Method for degrading organic pollutants containing carbonyl and carboxyl groups by using oxygen vacancies of cryptomelane
By using a manganese-potassium ore oxygen vacancy catalyst to react with organic pollutants containing carbonyl and carboxyl groups at room temperature and pressure, hydrogen peroxide is generated for degradation, solving the problem of requiring additional oxidants in traditional methods and achieving efficient and environmentally friendly pollutant degradation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAMEN UNIV OF TECH
- Filing Date
- 2023-04-07
- Publication Date
- 2026-06-05
AI Technical Summary
Existing technologies are difficult to efficiently degrade organic pollutants containing carbonyl and carboxyl groups, and traditional methods require the addition of oxidants, which may lead to secondary pollution, and the applicable pH range is limited.
The oxygen vacancies in manganese-potassium ore react with organic pollutants containing carbonyl and carboxyl groups at room temperature and pressure to produce hydrogen peroxide for degradation. The manganese-potassium ore itself acts as a catalyst, eliminating the need for additional oxidants, and it has a wide applicable pH range.
It achieves efficient degradation of organic pollutants containing carbonyl and carboxyl groups at room temperature and pressure. The operation is simple, the catalyst can be recycled, the degradation efficiency is high, and the risk of secondary pollution is reduced.
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Figure CN116514211B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese potassium ore. Background Technology
[0002] With industrial development and the improvement of people's living standards, a large amount of recalcitrant organic wastewater is generated, including dyes, antibiotics, pharmaceuticals and personal care products (PPCPs). These organic pollutants are often carcinogenic or can lead to the formation of resistance genes, and are highly toxic, threatening human health.
[0003] Biological methods are insufficient to achieve satisfactory treatment results for these high-concentration organic wastewaters. Researchers have utilized various treatment technologies, including adsorption, membrane separation, and advanced oxidation processes (AOPs). AOPs can completely oxidize and degrade various organic pollutants, offering advantages such as high reactivity and high mineralization rates. The Fenton process is a classic example of an AOP, using ferrous ions to catalyze the generation of hydroxyl radicals from hydrogen peroxide, which can degrade various organic pollutants, with an oxidation potential as high as 2.8V. However, ferrous ions are prone to ferroagulation, leading to decreased treatment efficiency and difficulties in treating iron sludge. Therefore, in recent years, researchers have used metals or metal oxides as catalysts to catalyze the generation of free radicals from hydrogen peroxide and persulfate to degrade organic pollutants. Among these, manganese oxides have attracted increasing attention due to the abundance of variable valence states of manganese, high redox potential, stable catalytic performance, and low toxicity. However, the above methods require the addition of oxidants such as hydrogen peroxide or persulfate during the reaction process, which can easily cause secondary pollution.
[0004] On the other hand, natural manganese potassium ore is a good raw material for wastewater treatment, generally utilizing its adsorption and oxidizing properties. Being a natural raw material, it can reduce secondary pollution. However, the active components of natural manganese potassium ore are limited, and wastewater treatment processes require strongly acidic conditions, thus restricting its applicability. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to provide a method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese potassium ore. This method utilizes the oxygen vacancies in manganese potassium ore and the carbonyl and carboxyl groups that are present in the organic pollutants themselves. Hydrogen peroxide can be generated during the reaction process without the need to add other oxidants. Furthermore, the method has a wide applicable pH range and can be completed under normal temperature and pressure air conditions.
[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is:
[0007] A method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese potassium ore involves adding manganese potassium ore to wastewater containing organic pollutants with carbonyl and carboxyl groups, mixing thoroughly to generate hydrogen peroxide, which further degrades the organic pollutants; wherein the manganese potassium ore is an octahedral molecular sieve of manganese oxide mineral with the crystal form α-MnO2.
[0008] Preferably, manganese-potassium ore is recovered after the degradation reaction of organic pollutants. This involves solid-liquid separation of the degradation reaction products, collection of solid products, washing with ultrapure water and drying to obtain recovered manganese-potassium ore for reuse.
[0009] Preferably, manganese-potassium ore is recovered after the degradation reaction of organic pollutants. This involves solid-liquid separation of the degradation reaction products, collection of solid products, ultrasonication of the solid products in acetic acid medium, washing with ultrapure water, and drying to obtain recovered manganese-potassium ore for reuse.
