Preparation method and application of modified zeolite filter material for intensively and synchronously removing dissolved manganese and ammonia nitrogen in surface water

Abstract

The invention discloses a preparation method and application of a modified zeolite filter material for intensively and synchronously removing dissolved manganese and ammonia nitrogen in surface water, and aims to solve the problems that two pollutants, namely manganese and ammonia nitrogen, cannot be synchronously removed by an existing manganese removal process, and the cost of natural manganese sand is relatively high. The preparation method of the modified zeolite filter material comprises the following steps: 1, sieving clinoptilolite; 2, dipping the screened clinoptilolite in a dilute nitric acid solution; 3, putting the initial zeolite into a bivalent manganese salt solution with the concentration of 0.2-0.5 mol / L, and carrying out oscillation adsorption treatment; and 4, immersing the zeolite particles adsorbed with the divalent manganese into a mixed solution of permanganate and sodium hydroxide for adsorption reaction, and washing and drying to obtain the modified zeolite filter material. The modified zeolite filter material is used as a filter material for surface water treatment, two pollutants of manganese and ammonia nitrogen can be rapidly and effectively removed, the removal rate of manganese ions in water can reach 95%, and the removal rate of ammonia nitrogen can reach 90% or above.

Description

Technical Field

[0001] The invention relates to a method for preparing a modified zeolite filter material and a method for treating sewage containing dissolved manganese and ammonia nitrogen by using the modified zeolite filter material. Background Art

[0002] Manganese is a common transition metal element in geology and is abundant in content. Surface water often contains excessive dissolved manganese, posing a threat to drinking water safety. Long-term intake of excessive manganese can cause adverse symptoms such as fatigue, dizziness and memory loss, and even affect children's intellectual development. In view of the problem of excessive manganese ion content in drinking water sources, it is necessary to invent a cheap and effective way to remove manganese. Due to agricultural activities, industrial production and daily life, ammonia nitrogen has gradually become a new pollutant in surface water, which can easily lead to the massive reproduction of algae in water bodies, causing serious biological pollution problems. The eutrophication solution of water bodies causes the traditional manganese removal process to have a poor manganese removal effect, and at the same time causes seasonal manganese pollution problems.

[0003] At present, the most commonly used manganese removal technology is aeration contact oxidation filtration removal of manganese. The soluble manganese in the water is oxidized into manganese active filter membrane through aeration. The manganese active filter membrane has the effect of contact oxidation removal of manganese, but the manganese active filter membrane has a long maturity period, weak activity, and unstable manganese removal effect. Insufficient manganese sand production and high cost also limit the promotion of this technology.

[0004] Chemical oxidation is often used to remove manganese from surface water, and the commonly used oxidants are potassium permanganate and sodium hypochlorite. It is difficult to control the dosage of potassium permanganate. Insufficient potassium permanganate will cause the manganese content in the effluent to exceed the standard, and excessive dosage will cause the water color to change. Chlorine alone has a poor effect on manganese removal, low oxidation efficiency, and the actual chlorine dosage is greater than the theoretical stoichiometric ratio (1.3 mg). The oxidation time is also long. Therefore, it is necessary to propose a practical treatment process to achieve the simultaneous removal of the two pollutants in view of the shortcomings of existing technologies and the current status of water pollution. Summary of the invention

[0005] The purpose of the present invention is to solve the problem that the existing manganese removal process cannot simultaneously remove the two pollutants, manganese and ammonia nitrogen, and the cost of natural manganese sand is relatively high, and to provide a preparation method and application of a modified zeolite filter material for enhanced simultaneous removal of dissolved manganese and ammonia nitrogen in surface water.

