Al2O3 / Cu(OH)2 and Fe3O4 / Cu(OH)2 prepared by taking γ-Al2O3 and Fe3O4 as the carrier is the highest, and the pseudo-first-order apparent rate constant k of the degradation of TBBPA is 2.5 and 6 times that of Cu(OH)2 without carrier, respectively. 1 O2, and then deeply oxidize and degrade organic matter. Especially, the catalytic performance of the carrier γ-Al2O3 / Cu(OH)2 and Fe3O4 / Cu(OH)2 prepared by taking γ-Al2O3 and Fe3O4 as the carrier is the highest, and the pseudo-first-order apparent rate constant k of the degradation of TBBPA is 2.5 and 6 times that of Cu(OH)2 without carrier, respectively.

[0020] (2) In the present application, the metal oxide rich in surface hydroxyl groups is used as the carrier to improve the activity and stability of Cu(OH)2 by the interaction between the carrier and Cu(OH)2, to disperse and fix Cu(OH)2 by the confinement effect, and to effectively avoid the problems of Cu(OH)2 agglomeration in the solution and dehydration to generate CuO at high temperature, so that the catalyst exhibits good thermal stability, anti-interference ability and relatively wide pH application range. The thermal stability of Cu(OH)2 without carrier is very poor, which will be dehydrated and converted into CuO with lower activity at more than 25℃; and the speed of the metal oxide loaded Cu(OH)2 activated PMS to degrade TBBPA gradually increases with the temperature from 15℃ to 55℃, which has good thermal stability. In addition, the stability of the metal oxide loaded Cu(OH)2 catalyst is significantly improved, which can still degrade 93% of TBBPA after 5 cycles, while the Cu(OH)2 without carrier can only degrade 62% of TBBPA.

[0021] In summary, the metal oxide loaded copper hydroxide substance and the method for activating PMS to degrade brominated pollutants prepared by the present application utilize the metal oxide loaded copper hydroxide or its stable product to perform degradation, which has the advantages of simple and convenient process operation (in-situ loading), mild reaction conditions (weak alkaline pH and room temperature), short time consumption (fast and efficient), no need of high temperature and high pressure and organic solvent, and can be directly applied to on-site degradation of pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The transmission electron microscope, infrared absorption spectrum and ultraviolet-visible diffuse reflectance spectrum of γ-Al2O3 / Cu(OH)2 prepared in-situ in Example 1 of the present application are shown in FIG. 1; wherein Figure 1 a in FIG. 1 is the transmission electron microscope of γ-Al2O3, Figure 1 b in FIG. 1 is the transmission electron microscope of Cu(OH)2, Figure 1 c in FIG. 1 is the transmission electron microscope of γ-Al2O3 / Cu(OH)2, and the scale of the electron microscope is 5nm; wherein Figure 1 d in FIG. 1 is the ultraviolet-visible diffuse reflectance spectrum of the raw material and the corresponding product of Example 1; wherein Figure 1 e in FIG. 1 is the Fourier transform infrared spectrum of the raw material and the corresponding product of Example 1;

[0023] Figure 2 The degradation curve of different metal oxide loaded copper hydroxide and pure copper hydroxide activated persulfate to degrade tetrabromobisphenol A in Example 2 of the present application is shown in FIG. 2;

[0024] Figure 3 The degradation rate constant k of different metal oxide loaded copper hydroxide and pure copper hydroxide activated persulfate to degrade tetrabromobisphenol A in Example 2 of the present application is shown in FIG. 3;

[0025] Figure 4 Figure for degradation test of different carriers in the embodiment of the present application; Figure 4 a in Figure is degradation curve when different kinds of Al2O3 are used as carriers; Figure 4 b in Figure is degradation rate number k of Cu(OH)2 loaded with iron oxide based on different Fe 3+ content in Example 4;

