Preparation method and application of zeolite denitrifier

Abstract

The present invention discloses a preparation method and application of a zeolite denitrifier. The preparation method of the zeolite denitrifier of the present invention comprises the following steps: (1) washing, drying, grinding and screening a natural micron zeolite raw material to obtain a micron zeolite with uniform particles; (2) roasting and cooling the micron zeolite obtained in step (1) to obtain a heat-modified zeolite; (3) mixing the heat-modified zeolite obtained in step (2) with a disodium sulfosuccinate decyl polyoxyethylene (6) ether ester solution, heating and stirring, filtering, washing and drying to obtain a zeolite denitrifier. The present invention successfully prepares a new type of zeolite denitrifier by treating natural micron zeolite with a heat treatment combined with a modifier. The preparation method is simple, and the denitrification efficiency of the prepared zeolite denitrifier is significantly improved, providing a highly efficient and practical new material for the field of river pollution control.

Description

Technical Field

[0001] The invention relates to the technical field of zeolite modification, and in particular to a preparation method and application of a zeolite denitrification agent. Background Art

[0002] With the continuous development of economy and the acceleration of urbanization, the pollution of rivers and lakes is becoming more and more serious, and the ecosystem of rivers and lakes is seriously damaged. Therefore, the treatment of polluted rivers is an important issue related to social and economic development and social stability.

[0003] There are many factors affecting river pollution. Nitrogen and phosphorus are important causes of river pollution. Relying solely on the self-purification ability of the river cannot quickly remove pollutants and reach usable water quality standards. At present, the methods for treating river water are roughly divided into biological methods, ecological methods, chemical methods and physical methods. Under suitable conditions, these methods can treat polluted river water well, but these methods all have certain problems. Biological methods are a more widely used method, but there are problems such as slow effect, long treatment time, large area, high energy consumption, and low nitrogen and phosphorus removal efficiency. The ecological method also has the problem of long treatment time and low overall treatment effect. The chemical method has problems such as high risk of secondary pollution, unstable treatment effect, destruction of the ecological balance of the water body, and high cost. The current physical methods mainly include sewage interception and diversion, sediment dredging, water diversion and siltation, and adsorption. Among them, sewage interception and diversion are difficult to implement; sediment dredging has the problem that the removed sediment is difficult to handle, and long-term stacking is prone to secondary pollution; water diversion and silt flushing will have a certain negative effect on the ecosystem of the water diversion area and the water use area, and cannot completely remove pollutants, but only reduce the concentration of pollutants; the adsorption method uses porous solids, nitrogen and phosphorus are combined with porous solids through van der Waals forces or electrons are exchanged between nitrogen and phosphorus and porous solids, generating new chemical bonds to achieve the purpose of enriching pollutants. However, conventional adsorbents, such as zeolites. However, the current removal effect of zeolites on ammonia nitrogen cannot meet the expected standards, and further improvement and optimization are still needed to meet actual needs.

[0004] In summary, there is an urgent need to develop a new material based on natural zeolite to improve denitrification capacity. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a preparation method and application of a zeolite denitrifier. The present invention successfully prepares a new type of zeolite denitrifier by treating natural micron zeolite by heat treatment combined with a modifier. The preparation method is simple, and the denitrification efficiency of the prepared zeolite denitrifier is significantly improved, providing a highly efficient and practical new material for the field of river pollution control.

[0006] The technical solution of the present invention is as follows:

[0007] A zeolite denitrifier, wherein the preparation method of the zeolite denitrifier comprises the following steps:

[0008] (1) washing, drying, grinding and screening the natural micron zeolite raw material to obtain micron zeolite with uniform particles;

[0009] (2) calcining and cooling the micron zeolite obtained in step (1) to obtain thermally modified zeolite;

[0010] (3) The heat-modified zeolite obtained in step (2) is mixed with a solution of disodium decyl polyoxyethylene (6) sulfosuccinate, heated and stirred, filtered, washed and dried to obtain a zeolite denitrifier.

[0011] Furthermore, in step (1), the particle size of the natural micron zeolite is 0.5-15 μm.

[0012] Furthermore, in step (1), the drying temperature is 100-110° C. and the drying time is 3-9 h.

