A new filter material suitable for sulfur autotrophic denitrification and a preparation method and application thereof

Abstract

The application provides a new filter material suitable for sulfur autotrophic denitrification and a preparation method and application thereof, different types of sulfur-containing raw materials are added into a carrier material containing silicate and aluminate, and then an activator is used to activate the carrier material, and finally the new filter material has the characteristics that the sulfur sources are rich in types and uniformly dispersed in the structure of the carrier material. The application also provides a simple preparation method and a multi-layer wrapping type preparation method of the new filter material, the sulfur sources and carbon sources of the new filter material prepared by the multi-layer wrapping type preparation method can be more uniformly distributed on the outer surface and inner pores of the filter material, slowly release the sulfur sources and carbon sources in the water body, conducive to the aggregation and continuous growth of microorganisms, effectively improve the denitrification efficiency, and the new filter material has high mechanical strength, strong impact resistance, is not easy to lose excessive service life due to consumption of microorganisms, and has a long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage advanced treatment, and further relates to a new filter material suitable for sulfur autotrophic denitrification, and a preparation method and application thereof. BACKGROUND

[0002] In the wastewater discharge of petrochemical, coal chemical industry and other industrial industries, total nitrogen is one of the important pollutants, and denitrification is an important step in the wastewater treatment process, and denitrification is the most critical step in the denitrification reaction. Although the traditional heterotrophic denitrification technology is mature, it needs to add carbon source, and the sludge production is large, which is easy to cause secondary pollution. Sulfur autotrophic denitrification is a new type of treatment process, which has the characteristics of high treatment efficiency, low sludge production and low energy consumption. Sulfur autotrophic denitrification is a process in which microorganisms use reduced sulfur as an electron donor to reduce nitrate nitrogen in water to nitrogen gas through autotrophic denitrification and other reactions, and hydrogen ions and sulfates are also produced during the reaction, which affect the water quality. This technology usually uses a fixed bed as a reactor, needs to add appropriate sulfur-containing filter material and supplement appropriate alkali source to adjust the pH value of the water body for the growth of microorganisms and the biochemical reaction.

[0003] At present, the filter materials on the market are mainly ceramic filter materials, high polymer filter materials and natural porous filter materials. This kind of filter material generally has a relatively high specific surface area, which can provide a good growth environment for microorganisms, but it cannot continuously provide the sulfur source required by microorganisms, and cannot meet the continuous growth of microorganisms, and needs to continuously add soluble sulfur source, which has high operation cost.

[0004] In addition, artificial synthetic filter materials can be generally divided into three categories. The first category is to use sulfur-containing minerals as raw materials to prepare filter materials. For example, patent CN 104150592 B B discloses using pyrite as a raw material, patent CN 110818077 B discloses using sulfur-containing tailings as a raw material, and patent CN 114772723 B discloses using molten sulfur powder as a raw material. Although the above filter materials have a very sufficient sulfur source, they will also produce a large amount of sulfates, causing serious secondary pollution, and excessive sulfur will affect the growth of microorganisms. The second category is to modify the surface of synthetic porous materials by means of impregnation and other surface modification methods. For example, the filler provided in patent CN 110467276 B is a ceramsite that has been sequentially soaked in alkali solution and sulfur-loaded soaking treatment. Although this method obtains a surface sulfur-modified material, as the surface sulfur source is consumed, the denitrification efficiency also decreases, and the filter material needs to be replaced frequently, which is not conducive to the continuous growth of microorganisms. The third category is to add a sulfur source during material preparation. The proportion of sulfur source in materials prepared by this method is quite different. For example, patent CN 107487840 B provides a filter material prepared by mixing sulfur, carbonate and other materials, with a sulfur content of 40%-80%. Similarly, the filter material prepared in patent CN 113121013 B has a sulfur content of 55%-95%. Artificially synthesized filter materials with high sulfur content have the same problems as sulfur-containing mineral filter materials. For example, patent CN 107151050 B provides a filter material prepared by mixing activated carbon and sulfur, with a sulfur content of less than 30%. Similarly, the filter material prepared in patent CN 112430053 B has a sulfur content of 10%-15%. The characteristic of this composite filter material is that the sulfur content in the material is relatively low. Although it promotes denitrification of microorganisms to some extent, most microorganisms can only grow on the surface of the filter material, and it is difficult for the sulfur source in the filter material to be released to the surface of the filter material, thereby affecting the denitrification effect.

[0005] In summary, there is an urgent need to develop a sulfur autotrophic denitrification filter material that has an adequate and slow-release sulfur source, can provide a certain alkalinity and carbon source, and is suitable for the aggregation and growth of microorganisms. SUMMARY

[0006] In view of the problems of low denitrification efficiency, easy loss of filter material, and unfavorable microbial aggregation and growth in the prior art, the present application aims to provide a new filter material suitable for sulfur autotrophic denitrification, a preparation method and application thereof, wherein different types of sulfur-containing raw materials are added to a carrier material containing silicate and aluminate, and then the carrier material is activated by using an activator, so that the new filter material has the characteristics of rich types of sulfur source and uniform dispersion of the sulfur source in the structure of the carrier material.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions.

[0008] A new filter material suitable for sulfur autotrophic denitrification is prepared from the following components in a mass ratio:

[0009] Carrier powder: sulfur-containing powder: activator solution: sulfur-containing liquid material = 1: (0.17-0.75): (0.20-0.50): (0.17-0.30); the carrier powder is a mineral material or solid waste material containing silicate and aluminate.

