Multi-pollutant synergistic purification solid waste-based functional material and preparation method and application thereof

Abstract

The application discloses a kind of multi-pollutant synergic purification solid waste base functional materials and its preparation method and application, material raw material component is according to mass fraction, including dry powder 100 parts, water 35~50 parts and animal protein foaming agent 0.3~1.2 parts, dry powder includes fly ash, steel slag, dewatering municipal residual sludge and cement.The application uses three kinds of bulk industrial solid waste as core raw material, compound cement as cement base material, porous filter material is prepared by using animal protein foaming process combined with steam curing, can be adapted to three kinds of working condition scenes of organic pollution, fluorine phosphorus heavy metal composite pollution, filtration equipment, fly ash, steel slag, sludge, cement ratio is 3:1:3:3, 3:3:1:3 and 3:2:1:4 respectively.The application can realize multi-pollutant synergic purification, and mechanical strength is controllable, operation and maintenance cost is greatly reduced, simultaneously significantly improves solid waste resource efficiency, is widely applicable, low carbon and environmental protection.

Description

Technical Field

[0001] This invention belongs to the field of water pollution filter material technology, specifically relating to a multi-pollutant synergistic purification solid waste-based functional material, its preparation method, and its application. Background Technology

[0002] Currently, the two major industry challenges of large-scale industrial solid waste storage pressure and complex water pollution treatment are becoming increasingly prominent, and existing technical solutions have obvious shortcomings.

[0003] (I) Deficiencies in Traditional Disposal Pathways for Three Types of Bulk Solid Waste The thermal power industry continuously generates fly ash, steel slag (a byproduct of iron and steel smelting), and residual sludge from municipal wastewater treatment plants, which are the three largest categories of solid waste produced in China. Their resource utilization levels are generally low. 1. The comprehensive utilization rate of steel slag is less than 30%. A large amount of steel slag is stored in the open, occupying land resources. Free calcium and heavy metals inside the steel slag are leached into the soil and groundwater by rainwater, causing heavy metal and alkaline pollution. 2. The annual production of fly ash from thermal power plants is enormous, and the stockpile is increasing year by year. Traditional landfill disposal capacity is constantly strained, and simple stockpiling can easily lead to dust pollution. 3. Municipal waste sludge has a high water content and rich organic matter content, resulting in high costs for dewatering and stabilization. Landfilling poses a risk of leachate pollution, while incineration is energy-intensive and generates large carbon emissions.

[0004] Currently, the mainstream resource utilization products of the three types of solid waste are only low-end products such as roadbed filler, ordinary aerated building materials, and backfill soil. These products have extremely low added value and lack high-value and environmentally functional utilization pathways, making it impossible to achieve synergistic effects between solid waste disposal and pollution control.

[0005] (II) Existing water treatment filter media technology has multiple shortcomings. Domestic surface water and wastewater treatment plant effluent generally exhibit complex micro-pollution characteristics, with suspended solids, organic pollutants, nitrogen and phosphorus nutrients, fluoride ions, and heavy metal ions coexisting in the water. The water quality composition varies greatly, and the treatment conditions are complex. Existing water purification filter media are difficult to adapt to the differentiated treatment needs. 1. Traditional commercial filter media (quartz sand, columnar activated carbon) rely solely on physical interception or physical adsorption to purify water, resulting in limited functionality and an inability to simultaneously remove phosphorus, fluoride, and heavy metal ions. Activated carbon is expensive to produce and requires frequent replacement, leading to high water treatment operation and maintenance costs. Quartz sand lacks adsorption and ion exchange properties, resulting in extremely poor nitrogen and phosphorus removal effects.

[0006] 2. Existing publicly available solid waste-based water treatment filter media all use fixed raw material ratios, which cannot flexibly adjust the composition according to the type of water pollution. This has three major drawbacks: First, the sludge content is fixed, the organic carbon source content cannot be adjusted, the microbial biofilm effect is poor, and the ability to biodegrade organic pollutants and remove nitrogen is weak; Second, the steel slag ratio is constant, the calcium and silicon active sites on the filter media surface are insufficient, and the removal efficiency of heavy metals, fluoride and phosphorus is low; Third, the cement content is fixed, the mechanical strength cannot be adjusted as needed, and the filter media in high-strength filtration equipment has a high wear rate and short service life.