[0026] Figure 5 Figure for influence of Cu(OH)2 loading amount, γ-Al2O3 amount, PMS amount and system pH on catalytic performance of γ-Al2O3 / Cu(OH)2 composite material in Example 5 of the present application; Figure 5 a in Figure is degradation rate k based on Example 5 varying with Cu(OH)2 loading amount; Figure 5 b in Figure is degradation rate k based on Example 5 varying with γ-Al2O3 amount; Figure 5 c in Figure is degradation rate k based on Example 5 varying with PMS concentration; Figure 5 d in Figure is degradation rate k based on Example 6 varying with pH;

[0027] Figure 6 Figure for test of influence of reaction temperature of system on catalytic performance of Cu(OH)2, γ-Al2O3 / Cu(OH)2 and Fe3O4 / Cu(OH)2 composite materials in Example 7 of the present application; Figure 6 a in Figure is degradation rate k based on γ-Al2O3 / Cu(OH)2 system varying with temperature; Figure 6 b in Figure is photo of Cu(OH)2 at 25℃ and 55℃;

[0028] Figure 7 Figure for magnetic separation and recovery performance of Fe3O4 / Cu(OH)2 and effect of repeatedly using Fe3O4 / Cu(OH)2 to catalyze degradation of tetrabromobisphenol A by persulfate in Example 8 of the present application; Figure 7 a in Figure is separation and recovery effect based on Fe3O4 / Cu(OH)2; Figure 7 b in Figure is absorbance change of solution after cyclic reaction based on Fe3O4 / Cu(OH)2; Figure 7 c in Figure is cyclic degradation curve based on Fe3O4 / Cu(OH)2; Figure 7 d in Figure is cyclic degradation curve based on Cu(OH)2; DETAILED DESCRIPTION

[0029] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0030] In the embodiments of the present application, a method for preparing a metal oxide supported copper hydroxide catalyst system ex situ and a method for preparing a metal oxide supported copper hydroxide catalyst system in situ are provided respectively.

[0031] The method for preparing a metal oxide supported copper hydroxide catalyst system ex situ specifically comprises:

[0032] The metal oxide is mixed with the divalent copper salt solution at room temperature, and the reaction is carried out after adjusting the pH to 7-10. The reaction time is controlled to be 2-30 min, and a mixed solution after reaction is obtained.

[0033] The mixed solution obtained by the above reaction is directly used as the metal oxide supported copper hydroxide catalyst system.

[0034] Or the mixed solution is filtered, washed with water and dried to obtain a metal oxide supported copper hydroxide catalyst powder.

[0035] The method for preparing a metal oxide supported copper hydroxide catalyst system in situ specifically comprises:

[0036] The metal oxide is added into an organic pollutant solution to form a mixed solution at room temperature, and then the divalent copper salt solution is added for mixing. The reaction is carried out after adjusting the pH to 7-10. The reaction time is controlled to be 2-30 min.

[0037] The metal oxide supported copper hydroxide catalyst system obtained by the reaction is a mixed solution system, that is, the solution to be degraded containing the metal oxide supported copper hydroxide catalyst system is directly formed by the in-situ preparation method.

[0038] In the solution to be degraded containing the metal oxide supported copper hydroxide catalyst system, the peroxymonosulfate is directly added for degrading the organic pollutants.

[0039] Based on the catalyst systems prepared by the above two methods, the catalyst system can be used for activating PMS to degrade bromophenol organic matter, and the corresponding methods for activating PMS to degrade bromophenol organic matter are in-situ degradation method and ex-situ degradation method respectively.

[0040] The method for activating PMS to degrade bromophenol organic matter provided by the embodiments of the present application is an in-situ degradation method, which specifically comprises the following steps:

[0041] Preparation of the solution to be degraded:

[0042] Add an appropriate amount of metal oxide powder to a bromophenol organic solution, disperse it evenly by ultrasonication, and then add a divalent copper salt solution dropwise.

[0043] The metal oxide is one of aluminum oxide, iron oxide, titanium dioxide, zinc oxide, and magnesium oxide; preferably γ-type aluminum oxide and iron(III) oxide.

