Conditioner for sludge dewatering as well as preparation method and application thereof

Abstract

The invention provides a conditioner for sludge dewatering as well as a preparation method and application thereof, and relates to the technical field of sludge treatment. The conditioner for sludge dewatering is prepared from the following components in parts by weight: 0.3 to 0.4 part of acrylamide, 25 to 30 parts of trimethylallylammonium chloride, 65 to 70 parts of dimethyl diallyl ammonium chloride, 1.0 to 2.0 parts of a surfactant, 1.1 to 1.8 parts of a photoinitiator and 150 to 170 parts of deionized water. By avoiding the use of a large amount of inorganic coagulant and lime, the combustion value of the sludge is kept, the water content of the sludge is lower than 50%, incineration treatment of a power plant is facilitated, and green emission is achieved. The conditioner is neutral and small in dosage, corrosion to the filter cloth is avoided, blockage of the filter cloth is reduced under the promotion action of the surfactant, sludge can be conveniently stripped from the filter cloth, the service life of equipment is prolonged, and the use cost of the conditioner, the transportation cost of the sludge and the operation cost of the plate and frame desliming machine are reduced.

Description

Technical Field

[0001] This invention relates to the field of sludge treatment technology, and in particular to a sludge dewatering conditioner, its preparation method, and its application. Background Technology

[0002] With the rapid development of my country's economy and the acceleration of urbanization, the scale of urban sewage treatment is constantly expanding, and sludge production is also increasing rapidly. Sludge has a high moisture content, resulting in significant treatment costs. For example, the annual sludge dewatering cost for a 300,000-ton-level sewage treatment plant can reach as high as 80 million yuan, placing a heavy burden on enterprises and society. Therefore, how to reduce the moisture content of sludge and lower operating costs by combining specialized machinery and efficient chemicals for sludge dewatering is a pressing technical problem that sewage treatment plants need to solve.

[0003] Currently, the sludge discharged from urban wastewater treatment plants generally has a moisture content as high as 80%. A commonly used sludge dewatering process is chemical modification—plate and frame dewatering. The core technology of this process is the chemical conditioning (modification) of the sludge. Traditional sludge conditioning agents are polyaluminum chloride and lime. Specifically, 150 kg of polyaluminum chloride and 200 kg of lime need to be added to every 1000 kg of sludge.

[0004] This process has the following disadvantages: 1. Adding lime increases the amount of sludge discharged and reduces the overall calorific value. Lime itself is also a high-energy-consuming and high-polluting industry, which can easily cause secondary pollution. 2. The calorific value of the conditioned sludge is low, which is not conducive to disposal and utilization methods such as composting, incineration, and brick making. 3. The moisture content of the conditioned sludge is not less than 65%, which is difficult to meet current environmental protection requirements.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a sludge dewatering conditioner, its preparation method, and its application. This avoids the use of large amounts of inorganic coagulants and lime, thus maintaining the original calorific value of the sludge and ensuring the sludge moisture content is below 50%, facilitating sludge incineration by power plants and significantly reducing sludge emissions, achieving green emissions. Furthermore, the conditioner is neutral and used in small quantities, avoiding the corrosion of filter cloth caused by acidic inorganic coagulants. The surfactant promotes filter cloth clogging, facilitating sludge removal from the filter cloth and extending equipment life. Simultaneously, the overall dosage of the conditioner is reduced, lowering the cost of conditioner use, sludge transportation costs, and the operating costs of the plate and frame dewatering machine.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a sludge dewatering conditioner, comprising the following components by weight: 0.3-0.4 parts acrylamide, 25-30 parts trimethylpropene ammonium chloride, 65-70 parts dimethyl diallyl ammonium chloride, 1.0-2.0 parts surfactant, 1.1-1.8 parts photoinitiator, and 150-170 parts water.

[0008] Furthermore, based on the above technical solution, the surfactant is a cationic surfactant, including one or more of polydimethyldiallylammonium chloride, hexadecyltrimethylammonium bromide, chitosan and its derivatives, and octadecyltrimethylammonium chloride; And / or, the photoinitiator includes one or more of ferrocene, 2-isopropylthioxanthone, α-hydroxyisobutyrylbenzene, and 1-hydroxycyclohexylphenyl ketone.

[0009] Furthermore, based on the above technical solution, the sludge dewatering conditioner is a colorless or pale yellow liquid conditioner. And / or, the viscosity of the conditioner used for sludge dewatering is 8000-12000 Cp.

[0010] The present invention also provides a method for preparing the conditioner for sludge dewatering as described above, comprising the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the mixture is stirred at low temperature to obtain a mixture. S3. Surface modification: The surfactant is premixed with the remaining deionized water and then added to the mixture, and the mixture is heated to obtain a modified solution. S4. Maturation treatment: The modified solution is cooled down, then a photoinitiator is added to carry out a photocatalytic reaction. Finally, the temperature is raised to 70°C and the reaction is stopped to obtain a conditioner for sludge dewatering.