[0006] The preparation method of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water of the present invention is achieved by the following steps:

[0007] 1. Screen the clinoptilolite to select the clinoptilolite with a particle size of 0.8 to 1.2 mm;

[0008] 2. washing and drying the screened clinoptilolite, then immersing it in a dilute nitric acid solution, and then washing and drying it to obtain an initial zeolite;

[0009] 3. placing the initial zeolite in a divalent manganese salt solution with a concentration of 0.2-0.5 mol / L for oscillation adsorption treatment to separate and obtain zeolite particles adsorbed with divalent manganese;

[0010] 4. Under oscillation conditions, immersing the zeolite particles adsorbed with divalent manganese in a mixed solution of permanganate and sodium hydroxide, heating in a water bath at 50 to 70° C. for 10 to 16 hours for adsorption reaction, and obtaining a modified zeolite filter material after washing and drying;

[0011] The concentration of sodium hydroxide in the mixed solution of potassium permanganate and sodium hydroxide in step 4 is 0.3-0.6 mol / L, and the concentration of permanganate is 0.15-0.3 mol / L.

[0012] The modified zeolite filter material for enhanced simultaneous removal of dissolved manganese and ammonia nitrogen in surface water is used as the modified zeolite filter material and quartz sand as the supporting layer, and water containing dissolved manganese and ammonia nitrogen flows through the filter material from top to bottom for filtration.

[0013] The invention provides a preparation method and application of a modified zeolite filter material for strengthening the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water. Manganese oxide is loaded on the surface of clinoptilolite under alkaline conditions by water bath heating. The surface of the filter material contains rich hydroxyl functional groups and Mn-O-Mn structures. The surface of the filter material is negatively charged, and metal cations and ammonium ions in water can be effectively adsorbed through chemical bonding and electrostatic action. Sodium hypochlorite added before filtration can effectively oxidize the adsorbed dissolved manganese ions and ammonium ions under the catalytic action of manganese oxide on the surface of zeolite. The oxidized manganese ions are converted into trivalent manganese and tetravalent manganese oxides, and the ammonium ions are oxidized into nitrates. The newly generated manganese oxide is attached to the surface of the filter material, realizing the filter material renewal process, continuing to adsorb manganese ions and ammonium ions, catalyzing sodium hypochlorite to oxidize the two pollutants, and realizing the removal of green cycle pollutants without causing secondary pollution.

[0014] The preparation method of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water and its application include the following beneficial effects:

[0015] 1. The preparation method of the modified zeolite filter material in the present invention is simple and easy to implement, and the construction of the filter column filled with the modified zeolite filter material, the filter tank of the manganese-loaded zeolite or the filter pool of the manganese-loaded zeolite is easy to implement, and a good denitrification and manganese removal effect is achieved;

[0016] 2. The water treatment method of the present invention can quickly and effectively remove two pollutants, manganese and ammonia nitrogen. The process flow is simple and can be applied to water plants with centralized water supply. It can also be made into an integrated device for treating rural groundwater. It is low-priced and easy to use, and has broad application prospects in the water treatment industry.

[0017] 3. The modified zeolite filter material of the present invention is applied to existing water plants and is easy to transform. It only needs to partially or completely replace the original filter material of the water plant with the modified filter material and add a pre-filtration sodium hypochlorite dosing device to achieve pollutant removal;

[0018] 4. In case of sudden water pollution, sodium hypochlorite can be added immediately to ensure the safety of drinking water. When the source water is not polluted, the addition of sodium hypochlorite can be suspended to save the cost of the agent.

[0019] 5. The modified zeolite filter material prepared by the present invention combined with the sodium hypochlorite pre-oxidation method can achieve a removal rate of 95% for manganese ions in water and a removal rate of more than 90% for ammonia nitrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the operation of a modified zeolite filter column for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water in an embodiment;

[0021] Figure 2 The figure is a physical picture of the surface color change of the modified zeolite filter material before and after operation under chlorine addition conditions in the application example, wherein the left figure is the modified zeolite filter material before operation, and the right figure is the modified zeolite filter material after one week of operation. After long-term operation, the surface color of the filter material is obviously deepened, and new manganese oxides are loaded on the surface of the filter material;

[0022] Figure 3 This is a test graph of the dissolved manganese removal rate of different application examples in the application example after continuous operation for 7 days;

[0023] Figure 4 This is a test chart of ammonia nitrogen removal rates of different application embodiments after continuous operation for 7 days in the application embodiments. DETAILED DESCRIPTION

[0024] Specific implementation method 1: The preparation method of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water in this implementation method is implemented according to the following steps:

[0025] 1. Screen the clinoptilolite to select the clinoptilolite with a particle size of 0.8 to 1.2 mm;

