Preparation method of in-situ nano manganese dioxide and zeolite composite material and application of in-situ nano manganese dioxide and zeolite composite material in removal of metal ions and micropollutants in water

Abstract

The invention discloses a preparation method of an in-situ nano manganese dioxide and zeolite composite material and application of the composite material in removal of metal ions and micropollutants in water, and belongs to the field of drinking water source water treatment. The preparation method of the in-situ nano manganese dioxide and zeolite composite material comprises the following steps: 1, pretreating natural zeolite; 2, preparing acid-treated zeolite; and 3, preparing the in-situ nano manganese dioxide and zeolite composite material. According to the invention, an impregnation-calcination method is adopted, MnO2 is loaded in situ on the pore channels and the surface of the acid-treated zeolite, and uniform growth of nanometer and sub-nanometer layered manganese dioxide is realized based on the nanometer pore channel structure of the zeolite. According to the structure, the reactivity of various oxidants represented by monopersulfate is stimulated, macromolecules and background substances with the same electric property are excluded through the confinement effect, interference of non-target objects on the oxidation process is reduced, and a new thought and technical support are provided for solving the problem of combined pollution of drinking water.

Description

Technical Field

[0001] The present invention belongs to the field of drinking water source water treatment, and particularly relates to a preparation method of an in-situ nano manganese dioxide @ zeolite composite material and its application in removing metal ions and micropollutants in water. Background Art

[0002] Excessive manganese is a common environmental problem in drinking water treatment and has been reported globally. Due to the widespread distribution of manganese in the earth's crust, its enrichment in groundwater and surface water is relatively common. In recent years, the eutrophication problem of surface water bodies such as rivers and lakes has become increasingly serious, and the thermal stratification phenomenon in lakes and reservoirs in summer has intensified, causing the dissolved manganese in the sediment to be released into the overlying water body, further aggravating the manganese pollution of the water body. Excessive manganese ions not only affect the color and taste of water, but also have an adverse impact on industrial production (such as the paper-making and textile industries), and pose a potential threat to human health. Long-term intake of drinking water with a high manganese content may lead to health problems such as fatigue, dizziness, and memory decline, and may even affect the nervous system development and cognitive ability of children. In addition, affected by geological conditions and industrial activities, other metal ion pollutions may also accompany in the drinking water source water, further increasing the water quality safety risk. Therefore, the efficient removal of manganese and other metal ions in water bodies has important environmental and public health significance.

[0003] With the intensification of human activities, the detection rate of emerging pollutants in drinking water source water has gradually increased. Among them, organic micropollutants (such as drug residues, endocrine disruptors, etc.) have chemical stability, and their concentrations are usually at the level of a few tenths to a few micrograms per liter. They have bioaccumulation and potential ecological risks, and may be transmitted through the food chain and affect the safety of drinking water. In addition, the problem of ammonia nitrogen pollution in surface water is becoming increasingly prominent, which not only aggravates water eutrophication, but also increases the difficulty and cost of drinking water treatment, posing greater challenges to traditional water treatment processes. Therefore, there is an urgent need to develop a water treatment technology that can achieve the efficient and synergistic removal of multiple pollutants, with both high efficiency and economic feasibility, to meet the drinking water safety guarantee requirements under complex water quality conditions.

[0004] At present, the treatment of drinking water source water pollution is becoming increasingly complex and the treatment difficulty is getting higher and higher. At the same time, traditional manganese removal technologies have limitations, such as the long start-up period of the contact oxidation manganese removal filter, the insufficient production and high cost of natural manganese sand, the large chlorine dosage in chlorine contact oxidation and the generation of disinfection by-products, etc. Moreover, the high organic matter in the source water often has an adverse impact on the removal of manganese and other pollutants. Summary of the Invention

[0005] In order to solve the above technical problems, from the perspective of confinement catalysis, the present invention proposes a preparation method of an in-situ nano manganese dioxide @ zeolite composite material and its application in removing metal ions and micropollutants in water.

[0006] A preparation method of an in-situ nano manganese dioxide @ zeolite composite material is specifically completed according to the following steps:

[0007] I. Pretreatment of natural zeolite:

[0008] Ball-mill and sieve the natural zeolite, then wash it with water, drain the water and air-dry it naturally to obtain the pretreated natural zeolite;

[0009] II. Preparation of acid-treated zeolite:

[0010] Add the pretreated natural zeolite into a nitric acid solution, oscillate and react for a period of time under the condition of constant temperature water bath, wash it with water several times and dry it after the reaction to obtain the acid-treated zeolite;

[0011] III. Preparation of in-situ nano manganese dioxide @ zeolite composite material:

[0012] Mix the acid-treated zeolite with a manganese solution, ultrasonicate, adjust the pH of the system to 7, then oscillate and react under the condition of water bath, age at room temperature, filter, rinse and dry after the reaction, and finally calcine to obtain the in-situ nano manganese dioxide @ zeolite composite material.

[0013] An in-situ nano manganese dioxide @ zeolite composite material is used to remove metal ions and micropollutants in source water; the metal ions are Mn 2+ 、Fe 2+ 、Pb 2+ 、Cs + and Sr 2+ one or more of them; the micropollutants are one or more of ammonia nitrogen, sulfamethoxazole and bisphenol A.

