A sludge solidifying agent based on modified components, and a preparation method and application thereof

Abstract

The application relates to the field of water treatment, in particular to a sludge solidifying agent based on modified components and a preparation method and application thereof. The sludge solidifying agent based on modified components is prepared from the following raw materials in parts by mass: inorganic solidifying base material 40-60 parts, polymer modifier 15-25 parts, nano material 5-10 parts, pH regulator 2-5 parts, plasticizer 3-8 parts, water reducing agent 0.5-1.2 parts, antifreezing agent 2-5 parts, expanding agent 2-5 parts, preservative 0.2-0.5 parts and water 20-40 parts. The sludge solidifying agent prepared finally not only has good adaptability to complex sludge, but also can greatly improve the durability problem after use, effectively reduces cracks, peeling and the like in long-term use, maintains the water content after solidification in a suitable stage, thereby meeting the solidification demand of existing water treatment sludge, and has very excellent application prospect.

Description

Technical Field

[0001] This application relates to the field of water treatment, and in particular to a sludge solidification agent based on modified components, its preparation method, and its application. Background Technology

[0002] With rapid urbanization and industrial development, wastewater discharge is constantly increasing, resulting in a large amount of difficult-to-treat sludge. This sludge typically contains high levels of moisture and organic matter, and may also contain heavy metals and other harmful substances. Improper disposal can cause serious environmental pollution. Traditional sludge treatment methods such as landfill and incineration not only consume land resources but also pose a risk of secondary pollution. Therefore, there is an urgent need to develop efficient and environmentally friendly sludge treatment technologies.

[0003] In recent years, sludge solidification has received widespread attention as an effective treatment method. The solidification process involves adding specific chemical agents (i.e., solidifying agents) to absorb or remove moisture from the sludge, thereby forming solid blocks with a certain strength and stability. This not only reduces the volume of sludge but also prevents the migration and diffusion of pollutants, facilitating subsequent safe disposal.

[0004] Currently available sludge solidification agents on the market are mainly composed of inorganic components such as cement and lime, which can effectively reduce the water content of sludge and provide a certain mechanical strength. However, traditional solidification agents have revealed some problems in practical applications: for example, due to their simple composition, they have poor adaptability to complex sludge from different sources; in addition, the solidified products often have insufficient durability, and are prone to cracking and peeling when exposed to the natural environment for a long time, which can lead to the re-release of pollutants into the environment; finally, the water content is also prone to continuously increasing after solidification.

[0005] Therefore, to address the aforementioned issues, this application provides a sludge solidification agent based on modified components and its preparation method. The sludge solidification agent ultimately obtained in this application not only exhibits excellent adaptability to complex sludge but also significantly improves the problem of insufficient durability after use. It effectively reduces cracking and peeling during long-term use, maintaining the moisture content after solidification at an appropriate level, thereby meeting the solidification requirements of existing water treatment sludge and demonstrating excellent application prospects. Summary of the Invention

[0006] To address the aforementioned problems, the first aspect of this application provides a sludge solidification agent based on modified components, wherein the raw materials, by weight, are: 40-60 parts of inorganic solidification substrate, 15-25 parts of polymer modifier, 5-10 parts of nanomaterials, 2-5 parts of pH adjuster, 3-8 parts of plasticizer, 0.5-1.2 parts of water-reducing agent, 2-5 parts of antifreeze, 2-5 parts of expansion agent, 0.2-0.5 parts of preservative, and 20-40 parts of water.

[0007] As a preferred embodiment, the inorganic curing substrate is a composition of ordinary silicate cement, fly ash, and slag powder.

[0008] As a preferred embodiment, the mass ratio of fly ash to slag powder in the ordinary silicate cement is (25~35):(10~15):(5~10).

[0009] As a preferred embodiment, the mass ratio of fly ash to slag powder in the ordinary silicate cement is (28~33):(12~14):(6~8).

[0010] As a preferred embodiment, the ordinary silicate cement has a strength grade of 42.5.

[0011] As a preferred embodiment, the fly ash is either Class F fly ash or Class C fly ash.

[0012] As a preferred embodiment, the fly ash is Class F fly ash.

[0013] As a preferred embodiment, the slag powder has an average specific surface area of ​​500~700 m². 2 / kg.

[0014] As a preferred embodiment, the slag powder has an average specific surface area of ​​550~600 m². 2 / kg.

[0015] As a preferred embodiment, the mass ratio of the inorganic curing substrate, polymer modifier, and nanomaterial is (45~55):(16~22):(7~10).

