A method for catalytic oxidation of manganese ions in drinking water
By using a metal-pillared bentonite catalyst to rapidly oxidize manganese ions in drinking water with free chlorine, the problems of slow oxidation rate and low efficiency in existing technologies are solved, achieving a high-efficiency and low-cost manganese ion removal effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEILONGJIANG UNIV
- Filing Date
- 2024-05-29
- Publication Date
- 2026-06-30
AI Technical Summary
In existing technologies, the catalytic oxidation of manganese ions in drinking water suffers from slow oxidation rate, low efficiency, and high cost.
Metal-pillared bentonite was used as a catalyst and added to an aqueous solution containing divalent manganese ions along with free chlorine. The manganese ions were removed by stirring and oxidation. The high specific surface area and catalytic sites of the metal-pillared bentonite were utilized to achieve rapid oxidation.
It significantly improves the oxidation rate of manganese ions, shortens the reaction time, reduces the processing space, and can effectively remove pollutants such as bacteria and algae from the water, thereby reducing operating costs.
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Figure CN118598335B_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of drinking water purification technology, and in particular relates to a method for catalytic oxidation of manganese ions in drinking water. Background Technology
[0002] Manganese is a ubiquitous element in the natural environment, existing in ionic form in various water bodies, especially groundwater and deep surface water. Although manganese is one of the essential trace elements for the human body, playing a crucial role in various physiological functions, excessive intake of Mn can lead to health problems. 2+ However, it may have adverse effects on human health, including neurological dysfunction, decreased sleep quality, impaired motor coordination, and cognitive impairment. Therefore, it is important to ensure that Mn levels in drinking water are within acceptable limits. 2+ Maintaining safe levels of harmful substances is an important task in the field of public health.
[0003] Traditional manganese removal methods include chemical oxidation, ion exchange, adsorption, and biological treatment; while these methods can remove Mn to some extent... 2+ However, traditional aeration manganese removal processes often suffer from problems such as low processing efficiency, high cost, complex operation, and potential secondary pollution. For example, during the aeration filtration process, Mn... 2+ Oxidation to tetravalent manganese requires a stronger oxidizing environment, resulting in problems such as insufficient oxidation, poor manganese removal efficiency, cumbersome processes, high operating costs, frequent regeneration, high wastewater ratio, large footprint, and difficult management and maintenance. However, under natural conditions, chlorination oxidizes Mn... 2+ The process is extremely slow; adsorption and ion exchange methods require regular replacement of adsorbents or ion exchange resins, increasing operating costs.
[0004] To improve the soluble Mn 2+ To determine the oxidation rate and efficiency of Mn, researchers used strong oxidants such as chlorine dioxide, potassium permanganate, or ozone to oxidize it. 2+ The formation of insoluble MnOx followed by solid-liquid separation yielded satisfactory results, but was expensive. Chlorine is inexpensive and readily available, and its oxidation process disinfects bacteria and viruses, but its oxidation rate is slow. To improve the catalytic oxidation rate of chlorine, researchers have recently explored the use of catalysts to enhance oxidation efficiency, such as activated carbon, coagulant hydrolysis products, and kaolin. These catalysts have been found to increase the oxidation rate and remove MnOx from drinking water. 2+ The concentration was reduced to below 0.1 mg / L; the catalytic effect may be related to the specific surface area of the catalyst and the activation sites provided by the surface, but these catalyst surfaces are difficult to modify or control, resulting in low catalytic oxidation efficiency. Therefore, it is necessary to develop catalysts with large specific surface areas and controllable surface groups to catalyze the oxidation of Mn with chlorine. 2+ Oxidation is crucial. Summary of the Invention
[0005] This application provides a method for the catalytic oxidation of manganese ions in drinking water, solving the problem of removing Mn. 2+ The problem of slow catalytic oxidation and poor effect in the water purification process.