[0013] Furthermore, in step (1), the mesh size of the sieve used for grinding and screening is 200 meshes.

[0014] Furthermore, in step (2), the calcination temperature is 100-300°C and the calcination time is 2-4 h.

[0015] Furthermore, in step (3), the mass concentration of the disodium decyl polyoxyethylene (6) sulfosuccinate solution is 0.15-0.3%.

[0016] Furthermore, in step (3), the mass volume ratio of the thermally modified zeolite to the disodium decyl polyoxyethylene (6) sulfosuccinate ester solution is 40-60 g / L.

[0017] Furthermore, in step (3), the heating and stirring is carried out at a temperature of 25-35°C, a speed of 50-350 r / min, and a time of 1-3 h.

[0018] Furthermore, in step (3), the pore size of the filter membrane used for filtration is 0.25-0.55 μm;

[0019] Furthermore, in step (3), the drying temperature is 60-70°C and the drying time is 8-12 h.

[0020] An application of the zeolite denitrifier, wherein the zeolite denitrifier is used to remove ammonia nitrogen in wastewater.

[0021] The beneficial technical effects of the present invention are:

[0022] The zeolite denitrifier prepared by the present invention can remove ammonia nitrogen efficiently compared with natural zeolite. The present invention first optimizes the thermal modification conditions of natural zeolite, and on the basis of obtaining a relatively good denitrification capacity, further modifies the thermally modified zeolite by a modifier, wherein the present invention also optimizes the type of modifier and the modification conditions, and the zeolite denitrifier finally obtained has excellent ammonia nitrogen removal performance. Disodium decyl polyoxyethylene (6) sulfosuccinate is adsorbed on the surface of zeolite to form adsorption sites, which has a better adsorption effect on ammonia nitrogen in wastewater. At the same time, the sodium ions therein are exchanged with the aluminum ions in the zeolite, increasing the exchange capacity of the sodium ions of the zeolite with the ammonia nitrogen ions of the wastewater, thereby increasing the ammonia nitrogen removal effect of the zeolite.

[0023] The zeolite denitrifier of the present invention was used to conduct adsorption experiments on laboratory self-made wastewater to achieve denitrification of the wastewater. Under the same conditions, the denitrification effect of the zeolite denitrifier prepared by the present invention is better than that of natural zeolite, providing a highly efficient and practical new material for the field of river pollution control. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a graph showing the effect of the zeolite denitrifier prepared in Example 1 of the present invention on removing ammonia nitrogen as a function of dosage.

[0025] Figure 2 This is a graph showing the effect of the zeolite denitrifier prepared in Example 1 of the present invention on removing ammonia nitrogen as a function of the adsorption temperature.

[0026] Figure 3 This is a graph showing the effect of the zeolite denitrifier prepared in Example 1 of the present invention on removing ammonia nitrogen as a function of pH value.

[0027] Figure 4 This is a graph showing the effect of the zeolite denitrifier prepared in Example 1 of the present invention on removing ammonia nitrogen as a function of reaction time.

[0028] Figure 5 This is the XRD diagram of the zeolite denitrification agent prepared in Example 2 of the present invention before and after modification.

[0029] Figure 6 This is a SEM image of the zeolite denitrification agent prepared in Example 3 of the present invention before modification.

[0030] Figure 7 This is a SEM image of the modified zeolite denitrifier prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0032] The natural micron zeolite used in the following examples was purchased from Beijing Anjiwu Technology Co., Ltd., and its main component is clinoptilolite micron zeolite with a particle size of 0.5-15 μm.

[0033] The disodium decyl polyoxyethylene (6) sulfosuccinate solution described in the following examples is an aqueous solution of disodium decyl polyoxyethylene (6) sulfosuccinate.

[0034] Example 1

[0035] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0036] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 100 °C for 9 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0037] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0038] (3) Add 50 g of the thermally modified zeolite into 1 L of a 0.18% mass percent solution of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., thermally modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 50 g / L), then modify at 30 °C and 250 r / min for 2 h, filter with a 0.45 μm filter membrane, wash with deionized water 2 to 3 times, and dry at 60 °C for 12 h to obtain a zeolite denitrifier.