[0014] Principle of the present invention:

[0015] Zeolite is a common porous material medium with adjustable pore size and stable framework structure, making it an excellent carrier for loading, doping and encapsulating metal catalysts. Its nano-scale pores can effectively inhibit the agglomeration of active species, anchor single atoms and stabilize catalytic active sites, reduce oxidation and agglomeration effects, and thus promote the efficient transport of reactants and products in the confined space. In addition, the confinement effect can enhance interfacial electron transfer and improve the adsorption ability of reaction molecules, making zeolite widely concerned in the fields of adsorption and catalysis. Based on this, the present invention adopts the impregnation-calcination method to in-situ load MnO2 in the pores and on the surface of acid-treated zeolite, and relies on the nano-scale pore structure of zeolite to realize the uniform growth of nano- and sub-nano-scale layered manganese dioxide. This structure not only helps to stimulate the reaction activity of various oxidants represented by single peroxymonosulfate (PMS), but also uses the confinement effect to exclude macromolecules and co-charged background substances, reducing the interference of non-target substances on the oxidation process.

[0016] Advantages of the present invention:

[0017] 1. Based on the confined catalysis theory, the present invention constructs an in-situ nano-manganese dioxide@zeolite composite material. The prepared material realizes the stable loading and distribution of nano-MnO2 in the zeolite pore channels and surface regions, effectively improving its catalytic reaction activity. This material can efficiently catalyze the activation of peroxymonosulfate (PMS) to generate reactive oxygen species, and then oxidize and remove various pollutants, including organic micropollutants, metal ions (Fe 2+ 、Mn 2+ 、Pb 2+ etc.) and ammonia nitrogen. This catalytic system has good anti-interference ability against common water interference substances such as natural organic matter, ensuring its stable operation and high purification effect in complex water quality environments;

[0018] 2. The peroxymonosulfate selected in the present invention has stable chemical properties, and most industrial products are solids, which are convenient for transportation and storage. Compared with chlorine-based oxidants, there is no need to configure additional generating equipment, simplifying the system purchase, installation and operation and maintenance processes, and reducing the engineering implementation cost;

[0019] 3. The filtration system constructed in the present invention starts quickly and has high purification efficiency: the prepared in-situ nano-manganese dioxide@zeolite composite material can be directly used as filter media to fill filter columns or filter tanks, and form a catalytic oxidation filtration system in combination with peroxymonosulfate. This system does not require pretreatment or pre-oxidation in the startup stage, can stably remove pollutants in water at the initial stage of operation, the manganese ion concentration in the effluent can quickly drop below the limit value of the "Sanitary Standard for Drinking Water", and the organic matter removal rate is as high as over 80%, showing excellent purification ability;

[0020] 4. The catalytic oxidation enhanced filtration process provided by the present invention is simple, easy to operate, and has low operating costs. During the filtration process, there is no need to continuously add coagulants or flocculants, and only by controlling the dosing concentration of peroxymonosulfate, high-efficiency pollutant removal effects can be achieved. Compared with existing enhanced filtration technologies, this method simplifies the operation steps, reduces the dosage of chemicals and the sludge production. Description of the Drawings

[0021] Figure 1 is the concentration of manganese ions in the effluent of the dynamic filtration of the filter column constructed with an in-situ nano-manganese dioxide@zeolite composite material in Comparative Example 1;

[0022] Figure 2 is the efficiency of the filter column constructed with an in-situ nano-manganese dioxide@zeolite composite material in Example 2 to catalytically oxidize and filter out dissolved manganese in chlorine tap water by peroxymonosulfate;

[0023] Figure 3For the filter columns constructed with an in-situ nano-manganese dioxide@zeolite composite material in Examples 3-5, the efficiency of catalytically oxidizing and filtering out dissolved manganese in organic chlorine tap water by single persulfate;

[0024] Figure 4 For the filter columns constructed with an in-situ nano-manganese dioxide@zeolite composite material in Examples 6-7, the efficiency of catalytically oxidizing and filtering out dissolved manganese in surface water by single persulfate or sodium hypochlorite. Specific implementation manners

[0025] Specific implementation manner one: A preparation method of an in-situ nano-manganese dioxide@zeolite composite material in this implementation manner is specifically completed according to the following steps:

[0026] I. Pretreatment of natural zeolite:

[0027] Ball-mill and sieve natural zeolite, then wash it with water, drain the water, and air-dry it naturally to obtain pretreated natural zeolite;

[0028] II. Preparation of acid-treated zeolite:

[0029] Add the pretreated natural zeolite to a nitric acid solution, oscillate and react under constant temperature water bath conditions for a period of time, wash it several times with water and dry it after the reaction to obtain acid-treated zeolite;

[0030] III. Preparation of in-situ nano-manganese dioxide@zeolite composite material:

[0031] Mix the acid-treated zeolite with a manganese solution, ultrasonicate, adjust the pH of the system to 7, then oscillate and react under water bath conditions, age at room temperature, filter, rinse, dry, and finally calcine to obtain the in-situ nano-manganese dioxide@zeolite composite material.