[0006] This application provides a method for preparing metal-pillared bentonite, which involves adding metal-pillared bentonite and free chlorine to an aqueous solution containing divalent manganese ions, and then stirring, oxidizing, and separating the mixture in a reactor.
[0007] In one embodiment,
[0008] The method for preparing the metal-pillared bentonite is as follows:
[0009] Step 1: Disperse bentonite in water, shake and let it settle to obtain upper bentonite slurry;
[0010] Step 2: Disperse the upper bentonite slurry in an inorganic solution, stir at room temperature, filter and separate to obtain purified sodium-based bentonite;
[0011] Step 3: Add sodium hydroxide solution dropwise to metal chloride solution, control the ratio of hydroxide ions to metal ions, stir, and age in water bath to obtain pillaring agent;
[0012] Step 4: After mixing the purified sodium-based bentonite with water at a certain mass ratio, add the pillaring agent and mix, controlling the ratio of metal ions to bentonite, and then stir and process to obtain metal-pillared bentonite.
[0013] In one embodiment,
[0014] The water used in step one is deionized water, and the particle diameter in the upper bentonite slurry is less than 2 μm.
[0015] In one embodiment,
[0016] The inorganic solution mentioned in step two is a sodium chloride solution. sodium The solution concentration was 1.0 mol / L, and the stirring time was 12 h.
[0017] In one embodiment,
[0018] In step three, the concentrations of both the sodium hydroxide solution and the metal chloride solution are 0.5 mol / L. The metal chloride solution is one of AlCl3, FeCl3, or TiCl4. The stirring time is 1-3 h, and the water bath aging time is 12-96 h at a temperature of 60 ℃. Preferably, the optimal water bath aging time is 24 h.
[0019] In one embodiment,
[0020] The ratio of hydroxide ions to metal ions in step three is 2-3:1, preferably 2.4:1.
[0021] In one embodiment,
[0022] In step four, the mass ratio of purified sodium-based bentonite to water is 2:98, and the ratio of metal ions to bentonite is 5-40 mmol metal ions / 1 g bentonite. Preferably, the optimal ratio of metal ions to bentonite is 15 mmol metal ions / 1 g bentonite.
[0023] In one embodiment,
[0024] The specific steps of post-processing in step four are as follows: aging, washing with water until there are no chloride ions, drying, and calcining. The aging time is 12-48 h, the drying temperature is 103-105 ℃, and the calcination temperature is 400-600 ℃. Preferably, the optimal aging time is 24 h and the optimal calcination temperature is 500 ℃.
[0025] This application also provides a method for catalytic oxidation of manganese ions in drinking water, which is a method for preparing metal-pillared bentonite according to any of the above embodiments, wherein the metal-pillared bentonite and free chlorine are added to an aqueous solution containing divalent manganese ions, and the mixture is stirred, oxidized, and separated in a reactor.
[0026] In one embodiment,
[0027] The metal-pillared bentonite comprises 1-40 parts, the free chlorine comprises 2-5 parts, and the divalent manganese ion aqueous solution comprises 1 part.
[0028] In one embodiment,
[0029] The free chlorine is one of chlorine gas, liquid chlorine, or sodium hypochlorite.
[0030] This application provides a method for the catalytic oxidation of manganese ions in drinking water. Metal-pillared bentonite serves as a highly efficient catalyst, providing catalytic sites for the rapid catalytic oxidation of Mn ions in water by chlorine. 2+ It also has a high specific surface area and porosity, making it suitable for Mn. 2+ The product MnOx provides the loading, and MnOx has autocatalytic activity, accelerating the reaction of Mn in water. 2+Oxidation significantly shortens reaction time and reduces processing space, and effectively removes pollutants such as bacteria, viruses, and algae from water. The larger the specific surface area of the metal-pillared bentonite, the more surface activation sites it has, resulting in a more significant catalytic oxidation effect. The oxidation product, MnOx, can be recycled and used for manganese recovery. This invention can rapidly initiate chlorine catalytic oxidation reactions, unaffected by region, water quality, manganese content, or filter rate, and can flexibly handle various MnOx conditions. 2+ The water source that exceeds the standard has a small footprint and requires little space, making it easy to manage and maintain, thus ensuring drinking water safety. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 Mn in the absence of catalyst and in the presence of catalyst in Examples 1 and 2 2+ Concentration versus time curve;
[0033] Figure 2 This is a scanning electron microscope image of sodium-based bentonite.
