A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof

Abstract

The present invention discloses a high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof. The filler comprises the following components, by mass percentage: 20-40% clay mineral, 15-25% modified zeolite, 15-25% steelmaking slag, 10-15% limestone, 5-10% fly ash, 8-14% ethyl cellulose, and 3-8% swelling additive. The particle size of the clay mineral and limestone is ≤0.2 mm, and the particle size of the modified zeolite and steelmaking slag is ≤1 mm. The artificial wetland filler obtained by the present method has high mechanical strength and porosity, and has a higher adsorption capacity for ammonia nitrogen and phosphorus in wastewater. The treated water contains less ammonia nitrogen, total phosphorus, and suspended solids, resulting in better water quality, facilitating the use of artificial wetlands for domestic water restoration.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological environment water purification, and in particular to a high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof. Background Art

[0002] Constructed wetlands, a new remediation technology for polluted water bodies, create a wetland ecosystem through artificial simulation. They primarily utilize the organic integration of physical, chemical, and biological processes within a complex ecosystem of filler matrix, aquatic or marsh-dwelling plants, and microorganisms that grow within the filler matrix to purify wastewater. The filler is the carrier of the constructed wetland, providing a habitat and nutrients for the growth and reproduction of plants and microorganisms, and playing a crucial role in remediating polluted water bodies. However, the types of fillers currently used as matrix for constructed wetlands are limited, with searches currently finding the following:

[0003] CN114031184A discloses an artificial wetland matrix and system. The matrix primarily utilizes 34-49% steel slag, 49-64% lignite, and 2% activated sludge. The matrix utilizes the combined properties of steel slag and lignite, which have strong denitrification and phosphorus removal capabilities and carbon sequestration. The matrix contains a high proportion of steel slag and lignite, resulting in high demand and high costs. Lignite, which accounts for the largest proportion, has a high moisture content and a relatively low ability to retain wastewater. Furthermore, lignite has a small specific surface area, which reduces the opportunity for humic acids in the lignite to react with wastewater.

[0004] CN115093031A discloses a wetland matrix preparation method and constructed wetland system. The constructed wetland matrix uses volcanic rock or zeolite, which undergoes a series of reactions to produce a porous granular material loaded with MnO2. Volcanic rock or zeolite is a porous granular material, and soaking it in hydrochloric acid solution can easily cause some pores to absorb the hydrochloric acid, which then does not react with manganese, causing secondary water pollution.

[0005] The information disclosed in this background section is only intended to enhance understanding of the overall background of the invention and should not be considered as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the Invention

[0006] The purpose of the present invention is to provide a high-strength, lightweight, porous adsorption filler for artificial wetlands. The selection of filler composition and particle size promotes the obtained filler to absorb phosphorus, nitrogen and dim in sewage, thereby improving the ability of artificial wetlands to repair sewage.

[0007] At the same time, the present invention also provides a method for preparing high-strength, lightweight, porous adsorption filler for artificial wetlands. The selection of heating rate, calcination temperature, and calcination time during the preparation process increases the mechanical strength of the filler, improves the porosity, and reduces the weight of the filler, ultimately obtaining a high-strength, lightweight, porous adsorption filler.

[0008] To achieve the above-mentioned objectives, the present invention provides a high-strength, lightweight, porous adsorption filler for artificial wetlands, characterized in that, by mass percentage, the high-strength, lightweight, porous adsorption filler for artificial wetlands is composed of the following components: 20-40% clay minerals, 15-25% modified zeolite, 15-25% steelmaking slag, 10-15% limestone, 5-10% fly ash, 8-14% ethyl cellulose and 3-8% expansion additives; wherein the particle size of the clay minerals and limestone is ≤0.2mm; and the crushed particle size of the modified zeolite and steelmaking slag is ≤1mm.

[0009] Preferably, in the above technical solution, the clay mineral is one or a mixture of sepiolite, palygorskite, illite or kaolinite; further, the clay mineral is palygorskite.

