Method for preparing adsorption catalytic composite materials by synergistically utilizing waste incineration fly ash and printing and dyeing sludge, and its products and applications

Abstract

The present invention discloses a method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge, as well as its products and applications. The preparation process of the present invention is simple, and the main raw materials required are waste incineration fly ash and printing and dyeing sludge, which can achieve full resource utilization of waste incineration fly ash and printing and dyeing sludge. The adsorption catalytic composite material prepared by the present invention through secondary pyrolysis has both catalytic and adsorption properties, and the maximum adsorption capacity of COD, heavy metals, ammonia nitrogen and total phosphorus is 1563mg / g, 102mg / g, 257mg / g and 186mg / g, respectively. After superimposing the catalytic function, the converted maximum COD, heavy metals, ammonia nitrogen and total phosphorus adsorption capacity are 2985mg / g, 287mg / g, 443mg / g and 324mg / g, respectively.

Description

Technical Field

[0001] The present invention belongs to the field of hazardous waste resource utilization, and specifically relates to a method for preparing an adsorption catalytic composite material by collaboratively utilizing waste incineration fly ash and printing and dyeing sludge, as well as its products and applications. Background Art

[0002] Waste incineration fly ash is a fine particle produced during the incineration of municipal solid waste. It contains large amounts of heavy metals (such as lead, cadmium, mercury, and chromium), dioxins, and other toxic and hazardous substances. If this fly ash is directly landfilled or piled without effective treatment, the heavy metals and organic pollutants will gradually migrate into the soil and water under natural conditions, causing long-term and irreversible environmental pollution. Currently, common methods for treating incineration fly ash include cement solidification, chemical stabilization, and melt treatment. However, these methods often suffer from high processing costs, waste of resources, and the risk of secondary pollution. For example, the cement solidification process requires the addition of large amounts of cement and other curing agents, which increases processing costs and volume, and also poses risks to the long-term stability of the solidified product. Melt treatment requires extremely high equipment requirements, consumes a lot of energy, and the resulting vitreous body is difficult to further utilize.

[0003] Printing and dyeing sludge is waste generated during the textile printing and dyeing process. It primarily contains large amounts of organic matter, heavy metal ions, and pathogens. Currently, the main treatment methods for printing and dyeing sludge include landfilling, incineration, and composting. However, landfilling consumes significant land resources and poses the risk of leachate contamination; incineration requires significant energy consumption and may produce harmful gas emissions; and composting, due to the complex organic matter and high heavy metal content in printing and dyeing sludge, is difficult to effectively utilize as fertilizer.

[0004] In the context of resource recycling and sustainable development, the synergistic utilization of waste incineration fly ash and printing and dyeing sludge to prepare high-value-added adsorption-catalytic composite materials not only effectively addresses the disposal challenges of these two hazardous wastes but also fosters the development of novel environmental remediation materials, effectively transforming waste into valuable resources. Traditional adsorbents and catalytic materials often suffer from high costs, raw material scarcity, or complex preparation processes, limiting their application in large-scale environmental remediation projects. However, the diverse components found in waste incineration fly ash and printing and dyeing sludge, such as minerals like silicon, aluminum, and calcium in fly ash and organic matter and some metal ions in printing and dyeing sludge, provide a rich raw material base for the preparation of high-performance adsorption-catalytic composite materials. Through rational process design, the active components of these two wastes can be synergistically integrated into the composite. Minerals in fly ash are used to construct an adsorption matrix with a high specific surface area and a specialized pore structure. Furthermore, organic matter and metal ions in printing and dyeing sludge are modified or loaded onto the matrix, endowing the composite with efficient adsorption and catalytic activity, enabling the simultaneous removal and degradation of multiple pollutants, including dyes and heavy metal ions, from wastewater. This will not only help reduce environmental governance costs, but also promote the solid waste treatment industry to develop in the direction of resource utilization, harmlessness and efficiency, with significant social, environmental and economic benefits. It is imperative to develop this method. Summary of the Invention

[0005] Purpose of the invention: The technical problem to be solved by the present invention is to provide a method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge.

[0006] The technical problem that the present invention also aims to solve is to provide an adsorption catalytic composite material prepared by the method.

[0007] The final technical problem to be solved by the present invention is to provide an application of the adsorption catalytic composite material in the treatment of landfill leachate.