[0034] Figure 3 This is the energy spectrum of sodium-based bentonite;
[0035] Figure 4 The N2 adsorption-desorption curve (BET) of sodium-based bentonite.
[0036] Figure 5 This is a scanning electron microscope image of the aluminum-pillared bentonite in Example 1;
[0037] Figure 6 The energy spectrum of the aluminum-pillared bentonite in Example 1 is shown.
[0038] Figure 7 X-ray diffraction patterns of sodium-based bentonite and aluminum-pillared bentonite in Examples 1 and 2;
[0039] Figure 8 The N2 adsorption-desorption curve (BET) of the catalyst in Example 1 is shown below.
[0040] Figure 9 Aluminum-pillared bentonite catalytic chlorination of Mn in water 2+ Schematic diagram;
[0041] Figure 10 This is a scanning electron microscope image of the oxidation products of aluminum-pillared bentonite in Example 1;
[0042] Figure 11 X-ray diffraction patterns of the aluminum-pillared bentonite oxidation products in Examples 1 and 2;
[0043] Figure 12 The image shows the N2 adsorption-desorption curve (BET) of the catalyst in Example 2. Detailed Implementation
[0044] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, this application will be further described in detail. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit this application.
[0045] Example 1
[0046] Add 20 parts aluminum-pillared bentonite and 3 parts sodium hypochlorite to 1 part Mn 2+ In an aqueous solution, the mixture was mechanically stirred, oxidized, and separated by filtration in a completely mixed reactor; the results are as follows. Figure 1 As shown, Mn 2+ The concentration of Mn in the solution was as low as 0.04 mg / L within 120 min, while the concentration in the solution without a catalyst was lower. 2+ The content remains above 0.45 mg / L, but the oxidation rate is increased by more than 10 times.
[0047] The preparation method of aluminum-pillared bentonite is as follows:
[0048] Step 1: Disperse bentonite in deionized water, shake vigorously, and collect the slurry with particle diameter less than 2 μm to obtain the upper bentonite slurry.
[0049] Step 2: Disperse the upper bentonite slurry in an equal volume of 1.0 mol / L NaCl solution, stir at room temperature for 12 h, filter and separate, repeat 3 times to obtain purified sodium-based bentonite; the structure and characterization of sodium-based bentonite are as follows. Figure 2-4 As shown;
[0050] Step 3: Slowly add 0.5 mol / L NaOH solution dropwise to 0.5 mol / L AlCl3 solution, controlling the [OH] content. - ] :[Al 3+ The ratio of [ ] to [ ] is 2.4:1. Stir for 1-3 hours, and age in a constant temperature water bath at 60 ℃ for 24 hours to obtain the pillar proppant.
[0051] Step 4: Disperse 2 parts of purified sodium bentonite into 98 parts of water, controlling [Al] 3+The [[bentonite]] ratio was 15 mmol / g. After stirring, the mixture was aged for 24 h, washed with water until chloride ions were removed, dried at 103-105 °C, and calcined to 500 °C to obtain aluminum-pillared bentonite. The specific surface area of the aluminum-pillared bentonite was 220 m². 2 / g, the structure and characterization of aluminum-pillared bentonite are as follows: Figure 5-8 As shown.