[0010] In some embodiments, the content of SiO2 component in the carrier powder is 50%-80%, and the content of Al2O3 component is 5%-35%; and / or, the molar ratio of Si and Al in the carrier powder is 1.61-4.46; and / or, the content of S in the sulfur-containing powder is greater than 50%.

[0011] In some embodiments, the carrier powder is one or more of kaolin, bentonite, diatomite, fly ash, medical stone powder, silicon powder, and aluminum powder; and / or, the sulfur-containing powder is one or more of sulfur fine powder, pyrite, pyrrhotite, and magnetite; and / or, the activator solution is one or more of sodium hydroxide solution, sodium silicate solution, sodium carbonate solution, and sodium bicarbonate solution; and / or, the sulfur-containing solution is one or more of sodium thiosulfate solution, sodium sulfide solution, sodium polysulfide solution, sodium tetrathionate solution, and sodium hyposulfite solution.

[0012] The present application also provides a preparation method of the new filter material described above, comprising the following steps:

[0013] S11, the carrier powder, the sulfur-containing powder, the activator solution, and the sulfur-containing liquid material are weighed according to the component ratio of the new filter material;

[0014] S12, uniformly mixing the weighed carrier powder, the sulfur-containing powder, the activator solution and the sulfur-containing liquid to obtain a mixed slurry;

[0015] S13, pouring the mixed slurry into a mold for aging until the surface is completely hardened to obtain a mixed solid;

[0016] S14, placing the mixed solid into an oven for activation after demolding;

[0017] S15, obtaining the new filter material after crushing, screening, washing and drying the activated mixed solid.

[0018] In some embodiments, in the step S13, the temperature of the aging is room temperature, and the time of the aging is 12-24 hours; and / or, in the step S14, the temperature of the activation is 80-145℃, and the time of the activation is 1-3 days; and / or, in the step S15, the temperature of the drying is 80-105℃.

[0019] In some embodiments, in the step S15, the particle size of the crushed mixed solid is 0.01-5mm; and / or, in the step S15, the particle size of the screened mixed solid is 2-4.75mm.

[0020] The application also provides a preparation method of the new filter material, comprising the following steps:

[0021] S21, weighing the carrier powder, the sulfur-containing powder, the activator solution and the sulfur-containing liquid according to the component proportions of the new filter material;

[0022] S22, adding the carrier powder and the sulfur-containing powder into a mixing granulator according to the proportions to uniformly mix to obtain a mixed powder;

[0023] S23, adding an appropriate amount of the activator solution into the mixing granulator to wet and activate the mixed powder to obtain a mixed granule;

[0024] S24, adding an appropriate amount of the sulfur-containing liquid into the mixing granulator to form a thin sulfur-containing film layer on the surface of the mixed granule;

[0025] S25, repeating the step S23 and the step S24 to make the mixed powder and the sulfur-containing liquid layer by layer to obtain a filter granule;

[0026] S26, after the size of the filter granule reaches a preset size, aging and activating the filter granule to obtain the new filter material with a multi-layer wrapping type.

[0027] In some embodiments, in the step S23, the amount of the activator solution added is 1.71% to 5.71% of the total mass of the mixed powder; and / or, in the step S24, the amount of the sulfur-containing liquid added is 1.43% to 5.14% of the total mass of the mixed powder.

[0028] In some embodiments, in the step S22, the mixing time of the carrier powder and the sulfur-containing powder is 2 to 5 minutes; and / or, in the step S25, the number of cycles of repeating the step S23 and the step S24 is 5 to 10, and the interval time between cycles is less than or equal to 2 minutes; and / or, in the step S26, the activation temperature is 80 to 150 DEG C; and / or, in the step S26, the aging temperature is room temperature, and the aging time is 12 to 24 hours; and / or, in the step S26, the preset size of the filtered material particles is 2.5 to 4 mm.

[0029] The application also provides the use of the above-mentioned new filter material in a fixed bed reactor for treating sewage.

[0030] Compared with the prior art, the application can bring the following beneficial effects:

[0031] 1. The application adds different types of sulfur-containing raw materials into a carrier material containing silicate and aluminate, and then activates the carrier material using an activator, to finally obtain a new filter material with rich and uniformly dispersed sulfur sources. The surface and pore structure of the new filter material are embedded with different types and forms of rich sulfur sources. Compared with single sulfur-containing filter materials such as pyrite and pyrite, the new filter material has more sulfur sources as electron donors, which can significantly improve the denitrification capacity of the filter material and broaden the application scenarios of different types of water bodies.

[0032] 2. The new filter material provided by the application contains a certain amount of hydroxyl active components in the surface and pore structure. When the filter material is in water, the active components on the surface layer of the filter material can quickly attract the aggregation of microorganisms, effectively shortening the start-up time of the denitrification biological filter.

[0033] 3. The new filter material provided by the application has a large number of pore structures, so the specific surface area is high, the filter material itself has strong adsorption, which is conducive to the adhesion of microorganisms, and the mechanical strength of the filter material is high, the impact resistance of the sewage load is strong, so the consumption loss of the filter material is reduced, which is conducive to prolonging the service life of the filter material.

[0034] 4. The application provides a preparation method of a multi-layer wrapped novel filter material, the sulfur source and the carbon source are more uniformly distributed on the outer surface of the filter material and in the inner layer pore structure, when the outer layer sulfur source and the carbon source are released in the water body, the volume loss of the outer layer sulfur source and the carbon source will increase the pore volume of the filter material, so that the sulfur source and the carbon source in the inner layer pore structure are also gradually released, the graded release of the sulfur source and the carbon source can continuously provide the electron donor of the autotrophic denitrifying bacteria and the required carbon for growth, prolonging the service time of the filter material and solving the problem of too fast consumption of the filter material.