[0026] 2. washing and drying the screened clinoptilolite, then immersing it in a dilute nitric acid solution, and then washing and drying it to obtain an initial zeolite;

[0027] 3. placing the initial zeolite in a divalent manganese salt solution with a concentration of 0.2-0.5 mol / L for oscillation adsorption treatment to separate and obtain zeolite particles adsorbed with divalent manganese;

[0028] 4. Under oscillation conditions, immersing the zeolite particles adsorbed with divalent manganese in a mixed solution of permanganate and sodium hydroxide, heating in a water bath at 50 to 70° C. for 10 to 16 hours for adsorption reaction, and obtaining a modified zeolite filter material after washing and drying;

[0029] The concentration of sodium hydroxide in the mixed solution of potassium permanganate and sodium hydroxide in step 4 is 0.3-0.6 mol / L, and the concentration of permanganate is 0.15-0.3 mol / L.

[0030] The particle size of the zeolite in step 1 of this embodiment is 0.8-1.2 mm, the non-uniformity coefficient is 1.4-1.6, and the density is 2.2 g / cm 3 .

[0031] The modified zeolite filter material of this embodiment is a zeolite surface loaded with manganese dioxide material under alkaline water bath heating conditions.

[0032] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that the volume fraction of nitric acid in the dilute nitric acid solution in step 2 is 5% to 6%.

[0033] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that the divalent manganese salt solution in step three is a manganese sulfate solution, and the concentration of the manganese sulfate solution is 0.3 mol / L.

[0034] Specific implementation method 4: The difference between this implementation method and any one of specific implementation methods 1 to 3 is that in step 3, a shaking table is used for oscillation adsorption treatment, and the shaking table speed is controlled to be 50-500 r / min and the amplitude is 10-30 mm.

[0035] Specific implementation mode 5: This implementation mode is different from specific implementation modes 1 to 4 in that the oscillation adsorption treatment time in step 3 is 10 to 16 hours.

[0036] Specific implementation method 6: This implementation method is different from any one of specific implementation methods 1 to 5 in that the molar ratio of sodium hydroxide to permanganate in the mixed solution of permanganate and sodium hydroxide in step 4 is 2:1.

[0037] Specific embodiment 7: This embodiment is different from any one of specific embodiments 1 to 6 in that in step 4, the adsorption reaction is carried out by heating in a water bath at 60° C. for 12 h.

[0038] Specific implementation method eight: In this implementation method, the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water is used as the filter material, quartz sand is used as the supporting layer, and water containing dissolved manganese and ammonia nitrogen flows through the filter material from top to bottom for filtration.

[0039] This embodiment is applicable to surface water containing manganese and ammonia nitrogen, and the pH of the surface water is 6.5-8.5.

[0040] In this embodiment, manganese-loaded zeolite particles are used as filter material and quartz sand is used as a supporting layer to construct a manganese-loaded zeolite filter column, filter tank or filter pool.

[0041] Specific embodiment nine: This embodiment is different from specific embodiment eight in that the water containing dissolved manganese and ammonia nitrogen passes through a mixing tank in advance, and the water containing dissolved manganese and ammonia nitrogen is mixed with a sodium hypochlorite solution in the mixing tank. The concentration of sodium hypochlorite in the system is 60 to 100 μM, and a pre-oxidation treatment is performed for 0.5 to 5 minutes.

[0042] Specific embodiment ten: This embodiment is different from specific embodiments eight or nine in that the water containing dissolved manganese and ammonia nitrogen flows through the filter material from top to bottom for filtration, and the contact time between the water containing dissolved manganese and ammonia nitrogen and the filter material is controlled to be 8 to 10 minutes.

[0043] Specific embodiment eleven: This embodiment is different from specific embodiments eight to ten in that a modified zeolite filter material is used as the filter material, and the thickness of the filter material is 15 to 30 cm.