[0052] like Figure 9 As shown, aluminum-pillared bentonite serves as a highly efficient catalyst for the chlorination of Mn. 2+ The process is as follows:
[0053] 1. The hydroxyl groups on the surface of aluminum-pillared bentonite (PILC) sheets first react with Mn in aqueous solution. 2+ PILC(Mn) is formed on the surface of PILC sheets through ion exchange bonding;
[0054] 2. PILC(Mn) is oxidized by free chlorine to PILC-MnOx. The surface of MnOx contains abundant hydroxyl groups, which rapidly react with Mn in aqueous solution. 2+ PILC-MnOx(Mn) is formed through ion exchange bonding;
[0055] 3. PILC-MnOx(Mn) is rapidly oxidized to PILC-MnOx(MnOx) by free chlorine. The MnOx generated in the reaction has an autocatalytic effect, further catalyzing the oxidation of Mn. 2+ Oxidation on the MnOx surface forms MnOx aggregates PILC-MnOx(MnOx)m, with the structure of the oxidation product as follows. Figure 10 As shown.
[0056] like Figure 11 As shown in the X-ray diffraction pattern, MnO x The main component is MnO2, with small amounts of Mn3O4 and Mn(OH)2. Before drying, the Mn2O3 in the sample was Mn(OH)2.
[0057] Aluminum-pillared bentonite can catalyze the rapid oxidation of Mn in water by chlorine. 2+ It can also remove pollutants such as bacteria, viruses and algae from the water at the same time.
[0058] Example 2
[0059] Add 20 parts aluminum-pillared bentonite and 3 parts sodium hypochlorite to 1 part Mn 2+ In an aqueous solution, the mixture was mechanically stirred, oxidized, and separated by filtration in a completely mixed reactor; the results are as follows. Figure 1 As shown, Mn 2+ The concentration of Mn in the solution was as low as 0.1 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.1 mg / L. 2+The content remains above 0.45 mg / L, but the oxidation rate is increased by more than 8 times.
[0060] The preparation method of aluminum-pillared bentonite is as follows:
[0061] Step 1: Disperse bentonite in deionized water, shake vigorously, and collect the slurry with particles smaller than 2 μm in diameter to obtain the upper bentonite slurry; the structure and characterization of sodium-based bentonite are as follows. Figure 2-4 As shown;
[0062] Step 2: Disperse the bentonite slurry in an equal volume of 1.0 mol / L NaCl solution, stir at room temperature for 12 h, filter and separate, repeat 3 times to obtain purified sodium-based bentonite;
[0063] Step 3: Slowly add 0.5 mol / L NaOH solution dropwise to 0.5 mol / L AlCl3 solution, controlling the [OH] content. - ] :[Al 3+ The ratio of [ ] to [ ] is 2.4:1. Stir for 1-3 hours, and age in a constant temperature water bath at 60 ℃ for 24 hours to obtain the pillar proppant.
[0064] Step 4: Disperse 2 parts of purified sodium bentonite into 98 parts of water, controlling [Al] 3+ The [[bentonite]] ratio was 15 mmol / g. After stirring, the mixture was aged for 24 h, washed with water until chloride ions were removed, dried at 103-105 °C, and calcined to 500 °C to obtain aluminum-pillared bentonite. The specific surface area of the aluminum-pillared bentonite was 110 m². 2 / g, the structure and characterization of aluminum-pillared bentonite are as follows: Figure 7 , 12 As shown.
[0065] like Figure 9 As shown, aluminum-pillared bentonite serves as a highly efficient catalyst for the chlorination of Mn. 2+ The process is as follows:
[0066] 1. The hydroxyl groups on the surface of aluminum-pillared bentonite (PILC) sheets first react with Mn in aqueous solution. 2+ PILC(Mn) is formed on the surface of PILC sheets through ion exchange bonding;
[0067] 2. PILC(Mn) is oxidized by free chlorine to PILC-MnOx. The surface of MnOx contains abundant hydroxyl groups, which rapidly react with Mn in aqueous solution. 2+ PILC-MnOx(Mn) binds via ion exchange;
[0068] 3. PILC-MnOx(Mn) is rapidly oxidized to PILC-MnOx(MnOx) by free chlorine. The MnOx generated in the reaction has an autocatalytic effect, further catalyzing the oxidation of Mn.2+ MnOx aggregates are formed by oxidation on the MnOx surface.