[0016] As a preferred embodiment, the mass ratio of the inorganic curing substrate, polymer modifier and nanomaterial is (48~53):(18~20):(8~9).

[0017] As a preferred embodiment, the polymer modifier is a combination of polyvinyl alcohol and modified polyacrylamide.

[0018] As a preferred embodiment, the mass ratio of polyvinyl alcohol to modified polyacrylamide is (1.2~1.8):(4.5~5.5).

[0019] As a preferred embodiment, the mass ratio of polyvinyl alcohol to modified polyacrylamide is (1.4~1.6):(4.8~5.2).

[0020] As a preferred embodiment, the preparation method of the modified polyacrylamide specifically includes the following steps: S1: Cyclohexyl methacrylate, glycidyl methacrylate, and N,N'-methylenebisacrylamide are added to an acryloyl chloride solution, nitrogen gas is introduced, and ammonium persulfate is added. The mixture is heated to 80-90℃ and reacted for 3-4 hours. The product is filtered out to obtain a preproduct; S2: The preproduct, acrylamide, N-n-butylacrylamide, and styrene are added to deionized water, nitrogen gas is introduced, and ammonium persulfate is added. The mixture is reacted for 4-4.5 hours, and sodium hydroxide is added 0.5 hours before the end of the reaction to adjust the pH to 7-7.5; S3: After the reaction is completed, the mixture is cooled to room temperature, the product is removed, and washed 2-3 times with deionized water. The washed product is placed in a vacuum drying oven and dried at 60-65℃ for 12-16 hours until the moisture content is ≤2.5wt%.

[0021] As a preferred embodiment, the mass ratio of cyclohexyl methacrylate, glycidyl methacrylate, and N,N'-methylenebisacrylamide is (5~6):(2~5):(0.5~1.2).

[0022] As a preferred embodiment, the mass ratio of cyclohexyl methacrylate, glycidyl methacrylate, and N,N'-methylenebisacrylamide is (5~5.5):(2.5~3.5):(0.6~0.8).

[0023] As a preferred embodiment, the mass ratio of the preproduct, acrylamide, N-n-butylacrylamide and styrene is (8~12):(25~30):(2~3):(3~4).

[0024] The modified polyacrylamide used in this application as a composite modifier effectively improves the durability and mechanical properties of the sludge solidifier after use, and effectively reduces cracking and peeling. It maintains a suitable moisture content in the solidified sludge for a long period, significantly enhancing the solidification effect. The acrylamide segments in the modified polyacrylamide work together with N-n-butylacrylamide to adsorb suspended microparticles in the sludge, promoting the faster aggregation of fine particles into larger flocs. While constructing the solidification system, it also facilitates the detachment of water molecules. Furthermore, the three-dimensional network segment structure formed by the ester segments and N,N'-methylenebisacrylamide increases the resistance to water molecule movement, preventing excessive continuous aggregation of water molecules and stabilizing the system's moisture content. The three-dimensional network segment structure further enhances the resistance to slippage between particles, molecules, and molecular segments after solidification, thereby improving the overall mechanical strength and toughness of the solidified sludge.

[0025] On the other hand, the cyclohexyl ester side chains contained in the modified polyacrylamide can achieve a certain degree of barrier to water molecule penetration in the three-dimensional network chain structure, and the styrene segments further improve the crosslinking density between polymer chains in the curing agent, increase the long-term stability of the cured system, and improve phenomena such as cracking and peeling during use.

[0026] As a preferred embodiment, the nanomaterial is modified titanium-based nanoparticles.

[0027] As a preferred embodiment, the preparation method of the modified titanium-based nanoparticles specifically includes the following steps: S1: Titanium dioxide and glutaric anhydride are mixed and added to DMF solvent, heated to 65-70°C and kept at that temperature for 2-3 hours. After completion, the mixture is centrifuged and filtered, and washed with ethanol 2-3 times to obtain pretreated titanium dioxide; S2: Pretreated titanium dioxide is mixed with tetrabutyl titanate and added to DMAc solvent, heated to 45-50°C, and ultrasonically dispersed at 400-500W for 20-30 minutes. Then, 1,4-naphthalenedicarboxylic acid and p-aminobenzoic acid are added and ultrasonically dispersed for another 20-30 minutes to obtain a mixed solution; S3: Hydrofluoric acid is added to the mixed solution, and then the mixed solution is transferred to a sealed reaction vessel and reacted at 120-130°C for 16-20 hours. After the reaction is completed, the mixture is naturally cooled to room temperature, and the solid product obtained is collected by centrifugation and filtration. The solid product is washed several times with ethanol to remove unreacted raw materials and other impurities, and then dried overnight at 80-85°C in a vacuum drying oven to obtain the final product.