[0011] Furthermore, based on the above technical solution, in step S1, the segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stirring should be carried out at a temperature of 9-11℃. If the stirring time is greater than 5 minutes, stir while maintaining a temperature of 12-15℃ until the acrylamide is dissolved. And / or, in step S1, the portion of deionized water accounts for 20-30% of the total weight of deionized water.

[0012] Furthermore, based on the above technical solution, in step S2, the temperature of the low-temperature stirring is ≤15℃, the stirring speed is 200-300rpm, and the stirring time is 30-45min.

[0013] Furthermore, based on the above technical solution, in step S3, the heating process includes: Raise the temperature to 35-40℃ and maintain the pH at 6.8-7.2.

[0014] Furthermore, based on the above technical solution, in step S4, the modified solution is cooled to ≤5℃, and then a photoinitiator is added; And / or, the photocatalytic reaction includes the following conditions: Under a protective atmosphere, a light source with a wavelength of 250-400 nm is used, with an illumination intensity of 10-100 mW / cm². 2 Under these conditions, stir at a speed of 50-80 rpm for 1.5-2.0 hours; The protective atmosphere includes one of nitrogen, argon, and helium; the pressure of the protective atmosphere is 0.05-0.2 MPa. And / or, in step S4, the heating rate to 70°C is 2-5°C / min.

[0015] The present invention also provides an application of the sludge dewatering conditioner prepared by the above-described method or the sludge dewatering conditioner prepared by the above-described method, wherein the sludge dewatering conditioner is used for dewatering treatment of sludge from urban sewage treatment plants, industrial organic sludge or oily sludge.

[0016] Furthermore, based on the above technical solution, the dosage of the sludge dewatering conditioner is 0.2-0.6% of the dry weight of the sludge.

[0017] The present invention provides a sludge dewatering conditioner, its preparation method, and its application, the beneficial effects of which include at least the following: 1. The sludge treated with the sludge dewatering conditioner provided by this invention has a low moisture content (≤50%) and an increased calorific value, which facilitates the incineration of the sludge, reduces the amount of sludge discharged, and achieves green emissions. 2. The surfactant added to the sludge dewatering conditioner of this invention can reduce filter cloth clogging and facilitate the sludge peeling off from the filter cloth. Moreover, the absence of acidic inorganic coagulants avoids corrosion of the filter cloth by inorganic coagulants, extending the equipment life. At the same time, since the conditioner is a liquid conditioner, it has high mixing uniformity with sludge, which can significantly reduce the overall dosage of conditioner, thereby reducing the cost of conditioner use, sludge transportation cost, and dewatering machine operating cost. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0019] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0020] According to a first aspect of the present invention, a sludge dewatering conditioner is provided, comprising, by weight, the following components: 0.3-0.4 parts of acrylamide (e.g., 0.32 parts, 0.34 parts, 0.36 parts, 0.38 parts, etc.), 25-30 parts of trimethylpropene ammonium chloride (e.g., 26 parts, 27 parts, 28 parts, 29 parts, etc.), 65-70 parts of dimethyl diallyl ammonium chloride (e.g., 66 parts, 67 parts, 68 parts, 69 parts, etc.), 1.0-2.0 parts of surfactant (e.g., 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, etc.), 1.1-1.8 parts of photoinitiator (e.g., 1.2 parts, 1.4 parts, 1.5 parts, 1.7 parts, etc.), and 150-170 parts of water (e.g., 155 parts, 160 parts, 165 parts, etc.).

[0021] Specifically, the sludge dewatering conditioner provided by this invention is composed of 0.3-0.4 parts acrylamide, 25-30 parts trimethylpropeneammonium chloride, 65-70 parts dimethyldiallylammonium chloride, 1.0-2.0 parts surfactant, 1.1-1.8 parts photoinitiator, and 150-170 parts water. Among these, trimethylpropeneammonium chloride (TMAMC), as a monomer with a high cationic charge density, plays a crucial role in the sludge dewatering conditioner. Because TMAMC does not contain long side chains, it maintains a high cationic charge density, effectively neutralizing the charge on the surface of negatively charged sludge particles, thereby significantly reducing inter-particle repulsion and promoting particle aggregation and flocculation. This charge neutralization not only enhances the flocculation effect but also makes the formed flocs more compact and stable, which is beneficial for the subsequent dewatering process.

