Sludge cell wall breaker and its application in sludge drying

Abstract

The application relates to the field of sludge treatment, and particularly discloses a sludge wall-breaking agent and application of the sludge wall-breaking agent in sludge drying; the sludge wall-breaking agent comprises a solid carrier and a surface active component, and the mass ratio of the solid carrier and the surface active component is (60-70):(30-40); the solid carrier is a porous diatomite substrate with surface grafted nanomaterials; and the surface active component comprises an amphoteric ionic surfactant and an anionic polymer; the application adopts the porous diatomite substrate with surface grafted nanomaterials, increases the adsorption sites and the reaction active sites of the solid carrier, can pierce the sludge colloidal structure, releases interstitial water and capillary bound water, and achieves the purpose of sludge-water separation; meanwhile, the amphoteric ionic surfactant and the anionic polymer are adopted as the surface active component, the sludge colloidal structure is destroyed and water molecules are released, the sludge colloidal particles are prevented from re-aggregation, and the sludge-water separation effect and the sludge drying efficiency are improved.

Description

A sludge cell disruptor and its application in sludge drying. Technical Field

[0001] This application relates to the field of sludge treatment, and in particular to a sludge cell disruptor and its application in sludge drying. Background Technology

[0002] Currently, the main methods for sludge treatment and disposal in my country include sanitary landfill, direct incineration, aerobic composting, and biogas production. While these methods have solved the sludge treatment problem to some extent, they still have many shortcomings. For example, sanitary landfill occupies a large amount of land resources and is prone to secondary pollution; direct incineration is energy-intensive and may produce harmful gases; aerobic composting has a long cycle and high site requirements; and biogas production is a complex process with low efficiency.

[0003] Furthermore, in the sludge treatment process, to improve sludge drying efficiency, mechanical extrusion is conventionally used to remove some of the water from the sludge, using pressure to squeeze out interstitial water and reduce the sludge's moisture content. Another method is thermal drying, which uses high-temperature hot air to dry the sludge, causing the moisture to evaporate rapidly. However, even after initial dewatering, these methods still result in a moisture content as high as 80%, leading to high transportation costs and large storage areas, further limiting the widespread application of existing technologies. Summary of the Invention

[0004] In order to improve the sludge treatment effect, this application provides a sludge cell disruptor and its application in sludge drying.

[0005] In a first aspect, this application provides a sludge cell-wall breaking agent, which adopts the following technical solution:

[0006] A sludge cell disruptor includes a solid carrier and a surface-active component, wherein the mass ratio of the solid carrier to the surface-active component is (60-70):(30-40), the solid carrier is a porous diatomaceous earth matrix with surface-grafted nanomaterials, and the surface-active component includes amphoteric surfactants and anionic polymers.

[0007] By employing the above technical solutions, grafting nanomaterials onto the surface of a porous diatomaceous earth matrix can bond the nanomaterials to the specific surface area and pore walls of the diatomaceous earth, increasing the adsorption sites and reactive sites of the solid carrier, and firmly loading the surface-active components onto the surface and pores of the carrier. Thorough mixing of the cell-wall disruptor and sludge allows the spike-like morphology of the disruptor to pierce the colloidal structure of the sludge, thereby releasing interstitial water and capillary-bound water, achieving sludge-water separation. Amphoteric surfactants can penetrate and disrupt the cell membranes and flocs of sludge, releasing intracellular water and converting it into free water, which can be easily removed by simple gravity sedimentation or mechanical dehydration. Simultaneously, amphoteric surfactants can emulsify hydrophobic oily substances in the sludge, reducing clogging of the filter media. Anionic polymers prevent sludge colloidal particles from re-aggregating to form new dense flocs through adsorption bridging and steric hindrance effects, thereby improving the durability of sludge disintegration and ensuring that sludge moisture continues to evaporate easily during dewatering and drying processes. This prevents water from being locked back in due to sludge re-aggregation, thus improving sludge-water separation efficiency and sludge drying efficiency.

[0008] Preferably, the porous diatomaceous earth matrix surface is grafted with nano-zinc oxide to form a solid carrier, and the aspect ratio of the solid carrier is (10-15):1.

[0009] By adopting the above technical solution, the resulting solid carrier has a rough surface and nano-edges, which can cut extracellular polymers and bacterial flocs in sludge, destroy the gel-like structure of sludge, release the encapsulated water, and promote sludge-water separation.