[0008] Technical solution: In order to solve the above technical problems, the present invention provides a method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge, comprising the following steps:

[0009] (1) Mixing printing and dyeing sludge and waste incineration fly ash, and stirring them evenly to obtain fly ash printing and dyeing mud;

[0010] (2) Pyrolyzing fly ash printing and dyeing mud, recovering the flue gas generated by pyrolysis, and obtaining carbonized slag and flue gas dust;

[0011] (3) Grinding the carbonized slag into powder to obtain carbonized powder;

[0012] (4) Mixing water and carbonized powder and stirring, separating the solid and liquid to obtain the desalted carbonized mud;

[0013] (5) Mixing flue gas dust, alkali salt and desalted carbonized mud, and stirring evenly to obtain metal-loaded carbonized mixed mud;

[0014] (6) Mixing water and metal-supported carbonized mixed mud, stirring for 2 to 6 hours, separating the solid and liquid to obtain a solid, and drying the separated solid to obtain a secondary pre-baked material;

[0015] (7) The secondary pre-baked material is pyrolyzed to obtain an adsorption catalytic composite material.

[0016] Wherein, the mass ratio of the mixed printing and dyeing sludge and waste incineration fly ash in step (1) is 40~80:100.

[0017] Wherein, the pyrolysis temperature in step (2) is 550-850°C, and the pyrolysis time is 0.5-3.5 hours.

[0018] The grinding time in step (3) is 5 to 25 minutes.

[0019] Wherein, the liquid-to-solid ratio of water to carbonized powder in step (4) is 2.5-12.5:1 mL / g, and the stirring time is 0.5-2.5 hours.

[0020] Wherein, the alkali salt in step (5) is any one of sodium hydroxide, sodium carbonate, calcium oxide, and calcium hydroxide, and the mass ratio of the flue gas dust, alkali salt and desalted carbonized mud is (0.5~2.5):(4~12):100.

[0021] Wherein, the liquid-to-solid ratio of water and metal-supported carbonized mixed mud in step (6) is 1-3:1 mL / g.

[0022] Wherein, the pyrolysis temperature in step (7) is 550-750°C, and the pyrolysis time is 0.5-2.5 hours.

[0023] The present invention also includes the adsorption catalytic composite material prepared by the method.

[0024] The present invention also includes the application of the adsorption catalytic composite material in the treatment of landfill leachate.

[0025] The reaction mechanism of the present invention is as follows: fly ash printing and dyeing mud is pyrolyzed, and the organic pollutants in the printing and dyeing mud are pyrolyzed to form a carbon-based surface. The heat released by the pyrolysis of the organic pollutants and the generated gases have a thermal excitation effect on the mineral components in the fly ash printing and dyeing mud, promoting the fusion of the minerals in the fly ash printing and dyeing mud, and intermixing with the formed carbon. At the same time, the inorganic chloride salts in the printing and dyeing mud and the waste incineration fly ash are promoted to continuously undergo chlorination reactions with heavy metal pollutants through carbon thermal chlorination and volatilize into the flue gas. Water and carbonized powder are mixed, and the soluble inorganic salts in the carbonized powder are dissolved in the water and removed by solid-liquid separation. Water and metal-loaded carbonized mixed mud are mixed, and the alkali salt releases hydroxide during the stirring process, which reacts with the heavy metal chloride to form a heavy metal hydroxide co-precipitate. The formed heavy metal hydroxide co-precipitate adheres to the surface of the carbon material or fills the pores of the carbon material. The secondary pre-baked material is pyrolyzed, and the heavy metal hydroxide co-precipitate is decomposed to form heavy metal oxides. Part of the heavy metal oxides is combined with carbon and further reduced to obtain an adsorption catalytic composite material mixed with heavy metal oxides, heavy metal elements, carbon materials, and inorganic minerals.

[0026] Beneficial effects: Compared with the prior art, the present invention has the following advantages: the preparation process is simple, and the main raw materials required are waste incineration fly ash and printing and dyeing sludge, which can achieve full resource utilization of waste incineration fly ash and printing and dyeing sludge. The adsorption catalytic composite material prepared by the present invention through secondary pyrolysis has both catalytic and adsorption properties, with maximum adsorption capacities of COD, heavy metals, ammonia nitrogen and total phosphorus of 1563mg / g, 102mg / g, 257mg / g and 186mg / g, respectively. After superimposing the catalytic function, the converted maximum adsorption capacities of COD, heavy metals, ammonia nitrogen and total phosphorus are 2985mg / g, 287mg / g, 443mg / g and 324mg / g, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Flowchart of the processing method of the present invention. DETAILED DESCRIPTION

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

[0029] Preparation of landfill leachate and mercury-containing leachate: The landfill leachate used in the experiment was obtained from Zhuji Sanfeng Environmental Protection Energy Co., Ltd. This batch of leachate had a COD concentration of 4152 mg / L, a total phosphorus concentration of 305 mg / L, and an ammonia nitrogen concentration of 1075 mg / L. Mercury-containing leachate was prepared by adding 500 mg of mercury to 1 L of landfill leachate and stirring thoroughly.