[0044] In this embodiment of the invention, the degradation of tetrabromobisphenol A (TBBPA) is taken as an example. The main component of the brominated contaminant solution is tetrabromobisphenol A. In this embodiment of the invention, 40 mg / L is selected. -1 The TBBPA solution is prepared for use, but the TBBPA solution is not limited during actual TBBPA degradation.

[0045] The molar ratio of metal oxide powder to divalent copper salt is (1–200):1; preferably (22–150):1. The divalent copper salt is selected according to the concentration of the target pollutant, including but not limited to copper sulfate, copper nitrate, or copper chloride.

[0046] The molar ratio of divalent copper salt to tetrabromobisphenol A is (0.001–0.175):1, preferably (0.016–0.112):1.

[0047] It should be noted that when the metal oxide is an iron oxide, iron(III) oxide (Fe3O4) with a ferric iron content of 50% is selected. The Fe3O4 magnetic nanoparticles prepared by the ultrasonic-assisted reverse co-precipitation method used in the embodiments of this application possess strong ferromagnetism, an average particle size of approximately 16.5 nm, and a specific surface area of ​​82.5 m². 2 g -1 It has advantages such as good dispersibility in water and good dispersion.

[0048] Degradation of the solution to be degraded:

[0049] Stir the above-mentioned solution to be degraded for 2 to 30 minutes, control the temperature of the degradation solution at 5 to 55°C and the pH at 8 to 10, so that the solution reaches adsorption-desorption equilibrium, and then quickly add PMS to start the degradation reaction of organic pollutants.

[0050] The molar ratio of divalent copper salt to persulfate is (0.448–0.0224):1, preferably (0.09–0.03):1.

[0051] The embodiment of the present application provides a method for degrading bromophenol organic matter by using metal oxide loaded copper hydroxide to activate PMS, and the embodiment of the present application detects the process of degrading bromophenol pollutants by using metal oxide loaded bivalent copper salt to activate PMS, and the specific process is as follows:

[0052] After adding PMS to start the degradation reaction of the organic pollutants in the solution to be degraded, a certain reaction time is interval, 1 mL of reaction solution is taken out and placed in a centrifugal tube containing 100 μL, 0.5 mol / L Na2S2O8, and the two are fully contacted by violent shaking to completely terminate the reaction. -1 -1 -1

[0053] After the reaction solution is centrifuged at 14000 rmp for 5 min, the supernatant is taken out, and the ultraviolet absorption of the reaction solution in the range of 200-375 nm is measured by using a Cary 60 ultraviolet-visible spectrophotometer, the concentration of TBBPA in the reaction solution is determined according to the absorbance of the absorption peak at 310 nm, so as to detect the degradation of TBBPA.

[0054] The following are some specific embodiments:

[0055] Embodiment 1: The preparation process and characterization of γ-Al2O3 in situ loaded Cu(OH)2 are as follows:

[0056] In a 50 mL solution to be degraded at 25°C, the concentration of TBBPA solution is fixed to 40 mg / L -1 , and 15 mg of γ-Al2O3 powder and 0.35 mL of 0.01 mol / L CuSO4 solution are contained therein. -1

[0057] The above-mentioned substances are mixed and stirred for 30 min, and it is measured that the solution to be degraded at this time is alkaline.

[0058] The mixed solution to be degraded is centrifuged, and the collected solid product is vacuum dried at 40°C for 12 h and then subjected to transmission electron microscope (TEM) test.

[0059] Meanwhile, the control sample Cu(OH)2 prepared according to the above-mentioned steps without adding γ-Al2O3.

[0060] From the TEM photos shown in a, b and c Figure 1 , it can be seen that γ-Al2O3 presents irregular nanosheet; when there is no carrier, Cu(OH)2 presents aggregated nanospheres with large particle size, and γ-Al2O3 / Cu(OH)2 appears nanospheres with uniform size and about 5-10 nm in diameter on the nanosheet, and Cu(OH)2 is uniformly loaded on γ-Al2O3.