[0028] As a preferred embodiment, the mass ratio of titanium dioxide to glutaric anhydride is (1~1.2):(0.2~0.25).

[0029] As a preferred embodiment, the titanium dioxide has an average particle size of 15~25nm.

[0030] As a preferred embodiment, the mass ratio of the pretreated titanium dioxide, tetrabutyl titanate, 1,4-naphthalenedicarboxylic acid and p-aminobenzoic acid is (0.5~0.6):(3.5~3.8):(4.2~4.5):(1.4~1.8).

[0031] As a preferred embodiment, the modified titanium-based nanoparticles have an average particle size of 400-500 nm.

[0032] This application utilizes a modified titanium-based nanoparticle composite structure, which possesses a good specific surface area and uniform pore size. This structure can effectively adsorb heavy metal ions and organic pollutants in sludge. Furthermore, through the guiding effect of surface titanium dioxide, it can significantly improve the pore size between sludge particles in the solidification agent system, reduce the occurrence of large pores, and form a relatively stable interconnection network, thereby increasing the overall mechanical strength of the solidification. On the other hand, the modified titanium-based nanoparticles can effectively capture small molecule pollutants and achieve chemical fixation through the reaction of surface functional groups with organic pollutant molecules, reducing the effectiveness and migration of pollutant molecules in the solidification system. Moreover, the overall structure of the modified particles can be embedded in the sludge matrix, acting as a skeletal support, restricting the movement of sludge particles, and thus stabilizing the supporting skeleton after solidification, effectively enhancing the mechanical properties after solidification.

[0033] As a preferred embodiment, the pH adjuster is at least one of calcium hydroxide, potassium hydroxide, and sodium hydroxide.

[0034] As a preferred embodiment, the pH adjuster is calcium hydroxide.

[0035] As a preferred embodiment, the plasticizer is at least one of polyethylene glycol, phthalate, citrate, and epoxidized soybean oil.

[0036] As a preferred embodiment, the plasticizer is a combination of phthalate and citrate.

[0037] As a preferred embodiment, the mass ratio of the phthalate to the epoxidized soybean oil is (2~2.2):(4~4.5).

[0038] As a preferred embodiment, the water-reducing agent is at least one of naphthalene-based high-efficiency water-reducing agents, aminosulfonate high-efficiency water-reducing agents, polycarboxylate-based high-performance water-reducing agents, and aliphatic high-efficiency water-reducing agents.

[0039] As a preferred embodiment, the water-reducing agent is an aminosulfonate high-efficiency water-reducing agent or a polycarboxylate high-performance water-reducing agent.

[0040] As a preferred embodiment, the antifreeze is a combination of calcium nitrate and propylene glycol.

[0041] As a preferred embodiment, the mass ratio of calcium nitrate to propylene glycol is (1~1.5):(5~6).

[0042] As a preferred embodiment, the expanding agent is at least one of calcium sulfoaluminate, magnesium oxide, silica fume, limestone powder, and bentonite.

[0043] As a preferred embodiment, the expanding agent is calcium sulfoaluminate.

[0044] As a preferred option, the preservative is boric acid or isothiazolinone.

[0045] As a preferred option, the preservative is boric acid.

[0046] The second aspect of this application provides a method for preparing the above-mentioned sludge solidification agent based on modified components, specifically including the following steps: S1: Mix the inorganic solidification substrate, polymer modifier and part of water, stir at 100~150 rpm for 30~40 min, then add nanomaterials and stir at 2000~3000 rpm for 15~20 min using a high-speed shear machine; S2: Add the remaining water, plasticizer, water-reducing agent, antifreeze, expansion agent and preservative in sequence, stirring at 600~800 rpm for 15~20 min with each addition, and finally add pH adjuster to adjust the pH to 7.5~8; S3: Mix the product of S2 with the sludge to be treated at a mass ratio of 1:(5~10), stir thoroughly at 400~500 rpm, and let stand for curing until solidified sludge is obtained.

[0047] The third aspect of this application covers the application of the above-mentioned modified sludge solidifying agents in municipal sewage sludge treatment, industrial wastewater sludge stabilization treatment, and river silt management.