[0030] Waste incineration fly ash: Waste incineration fly ash is provided by the Second Municipal Waste Incineration Power Plant in Changshu, Jiangsu Province, and mainly includes 38.14% CaO, 24.05% Cl, 10.21% SO3, 12.15% Na2O, 6.21% K2O, 3.17% SiO2, 1.41% Fe2O3, 1.19% Al2O3 and other components (loss on ignition and other inevitable impurities).

[0031] Printing and dyeing sludge: Printing and dyeing sludge is provided by Shaoxing Keqiao Tianyu Printing and Dyeing Co., Ltd. Its chemical composition mainly includes 43.86% SO3, 36.34% Fe2O3, 7.01% SiO2, 5.82% Al2O3, 2.93% CaO and other components (loss on ignition and other inevitable impurities).

[0032] Example 1 Effect of the mass ratio of printing and dyeing sludge and waste incineration fly ash on the performance of the prepared adsorption catalytic composite material

[0033] Printing and dyeing sludge and waste incineration fly ash were mixed in a mass ratio of 25:100, 30:100, 35:100, 40:100, 60:100, 80:100, 90:100, 100:100, and 110:100, respectively, and stirred evenly to obtain 9 parts of fly ash printing and dyeing mud. 9 parts of fly ash printing and dyeing mud were pyrolyzed respectively, and the flue gas generated by pyrolysis was recovered to obtain 9 parts of carbonized slag and 9 parts of flue gas dust, wherein the pyrolysis temperature was 550°C and the pyrolysis time was 0.5 hours. 9 parts of carbonized slag were ground into powder to obtain 9 parts of carbonized powder, wherein the grinding time was 5 minutes. Water and 9 parts of carbonized powder were mixed in a liquid-solid ratio of 2.5:1 mL / g, stirred for 0.5 hours, and solid-liquid separation was performed. The separated solid was desalted carbonized mud. Flue gas dust, alkali salt, and desalted carbonized mud were mixed in a mass ratio of 0.5:4:100 and stirred evenly to obtain 9 parts of metal-supported carbonized mixed mud, wherein the alkali salt was sodium hydroxide. Water and 9 parts of the metal-supported carbonized mixed mud were mixed in a liquid-to-solid ratio of 1:1 mL / g, stirred for 2 hours, and the solid-liquid separation was performed. The separated solid was dried to obtain 9 parts of secondary pre-baked material. The 9 parts of the secondary pre-baked material were pyrolyzed at 550°C for 0.5 hours to obtain 9 parts of the adsorption catalytic composite material.

[0034] Adsorption test: 9 portions of 1g adsorption catalytic composite material were added to 1L of mercury-containing landfill leachate, stirred at 120 rpm for 120 minutes, and then centrifuged at 5000 rpm for solid-liquid separation. The concentrations of different pollutants in the separated liquid were tested and the adsorption capacity was calculated. The specific tests and calculations are as follows: COD concentration test and COD adsorption capacity calculation: The chemical oxygen demand (COD) concentration of the leachate was measured in accordance with the national standard "Determination of Chemical Oxygen Demand in Water - Dichromate Method" (GB 11914-1989). The COD removal capacity was calculated according to formula (1), where is the COD adsorption capacity (mg / g), and are the COD concentrations of mercury-containing landfill leachate before and after treatment (mg / L), m is the adsorption-catalytic composite material (1 g), and V is the volume of mercury-containing landfill leachate (1 L).

[0035]

[0036] Total phosphorus concentration detection and total phosphorus adsorption capacity calculation: The total phosphorus concentration of the leachate was determined according to the standard "Water quality - Determination of phosphate and total phosphorus - Continuous flow - ammonium molybdate spectrophotometry" (HJ 670-2013). The total phosphorus adsorption capacity was calculated according to formula (2), where is the total phosphorus adsorption capacity (mg / g), and are the total phosphorus concentrations of domestic waste leachate before and after treatment (mg / L), m is the mass of the adsorption catalytic composite material (1 g), and V is the volume of mercury-containing landfill leachate (1 L).