[0007] 3. Existing solid waste filter media have a single water purification mechanism, relying only on physical adsorption or simple sedimentation reaction. They lack a multi-synergistic system of physical interception, ion exchange, chemical precipitation, surface complexation, and biodegradation. Their ability to remove multiple pollutants simultaneously is limited, making it difficult to meet the needs of treating complex micro-polluted water bodies.

[0008] In summary, existing technologies cannot simultaneously address the three major industry pain points of high-value disposal of bulk solid waste, simultaneous purification of multiple pollutants, and flexible adaptation to various scenarios. There is an urgent need to develop a solid waste-based functional filter material that can be customized in proportion, synergistically purifies water through multiple mechanisms, and can dispose of fly ash, steel slag, and sludge on a large scale. Summary of the Invention

[0009] Technical problem solved: To address the above-mentioned technical problems, this invention provides a multi-pollutant synergistic purification solid waste-based functional material, its preparation method and application, which can achieve synergistic purification of multiple pollutants, with controllable mechanical strength, significantly reduced operation and maintenance costs, and significantly improved solid waste resource utilization efficiency. It has a wide range of applications and is low-carbon and environmentally friendly.

[0010] Technical solution: A multi-pollutant synergistic purification solid waste-based functional material, the raw material components of which, by mass, include: 100 parts dry powder, 35-50 parts water and 0.3-1.2 parts animal protein foaming agent, wherein the dry powder includes fly ash, steel slag, dewatered municipal waste sludge and cement.

[0011] The preparation method of the above-mentioned multi-pollutant synergistic purification solid waste-based functional material includes the following steps: S1. Raw material pretreatment: Fly ash, steel slag and dewatered municipal waste sludge are crushed and sieved respectively; S2. Material mixing: Weigh the pretreated fly ash, steel slag, dewatered municipal sludge and cement according to the pollution conditions to be treated, and put them into the mixing equipment to dry mix to obtain mixed dry powder; S3. Foaming and pulping: Add water and animal protein foaming agent to the mixed dry powder and stir to form a foaming slurry; S4. Molding and processing: Inject the foamed slurry into a granulation mold to make granular filter media, or cast it into a brick mold to form block filter bricks; S5. Steam curing: After the granular filter media or block filter bricks are left to stand for pre-curing, steam curing is carried out, and after natural cooling, the finished solid waste-based functional material is obtained.

[0012] Animal protein foaming agent is used to create pores. The foaming agent is stirred to generate uniform microbubbles. During the steam curing process of the green body, the bubbles solidify to form a hierarchical and interconnected porous structure. The pores are divided into macropores (water flow channels), mesopores (adsorption sites, biofilm attachment carriers), and micropores (ion exchange channels). The multi-level pore structure ensures mass transfer efficiency and pollutant contact area.

[0013] Multiple synergistic water purification mechanism system: (1) Physical interception: The porous skeleton of the filter media intercepts suspended solids and colloidal particles in the water, and quickly reduces the turbidity of the effluent; (2) Biodegradation: Sludge provides an organic carbon source, and microbial films are attached to the porous surface, which degrade COD, ammonia nitrogen and total nitrogen through nitrification and denitrification; (3) Ion exchange: Aluminosilicate crystals in fly ash and steel slag have cation exchange capacity, which can capture heavy metal cations such as lead, cadmium, copper and zinc in water. (4) Chemical precipitation: Calcium ions are dissolved from steel slag and react with phosphate and fluoride ions in water to form stable precipitates of calcium phosphate and calcium fluoride, thus fixing phosphorus and fluoride pollutants; (5) Surface complexation: Hydroxyl groups and active sites of metal oxides on the surface of the filter material form stable complexes with heavy metal ions to achieve long-term adsorption and fixation.

[0014] Preferably, the sieve mesh size in S1 is 100~200 mesh.

[0015] Preferably, the stirring time in S3 is 5~10 min.

[0016] Preferably, the particle size of the granular filter media in S4 is 3~10mm, the thickness of the block filter brick is 50~150mm, and the internal structure forms a connected porous structure.

[0017] Preferably, the pre-curing time in S5 is 2-4 hours; the steam curing temperature is 80-100℃ and the time is 12-24 hours.

[0018] The above-mentioned multi-pollutant synergistic purification solid waste-based functional materials are applicable to the following working conditions: organic polluted water bodies, composite polluted water bodies containing fluorine, phosphorus and heavy metals, and industrial filtration equipment.