[0032] Specific implementation manner two: The difference between this implementation manner and specific implementation manner one is that: the particle size of the pretreated natural zeolite in step I is 0.8 mm - 1.2 mm, and the coefficient of non-uniformity is 1.4 - 1.6; the natural zeolite in step I is one or more of clinoptilolite, mordenite, analcime, and heulandite. Other steps are the same as those in specific implementation manner one.

[0033] Specific implementation manner three: The difference between this implementation manner and one of specific implementation manner one or two is that: the concentration of the nitric acid solution in step II is 5 mol / L - 8 mol / L; the mass ratio of the pretreated natural zeolite to the nitric acid solution in step II is 1:1. Other steps are the same as those in specific implementation manner one or two.

[0034] Embodiment 4: The difference between this embodiment and any one of Embodiments 1 to 3 is as follows: In Step 2, the temperature of the constant-temperature water bath condition is 70°C to 80°C; the speed of the oscillating reaction in Step 2 is 100 r / min to 250 r / min, and the time of the oscillating reaction is 10 h to 12 h; after the reaction in Step 2, it is washed with water 3 to 5 times; the drying temperature in Step 2 is 50°C to 60°C. Other steps are the same as those in Embodiments 1 to 3.

[0035] Embodiment 5: The difference between this embodiment and any one of Embodiments 1 to 4 is as follows: The manganese solution in Step 3 is one or a mixture of a manganese nitrate solution, a manganese sulfate solution, and a manganese chloride solution; the concentration of manganese ions in the manganese solution in Step 3 is 0.3 mol / L; the mass ratio of the acid-treated zeolite to the manganese solution in Step 3 is 1:1. Other steps are the same as those in Embodiments 1 to 4.

[0036] Embodiment 6: The difference between this embodiment and any one of Embodiments 1 to 5 is as follows: In Step 3, the acid-treated zeolite and the manganese solution are mixed and ultrasonicated. The pH of the system is adjusted to 7 using ammonia water with a concentration of 1 mol / L and sulfuric acid with a concentration of 2 mol / L, and then an oscillating reaction is carried out under the condition of a water bath at 70°C to 80°C. The speed of the oscillating reaction is 100 r / min to 250 r / min, and the time of the oscillating reaction is 3 h to 4 h. After the reaction, it is aged at room temperature for 10 h to 12 h, filtered, and the product is rinsed 3 to 5 times with deionized water, and then dried at 105°C for 10 h to 12 h; the calcination temperature in Step 3 is 650°C, and the calcination time is 4 h. Other steps are the same as those in Embodiments 1 to 5.

[0037] Embodiment 7: The difference between this embodiment and any one of Embodiments 1 to 6 is as follows: An in-situ nano manganese dioxide@zeolite composite material is used to remove metal ions and micropollutants in source water; the metal ions are one or more of Fe 2 + , Mn 2+ , Pb 2+ , Cs + , and Sr 2+ ; the micropollutants are one or more of ammonia nitrogen, sulfamethoxazole, and bisphenol A. Other steps are the same as those in Embodiments 1 to 6.

[0038] Specific Embodiment 8: This embodiment differs from Specific Embodiments 1 to 7 in that monopersulfate is added to source water, and a filter column is prepared using an in-situ nano-manganese dioxide and zeolite composite material to filter the water and remove metal ions and micropollutants from the source water. The source water has a pH of 6.5 to 8.5, a temperature of 5°C to 20°C, and a total organic carbon content of 5 mg / L to 10 mg / L. Other steps are the same as Specific Embodiments 1 to 7.

[0039] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that an in-situ nano manganese dioxide@zeolite composite material is used to remove metal ions and micropollutants from source water, specifically by the following steps:

[0040] 1. Constructing filter columns, filter tanks or filter pools containing manganese-loaded filter media:

[0041] An in-situ nano manganese dioxide@zeolite composite material is used as a filter medium, and one or a combination of quartz sand and pebbles is used as a supporting layer to construct a filter column, filter tank or filter pool carrying manganese filter medium;

[0042] 2. Dynamic filtration and PMS oxidation filtration to remove pollutants:

[0043] The monopersulfate solution is mixed with source water through a pipeline, and the mixed solution is then filtered into a filter column, filter tank or filter pool containing the manganese-loaded filter material constructed in step 1 and remains there for a period of time;

[0044] 3. Regular backwashing:

[0045] After a certain period of filtration, backwashing is performed, and clean water enters the filter column, filter tank or filter tank in the opposite direction of operation to remove particles blocked in the filter material and reduce head loss during filtration. The other steps are the same as those of specific embodiments 1 to 8.

[0046] Embodiment 10: The difference between this embodiment and any one of Embodiments 1 to 9 is as follows: In Step 1, the thickness of the supporting layer is 3 cm; the height of the filter column is 20 cm; in Step 2, the concentration of metal ions in the source water is 0.5 mg / L to 1.0 mg / L, and the concentration of micropollutants is 0.5 μmol / L to 5 μmol / L; in Step 2, the monopersulfate in the monopersulfate solution is one or a mixture of several of potassium monopersulfate, sodium monopersulfate, and ammonium monopersulfate, and the monopersulfate solution is re-prepared every 24 h; in Step 2, the concentration of monopersulfate in the mixed solution is 2 μmol / L to 60 μmol / L; in Step 2, the time for mixing the monopersulfate solution and the source water through a pipeline is 2 min to obtain a mixed solution; the residence time in Step 2 is 6 min to 10 min; the source water in Step 2 includes surface water, groundwater, low-temperature and low-turbidity water bodies, and complex water bodies with high organic matter content; in Step 3, the backwashing intensity is 15 L / (m 2 ·s), and the backwashing time interval is 24 h. Other steps are the same as those in Embodiments 1 to 9.