[0037]

[0038] Ammonia nitrogen concentration detection and ammonia nitrogen adsorption capacity calculation: The ammonia nitrogen concentration of the leachate was determined according to the "Water Quality - Determination of Ammonia Nitrogen - Salicylic Acid Spectrophotometric Method" (HJ536-2009). The ammonia nitrogen adsorption capacity was calculated according to formula (3), where is the ammonia nitrogen adsorption capacity (mg / g), is the initial concentration of ammonia nitrogen in the leachate before treatment (mg / L), is the residual concentration of ammonia nitrogen in the treated leachate (mg / L), m is the mass of the adsorption-catalytic composite material (1 g), and V is the volume of the mercury-containing landfill leachate (1 L).

[0039]

[0040] Mercury ion concentration detection and adsorption capacity calculation: The mercury ion concentration in the leachate was determined according to the "Water quality - Determination of mercury, arsenic, selenium, bismuth and antimony - Atomic fluorescence method" (HJ 694-2014). The mercury ion adsorption capacity was calculated according to formula (4), where is the mercury ion adsorption capacity (mg / g), is the initial concentration of mercury ions in the leachate before treatment (mg / L), is the mercury ion concentration in the treated leachate (mg / L), m is the mass of the adsorption-catalytic composite material (1 g), and V is the volume of the mercury-containing landfill leachate (1 L).

[0041]

[0042] The test results of this embodiment are shown in Table 1.

[0043] Table 1 Effect of the mass ratio of printing and dyeing sludge and waste incineration fly ash on the performance of the prepared adsorption catalytic composite material

[0044]

[0045] As shown in Table 1, when the mass ratio of printing and dyeing sludge to waste incineration fly ash is less than 40:100 (e.g., in Table 1, the mass ratios of printing and dyeing sludge to waste incineration fly ash are 35:100, 30:100, 25:100, and lower ratios not listed in Table 1), the addition of printing and dyeing sludge is low, and the reaction between the printing and dyeing sludge and waste incineration fly ash is insufficient during the subsequent pyrolysis process. This results in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacity of the prepared adsorption-catalytic composite material as the mass ratio of printing and dyeing sludge to waste incineration fly ash decreases. When the mass ratio of printing and dyeing sludge to waste incineration fly ash is between 40 and 80:100 (e.g., in Table 1, the mass ratios of printing and dyeing sludge to waste incineration fly ash are 40:100, 60:100, and 80:100), the fly ash printing and dyeing sludge is pyrolyzed, and the organic pollutants in the printing and dyeing sludge undergo pyrolysis to form carbon-based surfaces. The heat and gases released by the pyrolysis of organic pollutants thermally stimulate the mineral components in the fly ash printing and dyeing mud, promoting the fusion of minerals in the fly ash printing and dyeing mud and their intermixing with the formed carbon. Simultaneously, through carbochlorination, inorganic chloride salts in the printing and dyeing mud and waste incineration fly ash undergo continuous chlorination reactions with heavy metal pollutants, which volatilize into the flue gas. Ultimately, the prepared adsorption-catalytic composite materials achieved COD removal capacities exceeding 1123 mg / g, total phosphorus removal capacities exceeding 76 mg / g, ammonia nitrogen removal capacities exceeding 189 mg / g, and mercury removal capacities exceeding 145 mg / g. When the mass ratio of printing and dyeing sludge to waste incineration fly ash exceeds 80:100 (as shown in Table 1, for ratios of 90:100, 100:100, and 110:100, as well as higher ratios not listed in Table 1), excessive addition of printing and dyeing sludge leads to an imbalance in the reaction between the two components during pyrolysis. This results in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacity of the prepared adsorption-catalytic composite material as the mass ratio of printing and dyeing sludge to waste incineration fly ash further increases. Overall, considering both benefits and costs, a ratio of 40 to 80:100 is most conducive to improving the performance of the prepared adsorption-catalytic composite material.