[0010] Preferably, the mass ratio of the manganese potassium ore to the organic pollutant is 20:1-30:1.
[0011] Preferably, the wastewater has a pH of less than 10.
[0012] Preferably, the mixing is performed using mechanical stirring, magnetic stirring, or oscillation methods.
[0013] Preferably, the mixing time is 0.5 hours to 4 hours.
[0014] Following the above approach, this invention utilizes α-MnO2 manganese potassium ore, which possesses high catalytic oxidation capabilities. When applied to the degradation of organic pollutants containing carbonyl and carboxyl groups, the manganese potassium ore itself acts as an oxidant, reducing high-valence manganese to low-valence manganese during the degradation process. Furthermore, the crystal structure of this manganese potassium ore contains low-valence Mn(II) and Mn(III), creating oxygen vacancies to balance charges, thus endowing it with certain oxygen vacancies and enhancing its catalytic performance. In addition, the manganese potassium ore contains a large amount of variable-valence Mn(IV), which oxidizes pollutants and reduces them to low-valence manganese, converting lattice oxygen into adsorbed oxygen and generating more oxygen vacancies. These oxygen vacancies are converted into reactive oxygen species, activating pollutants and their intermediates, which then combine with their carboxyl and carbonyl groups to generate hydrogen peroxide. This hydrogen peroxide is then decomposed under the catalytic action of the catalyst (manganese potassium ore), resulting in the deep degradation and removal of pollutants. Throughout the reaction process, the oxidation and adsorption capabilities of manganese potassium ore are utilized to degrade pollutants. Simultaneously, the oxygen vacancies in the manganese potassium ore catalyze the production of hydrogen peroxide from pollutants containing carbonyl and carboxyl groups, achieving deep removal of the pollutants themselves. Therefore, the oxidizing, adsorbing, and catalytic properties of manganese potassium ore are simultaneously leveraged. In summary, the catalyst required in this invention is inexpensive and readily available, has a wide applicable pH range, requires a small amount of catalyst, catalyzes the production of hydrogen peroxide from carboxyl and carbonyl organic pollutants for deep removal of the pollutants themselves, requires no additional oxidants, can be completed under ambient temperature and pressure conditions, is simple to operate, has high catalytic efficiency, and the catalyst is recyclable.
[0015] More specifically, the present invention has the following advantages:
[0016] (1) The reaction involved in this invention has a low activation energy and can proceed spontaneously under normal temperature and pressure air conditions. It is simple to operate and does not require the addition of other oxidants.
[0017] (2) The method of generating hydrogen peroxide by using oxygen vacancy catalysis of manganese potassium ore to produce pollutants containing carbonyl and carboxyl groups is simple to operate, has a wide pH range, and can generate hydrogen peroxide in a short time.
[0018] (3) The present invention utilizes the oxygen vacancy of manganese potassium ore to catalyze the generation of hydrogen peroxide from pollutants containing carbonyl and carboxyl groups. The catalyst can be recycled, which can effectively save costs. Attached Figure Description
[0019] Figure 1 The EPR spectrum of the manganese-potassium ore described in this invention;
[0020] Figure 2 The degradation rate of different pollutants removed from the manganese-potassium ore described in this invention;
[0021] Figure 3 The reaction mechanism of this invention;
[0022] Figure 4 This is a graph showing the removal rate of carmine by the manganese potassium ore described in this invention at different pH levels.
[0023] Figure 5 The graph shows the hydrogen peroxide concentration in the solution at different oscillation times in the example.
[0024] Figure 6 The carmine dye described in this invention is a cyclic degradation of manganese potassium ore. Detailed Implementation
[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.
[0026] This invention discloses a method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese potassium ore. Manganese potassium ore is added to wastewater containing organic pollutants with carbonyl (COOH) and carboxyl (C=O) groups. After thorough mixing, hydrogen peroxide is generated, which further degrades the organic pollutants. The manganese potassium ore used in this invention is synthetic manganese potassium ore, which is a highly catalytically active manganese oxide, also known as manganese oxide octahedral molecular sieve (OMS-2), with a crystal form of α-MnO2, and inherently possesses high catalytic oxidation ability. Due to the presence of low-valence Mn(II) and Mn(III) groups in its crystal structure, oxygen vacancies are generated in the crystal to balance the charge. Figure 1 The EPR spectrum of the manganese-potassium ore is shown. The electron paramagnetic resonance analysis results show that the manganese-potassium ore exhibits a significant EPR signal at a g value of 2.001, indicating that the manganese-potassium ore has abundant oxygen vacancies.