[0061] As shown in Figure 1As shown in d, UV-Vis DRS testing shows that white γ-Al2O3 has no absorption, while blue Cu(OH)2 has a broad characteristic absorption peak at 720 nm. γ-Al2O3 / Cu(OH)2 shows the same absorption peak at this position and is light blue, indicating the presence of Cu(OH)2 in γ-Al2O3 / Cu(OH)2.

[0062] like Figure 1 As shown in e, Fourier transform infrared spectroscopy (FT-IR) measurements indicate that γ-Al₂O₃ / Cu(OH)₂ is located in the 500–700 cm⁻¹ region. -1 and 750-900cm -1 The two broad absorption peaks at 1478 and 1373 cm⁻¹ are characteristic absorption peaks of γ-Al₂O₃, corresponding to the AlO₄ and AlO₆ absorption peaks, respectively; -1 The characteristic double peaks of Cu-OH at the point indicate that the in-situ prepared Cu(OH)2 was successfully loaded onto γ-Al2O3.

[0063] Example 2: Degradation reaction detection when different metal oxides are used as supports, as follows:

[0064] In a 50 mL solution system at 25°C, the concentration of TBBPA solution was fixed at 40 mg / L. -1 It contains metal oxide powder and 0.01 mol L -1 The solution was prepared using CuSO4, with the molar ratio of metal oxide to added copper sulfate maintained at 22:1.

[0065] Cu(OH)₂ was in situ supported on different metal oxides (γ-alumina, titanium dioxide, zinc oxide, magnesium oxide, and Fe₃O₄). Fe₃O₄ was prepared using ultrasound-assisted reverse coprecipitation, while the other metal oxides were commercially available products purchased from a reagent company. During the ultrasound-assisted reverse coprecipitation preparation of magnetic Fe₃O₄ nanoparticles, the total iron content was maintained at 10 mmol. 3 + It accounts for 50% of the total iron content. Metal oxides were mixed with CuSO4 and stirred for 30 min to allow the solution to reach adsorption-desorption equilibrium, thus preparing a Cu(OH)2 degradation solution system supported on different metal oxides. At this point, the measured degradation solution was alkaline, with a pH of approximately 8.

[0066] And following the above method, without using metal oxides to support Cu(OH)2, a control group solution system to be degraded was prepared.

[0067] Add 0.1 g L to the 50 mL degradation solution systems using different metal oxides and those without metal oxides. -1PMS initiates the degradation reaction of organic pollutants. After a certain time (0-15 min), a quenching agent is added, and the two are thoroughly mixed by shaking to completely terminate the reaction, and the degradation experiment is started.

[0068] The results are shown in Figure 2 and Figure 3 Pure Cu(OH)2 can slowly degrade TBBPA, and the degradation rate of TBBPA is 80% within 6 min; the degradation rate of the supported Cu(OH)2 composite catalyst (i.e., the metal oxide in situ supported Cu(OH)2 composite catalyst) system is significantly faster than that of the pure Cu(OH)2 system, and different metal oxide supports have different degrees of improvement of Cu(OH)2 activity. As shown in Figure 2 , the degradation time of the metal oxide in situ supported Cu(OH)2 composite catalyst in Example 2 is within 2-6 min, and the degradation rate is higher than 80%.

[0069] From Figure 3 , overall, the degradation rate of TBBPA conforms to the pseudo-first-order reaction kinetics, and the apparent degradation rate constant k (min -1 ) follows the order: Fe3O4 / Cu(OH)2>γ-Al2O3 / Cu(OH)2>TiO2 / Cu(OH)2>ZnO / Cu(OH)2>MgO / Cu(OH)2>Cu(OH)2, which is almost consistent with the Lewis acidity order of different metal oxides: γ-Al2O3>TiO2>ZnO>MgO. Cu(OH)2 is a basic compound, which is more likely to interact with acidic metal oxides, so the stronger the Lewis acidity of the metal oxide as a carrier, the stronger the interaction between the metal oxide and Cu(OH)2, which is more conducive to the dispersion of Cu(OH)2 on the carrier, thereby increasing the specific surface area of Cu(OH)2 and improving the activity. In addition, compared with other metal oxides, Fe 2+ / Fe 3+ on the surface of Fe3O4 has variable valence, not only has a certain ability to activate PMS, but also can promote the Cu 2+ / Cu 3+ cycle, so it has the greatest promoting effect on the activation of PMS by Cu(OH)2.