[0046] Example 2 Effect of the mass ratio of flue gas dust, alkali salt and desalted carbonized mud on the performance of the prepared adsorption catalytic composite material

[0047] Printing and dyeing sludge and waste incineration fly ash are mixed in a mass ratio of 80:100 and stirred evenly to obtain fly ash printing and dyeing mud. The fly ash printing and dyeing mud is pyrolyzed, and the flue gas generated by the pyrolysis is recovered to obtain carbonized slag and flue gas dust. The pyrolysis temperature is 700°C and the pyrolysis time is 2 hours. The carbonized slag is ground into powder to obtain carbonized powder. The grinding time is 15 minutes. Water and carbonized powder are mixed in a liquid-to-solid ratio of 7.5:1 mL / g, stirred for 1.5 hours, and the solid-liquid separation is carried out. The separated solid is desalinated carbonized mud. According to the mass ratio of 0.25:4:100, 0.3:4:100, 0.4:4:100, 0.5:2.5:100, 0.5:3:100, 0.5:3.5:100, 0.5:4:100, 1.5:4:100, 2.5:4:100, 0.5:8:100, 1.5:8:100, 2.5:8:100, 0.5 Flue gas dust, alkali salt, and desalted carbonized mud were mixed at a ratio of 1:12:100, 1.5:12:100, 2.5:12:100, 2.5:14:100, 2.5:16:100, 2.5:18:100, 3:12:100, 3.5:12:100, and 4:12:100, and stirred evenly to obtain 21 parts of metal-supported carbonized mixed mud, wherein the alkali salt was sodium carbonate. Water and 21 parts of the metal-supported carbonized mixed mud were mixed at a liquid-to-solid ratio of 2:1 mL / g, stirred for 4 hours, and the solid-liquid separation was performed. The separated solid was dried to obtain 21 parts of secondary pre-baked materials. The 21 parts of secondary pre-baked materials were pyrolyzed to obtain 21 parts of adsorption catalytic composite materials, wherein the pyrolysis temperature was 650°C and the pyrolysis time was 1.5 hours.

[0048] Adsorption test, COD concentration detection and COD adsorption capacity calculation, total phosphorus concentration detection and total phosphorus adsorption capacity calculation, ammonia nitrogen concentration detection and ammonia nitrogen adsorption capacity calculation, mercury ion concentration detection and adsorption capacity calculation were performed on 21 adsorption catalytic composite materials. The calculation method was the same as in Example 1. The test results of this example are shown in Table 2.

[0049] Table 2 Effect of the mass ratio of flue gas dust, alkali salt and desalted carbonized mud on the performance of the prepared adsorption catalytic composite material

[0050]

[0051] It can be seen from Table 2 that when the mass ratio of flue gas dust, alkali salt and desalted carbonized mud is less than 0.5:4:100 (such as in Table 2, the mass ratio of flue gas dust, alkali salt and desalted carbonized mud = 0.5:3.5:100, 0.5:3:100, 0.5:2.5:100, 0.4:4:100, 0.3:4:100, 0.25:4:100 and lower ratios not listed in Table 2), the addition of flue gas dust and alkali salt is small, and the flue gas dust, alkali salt and desalted carbonized mud do not react fully during the pyrolysis process of the secondary pre-baked material, resulting in the COD, total phosphorus, ammonia nitrogen and mercury removal capacity of the prepared adsorption catalyst significantly decreasing with the decrease of the mass ratio of flue gas dust, alkali salt and desalted carbonized mud. When the mass ratio of flue gas dust, alkali salt, and desalinated carbonized mud is 0.5-2.5:4-12:100 (as shown in Table 2, the mass ratios of flue gas dust, alkali salt, and desalinated carbonized mud are 0.5:4:100, 1.5:4:100, 2.5:4:100, 0.5:8:100, 1.5:8:100, 2.5:8:100, 0.5:12:100, 1.5:12:100, and 2.5:12:100), water and carbonized powder are mixed. The soluble inorganic salts in the carbonized powder dissolve in the water and are removed through solid-liquid separation. When water and the metal-loaded carbonized mud are mixed, the alkali salt releases hydroxide during stirring, which reacts with the heavy metal chloride to form a co-precipitate of heavy metal hydroxide. The co-precipitate of heavy metal hydroxide adheres to the surface of the carbon material or fills the pores of the carbon material. The secondary pre-baked material is pyrolyzed, and the co-precipitated heavy metal hydroxides decompose to form heavy metal oxides. Some of these heavy metal oxides then combine with carbon for further reduction, resulting in an adsorption-catalytic composite material comprised of heavy metal oxides, elemental heavy metals, carbon materials, and inorganic minerals. Ultimately, the prepared adsorption-catalytic composite material demonstrated COD removal capacities exceeding 1208 mg / g, total phosphorus removal capacities exceeding 86 mg / g, ammonia nitrogen removal capacities exceeding 205 mg / g, and mercury removal capacities exceeding 157 mg / g. When the mass ratio of flue gas dust, alkali salt and desalted carbonized mud is greater than 2.5:12:100 (as in Table 2, the mass ratio of flue gas dust, alkali salt and desalted carbonized mud = 2.5:14:100, 2.5:16:100, 2.5:18:100, 3:12:100, 3.5:12:100, 4:12:100 and higher ratios not listed in Table 2), excessive addition of flue gas dust and alkali salt leads to an imbalance in the reaction of flue gas dust, alkali salt and desalted carbonized mud during the secondary pyrolysis process, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen and mercury removal capacity of the prepared adsorption catalytic composite material with further increase in the mass ratio of flue gas dust, alkali salt and desalted carbonized mud. In summary, considering the benefits and costs, when the mass ratio of flue gas dust, alkali salt and desalination carbonized mud is equal to 0.5~2.5:4~12:100, it is most conducive to improving the performance of the prepared adsorption catalytic composite material.