[0010] Preferably, in the above technical solution, the modified zeolite is calcined at 300-350°C for 2-2.5h, and then ground into a material with a particle size of ≤1mm after calcination. The material with a particle size of ≤1mm is put into a 0.5mol / L CaCl2 modification solution and heated in a water bath at 75°C for 30min to obtain the obtained material.

[0011] Preferably, in the above technical solution, the expansion additive is alunite, calcium sulfoaluminate or modified ettringite, or a mixture of several thereof; further, the expansion additive is modified ettringite.

[0012] Preferably, in the above technical solution, the modified ettringite is calcined at 300-400° C. for 8-10 h, and then ground after calcination to obtain a material with a particle size of ≤0.1 mm.

[0013] To achieve the above object, the present invention also provides a method for preparing a high-strength, lightweight, porous adsorption filler for artificial wetlands, which is characterized by comprising the following steps:

[0014] (1) mixing 20-40% of clay mineral, 15-25% of modified zeolite, 15-25% of steelmaking slag, 10-15% of limestone, and 5-10% of fly ash and stirring the mixture to obtain an aggregate of a high-strength, lightweight, porous adsorption filler for a constructed wetland;

[0015] (2) adding 8-14% ethyl cellulose and 3-8% swelling additive to the aggregate, stirring evenly, adding clean water, stirring and reacting until no swelling occurs, and then kneading to obtain a raw material;

[0016] (3) Calcine the mixed material embryo, heat the calcination furnace to 300-470°C at a heating rate of 5-10°C / h, keep the temperature for 1.5-3.5h, then heat the calcination furnace to 800-950°C at a heating rate of 8-15°C / h, keep the temperature for 4.5-6.5h, calcine and cool, and then take it out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0017] Preferably, in the above technical solution, the mixed material embryo is made into a spherical shape with a particle size of ≤5-25mm.

[0018] Preferably, in the above technical solution, the calcination process is to calcine the mixed material green embryo, heat the calcination furnace to 300-460°C at a heating rate of 6-8°C / h, keep warm for 2-3h, then heat the calcination furnace to 850-900°C at a heating rate of 10-12°C / h, keep warm for 5-6h, calcine and cool, and then take it out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The mechanism of the selected filler components in improving the adsorption of artificial wetland fillers is as follows: First, after high temperature and CaCl2 treatment, the mechanical strength and adsorption of the modified zeolite are enhanced, the internal bound water escapes to form a loose and porous sponge-like structure, the internal surface area is increased, and Ca-type zeolite is formed on the surface, which improves the adsorption capacity of cations. At the same time, the charge of one oxygen atom in the aluminum oxide tetrahedron in the modified zeolite is not neutralized by the trivalent oxygen atom, resulting in charge imbalance, making the aluminum oxide tetrahedron negatively charged, and the ion exchange and adsorption of the modified zeolite increased; secondly, fly ash contains rich oxides such as SiO2, Al2O3, FeO, Fe2O3, CaO, TiO2, etc., which can remove the dullness in sewage, and some metal elements can react with phosphorus and nitrogen in sewage to form precipitates, thereby achieving the purpose of repairing domestic sewage; thirdly, steelmaking slag contains Ca 2+ Mg 2+ 、Mn 2+ Elements such as phosphorus have good absorption properties for wastewater; finally, palygorskite crystals are two-dimensional continuous silicon-oxygen tetrahedral sheets, and are rich in MgO, SiO2, and Al2O3. They have a large specific surface area and adsorption capacity, good rheological properties, and catalytic properties.

[0021] (2) The filler preparation method improves the adsorption, high strength and lightness of artificial wetland fillers. The principles are as follows: First, the selection of heating rate, calcination temperature and reaction time allows the nano-particle material to react fully and form a densely distributed and directional arranged network structure, thereby improving the filler strength; second, the selection of calcination temperature and reaction time allows the impurity gas and chemically bound water inside the filler to escape fully, thereby increasing the number of pores in the filler and increasing the porosity, reducing the filler weight; finally, the mixed material embryo is made into a sphere with a particle size of ≤5-18mm. This particle size selection and spherical filler are more conducive to the permeability of sewage. The combination of sphericity and porosity can improve the overall uniform force of the filler when the filler is under pressure in water, thereby enhancing the mechanical strength of the filler. DETAILED DESCRIPTION

[0022] The specific implementation methods of the present invention are described in detail below in conjunction with specific embodiments, but it should be understood that the protection scope of the present invention is not limited by the specific implementation methods.

