Composite porous phosphorus removal filter material and preparation method thereof

Abstract

The invention discloses a composite porous phosphorus removal filter material and a preparation method thereof, the filter material is prepared by taking aluminum hydroxide, limestone, concrete, perlite, modified zeolite, a foaming agent and a mixture of euglena, chlorella and spirulina as main components through the steps of pulping, foaming, coating, curing, crushing, screening and the like. The phosphorus removal efficiency is remarkably improved through ion exchange and chemical adsorption effects of the modified zeolite, the performance of the filter material is further enhanced through biological adsorption and biological assimilation effects of the microalgae, and in addition, the phosphorus removal effect of the filter material is further improved through stable precipitates formed by special components and phosphate. The filter material has the advantages of efficient phosphorus removal, environmental protection, no pollution, multifunctionality, economical efficiency and the like, is suitable for the fields of sewage treatment plants, lake remediation, aquaculture and the like, and has the advantages of high phosphorus removal efficiency, simple preparation process, low raw material cost and easiness in industrial production.

Description

Technical Field

[0001] The present invention relates to a composite porous phosphorus-removing filter material and a preparation method thereof, belonging to the technical fields of sewage treatment, water body restoration, etc. Background Art

[0002] Phosphorus is one of the important nutrient elements in water bodies. However, excessive phosphorus can lead to water eutrophication, trigger a large reproduction of algae (such as cyanobacteria blooms), consume dissolved oxygen in water, destroy the ecological balance of water bodies, and even produce toxic substances, threatening human health and the ecological environment. Phosphorus pollution mainly comes from agricultural runoff (such as fertilizer loss), industrial wastewater (such as phosphorus chemical industry, detergent production), and domestic sewage (such as washing wastewater and feces).

[0003] With the rapid development of industry and agriculture, the problem of phosphorus pollution in water bodies is becoming increasingly serious, leading to water eutrophication and damaging the ecological environment. Traditional phosphorus-removing methods (such as chemical precipitation method, adsorption method, etc.) have problems such as high cost, low efficiency, and secondary pollution. In recent years, the biological adsorption method has received extensive attention due to its environmental protection and high efficiency characteristics.

[0004] Microalgae such as Euglena, Chlorella, and Spirulina have natural phosphorus adsorption ability and can remove phosphorus in water through biological adsorption and biological assimilation. However, when microalgae are used alone, there are problems such as easy loss and difficult recovery. Therefore, it is of great significance to develop a composite filter material that combines the biological characteristics of microalgae and the physical adsorption characteristics of porous materials. In addition, by replacing ordinary zeolite with modified zeolite, the ion exchange ability and adsorption performance of the filter material can be further improved. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a composite porous phosphorus-removing filter material and a preparation method thereof, which can solve the problems of low phosphorus-removing efficiency, high cost, secondary pollution, etc. in the prior art.

[0006] A composite porous phosphorus-removing filter material according to the present invention, based on the total mass of the filter material, includes: 35-50% of hydroxyaluminum oxide, 15-25% of limestone, 5%-15% of concrete, 15-25% of perlite, 5-15% of modified zeolite, 1-3% of foaming agent, and 1-5% of a mixture of Euglena, Chlorella, and Spirulina.

[0007] The modified zeolite is obtained by soaking ordinary zeolite in an iron salt or aluminum salt solution, followed by drying and calcination.

[0008] The iron salt is ferric chloride (FeCl3), the aluminum salt is aluminum chloride (AlCl3), the soaking concentration is 0.1-0.5 mol / L, the soaking time is 2-4 hours, the drying temperature is 100-120 °C, and the calcination temperature is 400-500 °C.

[0009] The particle size of the filter material is 50 - 200 mm, the porosity is ≥ 60%, the bulk density is 385 - 410 kg / m 3 , and the dry density is 560 - 600 kg / m 3 , the specific surface area is 930 - 970 m 2 / g, the cylinder compressive strength is ≥ 4 MPa, the porosity is ≥ 75%, and the water absorption rate is ≥ 72%.