[0069] like Figure 11 As shown in the X-ray diffraction pattern, MnO x The main component is MnO2, with small amounts of Mn3O4 and Mn(OH)2. Before drying, the Mn2O3 in the sample was Mn(OH)2.
[0070] Aluminum-pillared bentonite can catalyze the rapid oxidation of Mn in water by chlorine. 2+ It can also remove pollutants such as bacteria, viruses and algae from the water at the same time.
[0071] Example 3
[0072] The difference between this embodiment and Embodiment 1 is that AlCl3 is replaced with FeCl3 to obtain iron-pillared bentonite with a specific surface area of 200 m². 2 / g; Add 20 parts of iron-supported bentonite and 3 parts of sodium hypochlorite to 1 part of Mn 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2+ The concentration of Mn in the solution was as low as 0.08 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.08 mg / L. 2+ The content remains above 0.45 mg / L, but the oxidation rate is increased by more than 9 times.
[0073] Example 4
[0074] The difference between this embodiment and Example 1 is that AlCl3 is replaced with TiCl4, resulting in titanium-pillared bentonite with a specific surface area of 262 m². 2 / g; Add 20 parts titanium-pillared bentonite and 3 parts sodium hypochlorite to 1 part Mn 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2+ The concentration of Mn in the solution was as low as 0.05 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.05 mg / L. 2+ The content remains above 0.45 mg / L, but the oxidation rate is increased by more than 10 times.
[0075] Example 5
[0076] The difference between this embodiment and Embodiment 1 is that [OH] is used. - ] and [Al 3+ The ratio of ] is determined by [OH] - ] : [Al 3+ ]=2.4 : 1 should be changed to [OH - ] : [Al 3+= 2 : 1, the specific surface area of the bentonite supported by aluminum columns is 165 m² 2 / g.
[0077] Example 6
[0078] The difference between this embodiment and Embodiment 1 is that [OH] is used. - ] and [Al 3+ The ratio of ] is determined by [OH] - ] : [Al 3+ ]=2.4 : 1 should be changed to [OH - ] : [Al 3+ =3 : 1, the specific surface area of the bentonite supported by aluminum columns is 142 m² 2 / g.
[0079] Example 7
[0080] The difference between this embodiment and Example 1 is that sodium hypochlorite is replaced with chlorine gas, and 20 parts of aluminum-pillared bentonite and 3 parts of chlorine gas are added to 1 part of Mn. 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2 + The concentration of Mn in the solution was as low as 0.1 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.1 mg / L. 2+ The content remains above 0.45 mg / L, but the oxidation rate is increased by more than 9 times.
[0081] Example 8
[0082] The difference between this embodiment and Example 1 is that sodium hypochlorite is replaced with liquid chlorine, and 20 parts of aluminum-pillared bentonite and 3 parts of liquid chlorine are added to 1 part of Mn. 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2 + The concentration of Mn in the solution was as low as 0.1 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.1 mg / L. 2+ The content remains above 0.45 mg / L, but the oxidation rate is increased by more than 10 times.
[0083] Example 9
[0084] The difference between this embodiment and Embodiment 1 is that the weight of aluminum-pillared bentonite is changed to 1 part, and 1 part of aluminum-pillared bentonite and 3 parts of sodium hypochlorite are added to 1 part of Mn. 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2+ The concentration of Mn in the solution was as low as 0.2 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.2 mg / L. 2+The content remains above 0.45 mg / L, while the oxidation rate increases by more than 5 times.
[0085] Example 10
[0086] The difference between this embodiment and Embodiment 1 is that the weight parts of aluminum-pillared bentonite are changed to 40 parts, and 40 parts of aluminum-pillared bentonite and 3 parts of sodium hypochlorite are added to 1 part of Mn. 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2+ The concentration of Mn in the solution was as low as 0.03 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.03 mg / L. 2+ The content remains above 0.45 mg / L, and the oxidation rate is increased by more than 11 times.