[0022] Furthermore, TMAMC exhibits a good synergistic effect with dimethyl diallyl ammonium chloride (DMDAAC). As a crosslinking monomer, DMDAAC can form a three-dimensional network structure during polymerization, significantly improving the crosslinking density and mechanical strength of the polymer. This crosslinking structure not only enhances the polymer's adsorption capacity but also effectively immobilizes flocs within the polymer network, further improving the stability and mechanical strength of the flocs. Through the synergistic effect of TMAMC and DMDAAC, the resulting polymer possesses not only a high cationic charge density but also an excellent crosslinking structure, thus significantly improving the dewatering performance of sludge. This polymer can effectively adsorb and immobilize sludge particles within the polymer network, forming dense flocs, thereby reducing the porosity between particles and lowering the water content of the sludge. Simultaneously, the enhanced crosslinking structure also improves the shear resistance of the flocs, making them less prone to breakage during dewatering, thereby further improving dewatering efficiency.

[0023] Furthermore, the present invention specifies a ratio of 25-30 parts TMAMC and 65-70 parts DMDAAC to ensure that the polymer has optimal cationic charge density, efficient flocculation effect, good cross-linking structure, and cost-effectiveness. If the amount of TMAMC is too low (e.g., less than 25 parts), the cationic charge density will be insufficient, failing to effectively neutralize the charge of negatively charged sludge particles, thus reducing the flocculation effect. If the amount of TMAMC is too high (e.g., more than 30 parts), the cationic charge density will be too high, increasing production costs and potentially causing excessive aggregation between particles, forming unstable flocs, which in turn affects the dewatering effect. If the amount of DMDAAC is too low (e.g., less than 65 parts), the cross-linking density will be insufficient, failing to form a dense three-dimensional network structure, thus reducing the polymer's mechanical strength and adsorption capacity, affecting the dewatering effect. If the amount of DMDAAC is too high (e.g., more than 70 parts), the cross-linking density will be too high, making the polymer too dense, affecting its solubility and dispersibility in water, thus reducing the flocculation effect.

[0024] Typically, without limitation, the water in the conditioner can be deionized water or purified water, etc.

[0025] As an optional embodiment of the present invention, the surfactant is a cationic surfactant, including one or more of polydimethyldiallylammonium chloride (PDMDAAC), hexadecyltrimethylammonium bromide, chitosan and its derivatives, and octadecyltrimethylammonium chloride.

[0026] As an optional embodiment of the present invention, the photoinitiator includes one or more of ferrocene salts, photoinitiator ITX (2-isopropylthioxanthone), photoinitiator 1173 (α-hydroxyisobutyrylbenzene), and photoinitiator 184 (1-hydroxycyclohexylphenyl ketone).

[0027] Specifically, photoinitiators can instantly generate a large number of active free radicals that attack the carbon-carbon double bonds of acrylamide (AM), trimethylpropene ammonium chloride (TMAMC), and dimethyl diallyl ammonium chloride (DMDAAC) molecules, initiating a chain of free radical copolymerization reactions. Because DMDAAC contains two double bonds, it also acts as a crosslinking agent, synergistically forming a three-dimensional network structure of polymer with TMAMC (which provides high cationic density). Moreover, photopolymerization reactions are usually carried out at room temperature or lower temperatures without the need for external heating, which greatly reduces energy consumption and avoids problems such as monomer volatilization, excessive polymer crosslinking, or decomposition that may be caused by high temperatures, which is more in line with the principles of green chemistry.

[0028] Furthermore, since both trimethylpropeneammonium chloride (TMAMC) and dimethyldiallylammonium chloride (DMDAAC) are highly reactive vinyl monomers, the photoinitiator can instantly generate a large number of active free radicals, which can simultaneously activate a large number of TMAMC and DMDAAC molecules, promoting their rapid copolymerization rather than their individual polymerization reactions. This ensures that the high cationic charge density of TMAMC can be uniformly embedded into the polymer backbone, rather than forming isolated blocks. This achieves efficient charge neutralization of the entire polymer network and avoids the problems of slow initiation speed and some DMDAAC possibly participating in the reaction of only one double bond, resulting in insufficient crosslinking density and loose polymer structure.

[0029] As an optional embodiment of the present invention, the sludge dewatering conditioner is a colorless or pale yellow liquid conditioner; The viscosity of the conditioner used for sludge dewatering is 8000-12000 Cp (e.g., 9000 Cp, 10000 Cp, 11000 Cp, 11500 Cp, etc.).

[0030] According to a second aspect of the present invention, a method for preparing the sludge dewatering conditioner as described above is provided, comprising the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the mixture is stirred at low temperature to obtain a mixture. S3. Surface modification: The surfactant is premixed with the remaining deionized water and then added to the mixture, and the mixture is heated to obtain a modified solution. S4. Maturation treatment: The modified solution is cooled down, then a photoinitiator is added to carry out a photocatalytic reaction. Finally, the temperature is raised to 70°C and the reaction is stopped to obtain a conditioner for sludge dewatering.