[0010] The foaming agent is one of sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium nitrite, sodium dodecyl sulfate, sodium lauroyl sarcosinate, and hydrolyzed sodium hydroxide.

[0011] The mass ratio of the mixture of Euglena, Chlorella, and Spirulina is 1:1:1.

[0012] A preparation method of a composite porous phosphorus-removing filter material includes the following steps:

[0013] Pulp making: Mix limestone powder and water in a ratio of 100 - 500 and stir, then add concrete powder and stir evenly;

[0014] Foaming: Add a foaming agent to the slurry, stir for 1 - 2 hours, and then add hydroxyaluminum oxide;

[0015] Coating: Add modified zeolite, perlite, and the mixture of Euglena, Chlorella, and Spirulina to the foamed slurry, stir, and then pump it into a coating machine;

[0016] Curing: Pump the coated foamed slurry into a curing pool for molding and curing;

[0017] Crushing: Put the cured composite porous hydroxyaluminum oxide into a crusher for crushing;

[0018] Screening: Feed the crushed filter material into a screening machine and screen it through a sieve with a pore size of 500 mm to obtain adsorption particles with a particle size less than 500 mm.

[0019] In the curing step, the curing temperature is 50 - 80 °C, and the curing time is 12 - 24 hours.

[0020] The filter material is applicable to fields such as sewage treatment plants, lake restoration, and aquaculture.

[0021] The filter material synergistically removes nitrogen and organic matter in water through the biological adsorption of microalgae and the ion exchange of modified zeolite.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1. The composite porous high-efficiency adsorption phosphorus-removing filter material of the present invention significantly improves the phosphorus-removing efficiency through the synergistic action of multiple mechanisms;

[0024] 2. The filter media of the present invention uses natural raw materials and biological materials. Limestone, perlite, zeolite, etc. are all natural minerals, which are widely sourced and harmless to the environment. Euglena, Chlorella, and Spirulina are natural microalgae with good biodegradability and will not cause secondary pollution. The filter media will not release harmful substances during use and is suitable for drinking water treatment and ecological restoration;

[0025] 3. The filter media of the present invention can not only efficiently remove phosphorus, but also Euglena, Chlorella, and Spirulina absorb ammonia nitrogen and nitrate in water through photosynthesis, significantly improving the nitrogen removal ability of the filter media. The synergistic effect of microalgae and modified zeolite can degrade some organic pollutants in water;

[0026] 4. The filter media of the present invention has economic advantages. Raw materials such as limestone, perlite, and zeolite are widely sourced and inexpensive. The preparation method of the filter media includes steps such as pulping, foaming, coating, curing, crushing, and screening. The process is simple and easy for industrial production. The filter media has high mechanical strength and chemical stability, with a service life of 6 to 9 months, reducing the replacement frequency and maintenance cost;

[0027] 5. The filter media of the present invention has excellent physical properties and can meet the mechanical strength requirements in practical applications;

[0028] 6. Through the synergistic effect of various components, the filter media of the present invention achieves the effect of 1 + 1 > 2. Modified zeolite provides physical adsorption and ion exchange capabilities, while microalgae provides biological adsorption and degradation capabilities. The synergy between the two significantly improves the overall performance of the filter media. Detailed implementation mode

[0029] The present invention will be further described below, but the protection scope of the present invention is not limited to the described content.

[0030] For clarity, not all features of the actual embodiments are described. In the following description, well-known functions and structures are not described in detail because they would obscure the present invention with unnecessary details. It should be considered that in the development of any actual embodiment, a large number of implementation details must be made to achieve the specific goals of the developer. For example, due to system or business-related limitations, changing from one embodiment to another. Additionally, it should be considered that such development work may be complex and time-consuming, but it is only routine work for those skilled in the art.