[0070] Example 3: Degradation reaction detection when different types of Al2O3 or iron oxides are used as carriers, as follows:

[0071] α-Al2O3, α and γ mixed Al2O3, and γ-Al2O3 were used to in situ load Cu(OH)2 to degrade TBBPA, and the effect of Cu(OH)2 activity was investigated.

[0072] In a 50 mL solution system at 25°C, the concentration of TBBPA solution was fixed at 40 mg / L. -1 It contains 0.1g L -1 Metal oxides and 70 μmol L -1 Cu(OH)2 was used as a support to prepare different Al2O3-based degradation solution systems by loading Cu(OH)2 onto metal oxides of α-Al2O3, α- and γ-mixed Al2O3, and γ-Al2O3.

[0073] The above substances were mixed and stirred for 30 minutes to allow the solution to reach adsorption-desorption equilibrium, thus preparing a degradation solution system with different Al2O3 as the carrier. At this point, the degradation solution was measured to be alkaline, with a pH of approximately 8.

[0074] Add 0.1 g L to the above 50 mL degradation solution system. -1 The PMS was used to initiate the degradation reaction of organic pollutants. After a certain reaction time (0–15 min), a quencher was added, and the mixture was shaken vigorously to ensure full contact between the two and completely terminate the reaction, thus initiating the degradation experiment.

[0075] Figure 4 As shown in Figure a, among different alumina, γ-Al2O3 / Cu(OH)2 prepared with γ-Al2O3 as the support exhibits the highest catalytic performance. α-Al2O3 shows the worst degradation effect, degrading only 50% of TBBPA after 4 minutes. γ-Al2O3 shows the best performance, with a degradation rate as high as 96% after 4 minutes. The degradation rate of the mixed α and γ Al2O3 falls between the two, with a degradation rate of 86% within the same time period. The interaction between different crystal forms of alumina and Cu(OH)2 varies. Compared to α-Al2O3, γ-Al2O3 has a surface rich in OH groups, which may be an important reason for the difference in activity. The -OH groups on the surface of γ-Al2O3 can form hydrogen bonds with the H atoms in Cu(OH)2. This hydrogen bond interaction can effectively bind and fix Cu(OH)2, which is beneficial for its dispersion on the γ-Al2O3 surface, effectively improving the dispersibility and specific surface area of ​​Cu(OH)2, thereby enhancing its catalytic activity and stability.

[0076] The results of TBBPA degradation by PMS with different iron oxide loadings and Cu(OH)2 activation are as follows: Figure 4 As shown in b: when Fe 3+ When the content is 0, the k of FeO / Cu(OH)2 is 0.351 min. -1 With Fe 3+ With the content increased to 50%, the degradation rate k increased to 1.576 min. -1 Continue to increase Fe 3+The content reaches 100%, and the degradation rate k remains basically unchanged. Compared with Fe 2+ Fe 3+ has a stronger coordination affinity for hydroxyl groups, and the surface of the prepared iron oxide carrier has more hydroxyl groups. However, the excessive Fe x O y in Fe 3+ destroys the Fe(II) / Fe(III) cycle in the system. Under the combined action of surface hydroxyl groups and Fe(II) / Fe(III), the degradation rate first increases and then remains unchanged with the increase of Fe 3+ . Considering the degradation and magnetic separation capabilities of Fe x O y , Fe3O4 with a Fe 3+ content of 50% is selected as the best iron oxide carrier.

[0077] Example 4: Influence of catalyst composition.