[0047] The following examples are used to verify the principle of the present invention:

[0048] Example 1: A preparation method of an in-situ nano manganese dioxide @ zeolite composite material is specifically completed according to the following steps:

[0049] I. Pretreatment of natural zeolite:

[0050] The natural zeolite is ball-milled, sieved, then washed with water, drained, and naturally air-dried to obtain pretreated natural zeolite;

[0051] In Step 1, the particle size of the pretreated natural zeolite is 0.8 mm to 1.2 mm, and the coefficient of uniformity is 1.4 to 1.6;

[0052] The natural zeolite in Step 1 is clinoptilolite;

[0053] II. Preparation of acid-treated zeolite:

[0054] The pretreated natural zeolite is added to a nitric acid solution, and the reaction is carried out by shaking under constant temperature water bath conditions for a period of time. After the reaction, it is washed with water 3 times and dried to obtain acid-treated zeolite;

[0055] In Step 2, the concentration of the nitric acid solution is 5 mol / L;

[0056] In Step 2, the mass ratio of the pretreated natural zeolite to the nitric acid solution is 1:1;

[0057] The temperature of the constant temperature water bath described in Step 2 is 70 °C; the speed of the oscillating reaction described in Step 2 is 250 r / min, and the time of the oscillating reaction is 12 h;

[0058] The temperature of the drying described in Step 2 is 50 °C;

[0059] III. Preparation of in-situ nano manganese dioxide @ zeolite composite material:

[0060] Mix the acid-treated zeolite with the manganese solution, ultrasonicate, adjust the pH of the system to 7 with 1 mol / L ammonia water and 2 mol / L sulfuric acid, then carry out an oscillating reaction under the condition of a water bath at 70 °C. The speed of the oscillating reaction is 250 r / min, and the time of the oscillating reaction is 4 h. After the reaction, age at room temperature for 12 h, filter, wash the product 5 times with deionized water, then dry at 105 °C for 12 h, and finally calcine to obtain the in-situ nano manganese dioxide @ zeolite composite material;

[0061] The manganese solution described in Step 3 is a manganese nitrate solution;

[0062] The concentration of manganese ions in the manganese solution described in Step 3 is 0.3 mol / L;

[0063] The mass ratio of the acid-treated zeolite to the manganese solution described in Step 3 is 1:1;

[0064] The temperature of the calcination described in Step 3 is 650 °C, and the time of the calcination is 4 h.

[0065] Example 2: Using an in-situ nano manganese dioxide @ zeolite composite material prepared in Example 1 to treat water, specifically, it is completed according to the following steps:

[0066] I. Construct a filter column with manganese-loaded filter media:

[0067] Using an in-situ nano manganese dioxide @ zeolite composite material as the filter media and quartz sand as the support layer, construct a filter column with manganese-loaded filter media;

[0068] II. Dynamic filtration combined with PMS oxidation filtration to remove pollutants:

[0069] Mix the single persulfate solution with the source water through a pipeline, and then the mixed solution enters the filter column with manganese-loaded filter media constructed in Step I for filtration and stays for a period of time. The water inlet mode is gravity flow;

[0070] III. Periodic backwashing:

[0071] After filtering for a certain period of time, carry out backwashing. The clean water enters the filter column in the reverse direction during operation to remove the blocked particulate matter in the filter media and reduce the head loss during filtration;

[0072] The thickness of the support layer in step 1 is 3 cm; the height of the filter column is 20 cm;

[0073] The source water in step 2 is Mn 2+ Dechlorinated tap water at a concentration of 1 mg / L has a pH of 7;

[0074] The monopersulfate in the monopersulfate solution in step 2 is potassium monopersulfate, and the monopersulfate solution is reconfigured and replaced every 24 hours;

[0075] The concentration of monopersulfate in the mixed solution in step 2 is 40 μmol / L;

[0076] In step 2, the monopersulfate solution and the source water are mixed through the pipeline for 2 minutes to obtain a mixed solution;

[0077] The dwell time described in step 2 is 10 minutes;

[0078] The backwash intensity in step 3 is 15L / (m 2 ·s), the backwashing time interval is 24h.

[0079] Comparative Example 1: This example omitted the use of monopersulfate solution and was specifically completed by the following steps:

[0080] 1. Constructing a filter column with manganese-loaded filter media:

[0081] A manganese-loaded filter column was constructed using an in-situ nano-manganese dioxide@zeolite composite material as the filter medium and quartz sand as the supporting layer.