[0031] As an optional embodiment of the present invention, in step S1, the portion of deionized water accounts for 20-30% of the total weight of deionized water (e.g., 22%, 25%, 27%, etc.). In step S1, the segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stir at a temperature of 9-11℃ (e.g., 9.5℃, 10℃, 10.5℃, etc.). When stirring for more than 5 minutes, maintain the temperature at 12-15℃ (e.g., 13℃, 13.5℃, 14℃, etc.) while stirring until the acrylamide is dissolved.

[0032] Specifically, in this invention, stirring is carried out at a temperature of 9-11°C for a stirring time of ≤5 min. The purpose is to suppress the self-polymerization reaction of acrylamide. The lower temperature also helps acrylamide molecules to be evenly dispersed in water, reducing local high concentrations and thus avoiding polymerization caused by local overheating. Subsequently, the temperature is raised to 12-15°C. The higher temperature helps to break the hydrogen bonds between acrylamide molecules, increasing its diffusion ability in water, thereby improving solubility and ensuring that acrylamide is completely dissolved.

[0033] Furthermore, if the temperature is maintained at 9-11℃ in step S1, it may prolong the dissolution time of acrylamide, or even prevent it from dissolving completely. Undissolved acrylamide particles may remain in the solution, affecting the uniformity of subsequent monomer mixing, resulting in uneven polymer performance and thus affecting the sludge dewatering effect. If the temperature is subsequently raised to above 15℃, acrylamide is prone to free radical polymerization at high temperatures, forming a polymer that is insoluble in water, increasing the viscosity and instability of the solution, making reaction control difficult, and affecting the performance of the final product.

[0034] As an optional embodiment of the present invention, in step S2, the temperature of the low-temperature stirring is ≤15℃ (e.g., 13℃, 13.5℃, 14℃, etc.), the stirring speed is 200-300rpm (e.g., 220rpm, 240rpm, 260rpm, 280rpm, etc.), and the stirring time is 30-45min (e.g., 35min, 40min, 43min, etc.).

[0035] Specifically, although the complete dissolution of acrylamide was ensured by segmented temperature control and stirring in step S1, there is still a risk of acrylamide undergoing self-polymerization in step S2 due to the introduction of TMAMC and DMDAAC into the system. By keeping the temperature of the system ≤15℃, the self-polymerization reaction of acrylamide can be further prevented; and if the temperature is too high, it may cause the decomposition or denaturation of TMAMC and DMDAAC, affecting the reaction effect.

[0036] In an optional embodiment of the present invention, step S3 includes the following heating process: Raise the temperature to 35-40℃ (e.g., 36℃, 37℃, 38℃, 39℃, etc.) and maintain the pH value at 6.8-7.2 (e.g., 6.9, 7.0, 7.1, etc.).

[0037] Specifically, in step S3, the trimethylpropene ammonium chloride, dimethyl diallyl ammonium chloride, and acrylamide in the mixture are modified by surfactants to improve their binding with negatively charged sludge particles, disrupt the colloidal stability of the sludge, generate denser and stronger flocs, and improve dewatering efficiency.

[0038] Furthermore, raising the temperature to 35-40℃ helps reduce the viscosity of the system, intensifies the movement of surfactant and monomer molecules, and promotes uniform mixing. However, if the temperature is raised too high, it significantly increases the risk of thermal polymerization of acrylamide (AM) and also causes hydrolysis of trimethylpropene ammonium chloride (TMAMC), resulting in a decrease in the cationicity of the final polymer and a weakening of its charge neutralization ability.

[0039] Furthermore, maintaining a pH of 6.8-7.2 is beneficial for cationic surfactants and cationic monomers (TMAMC, DMDAAC) to maintain their positive charge, thereby interacting more effectively with negatively charged sludge particles. For acrylamide (AM) units, a near-neutral environment can reduce their tendency to hydrolyze into anionic acrylic acid, avoid molecular chain coiling due to intramolecular positive and negative charge neutralization, thus maintaining the extended conformation of polymer molecular chains and exerting optimal adsorption bridging ability.

[0040] As an optional embodiment of the present invention, in step S4, the modified solution is cooled to ≤5℃ (e.g., 2℃, 3℃, 4℃, etc.) and then a photoinitiator is added; In step S4, the photocatalytic reaction includes the following conditions: Under a protective atmosphere, a light source with a wavelength of 250-400nm (280nm, 300nm, 350nm, 380nm, etc.) is used (the appropriate wavelength is selected based on the chosen photoinitiator), and the light intensity is 10-100mW / cm². 2 (e.g., 30mW / cm) 2 50mW / cm 2 70mW / cm 2 90mW / cm 2 Under the conditions of (etc.), stir at a speed of 50-80 rpm (e.g., 60 rpm, 70 rpm, 75 rpm, etc.) for 1.5-2.0 h (e.g., 1.6 h, 1.7 h, 1.8 h, 1.9 h, etc.). The protective atmosphere includes one of nitrogen, argon, and helium; the pressure of the protective atmosphere is 0.05-0.2 MPa (e.g., 0.07 MPa, 0.1 MPa, 0.15 MPa, etc.); the light source is a conventional medium-pressure mercury lamp; as the photocatalytic reaction proceeds, the temperature gradually rises from 5°C to room temperature.