[0035] 5. The application also provides a simple preparation method of the novel filter material, the method is simple, the process is mature, the preparation cost is effectively reduced while the efficient denitrification performance is maintained, the preparation period is short, the properties are stable, and the method is suitable for industrial application and promotion. BRIEF DESCRIPTION OF DRAWINGS

[0036] The above-mentioned characteristics, technical features, advantages and implementation modes of the application will be further described in the following preferred embodiments in a clear and understandable manner combined with the drawings.

[0037] Figure 1 The flow chart of the preparation method of the multi-layer wrapped novel filter material provided by the application. DETAILED DESCRIPTION

[0038] The technical solutions in the application will be described in a clear and complete manner combined with specific embodiments. The following embodiments are only used to more clearly illustrate the technical solutions of the application, and cannot be used to limit the protection scope of the application.

[0039] Embodiment 1

[0040] The application provides a novel filter material suitable for sulfur autotrophic denitrification, the novel filter material comprises solid material and liquid material, wherein the solid material comprises carrier powder and sulfur-containing powder, and the liquid material comprises activator solution and sulfur-containing liquid material.

[0041] The mass ratio of each component in the novel filter material is:

[0042] Carrier powder:sulfur-containing powder:activator solution:sulfur-containing liquid material = 1:(0.17-0.75):(0.20-0.50):(0.17-0.30).

[0043] The carrier powder described above is a mineral material or solid waste material containing silicate and aluminate.

[0044] In some embodiments, the content of the SiO2 component in the carrier powder described above is 50%-80%, and the content of the Al2O3 component is 5%-35%.

[0045] Preferably, the carrier powder is one or more of kaolin, bentonite, diatomite, fly ash, mica powder, silicon powder, and aluminum powder.

[0046] More preferably, the silicon powder and aluminum powder in the carrier powder serve as a supplementary source of silicon and aluminum, ensuring that the molar ratio of Si to Al in the carrier powder is 1.61-4.46. The carrier powder in this range of Si / Al molar ratio has a large specific surface area and high mechanical strength, which is conducive to the loading of different types of sulfur sources and use under high-load hydraulic conditions.

[0047] In some embodiments, the content of the S component in the sulfur-containing powder is greater than 50%.

[0048] The sulfur-containing powder is one or more of sulfur concentrate, pyrite, mackinawite, and pyrrhotite.

[0049] Preferably, the particle size of the sulfur-containing powder is less than 0.02 mm, and the sulfur-containing powder is sieved using a 800-mesh sieve.

[0050] More preferably, the sulfur-containing powder is sulfur concentrate, and the amount of sulfur concentrate used is 6%-43% of the total solid powder (sulfur-containing powder and carrier powder).

[0051] The pyrite, mackinawite, and pyrrhotite in step S1-2 serve as a replacement / supplement for the sulfur-containing powder, and the addition ratio is not more than 2 / 3 of the total amount of the sulfur-containing powder.

[0052] In some embodiments, the activator solution is an alkaline solution, preferably one or more of a sodium hydroxide solution, a sodium silicate solution, a sodium carbonate solution, and a sodium bicarbonate solution.

[0053] More preferably, a combination of a sodium hydroxide solution and a sodium silicate solution is used, and the mass ratio of the sodium hydroxide solution to the sodium silicate solution is 1:(0.54-1), wherein the concentration of the sodium hydroxide solution is 10%-30%wt, and the modulus of the sodium silicate solution is 3.1-3.4.

[0054] The sodium carbonate solution and the sodium bicarbonate solution can be used alone or simultaneously. The sodium carbonate and / or the sodium bicarbonate serve as a supplementary alkali source on the one hand and as an additional inorganic carbon source on the other hand, which is conducive to the growth of microorganisms.

[0055] The concentration of the sodium carbonate solution is 30%-60%wt, and the addition amount is not more than 1 / 10 of the total amount of the activator.

[0056] In some embodiments, the sulfur-containing solution is a soluble sulfur source, preferably one or more of a sodium thiosulfate solution, a sodium sulfide solution, a sodium polysulfide solution, a sodium tetrathionate solution, and a sodium dithionite solution.

[0057] Preferably, the sulfur-containing solution is selected from sodium thiosulfate solution, and accounts for more than 2 / 3 of the total amount of the sulfur-containing solution, and the concentration of the sodium thiosulfate solution is 40%-80%wt.

[0058] The above-mentioned sodium polysulfide, sodium tetra-thionate and sodium dithionite are one of the replaceable supplement of the sulfur-containing solution, but the total amount of the above-mentioned three sulfur-containing solutions does not exceed 1 / 3 of the total amount of the sulfur-containing solution, wherein the concentration of the sodium polysulfide solution is 35%-50%wt, the concentration of the sodium tetra-thionate solution is 35%-50%wt, and the concentration of the sodium dithionite solution is 20%-50%wt.

[0059] Example 2

[0060] On the basis of example 1, the application further provides a preparation method of the above-mentioned new filter material, which comprises the following steps:

[0061] S00, raw material preparation process:

[0062] S01, preparation of carrier powder:

[0063] One or more of kaolin, bentonite, diatomite, fly ash, silicon powder and aluminum powder are selected, and after drying at 105℃ for 24 hours, the materials are sieved through a 200 mesh sieve, and the fine powder of each material is uniformly mixed to obtain the carrier powder, which is stored in a sealed and dry state.