[0023] Example 1

[0024] A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof, comprising the following steps:

[0025] (1) Weigh 30 g of palygorskite, 19 g of modified zeolite, 19 g of steelmaking slag, 10 g of limestone, and 8 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0026] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0027] The modified zeolite is calcined at 350° C. for 2 hours, then ground into a material with a particle size of ≤1 mm, and the material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75° C. for 30 minutes to obtain;

[0028] (2) Weighing 9g of ethyl cellulose and 5g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 15mm; wherein,

[0029] The modified ettringite is calcined at 300°C for 8 hours and then ground to obtain a material with a particle size of ≤0.1 mm;

[0030] (3) The mixed material embryo is heated in a calcining furnace to 300°C at a heating rate of 7°C / h, kept warm for 3 hours, and then heated to 900°C in the calcining furnace at a heating rate of 11°C / h, kept warm for 6 hours. After calcination and cooling, it is taken out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0031] Example 2

[0032] A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof, comprising the following steps:

[0033] (1) Weigh 40 g of palygorskite, 15 g of modified zeolite, 15 g of steelmaking slag, 10 g of limestone, and 5 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0034] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0035] The modified zeolite is calcined at 300°C for 2.5 hours, ground into a material with a particle size of ≤1 mm, and then placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75°C for 30 minutes to obtain a modified zeolite.

[0036] (2) Weighing 12g of ethyl cellulose and 3g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 18mm; wherein,

[0037] The modified ettringite is calcined at 400°C for 8 hours and then ground to obtain a material with a particle size of ≤0.1 mm;

[0038] (3) The mixed material embryo is heated in a calcining furnace to 460°C at a heating rate of 8°C / h, kept warm for 2 hours, and then heated to 850°C in the calcining furnace at a heating rate of 10°C / h, kept warm for 5 hours. After calcination and cooling, it is taken out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0039] Example 3

[0040] A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof, comprising the following steps:

[0041] (1) Weigh 20 g of palygorskite, 15 g of modified zeolite, 25 g of steelmaking slag, 15 g of limestone, and 5 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0042] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0043] The modified zeolite is calcined at 300°C for 2.5 hours, then ground into a material with a particle size of ≤1 mm, and the material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75°C for 30 minutes to obtain;

[0044] (2) Weighing 14g of ethyl cellulose and 6g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 5mm; wherein,

[0045] The modified ettringite is calcined at 350° C. for 10 hours and then ground to obtain a material with a particle size of ≤0.1 mm;

[0046] (3) The mixed material embryo is heated in a calcining furnace to 400°C at a heating rate of 6°C / h, kept warm for 2.5 hours, and then heated to 900°C in the calcining furnace at a heating rate of 12°C / h, kept warm for 5.5 hours. After calcination and cooling, it is taken out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0047] Example 4

[0048] A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof, comprising the following steps:

[0049] (1) Weigh 20 g of palygorskite, 25 g of modified zeolite, 15 g of steelmaking slag, 13 g of limestone, and 7 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0050] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0051] The modified zeolite is calcined at 350° C. for 2.5 hours, then ground into a material with a particle size of ≤1 mm, and the material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75° C. for 30 minutes to obtain a modified zeolite.