[0048] The beneficial effects of this application are:

[0049] 1. The sludge solidifying agent based on modified components provided in this application not only has good adaptability to complex sludge, but also can significantly improve the problem of insufficient durability after use. It can effectively reduce cracks and peeling during long-term use and maintain the water content after solidification at an appropriate level, thereby meeting the solidification requirements of existing water treatment sludge and has excellent application prospects.

[0050] 2. The sludge solidifying agent based on modified components provided in this application has an acrylamide segment in the added modified polyacrylamide that can work with N-n-butylacrylamide to adsorb suspended microparticles in the sludge, thereby promoting the faster aggregation of fine particles in the sludge into larger flocs. While constructing the solidification system, it also facilitates the detachment of water molecules. Furthermore, the three-dimensional network segment structure formed by the polyester segments and N,N'-methylenebisacrylamide increases the resistance to the movement of water molecules and avoids excessive continuous aggregation of water molecules in the system, thereby stabilizing the water content of the system. The construction of the three-dimensional network segment structure further endows the solidified system with resistance to the sliding between particles, molecules, and molecular segments, thereby improving the overall mechanical strength and toughness of the solidified system.

[0051] 3. The sludge solidifying agent based on modified components provided in this application has a good specific surface area and uniform pore size through the modified titanium-based nanoparticle composite structure. It can effectively adsorb heavy metal ions and organic pollutants in sludge. Moreover, through the guiding effect of surface titanium dioxide, it can significantly improve the pore size between sludge particles in the solidifying agent system, reduce the occurrence of large pores, and form a relatively stable connection network, thereby enhancing the overall mechanical properties, water resistance, weather resistance and other properties after solidification. Detailed Implementation

[0052] The following will further illustrate and demonstrate the technical solutions described above in this application through specific implementation schemes. Furthermore, the following embodiments are merely practical examples used to illustrate and explain the content of the technical solutions in the specification, and should not limit the scope of the claims to be protected by this application. All technical products based on the technical solutions described in this application should be covered within the scope of protection of this application.

[0053] In the following embodiments, unless otherwise specified, the raw materials are all commercially available products or can be prepared by methods known to those skilled in the art.

[0054] Example 1

[0055] Example 1 provides a sludge solidification agent based on modified components, wherein the raw materials, by weight, are: 52 parts of inorganic solidification substrate, 18.8 parts of polymer modifier, 8.5 parts of nanomaterial, 2.8 parts of pH adjuster, 6.5 parts of plasticizer, 0.8 parts of water-reducing agent, 3.4 parts of antifreeze, 3.2 parts of expansion agent, 0.3 parts of preservative, and 32.5 parts of water.

[0056] The inorganic curing substrate is a composition of ordinary silicate cement, fly ash and slag powder, with a mass ratio of 32:12:8.

[0057] The strength grade of ordinary Portland cement is 42.5.

[0058] The fly ash is classified as Class F fly ash.

[0059] The average specific surface area of ​​slag powder is 580 m². 2 / kg, purchased from Shijiazhuang Zhouting Mineral Products Co., Ltd., China, S95 grade slag powder product.

[0060] The polymer modifier is a composition of polyvinyl alcohol PVA2488 and modified polyacrylamide in a mass ratio of 1.5:4.9.

[0061] The preparation method of modified polyacrylamide specifically includes the following steps, in parts by weight: S1: 5.4 parts of cyclohexyl methacrylate, 3.1 parts of glycidyl methacrylate and 0.68 parts of N,N'-methylenebisacrylamide are added to 60 parts of acryloyl chloride solution, nitrogen gas is introduced and 0.14 parts of ammonium persulfate are added, the temperature is raised to 85℃ and the reaction is carried out for 3.5 h, and the product is filtered out to obtain the preproduct; S2: 10.2 parts of the preproduct, 28.8 parts of acrylamide, 2.6 parts of N-n-butylacrylamide and 3.3 parts of styrene are added to 280 parts of deionized water, nitrogen gas is introduced and 0.26 parts of ammonium persulfate are added, the reaction is carried out for 4.5 h, and sodium hydroxide is added 0.5 h before the end of the reaction to adjust the pH to 7.2; S3: after the reaction is completed, the product is cooled to room temperature, the product is taken out and washed 3 times with deionized water, the washed product is placed in a vacuum drying oven and dried at 65℃ for 15 h until the moisture content is ≤2.5 wt%, which is the final product.