[0041] Specifically, cooling the temperature to ≤5℃ and then adding the photoinitiator can significantly reduce the thermal mobility of each component (especially the monomer) in the system, effectively suppressing thermally initiated polymerization that may occur after the photoinitiator is added and before the light irradiation begins, and ensuring that the polymerization reaction is dominated by light control.

[0042] As an optional embodiment of the present invention, in step S4, the heating rate to 70°C is 2-5°C / min (e.g., 3°C / min, 4°C / min, etc.).

[0043] Specifically, the purpose of raising the temperature to 70°C is to rapidly deactivate the residual initiator and short-chain free radicals, ensuring that the polymerization reaction is completely stopped, preventing changes in product performance during storage, and also promoting the improvement and stability of the crosslinking structure, making the formed polymer network more robust.

[0044] According to a third aspect of the present invention, an application of the sludge dewatering conditioner as described above is provided, the sludge dewatering conditioner being used for the dewatering treatment of sludge from municipal wastewater treatment plants, industrial organic sludge, or oily sludge.

[0045] As an optional embodiment of the present invention, the dosage of the sludge dewatering conditioner is 0.2-0.6% (e.g., 0.3%, 0.4%, 0.5%, etc.) of the sludge dry weight.

[0046] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0047] Example 1 This embodiment provides a sludge dewatering conditioner, which, by weight, comprises the following components: 0.3 parts acrylamide, 25 parts trimethylpropene ammonium chloride, 65 parts dimethyl diallyl ammonium chloride, 1.0 part octadecyltrimethylammonium chloride (surfactant), 1.1 parts photoinitiator ITX (2-isopropylthioxanthraquinone), and 150 parts deionized water.

[0048] This embodiment also provides a method for preparing a conditioner for sludge dewatering, comprising the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; The segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stir at a temperature of 10℃. If the stirring time is greater than 5 minutes, stir at a temperature of 15°C until the acrylamide is dissolved. The deionized water portion accounts for 20% of the total weight of deionized water.

[0049] S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the system temperature is kept ≤15℃. The mixture is stirred at 200 rpm for 30 min to obtain the mixture. S3. Surface modification: Octadecyltrimethylammonium chloride is premixed with the remaining deionized water and then added to the mixture. The temperature is simultaneously raised to 35°C and the pH is maintained at 6.8 to obtain a modified solution. S4. Aging Treatment: The modified solution is cooled to ≤5℃, and under nitrogen protection at a pressure of 0.2MPa, the photoinitiator ITX (2-isopropylthioxanthraquinone) is added. A light source with a wavelength of 380nm is used, and the light intensity is 40mW / cm². 2 Under these conditions, the mixture was stirred at a low speed of 60 rpm for 1.5 h; finally, the temperature was raised to 70 °C, and the reaction was stopped to obtain a liquid conditioner with a viscosity of 11286 Cp and a colorless color.

[0050] Example 2 This embodiment provides a sludge dewatering conditioner, which, by weight, comprises the following components: 0.35 parts acrylamide, 28 parts trimethylpropene ammonium chloride, 68 parts dimethyl diallyl ammonium chloride, 1.5 parts hexadecyltrimethylammonium bromide (surfactant), 1.5 parts photoinitiator 1173 (α-hydroxyisobutyrylbenzene), and 160 parts deionized water.

[0051] This embodiment also provides a method for preparing a conditioner for sludge dewatering, comprising the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; The segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stir at a temperature of 10℃. If the stirring time is greater than 5 minutes, stir at a temperature of 12°C until the acrylamide is dissolved. The deionized water portion accounts for 25% of the total weight of deionized water.

[0052] S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the system temperature is kept ≤15℃. The mixture is stirred at 250 rpm for 35 min to obtain the mixture. S3. Surface modification: Hexadecyltrimethylammonium bromide is premixed with the remaining deionized water and then added to the mixture. The temperature is simultaneously raised to 36°C and the pH is maintained at 7.0 to obtain a modified solution. S4. Curing Treatment: The modified solution is cooled to ≤5℃, and under nitrogen protection at a pressure of 0.2MPa, photoinitiator 1173 (α-hydroxyisobutyrylbenzene) is added. A light source with a wavelength of 250nm is used, and the light intensity is 60mW / cm². 2 Under these conditions, the mixture was stirred at a low speed of 50 rpm for 2.0 h, and then the temperature was raised to 70 °C to stop the reaction, resulting in a liquid conditioner with a viscosity of 9564 Cp and a light yellow color.