[0052] Example 3 Effect of secondary pyrolysis temperature on the performance of the prepared adsorption catalytic composite material

[0053] 9 parts of printing and dyeing sludge and 9 parts of waste incineration fly ash were mixed in a mass ratio of 80:100 and stirred to obtain 9 parts of fly ash printing and dyeing mud. The 9 parts of fly ash printing and dyeing mud were pyrolyzed, and the flue gas generated by the pyrolysis was recovered to obtain 9 parts of carbonized slag and 9 parts of flue gas dust. The pyrolysis temperature was 850°C and the pyrolysis time was 3.5 hours. The 9 parts of carbonized slag were ground into powder to obtain 9 parts of carbonized powder. The grinding time was 25 minutes. Water and 9 parts of carbonized powder were mixed in a liquid-to-solid ratio of 12.5:1 mL / g, stirred for 2.5 hours, and the solid-liquid separation was performed. The separated solid was desalinated carbonized mud. Flue gas dust, alkali salt, and desalinated carbonized mud were mixed in a mass ratio of 2.5:12:100 and stirred to obtain 9 parts of metal-loaded carbonized mixed mud, where the alkali salt was calcium oxide. Water and metal-supported carbonized mixed mud were mixed at a liquid-to-solid ratio of 3:1 mL / g, stirred for 6 hours, and then the solid-liquid separation was performed. The separated solid was dried to obtain 9 portions of secondary pre-baked materials. Each of the 9 portions of secondary pre-baked materials was pyrolyzed to obtain adsorption catalytic composite materials, wherein the pyrolysis temperatures were 475°C, 500°C, 525°C, 550°C, 650°C, 750°C, 775°C, 800°C, and 825°C, respectively, and the pyrolysis time was 2.5 hours.

[0054] Adsorption test, COD concentration detection and COD adsorption capacity calculation, total phosphorus concentration detection and total phosphorus adsorption capacity calculation, ammonia nitrogen concentration detection and ammonia nitrogen adsorption capacity calculation, mercury ion concentration detection and adsorption capacity calculation were performed on 9 adsorption catalytic composite materials. The experimental methods were the same as in Example 1. The test results of this example are shown in Table 3.

[0055] Table 3 Effect of secondary pyrolysis temperature on the properties of prepared adsorption catalytic composite materials

[0056]