[0062] The nanomaterial is modified titanium-based nanoparticles. The preparation method of the modified titanium-based nanoparticles specifically includes the following steps, by mass: S1: 1.1 parts of titanium dioxide and 0.24 parts of glutaric anhydride are mixed and added to 50 parts of DMF solvent, heated to 70℃ and kept at that temperature for 3 hours. After completion, centrifugation and filtration are performed, and the mixture is washed three times with ethanol to obtain pretreated titanium dioxide; S2: 0.55 parts of pretreated titanium dioxide and 3.6 parts of tetrabutyl titanate are mixed and added to 80 parts of DMAc solvent, heated to 50℃, and ultrasonically separated at 450W. S1: Disperse for 25 min, then add 4.4 parts of 1,4-naphthalenedicarboxylic acid and 1.6 parts of p-aminobenzoic acid and continue ultrasonic dispersion for 30 min to obtain a mixed solution; S2: Add 0.6 parts of hydrofluoric acid to the mixed solution, then transfer the mixed solution to a sealed reaction vessel and react at 120°C for 19 h. After the reaction is completed, cool naturally to room temperature, collect the solid product by centrifugation and filtration, wash several times with ethanol to remove unreacted raw materials and other impurities, and dry overnight at 85°C in a vacuum drying oven to obtain the final product.

[0063] The average particle size of titanium dioxide is 22 nm. The average particle size of modified titanium-based nanoparticles is 460 nm.

[0064] The pH adjuster is calcium hydroxide; the plasticizer is a combination of phthalate and citrate in a mass ratio of 2:4.5.

[0065] The water-reducing agent is a high-performance polycarboxylate water-reducing agent, purchased from Shanxi Kaidi Building Materials Co., Ltd., China, specifically the KDSP model product.

[0066] The antifreeze is a combination of calcium nitrate and propylene glycol in a mass ratio of 1.2:5.5.

[0067] The preservative is boric acid; the expanding agent is calcium sulfoaluminate.

[0068] The second aspect of this embodiment provides a method for preparing the above-mentioned sludge solidification agent based on modified components, specifically including the following steps: S1: Mix the inorganic solidification substrate, polymer modifier and a portion of water (70wt% of the total water volume), stir at 120 rpm for 35 min, then add nanomaterials and stir at 2500 rpm for 18 min using a high-speed shear press; S2: Add the remaining water (30wt% of the total water volume), plasticizer, water-reducing agent, antifreeze, expansion agent and preservative in sequence, stirring at 800 rpm for 15 min with each addition, and finally add pH adjuster to adjust the pH to 7.5; S3: Mix the product of S2 with the sludge to be treated at a mass ratio of 1:7, stir thoroughly at 450 rpm, and let stand for curing until solidified sludge is obtained.

[0069] Example 2

[0070] The specific implementation method of this embodiment is basically the same as that of Embodiment 1, except that: the sludge solidification agent based on the modified components, by mass, consists of: 46.5 parts of inorganic solidification substrate, 16.5 parts of polymer modifier, 7.2 parts of nanomaterials, 2.4 parts of pH adjuster, 6.3 parts of plasticizer, 0.6 parts of water-reducing agent, 2.8 parts of antifreeze, 2.9 parts of expansion agent, 0.28 parts of preservative, and 31.6 parts of water.

[0071] The inorganic curing substrate is a composition of ordinary silicate cement, fly ash and slag powder, with a mass ratio of 30.5:10:6.

[0072] The polymer modifier is a composition of polyvinyl alcohol PVA2488 and modified polyacrylamide in a mass ratio of 1.8:4.5.

[0073] Example 3

[0074] The specific implementation method of this embodiment is basically the same as that of Embodiment 1, except that: the sludge solidification agent based on the modified components, by mass, consists of: 55 parts of inorganic solidification substrate, 21.5 parts of polymer modifier, 10 parts of nanomaterials, 2.6 parts of pH adjuster, 5.2 parts of plasticizer, 0.6 parts of water-reducing agent, 3.1 parts of antifreeze, 2.2 parts of expansion agent, 0.25 parts of preservative, and 30.8 parts of water.

[0075] The inorganic curing substrate is a composition of ordinary silicate cement, fly ash and slag powder, with a mass ratio of 35:15:5.

[0076] The polymer modifier is a composition of polyvinyl alcohol PVA2488 and modified polyacrylamide in a mass ratio of 1.5:5.5.

[0077] Comparative Example 1

[0078] The specific implementation method of this comparative example is basically the same as that of Example 1, except that: the sludge solidification agent based on the modified components, by mass, consists of: 60.5 parts of inorganic solidification substrate, 8.5 parts of polymer modifier, 15.2 parts of nanomaterials, 2.1 parts of pH adjuster, 7.5 parts of plasticizer, 0.8 parts of water-reducing agent, 3.6 parts of antifreeze, 4.1 parts of expansion agent, 0.26 parts of preservative, and 34.5 parts of water.