[0082] 2. Dynamic filtration and PMS oxidation filtration to remove pollutants:

[0083] The source water enters the filter column containing the manganese-loaded filter material constructed in step 1 and is filtered and retained for a period of time, with the water inlet mode being gravity flow;

[0084] 3. Regular backwashing:

[0085] After a certain period of filtration, backwashing is performed, and clean water enters the filter column in the opposite direction of operation to remove particles blocked in the filter material and reduce head loss during filtration;

[0086] The thickness of the support layer in step 1 is 3 cm; the height of the filter column is 20 cm;

[0087] The source water in step 2 is Mn 2+ Dechlorinated tap water at a concentration of 1 mg / L has a pH of 7;

[0088] The dwell time described in step 2 is 10 minutes;

[0089] The backwash intensity in step 3 is 15L / (m 2 ·s), the backwashing time interval is 24h.

[0090] Figure 1 The manganese ion concentration in water dynamically filtered out by a filter column constructed using an in-situ nano-manganese dioxide@zeolite composite material in Control Example 1;

[0091] from Figure 1 It can be seen that after the filter column has been running for 24 hours, the manganese ion content in the effluent exceeds the standard. Without the addition of monopersulfate, the filter column cannot effectively remove dissolved Mn in the water by adsorption. 2+ .

[0092] Figure 2 The efficiency of removing dissolved manganese from chlorinated tap water by catalytic monopersulfate oxidation filtration using a filter column constructed using an in-situ nano-manganese dioxide@zeolite composite material in Example 2;

[0093] Depend on Figure 2 It can be seen that the divalent manganese in the filtered water catalyzed by the in-situ nano-manganese dioxide@zeolite composite material for monopersulfate oxidation is lower than 0.1 mg / L, and the manganese removal efficiency is stable and reliable.

[0094] Example 3: An in-situ nano-manganese dioxide@zeolite composite material prepared in Example 1 is used to treat water, specifically by the following steps:

[0095] 1. Constructing a filter column with manganese-loaded filter media:

[0096] A manganese-loaded filter column was constructed using an in-situ nano-manganese dioxide@zeolite composite material as the filter medium and quartz sand as the supporting layer.

[0097] 2. Dynamic filtration and PMS oxidation filtration to remove pollutants:

[0098] The monopersulfate solution is mixed with source water through a pipeline, and the mixed solution is then filtered into the filter column of the manganese-loaded filter material constructed in step 1 and retained for a period of time, with the water inlet mode being gravity flow;

[0099] 3. Regular backwashing:

[0100] After a certain period of filtration, backwashing is performed, and clean water enters the filter column in the opposite direction of operation to remove particles blocked in the filter material and reduce head loss during filtration;

[0101] The thickness of the support layer in step 1 is 3 cm; the height of the filter column is 20 cm;

[0102] The source water in step 2 is Mn 2+The dechlorinated tap water with a concentration of 1 mg / L has a pH value of 7 and the concentration of organic matter is 4 mg / L; the organic matter is the added humic acid;

[0103] In the single persulfate solution described in step 2, the single persulfate is potassium monopersulfate, and the single persulfate solution is re-prepared and replaced every 24 h;

[0104] In the mixed solution described in step 2, the concentration of single persulfate is 20 μmol / L;

[0105] In step 2, the time for mixing the single persulfate solution and the source water through the pipeline is 2 min to obtain a mixed solution;

[0106] In step 2, the residence time is 10 min;

[0107] In step 3, the backwashing intensity is 15 L / (m 2 ·s), and the backwashing time interval is 24 h.

[0108] Example 4: The difference between this example and Example 3 is that the drinking water source water described in step 2 is dechlorinated tap water with a Mn 2+ concentration of 1 mg / L and the concentration of organic matter is 7 mg / L; the organic matter is the added humic acid. Other steps and parameters are the same as those in Example 3.

[0109] Example 5: The difference between this example and Example 3 is that the drinking water source water described in step 2 is dechlorinated tap water with a Mn 2+ concentration of 1 mg / L and the concentration of organic matter is 10 mg / L; the organic matter is the added humic acid. Other steps and parameters are the same as those in Example 3.

[0110] Figure 3 For the efficiency of removing dissolved manganese in organic matter-containing chlorinated tap water by catalytic oxidation filtration of single persulfate using a filter column constructed with an in-situ nano-manganese dioxide@zeolite composite material in Examples 3 to 5;

[0111] From Figure 3 it can be seen that the organic matter in surface water is generally within 10 mg / L. Therefore, the process of catalytic oxidation filtration of single persulfate by the in-situ nano-manganese dioxide@zeolite composite material to remove dissolved manganese is less affected by organic matter and has good stability.