[0057] As shown in Table 3, when the secondary pyrolysis temperature is less than 550°C (e.g., in Table 3, the secondary pyrolysis temperature = 0.5:3.5:100, 0.5:3:100, 0.5:2.5:100, 0.4:4:100, 0.3:4:100, 0.25:4:100, and lower ratios not listed in Table 3), the pyrolysis temperature is low, and the material reaction is insufficient during the pyrolysis of the secondary pre-baked material. As a result, the COD, total phosphorus, ammonia nitrogen, and mercury removal capacity of the prepared adsorption catalytic composite material all decrease significantly with decreasing secondary pyrolysis temperature. When the secondary pyrolysis temperature is equal to 550-750°C (e.g., in Table 3, the secondary pyrolysis temperature = 550°C, 650°C, and 750°C), the secondary pre-baked material is pyrolyzed, and the heavy metal hydroxide co-precipitate decomposes to form heavy metal oxides. Some heavy metal oxides combine with carbon and undergo further reduction, resulting in an adsorption-catalytic composite material containing heavy metal oxides, elemental heavy metals, carbon materials, and inorganic minerals. Ultimately, the prepared composite material achieved COD removal capacities exceeding 1412 mg / g, total phosphorus removal capacities exceeding 96 mg / g, ammonia nitrogen removal capacities exceeding 223 mg / g, and mercury removal capacities exceeding 168 mg / g. When the secondary pyrolysis temperature exceeds 750°C (as shown in Table 3, for secondary pyrolysis temperatures of 775°C, 800°C, 825°C, and other higher ratios not listed in Table 3), the excessively high secondary pyrolysis temperature leads to an imbalance in the secondary pyrolysis process, resulting in a significant decrease in the COD, total phosphorus, ammonia nitrogen, and mercury removal capacities of the prepared adsorption-catalytic composite material with further increases in the secondary pyrolysis temperature. In summary, considering both cost and efficiency, a secondary pyrolysis temperature between 550°C and 750°C is most beneficial for improving the performance of the prepared adsorption-catalytic composite material.

[0058] Effects of different comparative processes on the performance of prepared adsorption catalytic composite materials

[0059] The process of the present invention involves mixing printing and dyeing sludge and waste incineration fly ash in a mass ratio of 80:100 and stirring evenly to obtain fly ash printing and dyeing mud. The fly ash printing and dyeing mud is pyrolyzed, and the flue gas generated by the pyrolysis is recovered to obtain carbonized slag and flue gas dust. The pyrolysis temperature is 850°C and the pyrolysis time is 3.5 hours. The carbonized slag is ground into powder to obtain carbonized powder, and the grinding time is 25 minutes. Water and carbonized powder are mixed in a liquid-to-solid ratio of 12.5:1 mL / g, stirred for 2.5 hours, and solid-liquid separation is performed. The separated solid is desalinated carbonized mud. Flue gas dust, alkali salt, and desalinated carbonized mud are mixed in a mass ratio of 2.5:12:100 and stirred evenly to obtain a metal-loaded carbonized mixed mud, wherein the alkali salt is calcium hydroxide. Water and the metal-loaded carbonized mixed mud are mixed in a liquid-to-solid ratio of 3:1 mL / g, stirred for 4 hours, and solid-liquid separation is performed. The separated solid is dried to obtain a secondary pre-baked material. The secondary pre-baked material was pyrolyzed to obtain an adsorption catalytic composite material, wherein the pyrolysis temperature was 650° C. and the pyrolysis time was 2.5 hours.

[0060] Comparative Process 1: Printing and dyeing sludge and waste incineration fly ash were mixed in a mass ratio of 80:100 and stirred to produce fly ash printing and dyeing mud. The fly ash printing and dyeing mud was pyrolyzed, and the flue gas generated was recovered to produce carbonized slag and flue gas dust. The pyrolysis temperature was 850°C and the pyrolysis time was 3.5 hours. The carbonized slag was ground into powder to produce carbonized powder. The grinding time was 25 minutes. Water and carbonized powder were mixed in a liquid-to-solid ratio of 12.5:1 mL / g, stirred for 2.5 hours, and the solid-liquid separation was performed. The separated solid was desalinated carbonized mud. Flue gas dust and desalinated carbonized mud were mixed in a mass ratio of 2.5:100 and stirred to produce mixed dust mud. Water and mixed dust mud were mixed in a liquid-to-solid ratio of 3:1 mL / g, stirred for 4 hours, and the solid-liquid separation was performed. The separated solid was dried to produce a secondary pre-baked material. The secondary pre-baked material was pyrolyzed to produce an adsorption-catalytic composite material. The pyrolysis temperature was 650°C and the pyrolysis time was 2.5 hours.