[0079] Comparative Example 2

[0080] The specific implementation method of this comparative example is basically the same as that of Example 1, except that: the sludge solidification agent based on the modified components, by mass, consists of: 58.8 parts of inorganic solidification substrate, 25.5 parts of polymer modifier, 2.1 parts of nanomaterial, 2.4 parts of pH adjuster, 5.5 parts of plasticizer, 0.7 parts of water-reducing agent, 3.1 parts of antifreeze, 2.6 parts of expansion agent, 0.24 parts of preservative, and 33.2 parts of water.

[0081] Comparative Example 3

[0082] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the polymer modifier is a composition of polyvinyl alcohol PVA2488 and modified polyacrylamide, with a mass ratio of 1.5:1.9.

[0083] Comparative Example 4

[0084] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the preparation method of the modified polyacrylamide specifically includes the following steps, in parts by weight: S1: 1.2 parts of cyclohexyl methacrylate, 5.5 parts of glycidyl methacrylate and 0.22 parts of N,N'-methylenebisacrylamide are added to 60 parts of acryloyl chloride solution, nitrogen gas is introduced and 0.11 parts of ammonium persulfate are added, the temperature is raised to 85°C and heated for 3.5 h, and the product is filtered out to obtain the preproduct; S2: 10.2 parts of The preproduct, consisting of 28.8 parts acrylamide, 2.6 parts N-n-butylacrylamide, and 3.3 parts styrene, was added to 280 parts deionized water. Nitrogen gas was introduced and 0.26 parts ammonium persulfate was added. The reaction was carried out for 4.5 hours, and sodium hydroxide was added 0.5 hours before the end of the reaction to adjust the pH to 7.2. S3: After the reaction was completed, the product was cooled to room temperature, removed, and washed three times with deionized water. The washed product was placed in a vacuum drying oven and dried at 65°C for 15 hours until the moisture content was ≤2.5 wt%.

[0085] Comparative Example 5

[0086] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the preparation method of modified polyacrylamide specifically includes the following steps, in parts by weight: S1: 5.4 parts of cyclohexyl methacrylate, 3.1 parts of glycidyl methacrylate and 0.68 parts of N,N'-methylenebisacrylamide are added to 60 parts of acryloyl chloride solution, nitrogen gas is introduced and 0.14 parts of ammonium persulfate are added, the temperature is raised to 85°C and heated for 3.5 h, and the product is filtered out to obtain the preproduct; S2: 5.5 parts of cyclohexyl methacrylate, cyclohexyl methacrylate, glycidyl methacrylate and N,N'-methylenebisacrylamide are added to cyclohexyl methacrylate ... cyclohexyl methacrylate, glycidyl methacrylate and N,N'-methylenebisacrylamide are added to cyclohexyl methacrylate solution, cyclohexyl methacrylate, glycidyl methacrylate and N,N'-methylenebisacrylamide are added to cyclohexyl methacrylate solution, cyclohexyl methacrylate, glycidyl methacrylate and N,N'-methylenebisacrylamide are added to cyclohexyl methacrylate solution, cyclohexyl methacrylate, glycidyl methacrylate and N,N'-methylenebisacrylamide are added to cyclohexyl methacrylate solution, cyclohexyl methacrylate, g The preproduct, consisting of 36.5 parts acrylamide, 3.2 parts N-n-butylacrylamide, and 1.5 parts styrene, was added to 300 parts deionized water. Nitrogen gas was introduced and 0.24 parts ammonium persulfate was added. The reaction was carried out for 4.5 hours, and sodium hydroxide was added 0.5 hours before the end of the reaction to adjust the pH to 7.2. S3: After the reaction was completed, the product was cooled to room temperature, removed, and washed three times with deionized water. The washed product was placed in a vacuum drying oven and dried at 65°C for 15 hours until the moisture content was ≤2.5 wt%.