[0064] S02, preparation of sulfur-containing powder:

[0065] One or more of sulfur fine powder, pyrite, pyrrhotite and magnetite are selected, if the above-mentioned materials are powders, they can be directly uniformly mixed to obtain the sulfur-containing powder, if the above-mentioned materials are in block form, they need to be crushed, ground and sieved, and then the fine powders of each material are uniformly mixed to obtain the sulfur-containing powder, which is stored in a sealed and dry state.

[0066] S03, preparation of activator solution:

[0067] One or more of sodium hydroxide solution, sodium silicate solution, sodium carbonate solution and sodium bicarbonate solution are selected, and the solutions are uniformly mixed to obtain the activator solution.

[0068] S04, preparation of sulfur-containing solution:

[0069] One or more of sodium thiosulfate crystal powder, sodium sulfide crystal powder, sodium polysulfide crystal powder, sodium tetra-thionate crystal powder and sodium dithionite crystal powder are selected, and the crystal powders are mixed and uniformly stirred with water to obtain the sulfur-containing solution, or the above-mentioned crystal powders are separately stirred with water to obtain separate solutions, and then the solutions are uniformly mixed to obtain the sulfur-containing solution.

[0070] S11, the components of the new filter material according to the embodiment 1 are weighed according to the above prepared carrier powder, sulfur-containing powder, activator solution and sulfur-containing liquid.

[0071] S12, the weighed carrier powder, sulfur-containing powder, activator solution and sulfur-containing liquid are simultaneously added into a stirrer for stirring and uniformly mixing to obtain a mixed slurry.

[0072] The stirring and mixing time is preferably 10-30 minutes.

[0073] S13, the mixed slurry is poured into a mold for aging until the surface is completely hardened to obtain a mixed solid material.

[0074] The aging temperature is room temperature and the aging time is 12-24 hours.

[0075] More preferably, the mixed slurry is placed in an environment with a certain humidity for aging. If the aging process is prevented in a dry environment, the aging effect of the carrier powder will be greatly reduced.

[0076] The mold is a hollow cube or cylinder mold, generally made of PVC plastic material, with a smooth surface, which is beneficial for the mixed slurry to harden and be demolded.

[0077] S14, the mixed solid material is demolded and placed in an oven for activation.

[0078] The activation temperature is 80-145°C and the activation lasts for 1-3 days.

[0079] Preferably, before the mixed solid material is placed in an oven at 80-145°C for activation, the mixed solid material is placed in a sealed container, the humidity in the sealed container is maintained, and the mixed solid material and the sealed container are placed in the oven for activation. The humidity in the sealed container is beneficial for the continuous activation effect of the mixed solid material.

[0080] S15, the activated mixed solid material is crushed, sieved, washed and dried to obtain a new filter material.

[0081] The crushing refers to crushing the mixed solid material into irregular solid particles by a crusher. The crushed mixed solid material is a solid particle with a particle size of 0.01-5mm.

[0082] The sieving refers to sieving the crushed solid particles (mixed solid material) through a sieving machine to obtain target particles (4-10 mesh). The particle size of the sieved solid particles is 2-4.75mm.

[0083] The washing mentioned above refers to washing the surface of the screened solid particles with clean water to remove the powder on the surface of the solid particles, so that the surface of the solid particles is free of impurities and does not affect the aggregation and growth of microorganisms.

[0084] The drying mentioned above refers to placing the washed solid particles in an oven and drying them at 80-105°C to remove water, thereby obtaining the novel filter material.

[0085] Example 3

[0086] The simple preparation method provided in Example 2 finally obtains filter material products in the shape of irregular solid particles. Although the filter material products can achieve high nitrogen removal efficiency, there is still room for improvement.

[0087] The inventors consider that due to the irregular shape of the filter material particles, the contact area between them increases, which reduces the space for the growth of microorganisms on the surface of the filter material. Therefore, from the perspective of improving the nitrogen removal efficiency and the shape of the product, the roundness of the filter material needs to be improved to reduce the contact area between the filter materials.

[0088] In this embodiment, the inventors provide a more efficient preparation method for a multi-layer wrapped novel filter material. This method not only optimizes the shape of the product particles, but also improves the use effect and service life of the filter material. In addition, it reduces the indirect carbon emissions generated during the preparation of the filter material during the shaping stage of the filter material, in response to the national double carbon policy requirements.

[0089] Based on Example 1 and Example 2, combined with Figure 1 the flowchart shown, the preparation method of the multi-layer wrapped novel filter material includes the following steps:

[0090] S20, raw material preparation process, same as step S00 in Example 1, raw material preparation process, which will not be repeated here.

[0091] S21, the prepared carrier powder, sulfur-containing powder, activator solution and sulfur-containing liquid are weighed according to the component allocation ratio of the novel filter material described in Example 1.

[0092] S22, add the carrier powder and sulfur-containing powder to the mixing granulator according to the proportion, and uniformly mix to obtain a mixed powder.

[0093] The mixing time of the above-mentioned carrier powder and sulfur-containing powder is preferably 2-5 minutes.

[0094] S23, add an appropriate amount of activator solution to the mixing granulator to wet and activate the mixed powder, and obtain mixed particles.

[0095] The amount of activator solution added in the above step S23 is 1.71%-5.71% of the total mass of the mixed powder.

[0096] S24, adding a proper amount of sulfur-containing liquid into the mixing granulator to form a thin film layer of sulfur-containing on the surface of the mixed granules.

[0097] The amount of sulfur-containing liquid added in step S24 is 1.43% to 5.14% of the total mass of the mixed powder.

[0098] S25, repeating step S23 and step S24 to make the mixed powder and sulfur-containing liquid layer by layer to obtain filter granules.

[0099] In step S25, the number of repeating cycles of step S23 and step S24 is 5 to 10, and the interval of the cycles is less than or equal to 2 minutes.