[0053] Example 3 This embodiment provides a sludge dewatering conditioner, which, by weight, comprises the following components: 0.4 parts acrylamide, 30 parts trimethylpropene ammonium chloride, 70 parts dimethyl diallyl ammonium chloride, 2.0 parts octadecyltrimethylammonium chloride (surfactant), 1.8 parts photoinitiator 184 (1-hydroxycyclohexylphenyl ketone), and 170 parts deionized water.

[0054] This embodiment also provides a method for preparing a conditioner for sludge dewatering, comprising the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; The segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stir at a temperature of 10℃. If the stirring time is greater than 5 minutes, stir at a temperature of 15°C until the acrylamide is dissolved. The deionized water portion accounts for 30% of the total weight of deionized water.

[0055] S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the system temperature is kept ≤15℃. The mixture is stirred at 300 rpm for 45 min to obtain the mixture. S3. Surface modification: Octadecyltrimethylammonium chloride is premixed with the remaining deionized water and then added to the mixture. The temperature is simultaneously raised to 40°C and the pH is maintained at 7.2 to obtain a modified solution. S4. Curing Treatment: The modified solution is cooled to ≤5℃. Under nitrogen protection at a pressure of 0.2MPa, photoinitiator 184 (1-hydroxycyclohexylphenyl ketone) is added. A light source with a wavelength of 250nm and an irradiance of 50mW / cm² is used. 2Under these conditions, the mixture was stirred at a low speed of 80 rpm for 2.0 h, and then the temperature was raised to 70 °C to stop the reaction, resulting in a colorless liquid conditioner with a viscosity of 10846 Cp.

[0056] Comparative Example 1 This comparative example uses traditional sludge conditioners: polyaluminum chloride and lime; Traditional sludge conditioners are prepared by adding 150 kg of polyaluminum chloride and 200 kg of lime to every 1000 kg of sludge.

[0057] Comparative Example 2 The main difference between this comparative example and Example 1 is that 15 parts of trimethylpropene ammonium chloride were added, while the remaining steps and technical parameters are the same as in Example 1.

[0058] Comparative Example 3 The main difference between this comparative example and Example 1 is that 40 parts of trimethylpropene ammonium chloride were added, while the remaining steps and technical parameters are the same as in Example 1.

[0059] Comparative Example 4 The main difference between this comparative example and Example 1 is that the stirring was carried out at 10°C throughout step S1, while the other steps and technical parameters were the same as in Example 1.

[0060] Comparative Example 5 The main difference between this comparative example and Example 1 is that in step S1, the segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stir at a temperature of 10℃. When the stirring time is greater than 5 minutes, stir while maintaining a temperature of 20°C. The remaining steps and technical parameters are the same as in Example 1.

[0061] Comparative Example 6 The main difference between this comparative example and Example 1 is that in step S2, after adding trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride to the premixed solution in sequence, the system temperature is kept at 25°C for mixing. The remaining steps and technical parameters are the same as in Example 1.

[0062] Comparative Example 7 The main difference between this comparative example and Example 1 is that trimethylpropene ammonium chloride is replaced with methacryloyloxyethyltrimethylammonium chloride, while the remaining steps and technical parameters are the same as in Example 1.

[0063] Comparative Example 8 Compared with Example 1, this comparative example replaces the photoinitiator with potassium persulfate, specifically including the following steps: This comparative example provides a sludge dewatering conditioner, which, by weight, comprises the following components: 0.3 parts acrylamide, 25 parts trimethylpropylene ammonium chloride, 65 parts dimethyl diallyl ammonium chloride, 1.0 part octadecyltrimethylammonium chloride, 1.1 parts potassium persulfate, and 150 parts deionized water.

[0064] This comparative example also provides a method for preparing a conditioner for sludge dewatering, comprising the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; The segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stir at a temperature of 10℃. If the stirring time is greater than 5 minutes, stir at a temperature of 15°C until the acrylamide is dissolved. The deionized water portion accounts for 20% of the total weight of deionized water.

[0065] S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the system temperature is kept ≤15℃. The mixture is stirred at 200 rpm for 30 min to obtain the mixture. S3. Surface modification: Octadecyltrimethylammonium chloride is premixed with the remaining deionized water and then added to the mixture. The temperature is simultaneously raised to 35°C and the pH is maintained at 6.8 to obtain a modified solution. S4. Maturation treatment: Add potassium persulfate to the modified solution and stir at 200 r / min for 15 min at 40°C; then cool to 8°C and stir at 60 rpm for 1.5 h to obtain a liquid conditioner.