[0044] Embodiment 1: The preparation method of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water in this embodiment is implemented according to the following steps:

[0045] 1. Screen the clinoptilolite to select the clinoptilolite with a particle size of 0.8-1.2 mm. The non-uniformity coefficient of the clinoptilolite is 1.4-1.6 and the density is 2.2 g / cm 3 ;

[0046] 2. Washing and drying the screened clinoptilolite, and then immersing it in a dilute nitric acid solution to remove impurities and particulate matter on the surface of the filter material to facilitate subsequent loading, and then washing and drying it naturally to obtain the initial zeolite;

[0047] 3. placing the initial zeolite in a 0.3 mol / L manganese sulfate solution for oscillation adsorption treatment for 6 hours, controlling the reciprocating oscillation speed to 150 r / min, the amplitude to 20 mm, and controlling the mass volume ratio of the initial zeolite to the divalent manganese salt solution to 1 kg / L, and separating and obtaining zeolite particles adsorbed with divalent manganese;

[0048] Fourth, immersing the zeolite particles adsorbed with divalent manganese in a mixed solution of potassium permanganate and sodium hydroxide at 60° C. for adsorption reaction for 12 hours under oscillation conditions, washing with deionized water, and naturally drying to obtain a modified zeolite filter material;

[0049] The concentration of sodium hydroxide in the mixed solution of potassium permanganate and sodium hydroxide in step 4 is 0.4 mol / L, and the concentration of potassium permanganate is 0.2 mol / L.

[0050] Application Example 1: The application process of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water in this embodiment is as follows:

[0051] 1. Construction of filter column containing manganese zeolite:

[0052] The modified zeolite filter material prepared in Example 1 was used as the filter material, the thickness of the filter material was 20 cm, and quartz sand was used as the supporting layer to construct a manganese-loaded zeolite filter column;

[0053] 2. Dynamic Filtering:

[0054] Water containing 1 mg / L dissolved manganese and 1 mg / L ammonia nitrogen enters the filter column filled with modified zeolite filter material from top to bottom. The contact time is 10 minutes to obtain filtered water. Before entering the filter column, it passes through a mixing tank. The sodium hypochlorite solution is mixed with the raw water in the mixing tank for 3 minutes. The addition concentration of sodium hypochlorite is 80 μM. Then it enters the filter column, and the water inlet flow rate is controlled at 2 mL / min.

[0055] During the operation of the filter column filled with modified zeolite filter material in this embodiment, sodium hypochlorite solution is added at the front end, which effectively improves the removal effect of the filter column on dissolved manganese and ammonia nitrogen. The removal rates of dissolved manganese and ammonia nitrogen are 95% and 93%, respectively, and the filter material does not need a maturation period to produce water that meets the standards.

[0056] Application Example 2: The application process of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water in this embodiment is as follows:

[0057] 1. Construction of filter column containing manganese zeolite:

[0058] The modified zeolite filter material prepared in Example 1 was used as the filter material, the thickness of the filter material was 20 cm, and quartz sand was used as the supporting layer to construct a manganese-loaded zeolite filter column;

[0059] 2. Dynamic Filtering:

[0060] Water containing dissolved manganese and ammonia nitrogen enters the filter column filled with modified zeolite filter material from top to bottom. The contact time is 10 minutes to obtain filtered water.

[0061] Application Example 3: The process of using zeolite filter material to remove dissolved manganese and ammonia nitrogen in surface water in this embodiment is as follows:

[0062] 1. Using clinoptilolite filter material as filter material, the thickness of the filter material is 20 cm, and quartz sand as a supporting layer to construct a manganese-loaded zeolite filter column;

[0063] 2. Dynamic Filtering:

[0064] Water containing dissolved manganese and ammonia nitrogen enters the filter column filled with modified zeolite filter material from top to bottom. The contact time is 10 minutes to obtain filtered water.

[0065] Application Example 4: The process of using manganese sand filter material to remove dissolved manganese and ammonia nitrogen in surface water in this embodiment is as follows:

[0066] 1. Using manganese sand as filter material and support layer, construct a manganese-loaded zeolite filter column;

[0067] 2. Dynamic Filtering:

[0068] Water containing dissolved manganese and ammonia nitrogen enters the filter column filled with modified zeolite filter material from top to bottom. The contact time is 10 minutes to obtain filtered water.