[0039] Example 2

[0040] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0041] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 105 °C for 3 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0042] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0043] (3) 60 g of the heat-modified zeolite was added to 1 L of a 0.18% mass percent solution of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., heat-modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 60 g / L), followed by modification at 35 °C and 350 r / min for 3 h, followed by filtration with a 0.55 μm filter membrane, washing with deionized water for 2 to 3 times, and drying at 70 °C for 8 h to obtain a zeolite denitrifier.

[0044] Example 3

[0045] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0046] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 110 °C for 6 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0047] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0048] (3) Add 55 g of the thermally modified zeolite into 1 L of a 0.18% mass percent solution of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., thermally modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 55 g / L), then modify at 40 °C and 150 r / min for 1 h, filter with a 0.25 μm filter membrane, wash with deionized water 2 to 3 times, and dry at 65 °C for 10 h to obtain a zeolite denitrifier.

[0049] Example 4

[0050] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0051] (1) The natural micron zeolite raw material with a particle size of 0.5-15 μm was washed with deionized water for 2-3 times, allowed to stand for 12 h, the supernatant was discarded, and then dried at 103 °C for 9 h. After grinding, it was passed through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0052] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200°C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0053] (3) 40 g of the heat-modified zeolite was added to 1 L of a 0.18% mass percentage concentration of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., heat-modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 40 g / L), followed by modification at 25 °C and 250 r / min for 2 h, followed by filtration with a 0.45 μm filter membrane, washing with deionized water for 2 to 3 times, and drying at 65 °C for 8 h to obtain a zeolite denitrifier.

[0054] Example 5

[0055] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0056] (1) The natural micron zeolite raw material with a particle size of 0.5-15 μm was washed with deionized water for 2-3 times, allowed to stand for 12 h, the supernatant was discarded, and then dried at 103 °C for 9 h. After grinding, it was passed through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0057] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200°C for 1 h. After cooling, a thermally modified zeolite is obtained.

[0058] (3) 40 g of the heat-modified zeolite was added to 1 L of a 0.15% mass percentage concentration of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., heat-modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 40 g / L), followed by modification at 25 °C and 250 r / min for 2 h, followed by filtration with a 0.45 μm filter membrane, washing with deionized water for 2 to 3 times, and drying at 65 °C for 8 h to obtain a zeolite denitrifier.

[0059] Example 6

[0060] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0061] (1) The natural micron zeolite raw material with a particle size of 0.5-15 μm was washed with deionized water for 2-3 times, allowed to stand for 12 h, the supernatant was discarded, and then dried at 103 °C for 9 h. After grinding, it was passed through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0062] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200°C for 2 h. After cooling, a thermally modified zeolite is obtained.

[0063] (3) 40 g of the heat-modified zeolite was added to 1 L of a 0.3% mass percent solution of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., heat-modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 40 g / L), followed by modification at 25 °C and 250 r / min for 2 h, followed by filtration with a 0.45 μm filter membrane, washing with deionized water for 2 to 3 times, and drying at 65 °C for 8 h to obtain a zeolite denitrifier.

[0064] Example 7

[0065] A thermally modified zeolite, the preparation method of which comprises the following steps:

[0066] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 103 °C for 9 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0067] (2) The micron zeolite is then placed in a muffle furnace and calcined at 300 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0068] Example 8

[0069] A thermally modified zeolite, the preparation method of which comprises the following steps:

[0070] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 103 °C for 9 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0071] (2) The micron zeolite is then placed in a muffle furnace and calcined at 103 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0072] Example 9

[0073] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0074] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 103 °C for 9 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0075] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0076] (3) 40 g of the heat-modified zeolite was added to 1 L of a 0.18% mass percentage concentration of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., heat-modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 40 g / L), followed by modification at 25 °C and 50 r / min for 1 h, followed by filtration with a 0.45 μm filter membrane, washing with deionized water for 2 to 3 times, and drying at 65 °C for 8 h to obtain a zeolite denitrifier.