[0052] (2) Weighing 12g of ethyl cellulose and 8g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 10mm; wherein,

[0053] The modified ettringite is calcined at 300°C for 10 hours and then ground to obtain a material with a particle size of ≤0.1 mm;

[0054] (3) The mixed material embryo is heated in a calcining furnace to 470°C at a heating rate of 5°C / h, kept warm for 1.5 hours, and then heated to 950°C in the calcining furnace at a heating rate of 8°C / h, kept warm for 4.5 hours. After calcination and cooling, it is taken out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0055] Example 5

[0056] A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof, comprising the following steps:

[0057] (1) Weigh 25g of palygorskite, 20g of modified zeolite, 15g of steelmaking slag, 10g of limestone and 10g of fly ash, mix them and stir them evenly to use as aggregate for high-strength, lightweight, porous adsorption filler for constructed wetlands; wherein,

[0058] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0059] The modified zeolite is calcined at 300°C for 2 hours, then ground into a material with a particle size of ≤1 mm, and the material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75°C for 30 minutes to obtain;

[0060] (2) Weighing 12g of ethyl cellulose and 8g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 15mm; wherein,

[0061] The modified ettringite is calcined at 400°C for 8 hours and then ground to obtain a material with a particle size of ≤0.1 mm;

[0062] (3) The mixed material embryo was heated in a calcining furnace to 350°C at a heating rate of 10°C / h, kept warm for 3.5 hours, and then heated to 850°C in the calcining furnace at a heating rate of 15°C / h, kept warm for 6.5 hours. After calcination and cooling, it was taken out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0063] Comparative Example 1

[0064] The method is basically the same as Example 1, except that the components used to prepare the high-strength, lightweight, porous adsorption filler for artificial wetlands are different. A high-strength, lightweight, porous adsorption filler for artificial wetlands and a method for preparing the same include the following steps:

[0065] (1) Weigh 30 g of palygorskite, 19 g of zeolite, 19 g of steelmaking slag, 10 g of limestone, and 8 g of fly ash, mix them, and stir them evenly to use as aggregate for the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0066] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of zeolite and steelmaking slag is ≤1mm;

[0067] (2) Weigh 9 g of ethyl cellulose and 5 g of ettringite, add them to the aggregate, mix and stir evenly, then add clean water and stir until the ethyl cellulose and ettringite react with the aggregate until they no longer expand, and then knead them into a mixed material green body with a particle size of 15 mm.

[0068] Comparative Example 2

[0069] The method is basically the same as Example 1, except that the method for obtaining the components for preparing the high-strength, lightweight, porous adsorption filler for artificial wetlands is different. A high-strength, lightweight, porous adsorption filler for artificial wetlands and a method for preparing the same include the following steps:

[0070] (1) Weigh 30 g of kaolinite, 19 g of modified zeolite, 19 g of steelmaking slag, 10 g of limestone, and 8 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0071] The particle size of kaolinite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0072] The modified zeolite was calcined at 580°C for 2 h, cooled after calcination, and then placed in a 1 mol / L CaCl2 modification solution and heated in a water bath at 75°C for 30 min.

[0073] (2) Weighing 9g of ethyl cellulose and 5g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 15mm; wherein,

[0074] The modified ettringite is calcined at 200° C. for 8 hours and then ground to obtain a material with a particle size of ≤0.1 mm.

[0075] Comparative Example 3

[0076] The method is basically the same as Example 1, except that the components used to prepare the high-strength, lightweight, porous adsorption filler for artificial wetlands are different. A high-strength, lightweight, porous adsorption filler for artificial wetlands and a method for preparing the same include the following steps:

[0077] (1) Weigh 30 g of palygorskite, 19 g of modified zeolite, 19 g of steelmaking slag, 10 g of limestone, and 8 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0078] The particle size of palygorskite and limestone is ≤0.2mm, and the particle size of modified zeolite and steelmaking slag is ≤1mm;

[0079] The modified zeolite is calcined at 350° C. for 2 hours, then ground into a material with a particle size of ≤1 mm, and the material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75° C. for 30 minutes to obtain;

[0080] (2) Weighing 14 g of modified ettringite and adding it to the aggregate, stirring evenly, then adding clean water and stirring, allowing the ethyl cellulose and modified ettringite to react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 15 mm; wherein,

[0081] The modified ettringite is calcined at 300° C. for 8 hours and then ground to obtain a material with a particle size of ≤0.1 mm.