[0019] Preferably, under the condition of organically polluted water bodies, the mass ratio of fly ash, steel slag, dewatered municipal waste sludge and cement is 3:1:3:3.

[0020] Preferably, under the condition of combined pollution of water bodies containing fluorine, phosphorus and heavy metals, the mass ratio of fly ash, steel slag, dewatered municipal waste sludge and cement is 3:3:1:3.

[0021] Preferably, under the operating conditions of industrial filtration equipment, the mass ratio of fly ash, steel slag, dewatered municipal waste sludge and cement is 3:2:1:4.

[0022] Beneficial effects: The present invention has the following effects: 1. Solid waste has significant resource utilization benefits, eliminating solid waste pollution at its source. This invention uses fly ash, steel slag, and municipal sludge as the main raw materials. These three types of solid waste account for a high proportion of the raw material system, which can be used for large-scale disposal and storage of solid waste, significantly reducing the demand for solid waste landfill capacity and eliminating secondary pollution of leachate, dust, soil, and groundwater caused by landfill. It transforms low-value-added solid waste into high-performance water treatment functional materials, significantly improving the economic value of solid waste resource products and realizing the transformation of solid waste disposal from "paid landfill" to "resource-based revenue generation".

[0023] 2. The formula can be flexibly customized, and the adaptability to various scenarios is fully covered. Existing solid waste filter media formulations are fixed and can only be adapted to a single water quality. This invention sets three sets of differentiated formulations to optimize performance for different operating conditions, namely organic pollution (river surface water, low-pollution effluent), fluoride, phosphorus and heavy metal pollution (industrial wastewater pretreatment, effluent with excessive heavy metals), and high-strength industrial filtration equipment (continuous flow filter, integrated wastewater treatment device). The organic pollution formulation has a high sludge content to increase the organic carbon source of the filter media, providing nutrition for microbial reproduction and enhancing the performance of biofilm denitrification and COD removal. The heavy metal fluoride and phosphorus formulation has a high steel slag content to provide a large number of calcium, magnesium and silicon active sites, which fix fluoride, phosphorus and heavy metal ions through ion exchange and surface complexation, thereby improving the ion exchange and precipitation removal capacity. The high-strength formulation has a high cement content to increase the strength of the filter media skeleton, reduce the water flow erosion wear rate, and extend the replacement cycle. It can be freely selected according to the project water quality and equipment type, and is suitable for all scenarios such as wastewater treatment plant effluent, river restoration, industrial wastewater, and constructed wetlands.

[0024] 3. Synergistic purification through multiple mechanisms, with strong ability to remove multiple pollutants simultaneously. Traditional filter media rely solely on adsorption or filtration, failing to simultaneously address complex pollutants. This invention, with its multi-level porous structure and synergistic effect of five water purification mechanisms, provides stable removal of suspended solids, organic pollutants, ammonia nitrogen, total phosphorus, fluoride, and heavy metals such as lead, cadmium, copper, and zinc. It produces effluent with minimal fluctuations in water quality, eliminates the need for layered packing of multiple filter media, simplifies water treatment infrastructure, and reduces equipment footprint.

[0025] 4. Controllable mechanical strength, significantly reducing operation and maintenance costs. A high-cement-content formula was developed for high-strength filtration equipment, resulting in high compressive strength of the filter media, low water flow erosion abrasion rate, and a 2-3 times longer filter media replacement cycle. All raw materials are industrial by-product solid waste, with procurement costs far lower than activated carbon and special modified adsorption filter media, reducing the amount of water treatment agents added and significantly lowering long-term operation and maintenance costs.

[0026] 5. Low-carbon and environmentally friendly, with green and low-carbon processes throughout the entire production and application process. The preparation process uses atmospheric pressure and low-temperature steam curing, eliminating the need for high-temperature calcination above 1000℃, resulting in low energy consumption and low carbon emissions. The core raw materials are fly ash, steel slag, and dewatered municipal sludge, while the cementitious substrate is ordinary silicate cement. The pore-forming agent is a commercially available animal protein foaming agent. All raw materials are free of high-cost chemical modifying reagents, are readily available, and have low costs. The animal protein foaming agent is a natural biological additive, free of toxic and harmful chemical additives. The filter media does not release toxic substances during use and can be recycled, crushed, and re-formulated after saturation and failure, achieving material recycling and eliminating the pressure of hazardous waste disposal. It has a triple benefit of ecology, environmental protection, and economy. Attached Figure Description