[0077] Examples 10-12

[0078] The preparation methods of Examples 10-12 and 9 are basically the same, except that the rotation speeds during the modification in step (3) of Examples 10-12 are 150 r / min, 250 r / min, and 350 r / min, respectively.

[0079] Embodiment 13

[0080] A zeolite denitrifier, the preparation method of which comprises the following steps:

[0081] (1) Wash the natural micron zeolite raw material with a particle size of 0.5-15 μm with deionized water for 2-3 times, let it stand for 12 h, pour out the supernatant, and then dry it at 103 °C for 9 h. After grinding, pass it through a 200-mesh sieve to obtain micron zeolite with uniform particle size distribution.

[0082] (2) The micron zeolite is then placed in a muffle furnace and calcined at 200 °C for 3 h. After cooling, a thermally modified zeolite is obtained.

[0083] (3) 40 g of the heat-modified zeolite was added to 1 L of a 0.18% mass percentage concentration of disodium decyl polyoxyethylene (6) sulfosuccinate (i.e., heat-modified zeolite: disodium decyl polyoxyethylene (6) sulfosuccinate solution = 40 g / L), followed by modification at 28 °C and 250 r / min for 2 h, followed by filtration with a 0.45 μm filter membrane, washing with deionized water for 2 to 3 times, and drying at 65 °C for 8 h to obtain a zeolite denitrifier.

[0084] Examples 14-16

[0085] The preparation methods of Examples 14-16 are basically the same as those of Example 11, except that the modification time in step (3) of Examples 14-16 is 0.5 h, 3 h, and 4 h, respectively.

[0086] Comparative Examples 1-3

[0087] The preparation methods of Comparative Examples 1-3 and Example 7 are basically the same, except that the calcination temperatures in step (2) of Comparative Examples 1-3 are 400°C, 500°C, and 600°C, respectively.

[0088] Comparative Examples 4-5

[0089] The preparation methods of Comparative Example 4-5 and Example 9 are basically the same, except that the rotation speeds during the modification in step (3) of Comparative Example 4-5 are 450 r / min and 550 r / min, respectively.

[0090] Comparative Examples 6-7

[0091] The preparation methods of Comparative Example 6-7 and Example 13 are basically the same, except that the modifiers in step (3) of Comparative Example 6-7 are dimethyl succinylsuccinate with a mass percentage concentration of 0.18% and disodium lauryl sulfonyl succinate with a mass percentage concentration of 0.18%, respectively.

[0092] Test example:

[0093] Preparation of ammonia nitrogen wastewater: Use distilled water to simulate the preparation, accurately weigh 3.819 g NH4Cl (bake at 120℃ for 2 h), transfer it to a 1 L volumetric flask, dilute to the mark, shake well, and store in a glass bottle as a stock solution, then transfer 10 mL to a 500 mL volumetric flask, make up to volume and shake well to obtain an ammonia nitrogen water sample with an ammonia nitrogen concentration of 20 mg / L.

[0094] Nitrogen adsorption experiment: Weigh a certain amount of zeolite denitrifier and place it in 400 mL of ammonia nitrogen wastewater at 25 °C and pH = 6.7. After constant temperature oscillation at 20 °C for 3 h, take a sample and measure the ammonia nitrogen in the ammonia nitrogen wastewater prepared above. Calculate the ammonia nitrogen removal rate of the zeolite denitrifier and the adsorption amount of the zeolite denitrifier according to the following formulas (1) and (2).

[0095] Ammonia nitrogen removal rate calculation formula:

[0096] (1)

[0097] Where: R is the ammonia nitrogen removal rate (%), C 0 is the initial concentration of ammonia nitrogen (mg / L), C t is the ammonia nitrogen concentration (mg / L) at different adsorption times.

[0098] Adsorption amount calculation formula:

[0099] (2)

[0100] Where: q e is the adsorption amount (mg / g), C 0 is the initial concentration of ammonia nitrogen (mg / L), C t is the ammonia nitrogen concentration (mg / L) at different adsorption times, V is the volume of adsorbed waste liquid (L), m is the dosage of zeolite (g).