[0087] Example 11
[0088] The difference between this embodiment and Embodiment 1 is that the weight parts of sodium hypochlorite are changed to 2 parts, and 20 parts of aluminum-pillared bentonite and 2 parts of sodium hypochlorite are added to 1 part of Mn. 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2+ The concentration of Mn in the solution was as low as 0.08 mg / L within 120 min, while the concentration in the solution without a catalyst was below 0.08 mg / L. 2+ The content remains above 0.45 mg / L, while the oxidation rate increases by more than 8 times.
[0089] Example 12
[0090] The difference between this embodiment and Embodiment 1 is that the weight parts of sodium hypochlorite are changed to 5 parts, and 20 parts of aluminum-pillared bentonite and 5 parts of sodium hypochlorite are added to 1 part of Mn. 2+ In an aqueous solution, Mn is subjected to mechanical stirring, oxidation reaction, and filtration separation in a completely mixed reactor. 2+ The concentration of Mn in the solution was as low as 0.04 mg / L within 120 min, while the concentration in the solution without a catalyst was lower. 2+ The content remains above 0.45 mg / L, while the oxidation rate increases by more than 11 times.
[0091] Example 13
[0092] The difference between this embodiment and Embodiment 1 is that the water bath aging time in step three is changed from 24 hours to 12 hours, and the specific surface area of the aluminum-supported bentonite is 185 m². 2 / g.
[0093] Example 14
[0094] The difference between this embodiment and Embodiment 1 is that the water bath aging time in step three is changed from 24 hours to 48 hours, and the specific surface area of the aluminum-supported bentonite is 235 m². 2 / g.
[0095] Example 15
[0096] The difference between this embodiment and Embodiment 1 is that the water bath aging time in step three is changed from 24 hours to 96 hours, and the specific surface area of the aluminum-supported bentonite is 243 m². 2 / g.
[0097] Example 16
[0098] The difference between this embodiment and Embodiment 1 is that the calcination temperature in step four is changed from 500 ℃ to 400 ℃, and the specific surface area of the aluminum-supported bentonite is 207 m². 2 / g.
[0099] Example 17
[0100] The difference between this embodiment and Embodiment 1 is that the calcination temperature in step four is changed from 500 ℃ to 600 ℃, and the specific surface area of the aluminum-supported bentonite is 212 m². 2 / g.
[0101] Example 18
[0102] The difference between this embodiment and Embodiment 1 is that [Al] 3+ The [[bentonite]] ratio was changed to 5 mmol / g, and the specific surface area of the aluminum-pillared bentonite was 85 m². 2 / g.
[0103] Example 19
[0104] The difference between this embodiment and Embodiment 1 is that [Al] 3+ The [[bentonite]] ratio was changed to 40 mmol / g, and the specific surface area of the aluminum-pillared bentonite was 221 m². 2 / g.
[0105] Example 20
[0106] The difference between this embodiment and Embodiment 1 is that the aging time in step four is changed from 24 hours to 12 hours, and the specific surface area of the aluminum-supported bentonite is 178 m². 2 / g.
[0107] Example 21
[0108] The difference between this embodiment and Embodiment 1 is that the aging time in step four is changed from 24 hours to 48 hours, and the specific surface area of the aluminum-supported bentonite is 228 m². 2 / g.