[0027] Figure 1 This is a completed image of the filter bricks; Figure 2 This is a cross-sectional view of the filter media. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] Example 1: Filter media suitable for organic slightly polluted water bodies (ratio 3:1:3:3) 1. Raw material pretreatment: Fly ash, steel slag, and dewatered municipal waste sludge are crushed separately and passed through a 120-mesh sieve to remove stones and large impurities; 2. Material weighing: Weigh 300kg of pretreated fly ash, 100kg of steel slag, 300kg of dewatered municipal sludge, and 300kg of ordinary Portland cement, totaling 1000kg of dry powder. Put them into a forced mixer and dry mix for 5 minutes until uniform. 3. Foaming and pulping: Add 420kg of clean water (42% of the total dry powder mass), add 6kg of animal protein foaming agent (0.6% of the dry powder mass), and stir continuously for 8 minutes to form a uniform foamed slurry with fine and interconnected air bubbles inside. 4. Molding: The slurry is fed into a ball granulator to form granular filter media preforms with a particle size of 5~8mm; 5. Pre-curing and steam curing: The green body is pre-cured at room temperature for 3 hours, then sent to a steam curing kiln and cured with steam at 90℃ and normal pressure for 18 hours. After natural cooling to room temperature, the finished granular filter material is obtained.

[0030] Performance testing: Filter media organic matter content 12.7%, porosity 62%, biofilm adhesion 1.86g / 100cm² 3 For river surface water with COD=65mg / L and ammonia nitrogen=8.2mg / L, the COD removal rate is 78.3%, the ammonia nitrogen removal rate is 86.1%, and the total phosphorus removal rate is 51.2%. It is suitable for the deep purification of slightly polluted river water and low-concentration sewage effluent.

[0031] Example 2: Filter media adapted for water bodies contaminated with fluoride, phosphorus, and heavy metals (ratio 3:3:1:3) 1. The raw material pretreatment is the same as in Example 1; 2. Material weighing: Weigh 300kg of fly ash, 300kg of steel slag, 100kg of dewatered municipal sludge, and 300kg of cement, for a total dry powder weight of 1000kg; 3. Foaming and pulping: 400 kg of clean water, 7 kg of animal protein foaming agent, stir for 7 minutes to foam; 4. Molding: Casting molds to produce 80mm thick block filter brick blanks; 5. Curing: Pre-curing for 2.5 hours, steam curing at 95℃ for 20 hours, and then cooling the finished product.

[0032] Performance testing: The filter media has a high content of calcium and magnesium active sites, a phosphorus saturation adsorption capacity of 28.6 mg / g, a fluoride ion removal rate of 92.4%, and lead and cadmium heavy metal removal rates of over 95%. It is suitable for the pretreatment of industrial wastewater containing 5 mg / L phosphorus, 3 mg / L fluoride, and 0.5 mg / L heavy metals, and can simultaneously and stably remove fluoride, phosphorus, and heavy metals. It is applicable to electroplating and chemical wastewater pretreatment processes.

[0033] Example 3: Filter media adapted for high mechanical strength wastewater treatment devices (ratio 3:2:1:4) 1. The raw material pretreatment is the same as in Example 1; 2. Material weighing: Weigh 300kg of fly ash, 200kg of steel slag, 100kg of dewatered municipal sludge, and 400kg of cement, for a total dry powder weight of 1000kg; 3. Foaming and pulping: 380kg water, 5kg foaming agent, stir for 6 minutes to foam; 4. Molding: Granulation to prepare 6~10mm high-strength granular filter media; 5. Curing: Pre-curing for 4 hours, steam curing at 100℃ for 24 hours, and then cooling the finished product.

[0034] Performance testing: The filter media has a compressive strength of ≥6.2MPa, an abrasion rate of only 1.1%, and shows no significant breakage after 6 months of continuous water flow scouring; it is suitable for high-speed integrated filtration equipment and continuous flow biological filter beds, and the filter media replacement cycle is extended to more than 24 months.

[0035] Comparative Example 1: Commercial Quartz Sand Filter Media Conventional 5mm quartz sand relies solely on physical interception and lacks adsorption and ion exchange capabilities; its COD removal rate is only 22%, its ammonia nitrogen removal rate is less than 15%, and it has almost no effect on removing fluoride, phosphorus, and heavy metals. Although it has high mechanical strength, its water purification function is singular and it cannot treat complex micro-polluted water bodies.