[0101] (1) Effect of modification conditions on the adsorption effect of zeolite denitrification agent

[0102] 4.0 g of the heat-modified zeolite obtained in step (2) of Example 4 of the present invention and the heat-modified zeolite prepared in Examples 7-8 and Comparative Examples 1-3 were added to 400 mL of ammonia nitrogen water sample with a pH of 6, respectively. After constant temperature oscillation at 30 ° C for 3 h, samples were taken to measure the ammonia nitrogen concentration in the wastewater. The ammonia nitrogen removal rate was calculated according to formula (1). The results are shown in Table 1.

[0103] Table 1

[0104]

[0105] From the results in Table 1, it can be seen that the temperature conditions for calcining natural micron zeolite have a significant effect on the ammonia nitrogen removal effect of the thermally modified zeolite. When the calcination temperature is 100-300 °C, the thermally modified zeolite exhibits a better ammonia nitrogen removal performance, but as the temperature increases to 400-600 °C, the ammonia nitrogen removal performance of the thermally modified zeolite shows a significant downward trend. Therefore, the temperature conditions of thermal modification have an important influence on the adsorption effect of the prepared thermally modified zeolite. This may be due to the large number of small pores in the zeolite. When the zeolite is calcined and modified, the pore size of the zeolite can be appropriately increased to improve the adsorption effect of ammonia nitrogen. When the temperature is too high, the spatial structure of the pore size of the zeolite may be destroyed, thereby reducing its adsorption capacity.

[0106] 4.0 g of the zeolite denitrifier prepared in Examples 9-12 of the present invention and Comparative Examples 4-5 were taken in turn and added to 400 mL of ammonia nitrogen water sample with a pH of 6, respectively. After constant temperature oscillation at 30 ° C for 3 h, samples were taken to determine the ammonia nitrogen concentration in the wastewater. The ammonia nitrogen removal rate was calculated according to formula (1). The results are shown in Table 2.

[0107] Table 2

[0108]

[0109] From the results in Table 2, it can be seen that the heat-modified zeolite was further modified using disodium decyl polyoxyethylene (6) sulfosuccinate as a modifier. As the speed conditions during modification increased, the ammonia nitrogen removal rate showed a trend of first increasing and then decreasing. When the speed conditions during modification were 5-350 r / min, the ammonia nitrogen removal effect of the zeolite denitrifier was better. When the speed increased to 450-550 r / min, its ammonia nitrogen removal effect showed a significant downward trend, indicating that the speed during modification had a significant effect on the performance of the zeolite denitrifier. This may be because as the rotation speed increases, the contact area between the thermally modified zeolite and the solution increases, the thermally modified zeolite particles are fully in contact with the disodium decyl polyoxyethylene (6) sulfosuccinate molecules in the solution, and the modification effect is improved, thereby improving the performance of the prepared zeolite denitrifier in removing ammonia nitrogen. However, when the rotation speed exceeds a certain limit, it is difficult for the thermally modified zeolite particles to fully contact with the disodium decyl polyoxyethylene (6) sulfosuccinate molecules in the solution, which will reduce the modification effect.

[0110] 4.0 g of the zeolite denitrifier prepared in Example 4, Example 11, and Examples 14-16 of the present invention were taken in turn and added to 400 mL of ammonia nitrogen water sample with a pH of 6. After constant temperature oscillation at 30°C for 3 h, samples were taken to determine the ammonia nitrogen concentration in the wastewater. The ammonia nitrogen removal rate was calculated according to formula (1). The results are shown in Table 3.

[0111] Table 3

[0112]

[0113] From the results in Table 3, it can be seen that the thermally modified zeolite was further modified using disodium decyl polyoxyethylene (6) sulfosuccinate as a modifier. As the modification time increases, the ammonia nitrogen removal rate first increases and then decreases. When the modification time is 1-3 h, the ammonia nitrogen removal rate of the zeolite denitrifier for ammonia nitrogen water samples is 91.11-94.09%, and when the time increases to 4 h, its ammonia nitrogen removal performance does not improve. Therefore, the modification time is more suitable when it is 1-3 h, and the ammonia nitrogen removal performance is optimal when the modification time is 2 h. This may be because as the contact time between the thermally modified zeolite particles in the solution and the disodium decyl polyoxyethylene (6) sulfosuccinate molecules in the solution increases, the modification is more sufficient, the modification effect is better, and the ammonia nitrogen removal effect is better. When the modification time is too long, the disodium decyl polyoxyethylene (6) sulfosuccinate molecules in the solution may block the pore size of the thermally modified zeolite, reducing the adsorption sites of the thermally modified zeolite, thereby weakening the ability to adsorb ammonia nitrogen and reducing the effect of removing ammonia nitrogen.