[0087] Comparative Example 6

[0088] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the preparation method of the modified titanium-based nanoparticles specifically includes the following steps, in parts by mass: S1: 2.5 parts of titanium dioxide and 0.15 parts of glutaric anhydride are mixed and added to 60 parts of DMF solvent, heated to 70°C and kept at that temperature for 3 hours. After completion, the mixture is centrifuged and filtered, and washed three times with ethanol to obtain pretreated titanium dioxide; S2: 1.1 parts of pretreated titanium dioxide and 3.6 parts of tetrabutyl titanate are mixed and added to 80 parts of DMAc solvent, and heated to 50°C. The mixture was ultrasonically dispersed at 450W for 25 min, then 4.4 parts of 1,4-naphthalenedicarboxylic acid and 1.6 parts of p-aminobenzoic acid were added and ultrasonically dispersed for another 30 min to obtain a mixed solution; S3: 0.6 parts of hydrofluoric acid were added to the mixed solution, and then the mixed solution was transferred to a sealed reaction vessel and reacted at 120℃ for 19 h. After the reaction was completed, the mixture was naturally cooled to room temperature, and the solid product was collected by centrifugation and filtration. The solid product was washed several times with ethanol to remove unreacted raw materials and other impurities, and then dried overnight at 85°C in a vacuum drying oven to obtain the final product.

[0089] Comparative Example 7

[0090] The specific implementation method of this comparative example is basically the same as that of Example 1, except that the preparation method of the modified titanium-based nanoparticles specifically includes the following steps, in parts by mass: S1: 1.1 parts of titanium dioxide and 0.24 parts of glutaric anhydride are mixed and added to 50 parts of DMF solvent, heated to 70°C and kept at that temperature for 3 hours. After completion, the mixture is centrifuged and filtered, and washed three times with ethanol to obtain pretreated titanium dioxide; S2: 0.25 parts of pretreated titanium dioxide and 5.2 parts of tetrabutyl titanate are mixed and added to 80 parts of DMAc solvent, and heated to 50°C. S1: Disperse the mixture by ultrasonication at 450W for 25 min, then add 4.8 parts of 1,4-naphthalenedicarboxylic acid and 2 parts of p-aminobenzoic acid and continue ultrasonic dispersion for 30 min to obtain a mixed solution; S2: Add 0.8 parts of hydrofluoric acid to the mixed solution, then transfer the mixed solution to a sealed reaction vessel and react at 120℃ for 19 h. After the reaction is completed, allow it to cool naturally to room temperature, collect the solid product by centrifugation and filtration, wash it several times with ethanol to remove unreacted raw materials and other impurities, and dry it overnight at 85°C in a vacuum drying oven to obtain the final product.

[0091] Performance Evaluation

[0092] In the examples and comparative examples, the sludge was industrial wastewater sludge (from the same batch). The solidified sludge of the examples and comparative examples was cured for 28 days at a temperature of 25±2℃ and a relative humidity of 80±3%. Then, according to the reference standards GBT23485-2009 and GB50869-2013, the unconfined compressive strength of the solidified sludge at 7 days and 28 days, the direct shear strength at 28 days, and the moisture content at 7 days were tested. The average value of 10 tests was recorded in Table 1.

[0093]

[0094] From the embodiments and comparative examples of this application, as well as the data results in Table 1, it can be seen that embodiments 1-3 of this application have significant advantages over comparative examples 1-7 in terms of cured mechanical properties, durability, weather resistance, and water resistance. This is mainly due to the combined effect of the functional resin modification, modified nanoparticles, and other formulations specified in this application. In contrast, comparative examples 1-7 did not adopt the technical solution specified in this application, resulting in significant disadvantages in the above performance tests. This further proves the necessity of the technical solution specified in this application for the technical effect of this application and for solving technical problems.

Claims

1. A sludge solidification agent based on modified components, characterized in that: By weight, the raw materials are: 40-60 parts inorganic curing substrate, 15-25 parts polymer modifier, 5-10 parts nanomaterials, 2-5 parts pH adjuster, 3-8 parts plasticizer, 0.5-1.2 parts water reducer, 2-5 parts antifreeze, 2-5 parts expansion agent, 0.2-0.5 parts preservative, and 20-40 parts water; The inorganic curing substrate is a composition of ordinary silicate cement, fly ash and slag powder; the mass ratio of ordinary silicate cement, fly ash and slag powder is (25~35):(10~15):(5~10). The polymer modifier is a composition of polyvinyl alcohol and modified polyacrylamide; the mass ratio of polyvinyl alcohol to modified polyacrylamide is (1.2~1.8):(4.5~5.5). The preparation method of the modified polyacrylamide specifically includes the following steps: S1: Cyclohexyl methacrylate, glycidyl methacrylate and N,N'-methylenebisacrylamide are added to an acryloyl chloride solution, nitrogen gas is introduced and ammonium persulfate is added, the temperature is raised to 80~90℃ and heated for 3~4h, and the product is filtered out to obtain the preproduct; S2: The preproduct, acrylamide, N-n-butylacrylamide and styrene are added to deionized water, nitrogen gas is introduced and ammonium persulfate is added, the reaction is carried out for 4~4.5h, and sodium hydroxide is added 0.5h before the end of the reaction to adjust the pH to 7~7.5; S3: After the reaction is completed, the product is cooled to room temperature, the product is taken out and washed with deionized water 2~3 times, the washed product is placed in a vacuum drying oven and dried at 60~65℃ for 12~16h until the moisture content is ≤2.5wt%, which is the final product; The mass ratio of cyclohexyl methacrylate, glycidyl methacrylate, and N,N'-methylenebisacrylamide is (5~5.5):(2.5~3.5):(0.6~0.8). The mass ratio of the preproduct, acrylamide, N-n-butylacrylamide and styrene is (8~12):(25~30):(2~3):(3~4).