[0031] A composite porous phosphorus-removing filter media, based on the total mass of the filter media, includes: 35 - 50% of hydroxyaluminum oxide, 15 - 25% of limestone, 5% - 15% of concrete, 15 - 25% of perlite, 5 - 15% of modified zeolite, 1 - 3% of foaming agent, and 1 - 5% of a mixture of Euglena, Chlorella, and Spirulina

[0032] The above composite porous phosphorus-removing filter material contains abundant hydroxyaluminum oxide. According to the principle that some hydroxy metal oxides have extremely strong selective adsorption ability for phosphorus in water with neutral pH and the adsorbed phosphorus can be rapidly desorbed when the pH becomes alkaline, it has the ability to target and adsorb orthophosphate. The reaction equations for adsorption, desorption, and phosphorus resource recovery are as follows:

[0033] Removing phosphorus from sewage (adsorption reaction)

[0034] Al-OOH + H2PO4 - =Al-O-HPO4 - + H2O

[0035] Regeneration of adsorption filter material (desorption reaction)

[0036] Al-O-HPO4 - + 3OH - =Al-OOH + PO4 3- + OH - + H2O

[0037] Phosphorus resource recovery (flocculation crystallization reaction)

[0038] PO4 3- + 3 / 2Ca(OH)2 = 1 / 2Ca3(PO4)2 + 3OH -

[0039] The mixture of Euglena, Chlorella, and Spirulina achieved efficient phosphorus removal through biological adsorption, biological assimilation, and synergistic action with modified zeolite. The cell walls of microalgae contain abundant polysaccharides, proteins, and lipid substances, and these components have a large number of functional groups (such as hydroxyl, carboxyl, amino, etc.). The functional groups achieve biological adsorption through electrostatic interaction, ion exchange, and complexation; microalgae can also convert phosphate into biomass through photosynthesis for their own growth and reproduction.

[0040] Performance tests were carried out on the above-mentioned composite porous phosphorus-removing filter material, and comparative experiments were conducted using comparative examples and examples. Specifically:

[0041] Comparative example

[0042] A commercially available porous diatomite high-efficiency phosphorus-removing filter material, whose components include: 20 - 30% diatomite; 45 - 55% silica; 8 - 11% cement; 6 - 10% lime; 2 - 4% gypsum; 1.5 - 2% aluminum powder, purchased from Henan Antong Environmental Protection Technology Co., Ltd.

[0043] Example 1

[0044] 1. Raw material ratio

[0045] Hydroxyaluminum oxide: 40%

[0046] Limestone: 20%

[0047] Concrete: 10%

[0048] Perlite: 20%

[0049] Modified zeolite: 8%

[0050] Foaming agent: 2%

[0051] Mixture of Euglena, Chlorella and Spirulina: 3%

[0052] 2. Preparation of modified zeolite

[0053] Soak ordinary zeolite in 0.3 mol / L ferric chloride (FeCl3) solution and stir for 3 hours.

[0054] After filtration, dry the zeolite at 110 °C for 3 hours.

[0055] Calcine the dried zeolite at 450 °C for 1.5 hours to obtain modified zeolite.

[0056] 3. Preparation steps

[0057] Mix limestone powder and water at a ratio of 1:300 and stir, then add concrete powder and stir evenly.

[0058] Add a foaming agent (sodium bicarbonate) to the slurry, stir for 1.5 hours and then add aluminum hydroxide.

[0059] Add the modified zeolite, perlite and the mixture of Euglena, Chlorella and Spirulina to the foamed slurry, stir and then pump it into a coating machine.

[0060] Pump the coated foamed mud into a curing pool for forming and curing.

[0061] Put the cured composite porous aluminum hydroxide into a crusher for crushing.

[0062] Send the crushed filter material to a screening machine and screen it through a sieve with a pore size of 500 mm to obtain adsorption particles with a particle size less than 500 mm.

[0063] Example 2

[0064] 1. Raw material ratio

[0065] Aluminum hydroxide: 45%

[0066] Limestone: 15%

[0067] Concrete: 10%

[0068] Perlite: 15%

[0069] Modified zeolite: 10%

[0070] Foaming agent: 3%

[0071] Mixture of Euglena, Chlorella, and Spirulina: 2%

[0072] 2. Preparation of modified zeolite

[0073] Soak ordinary zeolite in a 0.2 mol / L aluminum chloride (AlCl3) solution and stir for 4 hours.

[0074] After filtration, dry the zeolite at 120 °C for 2 hours.