[0112] Example 6: Using an in-situ nano-manganese dioxide@zeolite composite material prepared in Example 1 to treat water, specifically, it is completed according to the following steps:

[0113] I. Construct a filter column with manganese-loaded filter media:

[0114] Using an in-situ nano-manganese dioxide@zeolite composite material as the filter medium and quartz sand as the supporting layer, a filter column with a manganese-loaded filter medium is constructed;

[0115] II. Dynamic filtration combined with PMS oxidation filtration to remove pollutants:

[0116] Mix the peroxymonosulfate solution with the source water through a pipeline, and then the mixed solution enters the filter column with the manganese-loaded filter medium constructed in Step I for filtration and stays for a period of time. The water inlet method is gravity flow;

[0117] III. Regular backwashing:

[0118] After filtering for a certain period of time, backwashing is carried out. Clean water enters the filter column in the reverse direction during operation to remove the blocked particulate matter in the filter medium and reduce the head loss during filtration;

[0119] The thickness of the supporting layer described in Step I is 3 cm; the height of the filter column is 20 cm;

[0120] The source water described in Step II is surface water with a Mn 2+ concentration of 1 mg / L, a pH value of 6.8 - 7.5, and an organic matter concentration of 10 mg / L; the organic matter is the added humic acid;

[0121] In the peroxymonosulfate solution described in Step II, the peroxymonosulfate is potassium peroxymonosulfate, and the peroxymonosulfate solution is re-prepared and replaced every 24 hours;

[0122] The concentration of peroxymonosulfate in the mixed solution described in Step II is 40 μmol / L;

[0123] In Step II, the mixing time of the peroxymonosulfate solution and the source water through the pipeline is 2 minutes to obtain a mixed solution;

[0124] The residence time described in Step II is 10 minutes;

[0125] The backwashing intensity described in Step III is 15 L / (m 2 ·s), and the backwashing time interval is 24 hours.

[0126] Example 7: Using an in-situ nano-manganese dioxide@zeolite composite material prepared in Example 1 for water treatment, specifically, it is completed according to the following steps:

[0127] I. Construct a filter column with a manganese-loaded filter medium:

[0128] Using an in-situ nano-manganese dioxide@zeolite composite material as the filter medium and quartz sand as the supporting layer, a filter column with a manganese-loaded filter medium is constructed;

[0129] II. Dynamic filtration combined with PMS oxidation filtration to remove pollutants:

[0130] Mix sodium hypochlorite with source water through a pipeline, and then the mixed solution enters the filter column filled with manganese-loaded filter media constructed in Step 1 for filtration and stays for a period of time. The water inlet mode is gravity flow;

[0131] III. Regular backwashing:

[0132] After filtering for a certain period of time, conduct backwashing. Clean water enters the filter column in the opposite direction during operation to remove the blocked particulate matter in the filter media and reduce the head loss during filtration;

[0133] The thickness of the support layer described in Step 1 is 3 cm; the height of the filter column is 20 cm;

[0134] The source water described in Step 2 is surface water with a Mn 2+ concentration of 0.9 mg / L, a pH value of 7.6 - 7.8, and an organic matter concentration of 10 mg / L; the organic matter is added humic acid;

[0135] The sodium hypochlorite solution described in Step 2 is re-prepared every 24 hours;

[0136] The concentration of sodium hypochlorite in the mixed solution described in Step 2 is 40 μmol / L,

[0137] The mixing time of the peroxymonosulfate solution and the source water through a pipeline in Step 2 is 2 minutes to obtain a mixed solution;

[0138] The residence time described in Step 2 is 10 minutes;

[0139] The backwashing intensity described in Step 3 is 15 L / (m 2 ·s), and the backwashing time interval is 24 hours.

[0140] Figure 4 It is for the efficiency of catalytic oxidation filtration of dissolved manganese in surface water by using a filter column constructed with an in-situ nano-manganese dioxide@zeolite composite material in Examples 6 - 7;

[0141] From Figure 4 it can be seen that: The catalytic oxidation filtration of dissolved manganese in surface water by an in-situ nano-manganese dioxide@zeolite composite material is stable and efficient. Compared with the chlorine contact oxidation system, the effluent is always lower than 0.1 mg / L, proving that this process has good resistance to organic matter load.

[0142] Example 8: Use an in-situ nano-manganese dioxide@zeolite composite material prepared in Example 1 to treat water, which is specifically completed according to the following steps:

[0143] I. Construct a filter column filled with manganese-loaded filter media:

[0144] Using an in-situ nano-manganese dioxide@zeolite composite material as the filter media and quartz sand as the supporting layer, a filter column with manganese-loaded filter media is constructed;

[0145] II. Dynamic filtration combined with PMS oxidation for pollutant removal:

[0146] Mix the peroxymonosulfate solution with the source water through a pipeline, and then the mixed solution enters the filter column with manganese-loaded filter media constructed in Step I for filtration and stays for a period of time. The water inlet mode is gravity flow;

[0147] III. Periodic backwashing:

[0148] After filtering for a certain period of time, backwashing is carried out. Clean water enters the filter column in the reverse direction during operation to remove the blocked particulate matter in the filter media and reduce the head loss during filtration;

[0149] In Step I, the thickness of the supporting layer is 3 cm; the height of the filter column is 20 cm;

[0150] In Step II, the concentration of SMX in the source water is 3 μmol / L and the pH value is 7.0;

[0151] In Step II, the peroxymonosulfate in the peroxymonosulfate solution is potassium peroxymonosulfate, and the peroxymonosulfate solution is re-prepared and replaced every 24 hours;

[0152] In Step II, the concentration of peroxymonosulfate in the mixed solution is 30 μmol / L,

[0153] In Step II, the mixing time of the peroxymonosulfate solution and the source water through the pipeline is 2 minutes to obtain the mixed solution;

[0154] In Step II, the residence time is 10 minutes;

[0155] In Step III, the backwashing intensity is 15 L / (m 2 ·s), and the backwashing time interval is 24 hours.