2. The sludge solidification agent based on modified components according to claim 1, characterized in that: The average specific surface area of ​​the slag powder is 500~700 m². 2 / kg.

3. The sludge solidification agent based on modified components according to claim 2, characterized in that: The strength grade of the ordinary silicate cement is 42.5; the fly ash is either Class F fly ash or Class C fly ash.

4. The sludge solidification agent based on modified components according to claim 3, characterized in that: The inorganic curing substrate, polymer modifier and nanomaterial have a mass ratio of (45~55):(16~22):(7~10).

5. The sludge solidification agent based on modified components according to claim 4, characterized in that: The nanomaterial is modified titanium-based nanoparticles; the specific preparation method of the modified titanium-based nanoparticles is as follows. Includes the following steps: S1: Add titanium dioxide and glutaric anhydride to DMF solvent, heat to 65~70℃ and keep warm for 2~3h, centrifuge and filter, wash with ethanol 2~3 times to obtain pretreated titanium dioxide; S2: Pretreated titanium dioxide and tetrabutyl titanate are mixed and added to DMAc solvent. The mixture is heated to 45-50°C and ultrasonically dispersed at 400-500W for 20-30 minutes. Then, 1,4-naphthalenedicarboxylic acid and p-aminobenzoic acid are added and ultrasonically dispersed for another 20-30 minutes to obtain a mixed solution. S3: Hydrofluoric acid is added to the mixed solution. The mixed solution is then transferred to a sealed reaction vessel and reacted at 120-130°C for 16-20 hours. After the reaction is completed, the mixture is naturally cooled to room temperature. The solid product is collected by centrifugation and filtration. It is washed several times with ethanol to remove unreacted raw materials and other impurities. The product is then dried overnight in a vacuum drying oven at 80-85°C to obtain the final product.

6. The sludge solidification agent based on modified components according to claim 5, characterized in that: The mass ratio of titanium dioxide to glutaric anhydride is (1~1.2):(0.2~0.25); the average particle size of titanium dioxide is 15~25 nm.

7. The sludge solidification agent based on modified components according to claim 6, characterized in that: The mass ratio of the pretreated titanium dioxide, tetrabutyl titanate, 1,4-naphthalenedicarboxylic acid and p-aminobenzoic acid is (0.5~0.6):(3.5~3.8):(4.2~4.5):(1.4~1.8); the average particle size of the modified titanium-based nanoparticles is 400~500 nm.

8. The sludge solidification agent based on modified components according to claim 7, characterized in that: The antifreeze is a composition of calcium nitrate and propylene glycol; the mass ratio of calcium nitrate to propylene glycol is (1~1.5):(5~6).

9. A method for preparing a sludge solidification agent based on modified components according to any one of claims 1 to 8, characterized in that: Specifically, the following steps are included: S1: Mix the inorganic curing substrate, polymer modifier, and some water, and stir at 100-150 rpm for 30-40 minutes. Then add the nanomaterials and stir at 2000-3000 rpm for 15-20 minutes using a high-speed shear press. S2: Add the remaining water, plasticizer, water-reducing agent, antifreeze, expansion agent, and preservative in sequence, stirring at 600-800 rpm for 15-20 minutes with each addition. Finally, add a pH adjuster to adjust the pH to 7.5-8. S3: Mix the product of S2 with the sludge to be treated at a mass ratio of 1:(5-10), stir thoroughly at 400-500 rpm, and let it stand to cure until solidified sludge is obtained.

10. The application of a sludge solidifying agent based on modified components according to any one of claims 1 to 8 in municipal sewage sludge treatment, industrial wastewater sludge stabilization treatment and river silt treatment.

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