[0114] The zeolite denitrifiers prepared in Example 13 of the present invention and Comparative Examples 6-7 were taken in turn and added to 400 mL of ammonia nitrogen water sample with a pH of 6, respectively. After constant temperature oscillation at 30°C for 3 h, samples were taken to determine the ammonia nitrogen concentration in the wastewater. The ammonia nitrogen removal rate was calculated according to formula (1). The results are shown in Table 4.

[0115] Table 4

[0116]

[0117] From the results in Table 4, it can be seen that compared with the two modifiers of dimethyl succinylsuccinate and disodium lauryl sulfosuccinate, the zeolite denitrifier prepared by further modifying the thermally modified zeolite with disodium decyl polyoxyethylene (6) sulfosuccinate as a modifier has a significantly higher ammonia nitrogen removal rate, which provides a new and efficient material for the field of river pollution control.

[0118] (2) Effect of zeolite denitrification agent dosage on adsorption effect

[0119] 0.5 g, 1.0 g, 1.5 g, 2.0 g, 2.5 g, 3.0 g, 3.5 g, 4.0 g, and 4.5 g of the zeolite denitrifier prepared in Example 1 of the present invention were taken in sequence and added to 400 mL of ammonia nitrogen water sample with a pH of 6, respectively. After constant temperature oscillation at 30 ° C for 3 h, samples were taken to measure the ammonia nitrogen concentration in the wastewater. The ammonia nitrogen removal rate and the adsorption amount of the zeolite denitrifier were calculated according to formulas (1) and (2). The results are as follows: Figure 1As shown. Figure 1 The results show that with the gradual increase in the dosage of zeolite denitrifier, the ammonia nitrogen removal rate gradually increases and gradually tends to saturation, and the adsorption amount gradually decreases.

[0120] (3) Effect of temperature on the adsorption effect of zeolite denitrification agent

[0121] 4.0 g of 6 portions of the zeolite denitrifier prepared in Example 1 of the present invention were added to 400 mL of ammonia nitrogen water sample with a pH of 6, and samples were taken after constant temperature oscillation at 20°C, 30°C, 40°C, 50°C, and 60°C for 3 h. The ammonia nitrogen concentration in the wastewater at different treatment temperatures was measured, and the ammonia nitrogen removal rate and adsorption amount were calculated according to formulas (1) and (2). The results are as follows: Figure 2 As shown. Figure 2 The results show that with the gradual increase of adsorption temperature, the ammonia nitrogen removal rate and adsorption amount first increase and then tend to saturation, but the temperature when tending to saturation is relatively high. Considering cost-effectiveness in practical application, adsorption at room temperature is selected to ensure the removal effect and reduce costs.

[0122] (4) Effect of pH value on adsorption effect of zeolite denitrifier

[0123] Take 6 ammonia nitrogen water samples, adjust the pH to 2, 4, 6, 8, 10, and 12 with sodium hydroxide and hydrochloric acid, take 6 4.0 g zeolite denitrifiers prepared in Example 1 of the present invention, add them to 400 mL of the ammonia nitrogen water samples with different pH values, shake at 30 ° C for 3 h, take samples, measure the ammonia nitrogen concentration in the wastewater at different pH values, and calculate the ammonia nitrogen removal rate and adsorption amount according to formula (1) and (2). The results are as follows: Figure 3 As shown. Figure 3 The results show that the ammonia nitrogen removal effect varies greatly with different pH values. This is due to the different forms of NH4+ at different pH values. When the pH is 6-7, the ammonia nitrogen removal effect is better.