[0036] Comparative Example 2: Fixed ratio of ordinary solid waste filter media The ratio of fly ash:steel slag:sludge:cement is fixed at 2:2:2:2 and cannot be adjusted; the sludge content is moderate, and the biofilm formation rate is only 0.72g / 100cm². 3 The removal of organic pollutants is poor; the steel slag content is insufficient, and the phosphorus and fluoride removal rate is less than 60%; the cement content is too low, and the wear rate is 4.8%. It is prone to pulverization and failure in high-strength equipment and cannot be adapted to various water quality conditions.

[0037] Implementation Results Comparison Summary The three sets of embodiments can precisely adjust the material performance according to the characteristics of water pollution. The five types of water purification mechanisms work together to achieve a far superior efficiency in the simultaneous removal of organic pollutants, nitrogen, phosphorus, fluoride, and heavy metals compared to traditional quartz sand and fixed-ratio solid waste filter media. At the same time, it can dispose of three types of industrial solid waste on a large scale. The production process is simple, energy consumption is low, and the product form is flexible. It can comprehensively cover various water treatment scenarios such as surface water remediation, sewage treatment plant effluent, industrial wastewater, and constructed wetlands, and has multiple values ​​of environmental protection, economy, and resource utilization.

Claims

1. A multi-pollutant synergistic purification solid waste-based functional material, characterized in that, Its raw material components, by mass, include: 100 parts dry powder, 35-50 parts water, and 0.3-1.2 parts animal protein foaming agent, wherein the dry powder includes fly ash, steel slag, dewatered municipal waste sludge, and cement.

2. The preparation method of the multi-pollutant synergistic purification solid waste-based functional material according to claim 1, characterized in that, Includes the following steps: S1. Raw material pretreatment: Fly ash, steel slag and dewatered municipal waste sludge are crushed and sieved respectively; S2. Material mixing: Weigh the pretreated fly ash, steel slag, dewatered municipal sludge and cement according to the pollution conditions to be treated, and put them into the mixing equipment to dry mix to obtain mixed dry powder; S3. Foaming and pulping: Add water and animal protein foaming agent to the mixed dry powder and stir to form a foaming slurry; S4. Molding and processing: Inject the foamed slurry into a granulation mold to make granular filter media, or cast it into a brick mold to form block filter bricks; S5. Steam curing: After the granular filter media or block filter bricks are left to stand for pre-curing, steam curing is carried out, and after natural cooling, the finished solid waste-based functional material is obtained.

3. The preparation method of the multi-pollutant synergistic purification solid waste-based functional material according to claim 2, characterized in that, The sieve mesh size in S1 is 100~200 mesh.

4. The preparation method of the multi-pollutant synergistic purification solid waste-based functional material according to claim 2, characterized in that, The stirring time in S3 is 5~10 minutes.

5. The preparation method of the multi-pollutant synergistic purification solid waste-based functional material according to claim 2, characterized in that, The particle size of the granular filter media in S4 is 3~10mm, and the thickness of the block filter bricks is 50~150mm, forming a connected porous structure inside.

6. The preparation method of the multi-pollutant synergistic purification solid waste-based functional material according to claim 2, characterized in that, The pre-curing time in S5 is 2-4 hours; the steam curing temperature is 80-100℃ and the time is 12-24 hours.

7. The application of the multi-pollutant synergistic purification solid waste-based functional material according to claim 1 in the field of water treatment, characterized in that, The application is applicable to the following working conditions: organic polluted water, water with complex pollution containing fluorine, phosphorus and heavy metals, and industrial filtration equipment.

8. The application of the multi-pollutant synergistic purification solid waste-based functional material according to claim 7 in the field of water treatment, characterized in that, Under conditions of organically polluted water bodies, the mass ratio of fly ash, steel slag, dewatered municipal waste sludge, and cement is 3:1:3:

3.

9. The application of the multi-pollutant synergistic purification solid waste-based functional material according to claim 7 in the field of water treatment, characterized in that, Under conditions of combined pollution of water bodies containing fluorine, phosphorus, and heavy metals, the mass ratio of fly ash, steel slag, dewatered municipal waste sludge, and cement is 3:3:1:

3.

10. The application of the multi-pollutant synergistic purification solid waste-based functional material according to claim 7 in the field of water treatment, characterized in that, Under industrial filtration equipment operating conditions, the mass ratio of fly ash, steel slag, dewatered municipal waste sludge, and cement is 3:2:1:4.

Images