[0100] In other words, the number of cycles of adding the activator solution and the sulfur-containing liquid is 5 to 10, and the interval of the cycles is no more than 2 minutes. This way of adding the liquid in cycles facilitates the sulfur source being continuously wrapped when the filter granules roll in the mixing granulator. Compared with the one-time adding method, the sulfur source is more uniformly distributed in the filter granules, which is beneficial to the intermittent release of the sulfur source for the growth of microorganisms in the water body.

[0101] In some embodiments, in step S23, all the prepared activator solution is poured into the mixing granulator, and after the mixed powder gradually forms small granules, step S24 is performed, and the sulfur-containing liquid is added into the mixing granulator in batches. At this time, in step S25, only the sulfur-containing liquid is repeatedly added, the number of additions is 5 to 10, and the interval of the additions is no more than 2 minutes.

[0102] S26, after the size of the filter granules reaches the preset size, the filter granules are aged and activated to obtain the new filter material of the multi-layer wrapping type.

[0103] In the above step S26, the particle size of the filter granules is determined by the stirring speed of the mixing granulator, and the preset size of the filter granules is preferably 2.5 to 4 mm.

[0104] The aging temperature is room temperature, and the aging time is 12 to 24 hours.

[0105] The activation temperature is 80 to 150°C, and the activation can be performed in an oven.

[0106] More preferably, the activation process depends on the proportion of the liquid (sulfur-containing liquid and activator solution) in the new filter material. Only when the proportion of the liquid is higher than 0.2, the prepared filter granules need to be activated at 80 to 150°C, and the activation time should be prolonged with the increase of the amount of the liquid added, so as to ensure good particle strength and avoid the occurrence of phenomena such as powdering and scaling during use of the filter material.

[0107] In some embodiments, the mixing granulator described above is a 45-60° inclined cylinder structure, with uniform speed stirring blades inside, so that the materials can be uniformly stirred and mixed, and in addition, the scraper blades inside can make the materials attached to the inner wall of the cylinder fall off, further improving the uniformity of the material mixing.

[0108] Example 4

[0109] On the basis of Examples 1-3, the application further provides the application of the new filter material suitable for sulfur autotrophic denitrification described above: placing the new filter material described above in a fixed bed reactor for treating sewage, the new filter material providing the denitrifying microorganisms in the sewage with an electron donor, a sulfur source and an inorganic carbon source, and the denitrifying microorganisms converting the ammonia nitrogen in the sewage into nitrogen gas, thereby achieving purification of the sewage.

[0110] More specifically: the new filter material is used as a fixed bed filler, and activated sludge is inoculated into the filter material layer of the fixed bed, and the denitrifying microorganisms are acclimated for a period of time under a certain influent load. After acclimation, sewage purification can be started, and the influent amount of the sewage is gradually increased to the normal load, and after a period of continuous operation, the effluent quality is stable.

[0111] In order to better understand and use the above-mentioned scheme and effectively demonstrate the corresponding benefits, the new crystal seed suitable for a crystallization fluidized bed provided by the application, the preparation method and application thereof are further described in combination with specific examples as follows.

[0112] Example 5

[0113] On the basis of Examples 1, 2 and 4, this embodiment provides a specific preparation method and application of the new filter material, which can overcome the shortcomings of large carrier consumption ratio, easy breakage during use and slow start in the prior art. The specific preparation method and application are as follows:

[0114] S11, 60 parts of kaolin are weighed based on 100 parts by weight of the filter material system, dried in a 105°C oven for 12 hours, and then taken out and left to room temperature as a carrier powder;

[0115] 10 parts of sulfur powder are weighed as a sulfur-containing powder;

[0116] 10 parts of a 20%wt concentration sodium hydroxide solution and 10 parts of a 3.2 modulus sodium silicate solution are weighed as an activator solution;

[0117] 10 parts of a 50%wt concentration sodium thiosulfate solution are weighed as a sulfur-containing liquid material.

[0118] S12, the prepared carrier powder and sulfur-containing powder are mixed and uniformly stirred for 5 minutes, then the activator solution is added to the mixed material, continuously stirred for 5 minutes, and then the sulfur-containing liquid material is added, continuously stirred for 10 minutes, to form a mixed slurry.

[0119] S13, pour the mixed slurry into a shaping mold, shake to remove air in the slurry, and let stand for 24 hours at room temperature, then demold after hardening to obtain mixed solid material.

[0120] S14, place the mixed solid material in an oven at 105°C and activate for 3 days.

[0121] S15, crush the activated mixed solid material, screen with 10-mesh and 5-mesh screens, then wash away excess impurities and powder with clean water, and dry at 105°C to obtain the new filter material SDF-1 in irregular shape with a particle size of 2-4 mm.

[0122] The application process of the new filter material is as follows:

[0123] The new filter material prepared above is used as fixed bed filler to treat the effluent from the biochemical tank of a petrochemical enterprise wastewater treatment plant, which contains about 40-50 mg / L of nitrate nitrogen, and the addition amount of the new filter material accounts for 30%-45% of the total volume of the fixed bed. The activated sludge is inoculated into the filter material layer of the fixed bed, and the microorganisms are cultured and domesticated for 5 days under a 50% influent load. After gradually increasing the influent to the normal load, the effluent quality is stable, and the continuous operation is carried out for 20 days to test the denitrification effect. The specific nitrate nitrogen removal rate is shown in Table 1.