[0066] Performance testing Sludge from a municipal wastewater treatment plant was selected as the test sample. The test sample was divided into multiple portions and added to a plate and frame desludge dewatering machine along with the liquid conditioner obtained in the examples and comparative examples. The moisture content and thickness of the conditioned sludge were then tested. The amount of liquid conditioner added was 0.5% of the dry weight of the sludge.

[0067] (1) Methods for detecting moisture content: Weigh the initial mass: Take 15-30 grams of sludge sample treated with sludge conditioner, weigh its total mass, and record the total mass as M1. Drying treatment: Place the sludge sample in an oven preheated to 105-110℃ and dry for 1-2 hours, or until the sample reaches constant weight (the difference in mass between two consecutive weighings is less than 0.1%). Weigh the dried sample: Remove the sample, cool it to room temperature, and weigh the total mass as M2. Moisture content = (M1 - M2) / M1 × 100%; The test method for the initial sludge moisture content of the test samples is the same as above.

[0068] (2) Methods for detecting sludge thickness: Take 100g of sludge sample treated with sludge conditioner and put it into a standard cylindrical measuring cylinder (smooth inner wall, 100mm in diameter, equipped with a freely sliding piston head), smooth the surface, but avoid pre-compacting; Place the piston head into the measuring cylinder and bring it into contact with the sludge surface. Start the constant pressure loading device to apply a preset standard pressure (50 kPa) to the piston, and start the timer at the same time. Keep the pressure constant for 5 minutes. After the process is complete, record the position of the piston, which is the thickness of the sludge after compression (the smaller the thickness value, the lower the moisture content).

[0069] (3) Method for detecting the viscosity of liquid conditioner: At around 25°C, immerse the viscometer probe (Brookfield model) in the liquid conditioner and measure for 15 minutes, then record the viscosity value.

[0070] Performance data Table 1 As shown in Table 1, compared with Example 1, the traditional sludge conditioner used in Comparative Example 1 is a mixed solid, which has poor uniformity in the sludge and unsatisfactory dewatering effect, resulting in a higher moisture content of the sludge after conditioning compared with Example 1.

[0071] As shown in Table 1, compared with Example 1, Comparative Example 2 added less trimethylpropene ammonium chloride, resulting in insufficient cation charge density. This made it unable to effectively neutralize the negatively charged sludge particles, thereby reducing the flocculation effect and making the moisture content of the conditioned sludge higher than that of Example 1.

[0072] As shown in Table 1, compared with Example 1, Comparative Example 3 contains more trimethylpropene ammonium chloride, resulting in excessively high cationic charge density, increasing production costs, and causing excessive aggregation between particles, forming unstable flocs. This significantly increases the viscosity of the conditioner, thereby affecting the uniformity of mixing with the sludge, resulting in unsatisfactory dewatering effect and a higher moisture content in the conditioned sludge compared to Example 1.

[0073] As shown in Table 1, compared with Example 1, in Comparative Example 4, the stirring was carried out at 10°C in step S1. Some acrylamide could not be completely dissolved and remained in the solution, which affected the uniformity of subsequent monomer mixing, resulting in uneven polymer performance and thus affecting the sludge dewatering effect. As a result, the moisture content of the conditioned sludge was higher than that of Example 1.

[0074] According to Table 1, compared with Example 1, in Comparative Example 5, when the segmented stirring time in step S1 was greater than 5 min, the stirring temperature was too high, which caused acrylamide to undergo free radical polymerization, forming a polymer that is insoluble in water. This increased the viscosity of the solution, which in turn affected the uniformity of mixing with the sludge, resulting in an unsatisfactory dewatering effect and a higher moisture content in the conditioned sludge compared to Example 1.

[0075] According to Table 1, compared with Example 1, the system temperature in step S2 of Comparative Example 6 was too high, which not only caused the acrylamide to undergo a self-polymerization reaction, but also triggered the decomposition of trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride. The viscosity of the conditioner decreased, the flocculation effect was poor, and the moisture content of the sludge after conditioning was higher than that of Example 1.

[0076] According to Table 1, compared with Example 1, in Comparative Example 7, trimethylpropene ammonium chloride was replaced with methacryloyloxyethyltrimethylammonium chloride. Methacryloxyethyltrimethylammonium chloride has a longer side chain and a lower cationic charge density, which affects the neutralization of the negative charge on the surface of the sludge particles, resulting in an unsatisfactory dewatering effect and a higher moisture content in the conditioned sludge compared with Example 1.