[0027] The following are specific examples of using the above method to treat wastewater containing organic pollutants with carbonyl and carboxyl groups.
[0028] Example 1
[0029] Take 50 mL of 100 mg / L carmine solution and place it in a 100 mL polyethylene centrifuge tube. Add 0.1 g of manganese potassium ore and immediately place it in a 25 °C constant temperature water bath shaker and shake at 250 r / min for 4 h. Then, use a total organic carbon analyzer to determine its TOC concentration and calculate that the carmine degradation rate is 69.8%.
[0030] Example 2
[0031] Take 50 mL of 100 mg / L amoxicillin solution and place it in a 100 mL polyethylene centrifuge tube. Add 0.1 g of manganese potassium ore and immediately place it in a 25 °C constant temperature water bath shaker and shake at 250 r / min for 4 h. Then, use a total organic carbon analyzer to determine its TOC concentration and calculate that the amoxicillin degradation rate is 47.4%.
[0032] Example 3
[0033] Take 50 mL of 100 mg / L captopril solution and place it in a 100 mL polyethylene centrifuge tube. Add 0.1 g of manganese potassium ore and immediately place it in a 25 °C constant temperature water bath shaker and shake at 250 r / min for 4 h. Then, use a total organic carbon analyzer to determine its TOC concentration and calculate that the captopril degradation rate is 32.7%.
[0034] Figure 2 The results of Examples 1-3 above demonstrate the degree of pollutant degradation after mixing manganese potassium ore with pollutants for 4 hours. The experimental results show that manganese potassium ore can degrade organic pollutants containing carboxyl and carbonyl groups to a certain extent, converting some of the organic structures into carbon dioxide and water.
[0035] The reaction mechanism of the method described in this invention is as follows: Figure 3 As shown, the manganese potassium ore used in this invention is a synthetic manganese potassium ore, which is a manganese oxide with high catalytic activity, also known as manganese oxide octahedral molecular sieve (OMS-2), with a crystal form of α-MnO2, and inherently possesses high catalytic oxidation ability. Due to the presence of low-valence Mn(II) and Mn(III) in its crystal structure, oxygen vacancies are generated as a defect structure to balance the charge. Under certain conditions, lattice oxygen is converted into adsorbed oxygen, generating more oxygen vacancies, which further convert into reactive oxygen species that combine with pollutants containing carboxyl and carbonyl groups and their intermediate products to produce hydrogen peroxide. Hydrogen peroxide then deeply degrades and removes the pollutants. Therefore, the method described in this invention, when degrading organic pollutants containing carboxyl and carbonyl groups, will produce the intermediate product hydrogen peroxide, eliminating the need for additional oxidants. Furthermore, the method of this invention has a wide pH range and can be carried out under normal temperature and pressure air conditions.
[0036] Example 4
[0037] 50 mL of a 100 mg / L carmine solution (containing carbonyl and carboxyl groups) was selected, and 0.1 g of manganese potassium ore was added. After adjusting the pH of the solution with hydrochloric acid and sodium hydroxide, the solution was shaken at a constant temperature of 25 °C for different times in a shaker. The product was separated by centrifugation, and its absorbance was measured at 518 nm using a visible spectrophotometer. The removal rate of carmine was then calculated. Figure 4The removal rate of carmine by potassium manganese ore at different pH values was demonstrated. Experimental results show that potassium manganese ore can effectively remove pollutants over a wide pH range. As can be seen from the figure, a stirring time of more than half an hour is sufficient to achieve a high removal rate under acidic conditions; however, the removal rate is slightly lower under strongly alkaline conditions, requiring a longer stirring time, generally more than 2 hours, which can be optimized to 4 hours. It should be noted that the pH adjustment described above is only for verifying the removal rate at different pH values. In practical applications, it is not necessary to adjust the pH of the wastewater unless the wastewater itself is excessively alkaline and a high removal rate is required.
[0038] Example 5
[0039] 50 mL of a 100 mg / L carmine solution was placed in a 100 mL polyethylene centrifuge tube, and 0.1 g of manganese potassium ore was added. The tube was immediately placed in a 25°C constant temperature water bath and shaken at 250 r / min for 1 h. The concentration of hydrogen peroxide was measured to be 1.92 mg / L. The activation energy of the reaction was only 6.36 kJ / mol.