[0075] Calcine the dried zeolite at 500 °C for 1 hour to obtain modified zeolite.

[0076] 3. Preparation steps

[0077] Mix limestone powder and water in a ratio of 1:300 and stir. After adding concrete powder, stir evenly.

[0078] Add a foaming agent (sodium bicarbonate) to the slurry and stir for 1.5 hours, then add aluminum hydroxide.

[0079] Add the modified zeolite, perlite, and the mixture of Euglena, Chlorella, and Spirulina to the foamed slurry, stir, and then pump it into a coating machine.

[0080] Pump the coated foamed mud into a curing pool for forming and curing.

[0081] Put the cured composite porous aluminum hydroxide into a crusher for crushing.

[0082] Send the crushed filter material to a screening machine and screen it through a sieve with a pore size of 500 mm to obtain adsorption particles with a particle size less than 500 mm.

[0083] Example 3

[0084] 1. Raw material ratio

[0085] Aluminum hydroxide: 35%

[0086] Limestone: 25%

[0087] Concrete: 5%

[0088] Perlite: 25%

[0089] Modified zeolite: 5%

[0090] Foaming agent: 1%

[0091] Mixture of Euglena, Chlorella, and Spirulina: 4%

[0092] 2. Preparation of modified zeolite

[0093] Soak the ordinary zeolite in 0.1 mol / L aluminum chloride (AlCl3) solution and stir for 4 hours.

[0094] After filtration, dry the zeolite at 100 °C for 4 hours.

[0095] Calcine the dried zeolite at 400 °C for 1 hour to obtain the modified zeolite.

[0096] 3. Preparation steps

[0097] Mix and stir the limestone powder and water in a ratio of 1:300, and then add the concrete powder and stir evenly.

[0098] Add the foaming agent (sodium bicarbonate) to the slurry, stir for 1.5 hours, and then add aluminum hydroxide.

[0099] Add the modified zeolite, perlite, and the mixture of Euglena, Chlorella, and Spirulina to the foamed slurry, stir, and then pump it into the coating machine.

[0100] Pump the coated foamed mud into the curing pool for forming and curing.

[0101] Put the cured composite porous aluminum hydroxide into a crusher for crushing.

[0102] Send the crushed filter material to a screening machine and screen it through a sieve with a pore size of 500 mm to obtain adsorption particles with a particle size less than 500 mm.

[0103] Example 4

[0104] 1. Raw material ratio

[0105] Aluminum hydroxide: 50%

[0106] Limestone: 15%

[0107] Concrete: 15%

[0108] Perlite: 15%

[0109] Modified zeolite: 5%

[0110] Foaming agent: 1%

[0111] Mixture of Euglena, Chlorella, and Spirulina: 5%

[0112] 2. Preparation of modified zeolite

[0113] Soak the ordinary zeolite in 0.5 mol / L aluminum chloride (AlCl3) solution and stir for 2 hours.

[0114] After filtration, dry the zeolite at 120 °C for 2 hours.

[0115] The dried zeolite is calcined at 500 °C for 1 hour to obtain the modified zeolite.

[0116] 3. Preparation steps

[0117] Mix and stir the limestone powder and water in a ratio of 1:300, and then add the concrete powder and stir evenly.

[0118] Add the foaming agent (sodium bicarbonate) to the slurry, stir for 1.5 hours, and then add aluminum hydroxide.

[0119] Add the modified zeolite, perlite, and the mixture of Euglena, Chlorella, and Spirulina to the foamed slurry, stir, and then pump it into the coating machine.

[0120] Pump the coated foamed mud into the curing tank for forming and curing.

[0121] Put the cured composite porous aluminum hydroxide into the crusher for crushing.

[0122] Send the crushed filter material to the screening machine, screen it through a sieve with a pore size of 500 mm to obtain adsorption particles with a particle size less than 500 mm.