[0082] Comparative Example 4

[0083] The method is basically the same as Example 1, except that the components used to prepare the high-strength, lightweight, porous adsorption filler for artificial wetlands are different. A high-strength, lightweight, porous adsorption filler for artificial wetlands and a method for preparing the same include the following steps:

[0084] (1) Weigh 38g of steelmaking slag and 48g of fly ash, mix them and stir them evenly to use as aggregate for the high-strength, lightweight, porous adsorption filler of the constructed wetland; wherein the particle size of the steelmaking slag is ≤1mm;

[0085] (2) Weighing 9g of ethyl cellulose and 5g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 15mm; wherein,

[0086] The modified ettringite is calcined at 300°C for 8 hours and then ground to obtain a material with a particle size of ≤0.1 mm;

[0087] Comparative Example 5

[0088] The method is basically the same as Example 1, except that the particle size requirements for the components used to prepare the high-strength, lightweight, porous adsorption filler for artificial wetlands are different. A high-strength, lightweight, porous adsorption filler for artificial wetlands and a method for preparing the same include the following steps:

[0089] (1) Weigh 30 g of palygorskite, 19 g of modified zeolite, 19 g of steelmaking slag, 10 g of limestone, and 8 g of fly ash, mix them and stir them evenly to use as the aggregate of the high-strength, lightweight, porous adsorption filler for the constructed wetland;

[0090] The particle size of palygorskite and limestone is ≤1mm, and the particle size of modified zeolite and steelmaking slag is ≤5mm;

[0091] The modified zeolite is calcined at 350°C for 2 hours, then ground into a material with a particle size of ≤5 mm, and the material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75°C for 30 minutes to obtain;

[0092] (2) Weighing 9g of ethyl cellulose and 5g of modified ettringite, adding them to the aggregate, stirring evenly, and then adding clean water and stirring, so that the ethyl cellulose and modified ettringite react with the aggregate until they no longer expand, and then kneading them into a mixed material with a particle size of 15mm; wherein,

[0093] The modified ettringite is calcined at 300° C. for 8 hours and then ground to obtain a material with a particle size of ≤3 mm.

[0094] Comparative Example 6

[0095] The method is basically the same as Example 1, except that the calcination method is different. A high-strength, lightweight, porous adsorption filler for artificial wetlands and a preparation method thereof include the following steps:

[0096] (1) The mixed material embryo was heated in a calcining furnace to 900°C at a heating rate of 16°C / h, kept warm for 3 hours, and then heated to 300°C in the calcining furnace at a heating rate of 11°C / h, kept warm for 6 hours. After calcination and cooling, the embryo was taken out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

[0097] The porosity and mechanical strength of the artificial wetland fillers obtained by the above method were tested respectively. At the same time, the obtained fillers were applied to the vertical flow artificial wetland simulated sewage treatment system. During the 48h simulation test, sampling and detection of ammonia nitrogen, total phosphorus and suspended solids were carried out at two time points of 12h and 48h, and the average values ​​were taken. The color of the water was also observed. Among them, the porosity was measured by the simple compression strength of GB / T17431.1-2010; the ammonia nitrogen, total phosphorus and suspended solids were measured by the test method of GB18918-2002. By testing the ammonia nitrogen and phosphorus contents before and after sewage treatment, the ammonia nitrogen adsorption rate and phosphorus adsorption rate of the filler were calculated. The results are shown in Tables 1 and 2.

[0098] Table 1 Ammonia nitrogen, total phosphorus and suspended solids in water obtained after simulated sewage treatment by each group of fillers

[0099] Test items Ammonia nitrogen (mg / L) Total phosphorus (mg / L) Suspended solids (mg / L) Example 1 16.5 0.67 12.3 Example 2 16.6 0.73 12.1 Example 3 16.2 0.65 12.6 Example 4 16.4 0.63 12.3 Example 5 16.3 0.68 12.3 Comparative Example 1 21.6 1.23 14.6 Comparative Example 2 17.4 0.73 13.3 Comparative Example 3 16.9 0.76 13.4 Comparative Example 4 23.5 1.34 14.4 Comparative Example 5 17.1 0.73 13.6 Comparative Example 6 23.4 1.37 14.3