[0156] In Example 8, the SMX removal efficiency is 70% - 80%, and the treatment efficiency can be improved by increasing the filter layer depth.

[0157] Example 9: Using an in-situ nano-manganese dioxide@zeolite composite material prepared in Example 1 for water treatment, which is specifically completed according to the following steps:

[0158] I. Construct a filter column with manganese-loaded filter media:

[0159] Using an in-situ nano-manganese dioxide@zeolite composite material as the filter media and quartz sand as the supporting layer, a filter column with manganese-loaded filter media is constructed;

[0160] II. Dynamic filtration combined with PMS oxidation filtration to remove pollutants:

[0161] Mix the single - persulfate solution with the source water through a pipeline, and then the mixed solution enters the filter column filled with manganese - loaded filter media constructed in Step I for filtration and stays for a period of time. The water inlet method is gravity flow.

[0162] III. Regular backwashing:

[0163] After filtering for a certain time, perform backwashing. Clean water enters the filter column in the reverse direction during operation to remove the blocked particulate matter in the filter media and reduce the head loss during filtration.

[0164] The thickness of the support layer described in Step I is 3 cm; the height of the filter column is 20 cm.

[0165] The concentration of SMX in the source water described in Step II is 3 μmol / L, the concentration of Mn 2+ is 0.9 mg / L, and the pH value is 7.0.

[0166] The single - persulfate in the single - persulfate solution described in Step II is potassium monopersulfate, and the single - persulfate solution is re - prepared and replaced every 24 h.

[0167] The concentration of single - persulfate in the mixed solution described in Step II is 50 μmol / L.

[0168] The time for mixing the single - persulfate solution with the source water through a pipeline in Step II is 2 min to obtain a mixed solution.

[0169] The residence time described in Step II is 10 min.

[0170] The backwashing intensity described in Step III is 15 L / (m 2 ·s), and the backwashing time interval is 24 h.

[0171] In Example 9, the removal efficiency of SMX is 80%, and the removal rate of Mn 2+ is 95%. The treatment efficiency can be improved by increasing the depth of the filter layer.

[0172] Example 10: Use an in - situ nano - manganese dioxide@zeolite composite material prepared in Example 1 to treat water, which is specifically completed according to the following steps:

[0173] I. Construct a filter column filled with manganese - loaded filter media:

[0174] Use an in - situ nano - manganese dioxide@zeolite composite material as the filter media and quartz sand as the support layer to construct a filter column filled with manganese - loaded filter media.

[0175] II. Dynamic filtration combined with PMS oxidation filtration to remove pollutants:

[0176] Mix the single persulfate solution with the source water through a pipeline. The mixed solution then enters the filter column filled with manganese - loaded filter media constructed in Step 1 for filtration and stays for a period of time. The water inlet mode is gravity flow.

[0177] III. Regular backwashing:

[0178] After filtering for a certain period of time, conduct backwashing. The clean water enters the filter column in the reverse direction during operation to remove the blocked particulate matter in the filter media and reduce the head loss during filtration.

[0179] In Step 1, the thickness of the support layer is 3 cm; the height of the filter column is 20 cm.

[0180] In Step 2, the concentration of Fe 2+ in the source water is 1 mg / L, the concentration of Mn 2+ is 1.0 mg / L, and the pH value is 7.0.

[0181] In Step 2, the single persulfate in the single persulfate solution is potassium monopersulfate, and the single persulfate solution is re - prepared and replaced every 24 hours.

[0182] In Step 2, the concentration of single persulfate in the mixed solution is 50 μmol / L.

[0183] In Step 2, the time for mixing the single persulfate solution with the source water through the pipeline is 2 minutes to obtain the mixed solution.

[0184] In Step 2, the residence time is 10 minutes.

[0185] In Step 3, the backwashing intensity is 15 L / (m 2 ·s), and the backwashing time interval is 24 hours.

[0186] In Example 10, the removal rates of Fe 2+ and Mn 2+ are 95%.

Claims

1. A preparation method of an in-situ nano manganese dioxide @ zeolite composite material, characterized in that The preparation method is specifically completed according to the following steps: I. Pretreatment of natural zeolite: The natural zeolite is ball-milled and sieved, then washed with water, drained, and naturally air-dried to obtain the pretreated natural zeolite; II. Preparation of acid-treated zeolite: The pretreated natural zeolite is added to a nitric acid solution, and the mixture is oscillated and reacted under constant temperature water bath conditions for a period of time. After the reaction, it is washed with water several times and dried to obtain the acid-treated zeolite; III. Preparation of in-situ nano manganese dioxide@zeolite composite: The acid-treated zeolite is mixed with a manganese solution, ultrasonicated, the pH of the system is adjusted to 7, and then it is oscillated and reacted under water bath conditions. After the reaction, it is aged at room temperature, filtered, rinsed, and dried, and finally calcined to obtain the in-situ nano manganese dioxide@zeolite composite.