[0124] Example 6

[0125] Based on Examples 1, 3 and 4, this example provides a specific preparation method and application of the new filter material,

[0126] Specifically as follows:

[0127] S21, take 50 parts of kaolin and 10 parts of silicon powder, uniformly mix them, and place them in a 105°C oven for drying for 12 hours, then take them out and let stand to room temperature to obtain the carrier powder;

[0128] Take 10 parts of sulfur powder as the sulfur-containing powder;

[0129] Take 10 parts of 20%wt sodium hydroxide solution and 10 parts of sodium silicate solution with a modulus of 3.2 as the activator solution;

[0130] Take 10 parts of 50%wt sodium thiosulfate solution as the sulfur-containing liquid material.

[0131] S22, put the prepared carrier powder and sulfur-containing powder into a mixing granulator, uniformly mix for 5 minutes to obtain the mixed powder.

[0132] S23, 2 portions of sodium hydroxide solution and 2 portions of sodium silicate solution are added to the mixed powder in the mixing granulator, and the mixing granulator is continuously operated during the addition of the liquid to the mixed powder, and small particles begin to gradually form after the liquid is added to the mixed powder.

[0133] S24, one minute later, 2 portions of sulfur-containing liquid are added to the mixing granulator.

[0134] S25, the activator solution of step S23 and the sulfur-containing liquid of step S24 are repeatedly added, with 1 minute interval between each batch, a total of 5 batches, and the mixed powder and sulfur-containing liquid are layered and stacked to obtain filter particles.

[0135] S26, after the average particle size of the filter particles reaches about 3 mm, the granulation is terminated, the filter particles are poured into a flat tray and evenly laid out, and then aged at room temperature for 12 hours, and then placed in an oven and hardened at 105°C for 24 hours, to finally obtain a new type of filter material SDF-2 with a multi-layer wrapping.

[0136] The application process of the new filter material SDF-2 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0137] Example 7

[0138] With reference to Example 6, the difference is that:

[0139] 40 parts of kaolin and 20 parts of silica powder are uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-3.

[0140] The application process of the new filter material SDF-3 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0141] Example 8

[0142] With reference to Example 6, the difference is that:

[0143] 30 parts of kaolin and 30 parts of silica powder are uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-4.

[0144] The application process of the new filter material SDF-4 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0145] Example 9

[0146] With reference to Example 6, the difference is that:

[0147] 56 parts of bentonite and 4 parts of aluminum powder are uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-5.

[0148] The application process of the new filter material SDF-5 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0149] Example 10

[0150] With reference to Example 6, the difference is that:

[0151] 50 parts of diatomite and 10 parts of aluminum powder are weighed and uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-6.

[0152] The application process of the new filter material SDF-6 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0153] Example 11

[0154] With reference to Example 6, the difference is that:

[0155] 52 parts of fly ash and 8 parts of silica powder are weighed and uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-7.

[0156] The application process of the new filter material SDF-7 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0157] Example 12

[0158] With reference to Example 6, the difference is that:

[0159] 58 parts of corn-cake stone powder and 2 parts of aluminum powder are weighed and uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-8.

[0160] The application process of the new filter material SDF-8 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0161] Example 13

[0162] With reference to Example 6, the difference is that:

[0163] 20 parts of kaolin and 40 parts of bentonite are weighed and uniformly mixed as the carrier raw material, and the remaining preparation steps are the same as those of Example 6, to obtain a new filter material SDF-9.

[0164] The application process of the new filter material SDF-9 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0165] Example 14

[0166] With reference to Example 6, the difference is that:

[0167] Take 20 parts of kaolin, 30 parts of bentonite and 10 parts of diatomite uniformly mixed as carrier raw material, and the rest of the preparation steps are the same as example 6 to obtain a new filter material SDF-10.

[0168] The application process of the new filter material SDF-10 is the same as example 5, and the specific nitrate nitrogen removal rate is shown in table 1.

[0169] Example 15

[0170] Reference example 6, the difference is that:

[0171] Take 20 parts of kaolin, 20 parts of bentonite, 10 parts of diatomite and 10 parts of fly ash uniformly mixed as carrier raw material, and the rest of the preparation steps are the same as example 6 to obtain a new filter material SDF-11.

[0172] The application process of the new filter material SDF-11 is the same as example 5, and the specific nitrate nitrogen removal rate is shown in table 1.

[0173] Example 16

[0174] Reference example 6, the difference is that:

[0175] Take 20 parts of kaolin, 10 parts of bentonite, 10 parts of diatomite, 10 parts of fly ash and 10 parts of maifanite powder uniformly mixed as carrier raw material, and the rest of the preparation steps are the same as example 6 to obtain a new filter material SDF-12.

[0176] The application process of the new filter material SDF-12 is the same as example 5, and the specific nitrate nitrogen removal rate is shown in table 1.

[0177] Example 17

[0178] Reference example 7, the difference is that:

[0179] Take 7 parts of 50%wt concentration sodium thiosulfate solution and 3 parts of sodium polysulfide solution uniformly mixed as sulfur-containing liquid material, and the rest of the preparation steps are the same as example 7 to obtain a new filter material SDF-13.

[0180] The application process of the new filter material SDF-13 is the same as example 5, and the specific nitrate nitrogen removal rate is shown in table 1.

[0181] Example 18

[0182] Reference example 7, the difference is that:

[0183] Take 7 parts of 50%wt concentration sodium thiosulfate solution and 3 parts of 50%wt concentration sodium tetrathionate solution uniformly mixed as sulfur-containing liquid material, and the rest of the preparation steps are the same as example 7 to obtain a new filter material SDF-14.