[0100] Table 2 Mechanical strength, ammonia nitrogen adsorption rate, phosphorus adsorption rate, and porosity of the fillers obtained in each group

[0101]

[0102]

[0103] The results are shown in Tables 1 and 2 above. The method of the present invention selects modified zeolite and modified ettringite as filler component materials to obtain Example 1 of a high-strength, lightweight, porous adsorption filler for artificial wetlands. Compared with Comparative Example 1, the filler has many pores, greater strength, and better adsorption performance for ammonia nitrogen and phosphorus. The method of the present invention obtains Example 1 of a high-strength, lightweight, porous adsorption filler for artificial wetlands by adding ethyl cellulose to the components. Compared with Comparative Example 3, the filler strength is greater. The method of the present invention obtains Example 1 of a high-strength, lightweight, porous adsorption filler for artificial wetlands by adjusting the input ratio of each material and the preparation method. Compared with Comparative Examples 5 and 6, the filler has many pores, greater strength, and better adsorption performance for ammonia nitrogen and phosphorus. By comparing Example 1 with the comparative examples above, it is shown that the filler obtained by the method of the present invention has better adsorption performance and mechanical strength.

[0104] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A high-strength, lightweight, porous adsorption filler for artificial wetlands, characterized in that: The artificial wetland high-strength lightweight porous adsorption filler is composed of the following components by mass percentage: 20-40% clay minerals, 15-25% modified zeolite, 15-25% steelmaking slag, 10-15% limestone, 5-10% fly ash, 8-14% ethyl cellulose and 3-8% expansion additives; wherein, The particle size of the clay mineral and limestone is ≤0.2mm; The particle size of the modified zeolite and steelmaking slag is ≤1mm; The modified zeolite is calcined at 300-350° C. for 2-2.5 hours, and then ground into a material with a particle size of ≤1 mm. The material with a particle size of ≤1 mm is placed in a 0.5 mol / L CaCl2 modification solution and heated in a water bath at 75° C. for 30 minutes to obtain the modified zeolite; The expansion additive is modified ettringite, which is calcined at 300-400° C. for 8-10 hours and then ground to obtain a material with a particle size of ≤0.1 mm.

2. The high-strength, lightweight, porous adsorption filler for artificial wetlands according to claim 1, characterized in that: The clay mineral is one or a mixture of sepiolite, palygorskite, illite or kaolinite.

3. The high-strength, lightweight, porous adsorption filler for artificial wetlands according to claim 2, characterized in that: The clay mineral is palygorskite.

4. The method for preparing the high-strength, lightweight, porous adsorption filler for artificial wetlands according to any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Mixing 20-40% of clay mineral, 15-25% of modified zeolite, 15-25% of steelmaking slag, 10-15% of limestone, and 5-10% of fly ash and stirring the mixture to obtain an aggregate of a high-strength, lightweight, porous adsorption filler for a constructed wetland; (2) adding 8-14% ethyl cellulose and 3-8% expansion additive to the aggregate, mixing and stirring evenly, then adding clean water, stirring and reacting until the aggregate does not expand, and then kneading to obtain a raw material; (3) calcining the mixed material green body, wherein the calcination process is to heat the calcination furnace to 300-470°C at a heating rate of 5-10°C / h, keep the temperature for 1.5-3.5h, then heat the calcination furnace to 800-950°C at a heating rate of 8-15°C / h, keep the temperature for 4.5-6.5h, calcine and cool, and then take out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

5. The method for preparing the high-strength, lightweight, porous adsorption filler for artificial wetlands according to claim 4, characterized in that: The calcination process comprises calcining the mixed material green body, heating the calcination furnace to 300-460° C. at a heating rate of 6-8° C. / h, keeping the temperature for 2-3 hours, then heating the calcination furnace to 850-900° C. at a heating rate of 10-12° C. / h, keeping the temperature for 5-6 hours, calcining and cooling, and then taking the mixed material out of the furnace to obtain a high-strength, lightweight, porous adsorption filler for artificial wetlands.

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