[0124] (5) Effect of adsorption time on the adsorption effect of zeolite denitrifier

[0125] 4.0 g of the zeolite denitrifier prepared in Example 1 of the present invention was added to 400 mL of ammonia nitrogen water sample with a pH of 6, and samples were taken after constant temperature oscillation at 30 ° C for 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, and 4 h. The ammonia nitrogen concentration in the wastewater at different adsorption times was measured, and the ammonia nitrogen removal rate and adsorption amount were calculated according to formulas (1) and (2). The results are as follows: Figure 4 As shown. Figure 4 The results show that the ammonia nitrogen removal rate first increases and then gradually tends to saturation with the increase of adsorption time. After about 3 h of adsorption, the ammonia nitrogen removal rate and adsorption amount reach the highest.

[0126] (6) Structural changes of zeolite denitrifier before and after modification

[0127] The zeolite denitrifier (modified zeolite) prepared in Example 2 of the present invention and the natural micron zeolite raw material (pre-modified zeolite) were taken and their diffraction intensities at different Two-theta (2θ) angles were measured by Bruker AXS D8 X-ray diffractometer. The results are as follows: Figure 5 As shown. Figure 5 The results show that there are strong diffraction peaks at 2θ of 13.58°, 22.55°, 26.81°, and 30.17°, indicating that the zeolite has not changed its skeleton structure after modification. Secondly, it can be seen that after the natural micron zeolite is modified with disodium decyl polyoxyethylene (6) sulfosuccinate, the XRD spectrum peak tends to become wider, indicating that the particle size of the modified zeolite has become larger, that is, the addition of disodium decyl polyoxyethylene (6) sulfosuccinate may have a certain effect on the particle size of the zeolite.

[0128] The micron zeolite (natural zeolite) with uniform particle size distribution obtained in step (1) of Example 3 of the present invention and the zeolite denitrification agent (modified zeolite) prepared in Example 3 were examined for their morphological structures using a Zeiss Ev018 scanning electron microscope. The results were as follows: Figure 6 , Figure 7 As shown. Figure 6 The results show that the surface of natural zeolite is very rough and presents an irregular shape. Figure 7 The results show that the surface pores of the modified zeolite are more abundant, the microscopic morphology has changed, and the adsorption capacity of ammonia nitrogen has been greatly improved.

[0129] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A zeolite denitrifier, characterized in that: The preparation method of the zeolite denitrifier comprises the following steps: (1) washing, drying, grinding and screening the natural micron zeolite raw material to obtain micron zeolite with uniform particles; (2) calcining and cooling the micron zeolite obtained in step (1) to obtain thermally modified zeolite; (3) The heat-modified zeolite obtained in step (2) is mixed with a solution of disodium decyl polyoxyethylene (6) sulfosuccinate, heated and stirred, filtered, washed and dried to obtain a zeolite denitrifier.

2. The zeolite denitrifier according to claim 1, characterized in that In step (1), the particle size of the natural micron zeolite is 0.5-15 μm.

3. The zeolite denitrifier according to claim 1, characterized in that In step (1), the drying temperature is 100-110°C and the drying time is 3-9 hours.

4. The zeolite denitrifier according to claim 1, characterized in that In step (2), the calcination temperature is 100-300°C and the calcination time is 2-4 h.

5. The zeolite denitrifier according to claim 1, characterized in that In step (3), the mass percentage concentration of the disodium decyl polyoxyethylene (6) sulfosuccinate solution is 0.15-0.3%.

6. The zeolite denitrifier according to claim 1, characterized in that In step (3), the mass volume ratio of the thermally modified zeolite to the disodium decyl polyoxyethylene (6) sulfosuccinate ester solution is 40-60 g / L.

7. The zeolite denitrifier according to claim 1, characterized in that In step (3), the heating and stirring temperature is 25-35°C, the speed is 50-350 r / min, and the time is 1-3 h.

8. The zeolite denitrifier according to claim 1, characterized in that In step (3), the pore size of the filtration membrane is 0.25-0.55 μm.

9. The zeolite denitrifier according to claim 1, characterized in that In step (3), the drying temperature is 60-70°C and the drying time is 8-12 hours.

10. Use of the zeolite denitrifier according to any one of claims 1 to 9, wherein the zeolite denitrifier is used to remove ammonia nitrogen in wastewater.

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