[0184] The application process of the new filter SDF-14 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0185] Example 19

[0186] With reference to Example 7, the difference is that:

[0187] Take 7 parts of sodium thiosulfate solution with a concentration of 50% wt and 3 parts of sodium hyposulfite solution with a concentration of 50% wt and mix them uniformly as sulfur-containing liquid, and the remaining preparation steps are the same as those of Example 7, to obtain a new filter SDF-15.

[0188] The application process of the new filter SDF-15 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0189] Example 20

[0190] With reference to Example 7, the difference is that:

[0191] Take 11 parts of sodium hydroxide solution with a concentration of 15% wt and 9 parts of sodium silicate solution with a modulus of 3.2 and mix them uniformly as activator solution, and the remaining preparation steps are the same as those of Example 7, to obtain a new filter SDF-16.

[0192] The application process of the new filter SDF-16 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0193] Example 21

[0194] With reference to Example 7, the difference is that:

[0195] Take 13 parts of sodium hydroxide solution with a concentration of 10% wt and 7 parts of sodium silicate solution with a modulus of 3.2 and mix them uniformly as activator solution, and the remaining preparation steps are the same as those of Example 7, to obtain a new filter SDF-17.

[0196] The application process of the new filter SDF-17 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0197] Example 22

[0198] With reference to Example 7, the difference is that:

[0199] Take 37 parts of kaolin and 17 parts of silicon powder and mix them uniformly as carrier raw material, and take 16 parts of sulfur fine powder as sulfur-containing powder, and the remaining preparation steps are the same as those of Example 7, to obtain a new filter SDF-18.

[0200] The application process of the new filter SDF-18 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0201] Example 23

[0202] Reference to Example 7, except that:

[0203] Take 35 parts of kaolin and 15 parts of silica powder are uniformly mixed as carrier raw material, take 20 parts of sulfur concentrate powder as sulfur-containing powder, and the remaining preparation steps are the same as Example 7, to obtain a new filter material SDF-19.

[0204] The application process of the new filter material SDF-19 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0205] Example 24

[0206] Reference to Example 7, except that:

[0207] Take 29 parts of kaolin and 11 parts of silica powder are uniformly mixed as carrier raw material, take 30 parts of sulfur concentrate powder as sulfur-containing powder, and the remaining preparation steps are the same as Example 7, to obtain a new filter material SDF-20.

[0208] The application process of the new filter material SDF-20 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0209] Example 25

[0210] Reference to Example 7, except that:

[0211] Take 14 parts of sodium thiosulfate solution with a concentration of 50%wt as sulfur-containing liquid material, take 9 parts of sodium hydroxide solution with a concentration of 25%wt and 7 parts of sodium silicate solution with a modulus of 3.3 are uniformly mixed as activator solution, and the remaining preparation steps are the same as Example 7, to obtain a new filter material SDF-21.

[0212] The application process of the new filter material SDF-21 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0213] Example 26

[0214] Reference to Example 7, except that:

[0215] Take 18 parts of sodium thiosulfate solution with a concentration of 50%wt as sulfur-containing liquid material, take 7 parts of sodium hydroxide solution with a concentration of 30%wt and 5 parts of sodium silicate solution with a modulus of 3.4 are uniformly mixed as activator solution, and the remaining preparation steps are the same as Example 7, to obtain a new filter material SDF-22.

[0216] The application process of the new filter material SDF-22 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0217] Example 27

[0218] Reference to Example 7, except that:

[0219] Take 8 parts of sulfur concentrate and 2 parts of pyrite powder evenly mixed as sulfur-containing powder, and the remaining preparation steps are the same as Example 7 to obtain a new filter material SDF-23.

[0220] The application process of the new filter material SDF-23 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0221] Example 28

[0222] Reference to Example 7, except that:

[0223] Take 6 parts of sulfur concentrate and 4 parts of pyrite powder evenly mixed as sulfur-containing powder, and the remaining preparation steps are the same as Example 7 to obtain a new filter material SDF-24.

[0224] The application process of the new filter material SDF-24 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0225] Example 29

[0226] Reference to Example 7, except that:

[0227] Take 4 parts of sulfur concentrate and 6 parts of pyrite powder evenly mixed as sulfur-containing powder, and the remaining preparation steps are the same as Example 7 to obtain a new filter material SDF-25.

[0228] The application process of the new filter material SDF-25 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0229] Example 30

[0230] Reference to Example 7, except that:

[0231] Take 10 parts of pyrite powder as sulfur-containing powder, and the remaining preparation steps are the same as Example 7 to obtain a new filter material SDF-26.

[0232] The application process of the new filter material SDF-26 is the same as Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0233] Example 31

[0234] Reference to Example 7, except that:

[0235] Take 9.8 parts of 20%wt concentration sodium hydroxide solution, 0.4 parts of 60%wt concentration sodium carbonate solution and 9.8 parts of 3.2 modulus sodium silicate solution evenly mixed as activator solution, and the remaining preparation steps are the same as Example 7 to obtain a new filter material SDF-27.

[0236] The application process of the new filter SDF-27 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0237] Example 32

[0238] With reference to Example 7, the difference is that:

[0239] Take 9.6 parts of 20%wt concentration sodium hydroxide solution, 1 part of 50%wt concentration sodium carbonate solution and 9.4 parts of 3.2 modulus sodium silicate solution and mix them uniformly as an activator solution, and the remaining preparation steps are the same as those of Example 7 to obtain a new filter SDF-28.

[0240] The application process of the new filter SDF-28 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0241] Example 33

[0242] With reference to Example 7, the difference is that:

[0243] Take 9.2 parts of 20%wt concentration sodium hydroxide solution, 1.6 parts of 40%wt concentration sodium carbonate solution and 9.2 parts of 3.2 modulus sodium silicate solution and mix them uniformly as an activator solution, and the remaining preparation steps are the same as those of Example 7 to obtain a new filter SDF-29.