[0109] This application provides a method for the catalytic oxidation of manganese ions in drinking water, which involves adding metal-pillared bentonite and free chlorine to a solution containing Mn. 2+In an aqueous solution, Mn is removed from drinking water through stirring, oxidation reaction, and separation in a reactor. 2+ This application employs pillaring agents with different structures and compositions to achieve pillaring between bentonite layers, preparing metal-pillared bentonites with different specific surface areas and different numbers of activation sites. These metal-pillared bentonites, as highly efficient catalysts, can provide catalytic sites for the rapid chlorination of Mn in water. 2+ It also has a high specific surface area and porosity, making it suitable for Mn. 2+ The product MnOx provides the loading, and MnOx has autocatalytic activity, accelerating the reaction of Mn in water. 2+ Oxidation significantly shortens reaction time and reduces processing space, and effectively removes pollutants such as bacteria, viruses, and algae from water. The larger the specific surface area of the metal-pillared bentonite, the more surface activation sites it has, resulting in a more significant catalytic oxidation effect. The oxidation product, MnOx, can be recycled or recovered after precipitation and separation. This invention can rapidly initiate chlorine catalytic oxidation reactions, unaffected by region, water quality, manganese content, or filter rate, and can flexibly handle various MnOx conditions. 2+ The water source that exceeds the standard has a small footprint and requires little space, making it easy to manage and maintain, thus ensuring drinking water safety.
[0110] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for catalytic oxidation of manganese ions in drinking water, characterized in that, Metal-pillared bentonite and free chlorine are added to an aqueous solution containing divalent manganese ions for an oxidation reaction. The reaction is carried out by stirring, oxidation, and separation in a reactor. The free chlorine is one of chlorine gas, liquid chlorine, or sodium hypochlorite. The metal-pillared bentonite provides catalytic sites for the rapid oxidation of divalent manganese ions in aqueous solution by chlorine. Its high specific surface area and porous structure support the oxidation product MnOx of divalent manganese ions, which generates an autocatalytic effect on the surface of the metal-pillared bentonite to accelerate the oxidation of divalent manganese ions. The metal-pillared bentonite increases the oxidation rate by more than 10 times. The method for preparing the metal-pillared bentonite is as follows: Step 1: Disperse bentonite in water, shake and let it settle to obtain upper bentonite slurry; Step 2: Disperse the upper bentonite slurry in an inorganic solution, stir at room temperature, filter and separate to obtain purified sodium-based bentonite; Step 3: Add sodium hydroxide solution dropwise to metal chloride solution, control the ratio of hydroxide ions to metal ions, stir, and age in a water bath to obtain pillar proppant; the metal chloride solution is one of AlCl3, FeCl3 or TiCl4, and the ratio of hydroxide ions to metal ions is hydroxide ions: metal ions = 2-3: 1; Step 4: After mixing the purified sodium-based bentonite with water at a certain mass ratio, add the pillaring agent and mix, control the ratio of metal ions to bentonite, stir and process to obtain metal-pillared bentonite. The metal-pillared bentonite comprises 1-40 parts, the free chlorine comprises 2-5 parts, and the divalent manganese ion aqueous solution comprises 1 part.
2. A method of catalytic oxidation of manganese ions in drinking water according to claim 1, characterized in that, The water used in step one is deionized water, and the particle diameter in the upper bentonite slurry is less than 2 μm.
3. A method of catalytic oxidation of manganese ions in drinking water according to claim 1, characterized in that, The inorganic solution mentioned in step two is chloride. sodium Solution, the chlorinated sodium The solution concentration was 1.0 mol / L, and the stirring time was 12 h.
4. A method of catalytic oxidation of manganese ions in drinking water according to claim 1, characterized by, In step three, the concentrations of both the sodium hydroxide solution and the metal chloride solution are 0.5 mol / L. The stirring time is 1-3 h, and the water bath aging time is 12-96 h at a temperature of 60 ℃.
5. A method of catalytic oxidation of manganese ions in drinking water according to claim 1, characterized by, In step four, the mass ratio of purified sodium-based bentonite to water is 2:98, and the ratio of metal ions to bentonite is 5-40 mmol metal ions / 1 g bentonite.
6. A method of catalytic oxidation of manganese ions in drinking water according to claim 1, characterized by, The specific steps of post-processing in step four are as follows: aging, washing with water until there are no chloride ions, drying, and calcining. The aging time is 12-48 h, the drying temperature is 103-105 ℃, and the calcination temperature is 400-600 ℃.