[0077] The persulfate ions in potassium persulfate carry a negative charge, while trimethylpropeneammonium chloride (TMAMC) and dimethyldiallylammonium chloride (DMDAAC) are both strongly cationic monomers with a strong positive charge. Therefore, a large number of negative ions accumulate on the surface of these two monomer molecules. When the negatively charged persulfate radicals generated by potassium persulfate attempt to contact the positively charged reaction sites of TMAMC and DMDAAC, strong electron cloud repulsion and steric hindrance prevent effective chemical bonding. In contrast, the photoinitiator generates electrically neutral radicals that can approach and attack the reaction sites of both monomers without hindrance, thus achieving efficient and controllable polymerization. Therefore, according to Table 1, compared to Example 1, Comparative Example 8, where the photoinitiator was replaced with potassium persulfate, showed a less effective sludge dewatering effect than Example 1.

[0078] In summary, under the same sludge feed rate (with an error range of ±0.3%), the liquid conditioner provided by this invention, after mixing with sludge and dewatering through a plate and frame dewatering machine, results in sludge with a moisture content of less than 50% and a reduced thickness. This improves the dewatering effect, reduces sludge transportation costs, eliminates the need for lime addition, avoids secondary pollution, and achieves green emissions. Furthermore, since no lime is added, and with the action of surfactants, filter cloth clogging and corrosion are reduced, facilitating sludge removal from the filter cloth and extending equipment lifespan.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A conditioner for sludge dewatering, characterized in that, By weight, it comprises the following components: 0.3-0.4 parts acrylamide, 25-30 parts trimethylpropene ammonium chloride, 65-70 parts dimethyl diallyl ammonium chloride, 1.0-2.0 parts surfactant, 1.1-1.8 parts photoinitiator, and 150-170 parts water.

2. The sludge dewatering conditioner according to claim 1, characterized in that, The surfactant is a cationic surfactant, including one or more of polydimethyldiallylammonium chloride, hexadecyltrimethylammonium bromide, chitosan and its derivatives, and octadecyltrimethylammonium chloride; And / or, the photoinitiator includes one or more of ferrocene, 2-isopropylthioxanthone, α-hydroxyisobutyrylbenzene, and 1-hydroxycyclohexylphenyl ketone.

3. The sludge dewatering conditioner according to claim 1, characterized in that, The sludge dewatering conditioner is a colorless or pale yellow liquid conditioner; And / or, the viscosity of the conditioner used for sludge dewatering is 8000-12000 Cp.

4. A method for preparing a sludge dewatering conditioner as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Pre-dissolution: Acrylamide is added to a portion of deionized water and stirred in stages with controlled temperature to obtain a premixed solution; S2. Monomer mixing: Trimethylpropene ammonium chloride and dimethyl diallyl ammonium chloride are added sequentially to the premix, and the mixture is stirred at low temperature to obtain a mixture. S3. Surface modification: The surfactant is premixed with the remaining deionized water and then added to the mixture, and the mixture is heated to obtain a modified solution. S4. Maturation treatment: The modified solution is cooled down, then a photoinitiator is added to carry out a photocatalytic reaction. Finally, the temperature is raised to 70°C and the reaction is stopped to obtain a conditioner for sludge dewatering.

5. The method for preparing the sludge dewatering conditioner according to claim 4, characterized in that, In step S1, the segmented temperature-controlled stirring includes: When the stirring time is ≤5min, stirring should be carried out at a temperature of 9-11℃. If the stirring time is greater than 5 minutes, stir while maintaining a temperature of 12-15℃ until the acrylamide is dissolved. And / or, in step S1, the portion of deionized water accounts for 20-30% of the total weight of deionized water.

6. The method for preparing the sludge dewatering conditioner according to claim 4, characterized in that, In step S2, the temperature of the low-temperature stirring is ≤15℃, the stirring speed is 200-300rpm, and the stirring time is 30-45min.

7. The method for preparing the sludge dewatering conditioner according to claim 4, characterized in that, In step S3, the heating process includes: Raise the temperature to 35-40℃ and maintain the pH at 6.8-7.

2.

8. The method for preparing the sludge dewatering conditioner according to claim 4, characterized in that, In step S4, the modified solution is cooled to ≤5℃, and then a photoinitiator is added; And / or, the photocatalytic reaction includes the following conditions: Under a protective atmosphere, a light source with a wavelength of 250-400 nm is used, with an illumination intensity of 10-100 mW / cm². 2 Under these conditions, stir at a speed of 50-80 rpm for 1.5-2.0 hours; The protective atmosphere includes one of nitrogen, argon, and helium; the pressure of the protective atmosphere is 0.05-0.2 MPa. And / or, in step S4, the heating rate to 70°C is 2-5°C / min.

9. The application of a sludge dewatering conditioner prepared by any one of claims 1-3 or any one of claims 4-8, wherein the sludge dewatering conditioner is used for dewatering treatment of sludge from urban wastewater treatment plants, industrial organic sludge, or oily sludge.

10. The application according to claim 9, characterized in that, The dosage of the conditioner for sludge dewatering is 0.2-0.6% of the dry weight of the sludge.

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