[0078] Except for the experimental variables to be investigated, the basic experimental conditions and procedures are as follows: At 25 °C, in a 50 mL solution system to be degraded, the concentration of the TBBPA solution is fixed at 40 mg L -1 , which contains 0.1 g L -1 of γ-Al2O3 powder and 70 μmol L -1 of CuSO4 solution. Mix the above substances and stir for 30 min to make the solution reach the adsorption–desorption equilibrium. At this time, the solution to be degraded is measured to be alkaline with a pH of about 8.

[0079] Add 0.1 g L -1 of PMS to the above 50 mL degradation solution system to initiate the degradation reaction of organic pollutants. Within a certain reaction time (0 - 15 min), add a quenching agent and shake vigorously to make the two fully contact to completely terminate the reaction, and start the degradation experiment.

[0080] (1) Influence of Cu(OH)2 loading on the catalytic performance of γ-Al2O3 / Cu(OH)2 composite materials.

[0081] Change the dosage of copper sulfate to 0 - 110 μmol L -1 , and make its molar ratio to the added TBBPA be (0.001 - 0.175):1. Other operations are carried out according to the above basic experimental conditions.

[0082] As Figure 5 shown in a, as the dosage of Cu(II) increases from 0 to 70 μmol L -1, the k linearly increased, which was because with the increase of Cu(II) amount, the system could produce more active components. When γ-Al2O3 in situ loaded Cu(OH)2, the interaction between γ-Al2O3 and Cu(OH)2 was conducive to the dispersion of Cu(OH)2, which promoted its degradation rate to 3 times of Cu(OH)2. When the amount of Cu(II) was more than 70 μmol L -1 , the active sites produced by Cu(OH)2 activated PMS reached saturation, and the degradation rate was basically unchanged. Considering the economic benefits of the catalyst and the degradation of TBBPA, the optimal Cu(II) loading amount was selected as 10-70 μmol L -1 , and the molar ratio of copper sulfate to added TBBPA was (0.016-0.112):1.

[0083] (2) The effect of γ-Al2O3 amount on the catalytic performance of γ-Al2O3 / Cu(OH)2 composite material.

[0084] The amount of γ-Al2O3 was changed to 0.1-0.6 g L -1 , and the molar ratio of copper sulfate to added TBBPA was (0.016-0.112):1.

[0085] As shown in b of Figure 5 , with the increase of γ-Al2O3 amount from 0.1 g L -1 to 0.6 g L -1 , the k of γ-Al2O3 / Cu(OH)2 was stable at 1.15 min -1 . It was shown that the catalytic activity of γ-Al2O3 / Cu(OH)2 was independent of the amount of carrier γ-Al2O3, and Cu(OH)2 produced active sites and played a decisive role in degradation, while the main role of γ-Al2O3 was to disperse Cu(OH)2 to improve the degradation rate. Considering the economic benefits of the catalyst and the degradation of TBBPA, when the amount of γ-Al2O3 was 0.1 g L -1 to 0.6 g L -1 , the degradation effect was good, and the molar ratio of γ-Al2O3 to added copper sulfate was (22-134):1.

[0086] (3) The effect of PMS amount on the catalytic performance of γ-Al2O3 / Cu(OH)2 composite material.

[0087] The amount of PMS was changed to 0.01-0.2 g L -1 , and the molar ratio of copper sulfate to added PMS was (0.448-0.0224):1, and the other conditions were according to the above basic experimental conditions.

[0088] As shown in b of Figure 5as shown in c: As the PMS concentration increases from 0 to 0.1 g L -1 , the amount of reactive species generated in the system increases, and the rate constant k increases from 0.168 min -1 to 1.145 min -1 . As the PMS concentration further increases from 0.1 g L -1 to 0.15 g L -1 , the degradation rate of TBBPA begins to decline because high-concentration PMS generates excessive ROS, enhancing the self-scavenging effect or competition of free radicals, resulting in free radical self-quenching. Considering the economic effect and catalytic effect of PMS, 0.05 - 0.15 g L -1 is selected as the optimal PMS concentration, and the molar ratio of copper sulfate to PMS is (0.09 - 0.03):1 at this time.