[0123] Example 5

[0124] 1. Raw material ratio

[0125] Aluminum hydroxide: 40%

[0126] Limestone: 20%

[0127] Concrete: 10%

[0128] Perlite: 20%

[0129] Modified zeolite: 8%

[0130] Foaming agent: 2%

[0131] Mixture of Euglena, Chlorella, and Spirulina: 3%

[0132] Iron hydroxide: 3%

[0133] 2. Preparation of modified zeolite

[0134] Refer to Example 1

[0135] 3. Preparation steps

[0136] In the pulping step, mix and stir the limestone powder and water in a ratio of 1:300, add the concrete powder and iron hydroxide, and then stir evenly.

[0137] The remaining steps are the same as those in Example 1.

[0138] Example 6

[0139] 1. Raw material ratio

[0140] Hydroxyaluminum oxide: 40%

[0141] Limestone: 20%

[0142] Concrete: 10%

[0143] Perlite: 20%

[0144] Modified zeolite: 8%

[0145] Foaming agent: 2%

[0146] Mixture of Euglena, Chlorella and Spirulina: 3%

[0147] Lanthanum chloride: 1%

[0148] 2. Preparation of modified zeolite

[0149] Refer to Example 1

[0150] 3. Preparation steps

[0151] In the pulping step, mix limestone powder and water in a ratio of 1:300, stir, and then add concrete powder and lanthanum chloride and stir evenly.

[0152] The remaining steps are the same as those in Example 1.

[0153] Example 7

[0154] 1. Raw material ratio

[0155] Hydroxyaluminum oxide: 40%

[0156] Limestone: 20%

[0157] Concrete: 10%

[0158] Perlite: 20%

[0159] Modified zeolite: 8%

[0160] Foaming agent: 2%

[0161] Mixture of Euglena, Chlorella and Spirulina: 3%

[0162] Biochar: 5%

[0163] 2. Preparation of modified zeolite

[0164] Refer to Example 1

[0165] 3. Preparation steps

[0166] In the pulping step, limestone powder is mixed and stirred with water at a ratio of 1:300, and after adding concrete powder and biochar, it is uniformly stirred.

[0167] The remaining steps are the same as those in Example 1.

[0168] Performance tests were carried out on the comparative example and Examples 1-7, specifically:

[0169] 1) Phosphorus removal efficiency test

[0170] 1 L of eel farming wastewater, river sewage, and shrimp farming wastewater (seawater) were selected and poured into sample bottles containing 200 g of various types of adsorption filter materials respectively. The sample bottles were shaken for 2 min to make them fully contact and react. After standing for 20 min, the supernatant was taken, and the total phosphorus concentration value in the sewage before and after adsorption was measured using ammonium molybdate spectrophotometry. The experiment was repeated three times, and the measurement results are shown in the following table.

[0171] Table 1 Phosphorus removal efficiency test of different adsorption phosphorus removal filter materials

[0172]

[0173] 2) Adsorption capacity and regeneration times test

[0174] 1 g of various adsorption filter materials was weighed and placed in a 150 mL stoppered conical flask. 100 mL of phosphorus-containing wastewater with an initial concentration of 100 mg / L was added, and it was placed in a constant temperature oscillator and shaken at 150 r / min under the condition of 25 °C. After different durations, it was taken out to measure the phosphorus concentration in the solution, and the adsorption capacity was calculated by calculating the phosphorus adsorption capacity per unit adsorbent. The regeneration times of the adsorption filter materials were indirectly estimated by measuring the regeneration rate of each adsorbent. After testing, the adsorption capacity and regeneration times of different adsorption phosphorus removal filter materials are shown in Table 2.

[0175] Table 2 Performance comparison of different adsorption phosphorus removal filter materials

[0176]

[0177]

[0178] From the performance test results, it can be seen that by comparing the test results of Examples 1-4, it can be known that this filter material, through the synergistic effect of multiple components, achieves the effect of 1 + 1 > 2. The modified zeolite provides physical adsorption and ion exchange capabilities, and the microalgae provides biological adsorption and degradation capabilities. The two synergistically significantly improve the overall performance of the filter material.

[0179] From the test results of Examples 5-7, it can be seen that adding iron hydroxide, lanthanum chloride, and biochar to the filter material can all improve the phosphorus removal effect.