[0244] The application process of the new filter SDF-29 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0245] Example 34

[0246] With reference to Example 7, the difference is that:

[0247] Take 9 parts of 20%wt concentration sodium hydroxide solution, 2 parts of 30%wt concentration sodium carbonate solution and 9 parts of 3.2 modulus sodium silicate solution and mix them uniformly as an activator solution, and the remaining preparation steps are the same as those of Example 7 to obtain a new filter SDF-30.

[0248] The application process of the new filter SDF-30 is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0249] Comparative Example 1

[0250] Crush the blocky pyrite ore, screen out the particles with a particle size of 2-4 mm, wash the surface impurities and powder with clean water, and dry at 105°C for 24 hours to obtain a natural sulfur-containing mineral filter material.

[0251] The application process of the natural sulfur-containing mineral filter material is the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0252] Comparative Example 2

[0253] Sulfur powder, water and resin binder were added into a mixing granulator in a mass ratio of 1:0.15:0.25 to prepare granules with a particle size of 2-4 mm. After drying at 105°C for 24 hours, a bonded sulfur synthetic filter material was obtained.

[0254] The application process of the bonded sulfur synthetic filter material was the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0255] Comparative Example 3

[0256] Sulfur powder was placed into a 50%wt sodium thiosulfate solution, uniformly mixed into a suspension, and then molecular sieves with an average particle size of about 3 mm were immersed in the suspension. After continuous stirring for 12 hours, the molecular sieves were taken out and placed in an oven at 105°C for drying for 24 hours to obtain an impregnated sulfur synthetic filter material.

[0257] The application process of the impregnated sulfur synthetic filter material was the same as that of Example 5, and the specific nitrate nitrogen removal rate is shown in Table 1.

[0258] Table 1 Nitrate nitrogen removal rates of different filter materials prepared in Examples 5-30 and Comparative Examples 1-3

[0259]

[0260]

[0261] As can be seen from Table 1, the nitrate nitrogen removal rate of the new filter material provided by Examples 5-34 of the present application is 79.57%-90.14%, which is significantly higher than that of Comparative Examples 1-3, and it can be seen that the new filter material provided by the present application has higher nitrogen removal efficiency.

[0262] The above is only a preferred embodiment of the present application, and it should be noted that for those skilled in the art, without departing from the principles of the present application, several improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for preparing a filter media suitable for sulfur autotrophic denitrification, characterized in that, The method comprises the following steps: S21, according to the component of the filter material, the carrier powder, sulfur-containing powder, activator solution and sulfur-containing liquid material are weighed; wherein the mass ratio of the carrier powder, sulfur-containing powder, activator solution and sulfur-containing liquid material is 1:(0.17-0.75):(0.20-0.50):(0.17-0.30); the carrier powder is a mineral material containing silicate or solid waste material, and The content is 50%-80%, The content is 5%-35%, the molar ratio of Si and Al is 1.61-4.46; the content of S in the sulfur-containing powder is greater than 50%; the activator solution is alkaline; the sulfur-containing liquid material is a soluble sulfur source; S22, adding the carrier powder and the sulfur-containing powder into a mixing granulator in proportion, and uniformly mixing to obtain a mixed powder; S23, adding an appropriate amount of the activator solution into the mixing granulator to wet and activate the mixed powder, and obtaining mixed particles; S24, adding an appropriate amount of the sulfur-containing liquid into the mixing granulator to form a thin film layer containing sulfur on the surface of the mixed particles; S25, repeating the step S23 and the step S24 to make the mixed powder and the sulfur-containing liquid layer by layer, and obtaining filter particles; S26, after the size of the filter particles reaches a preset size, the filter particles are aged and activated to obtain the multi-layer wrapped filter material; the filter material can slowly release sulfur source when used in water.

2. The preparation method according to claim 1, wherein, in the step S23, the amount of the activator solution added is 1.71%-5.71% of the total mass of the mixed powder; and / or, in the step S24, the amount of the sulfur-containing liquid added is 1.43%-5.14% of the total mass of the mixed powder.

3. The preparation method according to claim 1, wherein, in the step S22, the mixing time of the carrier powder and the sulfur-containing powder is 2-5 minutes; and / or, in the step S25, the number of cycles of repeating the step S23 and the step S24 is 5-10, and the cycle interval time is less than or equal to 2 minutes; and / or, in the step S26, the activation temperature is 80-150℃; and / or, in the step S26, the aging temperature is room temperature, and the aging time is 12-24 hours; and / or, in the step S26, the preset size of the filter particles is 2.5-4 mm.

4. The preparation method according to claim 1, wherein, the carrier powder is one or more of kaolin, bentonite, diatomite, fly ash, medical stone powder, silicon powder, and aluminum powder; and / or, the sulfur-containing powder is one or more of sulfur fine powder, pyrite, pyrrhotite, and magnetite; and / or, the activator solution is one or more of sodium hydroxide solution, sodium silicate solution, sodium carbonate solution, and sodium bicarbonate solution; and / or, the sulfur-containing liquid is one or more of sodium thiosulfate solution, sodium sulfide solution, sodium polysulfide solution, sodium tetrathionate solution, and sodium hyposulfite solution.

5. A filter media suitable for sulfur autotrophic denitrification, characterized in that, The filter material is prepared by the preparation method of any one of claims 1-4.

6. Application of a filter material suitable for sulfur autotrophic denitrification, wherein the filter material of claim 5 is applied in a fixed bed reactor for treating wastewater. ​

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