[0089] Example 6: The influence of pH on degradation is as follows:

[0090] The influence of pH on the catalytic performance of γ-Al2O3 / Cu(OH)2 composite materials.

[0091] At 25 °C, in a 50 mL solution system to be degraded, the concentration of TBBPA solution is fixed at 40 mg L -1 , which contains γ-Al2O3 powder with a concentration of 0.1 g L -1 and copper sulfate solution.

[0092] Mix the above substances and stir for 30 min to make the solution reach adsorption - desorption equilibrium, and prepare a solution system to be degraded with different copper sulfate contents. Use borax buffer solution to adjust the pH of the solution to be degraded to 8 - 10.

[0093] Add PMS with a concentration of 0.1 g L -1 to the above 50 mL degradation solution system with different copper sulfate contents to initiate the degradation reaction of organic pollutants. Within a certain reaction time (0 - 15 min), add a quenching agent and shake vigorously to make the two fully contact to completely terminate the reaction, and start the degradation experiment.

[0094] As Figure 5 shown in d: As the pH increases from 8 to 10, the rate constant k of Cu(OH)2 increases significantly from 0.15 min -1 to 0.47 min -1 , and pH seriously affects the degradation of TBBPA. This is related to the influence of pH on the hydrolysis of Cu 2+ during the in-situ generation of Cu(OH)2: When the pH is low, Cu(II) mainly exists in the form of Cu 2+ , and when the pH is high, it exists in the form of Cu(OH)2 colloid. Compared with Cu 2+In contrast, Cu(OH)2colloid has higher activity, so the degradation rate of Cu(II) in the form of Cu(OH)2colloid is faster at higher pH. In contrast, the strong interaction between γ-Al2O3 and Cu(OH)2stabilizes the rate constant k at 1.15 min -1 , and the degradation rate is basically not affected by pH, and the stability is significantly improved. As mentioned above, the pH range of this experiment is 8-10.

[0095] Example 7: Thermal stability experiment

[0096] At 25°C, the concentration of TBBPA solution in 50 mL of the degradation solution system was fixed at 40 mg / L -1 , containing 0.1 g / L -1 of γ-Al2O3 and CuSO4 solution.

[0097] The above substances were mixed and stirred for 30 min to make the solution reach adsorption-desorption equilibrium, and the degradation solution system with different copper sulfate contents was prepared. At this time, the measured degradation solution was alkaline, with a pH of about 8.

[0098] The system temperature was changed to 5-55°C, and 0.1 g / L -1 of PMS was added to the above 50 mL degradation solution system with different copper sulfate contents to start the degradation reaction of organic pollutants. Within a certain time (0-15 min), a quenching agent was added, and the two were thoroughly mixed by shaking to completely terminate the reaction, and the degradation experiment was started.

[0099] As shown in a of Figure 6 : when the system temperature rises from 5°C to 55°C, the degradation rate of TBBPA by γ-Al2O3 / Cu(OH)2and Fe3O4 / Cu(OH)2significantly accelerates, and the degradation rate k increases from 0.061 min -1 , 0.229 min -1 to 0.238 min -1 , 0.700 min -1 . In contrast, the degradation rate of Cu(OH)2significantly decreases with the increase of temperature, showing an abnormal rule. At 25°C, Cu(OH)2can degrade 50% of TBBPA after 15 min of PMS activation, while at 55°C, the degradation rate is only 30%, and the degradation rate decreases with the increase of temperature. As shown in Figure 6b: Cu(OH)2is blue powder at 25℃, and the color of the catalyst gradually deepens with the increase of temperature, and it has changed into dark black when the temperature rises to 55℃, thus it can be known that the catalyst prepared at high temperature has been changed from Cu(OH)2into another substance. In contrast, the activity of γ-Al2O3 / Cu(OH)2and Fe3O4 / Cu(OH)2is not inhibited by temperature, and the degradation rate of TBBPA still increases with the increase of temperature, which shows that γ-Al2O3and Fe3O4can interact with Cu(OH)2supported on their surface, effectively fixing and dispersing Cu(OH)2to improve the thermal stability. In addition, γ-Al2O3and Fe3O4are rich in a large number of OH - groups on the surface, which can quickly supplement OH - groups at high temperature to prevent Cu(OH)2from losing water to cause structural changes and avoid the generation of low-activity CuO.