[0040] Example 6
[0041] Take 50 mL of 100 mg / L amoxicillin solution and place it in a 100 mL polyethylene centrifuge tube. Add 0.1 g of manganese potassium ore and immediately place it in a 25 °C constant temperature water bath shaker. Shake at 250 r / min for 1 h. The concentration of hydrogen peroxide was measured to be 1.16 mg / L.
[0042] Example 7
[0043] Take 50 mL of 100 mg / L captopril solution and place it in a 100 mL polyethylene centrifuge tube. Add 0.1 g of manganese potassium ore and immediately place it in a 25°C constant temperature water bath shaker. Shake at 250 r / min for 30 min. The concentration of hydrogen peroxide was measured to be 0.69 mg / L.
[0044] Example 8
[0045] The same steps as in Examples 5-7 were used, except for different shaking times. Specifically, 50 mL each of 100 mg / L carmine solution, amoxicillin solution, and captopril solution were placed in 100 mL polyethylene centrifuge tubes, and 0.1 g of manganese potassium ore was added to each. The tubes were then shaken at a constant temperature of 25°C for different times, and the hydrogen peroxide concentration was measured.
[0046] like Figure 5The experiment demonstrated the concentration of hydrogen peroxide in the solution at different time points after mixing manganese potassium ore with pollutants. The results showed that for pollutants containing carboxyl and carbonyl groups, a certain amount of hydrogen peroxide was generated in the solution after adding 0.1g of manganese potassium ore and shaking for a period of time.
[0047] Example 9
[0048] The manganese-potassium ore after the pollutant degradation reaction using the method described in this invention can be recovered and recycled. The specific method is as follows: After the degradation reaction, solid and liquid are separated, the solid product is collected, ultrasonicated in acetic acid medium, washed with ultrapure water, and then dried to obtain the recovered manganese-potassium ore. Specific embodiments are as follows:
[0049] 50 mL of a 100 mg / L carmine solution was selected, and 0.1 g of manganese potassium ore was added. The solution was shaken at a constant temperature of 25 °C for different times in a shaker. After solid-liquid separation, the absorbance of the liquid was measured and its decolorization rate was calculated. The solid product was then collected, sonicated in acetic acid medium, washed with ultrapure water, and dried. The recovered manganese potassium ore was reused to treat the carmine solution. Figure 6 The decolorization effect of repeatedly using potassium manganese ore to treat carmine solution was demonstrated. Experimental results show that potassium manganese ore has excellent reusability; after treatment with acetic acid, it still maintains an 85% decolorization rate for carmine even on the third cycle.
[0050] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the technical scope of the present invention. Therefore, any changes or modifications made in accordance with the claims and specification of the present invention should fall within the scope of the patent of the present invention.
Claims
1. A method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore, characterized in that: Manganese potassium ore is added to wastewater containing organic pollutants with carbonyl and carboxyl groups. After thorough mixing, hydrogen peroxide is generated. The hydrogen peroxide further degrades the organic pollutants, and the active oxygen generated during the reaction includes singlet oxygen. The crystal structure of the manganese potassium ore contains low-valence Mn(II) and Mn(III) and has a certain number of oxygen vacancies. The organic pollutants are carmine, amoxicillin, or captopril.
2. The method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore according to claim 1, characterized in that: After the degradation reaction of organic pollutants, manganese-potassium ore is recovered. This involves solid-liquid separation of the degradation reaction products, collection of solid products, washing with ultrapure water and drying to obtain recovered manganese-potassium ore for reuse.
3. The method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore according to claim 2, characterized in that: The collected solid product was first sonicated in acetic acid medium, then washed with ultrapure water and dried.
4. The method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore according to any one of claims 1-3, characterized in that: The mass ratio of the manganese potassium ore to the organic pollutants is 20:1-30:
1.
5. The method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore according to any one of claims 1-3, characterized in that: The wastewater has a pH of less than 10.
6. The method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore according to any one of claims 1-3, characterized in that: The mixing is performed using mechanical stirring, magnetic stirring, or oscillation methods.
7. The method for degrading organic pollutants containing carbonyl and carboxyl groups using oxygen vacancies in manganese-potassium ore according to any one of claims 1-3, characterized in that: The mixing time is 0.5 hours to 4 hours.