[0180] The composite porous high-efficiency phosphorus-adsorbing filter material of the present invention combines modified zeolite, microalgae and special components, achieving multiple advantages such as high-efficiency phosphorus removal, environmental protection and pollution-free, multi-functionality, economy, etc. Its excellent performance and broad application prospects make it an ideal choice in the field of water treatment. Supported by the data of the examples, the practicability and superiority of the present invention are further verified.

[0181] Although the technical solutions of the present invention have been described and listed in relatively detail, it should be understood that for those skilled in the art, making modifications to the above embodiments or adopting equivalent alternative solutions are obvious to those skilled in the art. These modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A composite porous phosphorus-removing filter material, characterized in that, Based on the total mass of the filter material, it includes: 35 - 50% of hydroxyaluminum oxide, 15 - 25% of limestone, 5% - 15% of concrete, 15 - 25% of perlite, 5 - 15% of modified zeolite, 1 - 3% of foaming agent, and 1 - 5% of a mixture of Euglena, Chlorella, and Spirulina.

2. The composite porous phosphorus removal filter material according to claim 1, characterized in that The modified zeolite is obtained by soaking ordinary zeolite in an iron salt or aluminum salt solution, followed by drying and calcination.

3. The composite porous phosphorus-removing filter medium according to claim 2, characterized in that, The iron salt is ferric chloride (FeCl3), and the aluminum salt is aluminum chloride (AlCl3). The soaking concentration is 0.1 - 0.5 mol / L, the soaking time is 2 - 4 hours, the drying temperature is 100 - 120 °C, and the calcination temperature is 400 - 500 °C.

4. A composite porous phosphorus-removing filter medium according to claim 1, characterized in that, The particle size of the filter material is 50 - 200 mm, the porosity is ≥60%, the bulk density is 385 - 410 kg / m 3 , the dry density is 560 - 600 kg / m 3 , the specific surface area is 930 - 970 m 2 / g, the cylinder compressive strength is ≥4 MPa, the porosity is ≥75%, and the water absorption rate is ≥72%.

5. A composite porous phosphorus-removing filter medium according to claim 1, characterized in that, The foaming agent is one of sodium carbonate, sodium bicarbonate, ammonium carbonate, ammonium nitrite, sodium dodecyl sulfate, sodium lauroyl sarcosinate, and hydrolyzed sodium hydroxide.

6. The composite porous phosphorus-removing filter material according to claim 1, wherein The mass ratio of the mixture of Euglena, Chlorella, and Spirulina is 1:1:

1.

7. A preparation method of a composite porous phosphorus-removing filter material according to any one of claims 1 to 6, characterized in that, It includes the following steps: Pulping: Mix and stir limestone powder and water in a ratio of 100 - 500, and then add concrete powder and stir evenly. Foaming: Add a foaming agent to the slurry, stir for 1 - 2 hours, and then add hydroxyaluminum oxide. Coating: Add modified zeolite, perlite, and the mixture of Euglena, Chlorella, and Spirulina to the foamed slurry, stir, and then pump it into a coating machine. Solidifying: Pump the coated foamed mud into a solidifying pool for forming and solidifying. Crushing: Put the solidified composite porous hydroxyaluminum oxide into a crusher for crushing. Screening: Send the crushed filter material into a screening machine and screen it through a sieve with a pore size of 500 mm to obtain adsorption particles with a particle size less than 500 mm.

8. The preparation method according to claim 7, characterized in that In the solidifying step, the solidifying temperature is 50 - 80 °C, and the solidifying time is 12 - 24 hours.

9. Use of a composite porous phosphorus-removing filter medium according to any one of claims 1 to 6 in removing phosphorus from phosphorus-containing wastewater, characterized in that, The filter material is applicable to fields such as sewage treatment plants, lake restoration, and aquaculture.

10. Use of a composite porous phosphorus-removing filter medium according to any one of claims 1 to 6 in removing nitrogen and organic matter from water, characterized in that, The filter material synergistically removes nitrogen and organic matter in water through the biological adsorption of microalgae and the ion exchange of modified zeolite.

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