[0100] Example 8: Magnetic separation and recovery experiment of Fe3O4 / Cu(OH)2

[0101] Separation and recovery: according to the above in-situ degradation steps, the catalyst is activated PMS to start the degradation experiment, and then the reaction solution after complete degradation of Fe3O4 / Cu(OH)2is placed on the magnet. The results are shown in Figure 7 a in the figure Figure 7 b in the figure: the magnetic Fe3O4 / Cu(OH)2in the solution quickly gathers at the magnet, and the absorbance of the solution decreases significantly. After 3 minutes of magnetic separation, the solution is completely clear and transparent, and the absorbance decreases to 0, which means that the Fe3O4 / Cu(OH)2particles have been completely recovered at this time, indicating that Fe3O4 / Cu(OH)2has excellent magnetic separation capacity and can be efficiently recovered by magnetic separation with a magnet, which is simple and convenient to operate, time-saving, and has practical application value.

[0102] Cyclic use: Fe3O4 / Cu(OH)2has been cycled for 5 times. In the cyclic experiment, the pollutants and oxidants consumed in each cycle need to be supplemented after each cycle, and the catalyst is activated PMS to start the degradation experiment according to the above in-situ degradation steps. The results are shown in Figure 7 c in the figure and Figure 7 d in the figure: after five cycles, the degradation rate of TBBPA in the Cu(OH)2system decreases to 37.4%, which shows that the stability of Cu(OH)2is very poor and cannot be recycled. As for Fe3O4 / Cu(OH)2, the stability of the catalyst is significantly improved, and it can still degrade 93% of TBBPA after 5 cycles, which shows that Fe3O4can effectively fix and disperse Cu(OH)2to improve the stability and help the cyclic use and practical application of the catalyst.

[0103] Those skilled in the art can easily understand that the above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An application of a metal oxide-supported copper hydroxide catalyst system for activating persulfate degradation of bromophenols; the metal oxide-supported copper hydroxide catalyst system comprises a metal oxide with hydroxyl-containing surfaces and copper hydroxide, wherein the metal oxide with hydroxyl-containing surfaces is γ-alumina or iron(III) oxide, and the molar ratio of the metal oxide with hydroxyl-containing surfaces to the copper hydroxide is (1-200):1; wherein, The metal oxide-supported copper hydroxide catalyst system is obtained by mixing the surface-hydroxyl-containing metal oxide and a divalent copper salt solution, adjusting the pH to 7-10, and then reacting.

2. The application according to claim 1, characterized in that, The molar ratio of the metal oxide to the copper hydroxide is (20-150):

1.

3. The application according to claim 1, characterized in that, The divalent copper salt is copper sulfate, copper nitrate, or copper chloride.

4. The application according to claim 1, characterized in that, The reaction time after mixing the surface-containing hydroxyl metal oxide and the divalent copper salt solution is 2 to 30 minutes.

5. The application according to claim 1, characterized in that, The degradation of bromophenolic organic compounds specifically includes: adding the metal oxide-supported copper hydroxide catalyst system to the bromophenolic organic compound solution, mixing evenly to form a solution to be degraded, and then adding a persulfate solution.

6. The application according to claim 1, characterized in that, The molar ratio of copper hydroxide to the bromophenolic organic compound is (0.001-0.5):1; the molar ratio of copper hydroxide to the persulfate is (0.01-1):

1.

7. The application according to claim 1, characterized in that, After the solution to be degraded is formed, the pH of the solution to be degraded is adjusted to 7-12.

8. The application according to claim 1, characterized in that, The temperature for degrading bromophenols is 5℃ to 55℃.

Images