[0069] After the filter columns in Application Example 2, Application Example 3 and Application Example 4 were run for 12 hours, 8 hours and 3 hours respectively, the dissolved manganese and ammonia nitrogen contents in the effluent exceeded the standard. According to the effects of various filter media and filter columns in removing dissolved manganese in water, it can be seen that when no chlorine is added, the adsorption capacity of simple zeolite for dissolved manganese and ammonia nitrogen is limited; the modified zeolite filter material prepared in the embodiment has a good adsorption effect on dissolved manganese and ammonia nitrogen.

[0070] During the initial operation, when the contact time between the raw water and the filter column was 10 minutes in Application Example 1, Application Example 2, Application Example 3 and Application Example 4, the removal rates of dissolved manganese were 94%, 92%, 7% and 92%, respectively, and the removal rates of ammonia nitrogen were 95%, 82%, 8% and 89%, respectively.

[0071] After one week of continuous operation, in Application Example 1, Application Example 2, Application Example 3 and Application Example 4, when the contact time between the raw water and the filter column was 10 minutes, the dissolved manganese removal rates were 98%, 21%, 20% and 29%, respectively, and the ammonia nitrogen removal rates were 94%, 19%, 13% and 29%, respectively.

Claims

1. A method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water, characterized in that The preparation method of the modified zeolite filter material is achieved by the following steps:

1. Screen the clinoptilolite to select the clinoptilolite with a particle size of 0.8 to 1.2 mm; 2. washing and drying the screened clinoptilolite, then immersing it in a dilute nitric acid solution, and then washing and drying it to obtain an initial zeolite; 3. placing the initial zeolite in a divalent manganese salt solution with a concentration of 0.2-0.5 mol / L for oscillation adsorption treatment to separate and obtain zeolite particles adsorbed with divalent manganese; 4. Under oscillation conditions, immersing the zeolite particles adsorbed with divalent manganese in a mixed solution of permanganate and sodium hydroxide, heating in a water bath at 50 to 70° C. for 10 to 16 hours for adsorption reaction, and obtaining a modified zeolite filter material after washing and drying; The concentration of sodium hydroxide in the mixed solution of potassium permanganate and sodium hydroxide in step 4 is 0.3-0.6 mol / L, and the concentration of permanganate is 0.15-0.3 mol / L.

2. The method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 1, characterized in that The volume fraction of nitric acid in the dilute nitric acid solution in step 2 is 5% to 6%.

3. The method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 1, characterized in that In step 3, the divalent manganese salt solution is a manganese sulfate solution, and the concentration of the manganese sulfate solution is 0.3 mol / L.

4. The method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 1, characterized in that In step 3, a shaking table is used for oscillating adsorption treatment, and the shaking table speed is controlled to be 50-500 r / min and the amplitude is 10-30 mm.

5. The method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 1, characterized in that The oscillation adsorption treatment time in step 3 is 10 to 16 hours.

6. The method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 1, characterized in that In step 4, the molar ratio of sodium hydroxide to permanganate in the mixed solution of permanganate and sodium hydroxide is 2:

1.

7. The method for preparing a modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 1, characterized in that In step 4, the adsorption reaction is carried out by heating in a water bath at 60° C. for 12 h.

8. Use of the modified zeolite filter material for enhancing simultaneous removal of dissolved manganese and ammonia nitrogen in surface water prepared as claimed in claim 1, characterized in that The modified zeolite filter material is used as the filter material, and quartz sand is used as the supporting layer. Water containing dissolved manganese and ammonia nitrogen flows through the filter material from top to bottom for filtration.

9. The use of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 8, characterized in that The water containing dissolved manganese and ammonia nitrogen passes through a mixing tank in advance, where the water containing dissolved manganese and ammonia nitrogen is mixed with a sodium hypochlorite solution, the concentration of sodium hypochlorite in the system is 60-100 μmol / L, and a pre-oxidation treatment is performed for 0.5-5 minutes.

10. The use of the modified zeolite filter material for enhancing the simultaneous removal of dissolved manganese and ammonia nitrogen in surface water according to claim 8, characterized in that The water containing dissolved manganese and ammonia nitrogen flows through the filter material from top to bottom for filtration, and the contact time between the water containing dissolved manganese and ammonia nitrogen and the filter material is controlled to be 8 to 10 minutes.

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