2. The preparation method of an in-situ nano manganese dioxide @ zeolite composite material according to claim 1, characterized in that The particle size of the pretreated natural zeolite described in step I is 0.8 mm to 1.2 mm, and the coefficient of non-uniformity is 1.4 to 1.6; the natural zeolite described in step I is one or more of clinoptilolite, mordenite, analcime, and heulandite.

3. The preparation method of an in-situ nano manganese dioxide @ zeolite composite material according to claim 1, characterized in that The concentration of the nitric acid solution described in step II is 5 mol / L to 8 mol / L; the mass ratio of the pretreated natural zeolite to the nitric acid solution described in step II is 1:

1.

4. The preparation method of an in-situ nano manganese dioxide @ zeolite composite material according to claim 1, characterized in that The temperature of the constant temperature water bath conditions described in step II is 70°C to 80°C; the oscillation reaction speed described in step II is 100 r / min to 250 r / min, and the oscillation reaction time is 10 h to 12 h; after the reaction in step II, it is washed with water 3 to 5 times; the drying temperature described in step II is 50°C to 60°C.

5. The preparation method of an in-situ nano manganese dioxide @ zeolite composite material according to claim 1, characterized in that The manganese solution described in step III is a mixed solution of one or several of manganese nitrate solution, manganese sulfate solution, and manganese chloride solution; the manganese ion concentration in the manganese solution described in step III is 0.3 mol / L; the mass ratio of the acid-treated zeolite to the manganese solution described in step III is 1:

1.

6. The preparation method of an in-situ nano manganese dioxide @ zeolite composite material according to claim 1, characterized in that In step III, the acid-treated zeolite is mixed with the manganese solution, ultrasonicated, the pH of the system is adjusted to 7 using ammonia water with a concentration of 1 mol / L and sulfuric acid with a concentration of 2 mol / L, and then it is oscillated and reacted under water bath conditions at 70°C to 80°C. The oscillation reaction speed is 100 r / min to 250 r / min, and the oscillation reaction time is 3 h to 4 h. After the reaction, it is aged at room temperature for 10 h to 12 h, filtered, and the product is rinsed 3 to 5 times with deionized water, and then dried at 105°C for 10 h to 12 h; the calcination temperature described in step III is 650°C, and the calcination time is 4 h.

7. Use of an in-situ nano manganese dioxide @ zeolite composite material prepared by the preparation method according to claim 1, characterized in that An in-situ nano-manganese dioxide @ zeolite composite material is used for removing metal ions and micropollutants in source water; the metal ions are one or more of Mn2+, Fe 2+ , Pb 2 +, Cs+ and Sr 2 +; the micropollutants are one or more of ammonia nitrogen, sulfamethoxazole and bisphenol A.

8. Use of an in-situ nano-manganese dioxide @ zeolite composite material according to claim 7, characterized in that Persulfate monopersulfate is added to the source water, and then an in-situ nano manganese dioxide@zeolite composite is prepared into a filter column to filter the water to remove metal ions and micro-pollutants in the source water; the pH value of the source water is 6.5 to 8.5, the temperature is 5°C to 20°C, and the total organic carbon content is 5 mg / L to 10 mg / L.

9. Use of an in-situ nano manganese dioxide @ zeolite composite material according to claim 7, characterized in that An in-situ nano manganese dioxide@zeolite composite is used to remove metal ions and micro-pollutants in the source water, and it is specifically completed according to the following steps: I. Construct a filter column, filter tank, or filter pool with a manganese-loaded filter material: Using an in-situ nano-manganese dioxide @ zeolite composite material as the filter media and a combination of one or both of quartz sand and pebbles as the supporting layer, a filter column, filter tank or filter pool with manganese-loaded filter media is constructed; II. Dynamic filtration combined with PMS oxidation for pollutant removal: Mix the peroxymonosulfate solution with the source water through a pipeline, and then the mixed solution enters the filter column, filter tank or filter pool with manganese-loaded filter media constructed in Step I for filtration and stays for a period of time; III. Regular backwashing: After filtering for a certain period of time, backwashing is carried out. Clean water enters the filter column, filter tank or filter pool in the reverse direction during operation to remove the blocked particulate matter in the filter media and reduce the head loss during filtration.

10. Use of an in-situ nano manganese dioxide @ zeolite composite according to claim 7, characterized in that In Step 1, the thickness of the supporting layer is 3 cm; the height of the filter column is 20 cm; in Step 2, the concentration of metal ions in the source water is 0.5 mg / L to 1.0 mg / L, and the concentration of micropollutants is 0.5 μmol / L to 5 μmol / L; in Step 2, the single persulfate in the single persulfate solution is one or a mixture of several of potassium monopersulfate, sodium monopersulfate, and ammonium monopersulfate, and the single persulfate solution is re-prepared every 24 h; in Step 2, the concentration of single persulfate in the mixed solution is 20 μmol / L to 60 μmol / L; in Step 2, the time for mixing the single persulfate solution and the source water through a pipeline is 2 min to obtain a mixed solution; the residence time in Step 2 is 6 min to 10 min; the source water in Step 2 includes surface water, groundwater, low-temperature and low-turbidity water bodies, and complex water bodies with high organic matter content; in Step 3, the backwashing intensity is 15 L / (m 2 ·s), and the backwashing time interval is 24 h.

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