[0061] Comparative Process 2: Printing and dyeing sludge and waste incineration fly ash were mixed in a mass ratio of 80:100 and stirred to produce fly ash printing and dyeing mud. The fly ash printing and dyeing mud was pyrolyzed, and the resulting flue gas was recovered to produce carbonized slag and flue gas dust. The pyrolysis temperature was 850°C and the pyrolysis time was 3.5 hours. The carbonized slag was ground into powder to produce carbonized powder, with the grinding time being 25 minutes. Water and carbonized powder were mixed in a liquid-to-solid ratio of 12.5:1 mL / g, stirred for 2.5 hours, and solid-liquid separation was performed. The separated solid was desalinated carbonized mud. Flue gas dust, alkali salt, and desalinated carbonized mud were mixed in a mass ratio of 2.5:12:100 and stirred to produce a metal-supported carbonized mixed mud, where the alkali salt was calcium hydroxide. Water and the metal-supported carbonized mixed mud were mixed in a liquid-to-solid ratio of 3:1 mL / g, stirred for 4 hours, and solid-liquid separation was performed. The separated solid was dried to produce an adsorption catalytic composite material.

[0062] Photocatalytic Removal Test: 1g of each of the catalytic composite material prepared by the present invention, and the adsorption catalytic composite materials prepared by Comparative Processes 1 and 2 was added to 1L of mercury-containing landfill leachate. The mixture was stirred at 120 rpm and irradiated with UV light for 120 minutes, or without UV light irradiation. The mixture was then centrifuged at 5000 rpm for solid-liquid separation. The concentrations of various pollutants in the separated liquid were measured, and the removal rates were calculated. The specific testing and calculations were the same as in Example 1.

[0063] The adsorption test, COD concentration detection and calculation of COD adsorption capacity, total phosphorus concentration detection and calculation of total phosphorus adsorption capacity, ammonia nitrogen concentration detection and calculation of ammonia nitrogen adsorption capacity, and mercury ion concentration detection and adsorption capacity calculation are all the same as in Example 1. The test results of this embodiment are shown in Table 4.

[0064] Table 4 Effects of different comparative processes on the properties of prepared adsorption catalytic composite materials

[0065]

[0066] As can be seen from Table 4, the adsorption composite catalytic material prepared by the process of the present invention has significant adsorption and photocatalytic properties. The COD, total phosphorus, ammonia nitrogen and mercury removal capacity achieved by the composite catalytic material prepared by the process of the present invention are significantly higher than those of comparative process 1 and comparative process 2 under the corresponding conditions with and without light.

Claims

1. A method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge, characterized in that: The following steps are involved: (1) Mixing printing and dyeing sludge and waste incineration fly ash, and stirring them evenly to obtain fly ash printing and dyeing mud; (2) Pyrolyzing fly ash printing and dyeing mud, recovering the flue gas generated by pyrolysis, and obtaining carbonized slag and flue gas dust; (3) Grinding the carbonized slag into powder to obtain carbonized powder; (4) Mixing water and carbonized powder and stirring, separating the solid and liquid to obtain the desalted carbonized mud; (5) Mixing flue gas dust, alkaline substances and desalted carbonized mud, and stirring evenly to obtain metal-loaded carbonized mixed mud; (6) Mixing water and metal-supported carbonized mixed mud, stirring for 2 to 6 hours, separating the solid and liquid to obtain a solid, and drying the separated solid to obtain a secondary pre-baked material; (7) Pyrolyzing the secondary pre-baked material to obtain an adsorption catalytic composite material; The mass ratio of the mixed printing and dyeing sludge and the waste incineration fly ash in step (1) is 40~80:100, the pyrolysis temperature in step (2) is 550~850℃, and the pyrolysis time is 0.5~3.5 hours. The alkaline substance in step (5) is any one of sodium hydroxide, sodium carbonate, calcium oxide, and calcium hydroxide, and the mass ratio of the flue gas dust, alkaline substance and desalted carbonized mud is (0.5~2.5):(4~12):100; the pyrolysis temperature in step (7) is 550~750℃, and the pyrolysis time is 0.5~2.5 hours.

2. The method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge according to claim 1, characterized in that: The grinding time in step (3) is 5 to 25 minutes.

3. The method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge according to claim 1, characterized in that: The liquid-to-solid ratio of water to carbonized powder in step (4) is 2.5-12.5:1 mL / g, and the stirring time is 0.5-2.5 hours.

4. The method for preparing an adsorption catalytic composite material by synergistically utilizing waste incineration fly ash and printing and dyeing sludge according to claim 1, characterized in that: The liquid-to-solid ratio of water and metal-supported carbonized mixed mud in step (6) is 1-3:1 mL / g.

5. The adsorption catalytic composite material prepared by the method according to any one of claims 1 to 4.

6. Use of the adsorption-catalytic composite material according to claim 5 in the treatment of landfill leachate.

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