[0010] Preferably, the method for grafting nano-zinc oxide onto the surface of the porous diatomaceous earth matrix includes the following specific steps: pre-grinding and acid-leaching the porous diatomaceous earth matrix, and drying it to obtain pre-treated diatomaceous earth; mixing zinc nitrate, citric acid, water, and anhydrous ethanol to form a reaction solution; adding polyethylene glycol and ammonia to the reaction solution; ultrasonically dispersing and heating in a water bath; finally adding the pre-treated porous diatomaceous earth matrix to the reaction solution for mixing and reaction; allowing it to stand; and then drying, grinding, and calcining the product to obtain the grafted composite of nano-zinc oxide and porous diatomaceous earth matrix.

[0011] By adopting the above technical solution, zinc oxide is loaded onto the surface and pores of diatomaceous earth, forming nanoscale needle-like protrusions on the surface of diatomaceous earth. This increases the specific surface area and roughness of the solid carrier, punctures the colloidal structure of sludge, and provides more active sites for subsequent cell wall disruption reactions.

[0012] Preferably, the mass ratio of the porous diatomaceous earth matrix, zinc nitrate, citric acid, and polyethylene glycol is 10:(10-12):(1-2):(0.5-0.8).

[0013] Preferably, the water bath heating temperature is (80-90)℃.

[0014] Preferably, the porous diatomaceous earth matrix has a particle size of 50-200 μm.

[0015] Preferably, the mass ratio of the zwitterionic surfactant to the anionic polymer is (2-4):1.

[0016] Preferably, the zwitterionic surfactant is cocamidopropyl betaine, and the anionic polymer is hydrolyzed polymaleic anhydride.

[0017] Secondly, this application provides an application of a sludge cell-wall breaking agent in sludge drying, employing the following technical solution:

[0018] The application of a sludge cell wall breaking agent in sludge drying includes the following specific steps: mixing a solid carrier and a surface-active component evenly to obtain a sludge cell wall breaking agent; mixing the sludge cell wall breaking agent with sludge; spraying in a liquid deodorizing additive; and finally adding a recycled fuel additive and stirring evenly to obtain sludge recycled fuel. The sludge drying process is completed by turning, drying, and collecting the material.

[0019] By employing the above technical solutions, the sludge cell-wall breaking agent, through thorough mixing with the sludge, utilizes its own spike-like morphology to pierce the colloidal structure of the sludge, releasing natural and biological water; the liquid deodorizing additive deodorizes through spraying; and the recycled fuel additive improves combustion performance. The drying process reduces the sludge moisture content through natural drying, completing the sludge drying process. By combining these processes, the sludge moisture content can be reduced quickly and efficiently in a relatively simple process, while the production process is free of secondary pollution and improves resource utilization.

[0020] Preferably, the amount of sludge cell disruptor added is (0.8-1.2)% of the sludge, the amount of liquid deodorizing additive added is (0.8-1.2)‰ of the sludge, and the amount of recycled fuel additive added is (30-50)% of the sludge.

[0021] In summary, this application has the following beneficial effects:

[0022] 1. This application utilizes nanomaterials grafted onto the surface of a porous diatomaceous earth matrix as a carrier to load surfactant components, forming a sludge cell-wall disruptor that can pierce the colloidal structure of sludge, thereby releasing interstitial water and capillary-bound water to achieve sludge-water separation. The surfactant can penetrate and disrupt the cell membranes and flocs of sludge, releasing intracellular water and converting it into free water. Simultaneously, it prevents sludge colloidal particles from re-aggregating to form new dense flocs, improving sludge-water separation efficiency and sludge drying efficiency.

[0023] 2. In this application, a solid carrier is formed by grafting nano-zinc oxide onto the surface of a porous diatomaceous earth matrix. Zinc oxide can form nano-scale needle-like protrusions on the surface of diatomaceous earth, increasing the specific surface area and roughness of the solid carrier, breaking the colloidal structure of sludge, and providing more active sites for subsequent cell wall disruption reactions. Detailed Implementation

[0024] The present application will be further described in detail below with reference to the embodiments.

[0025] All raw materials used in the examples are commercially available.

[0026] The sludge used in this embodiment is municipal sewage sludge with an initial moisture content of 95%.

[0027] Example 1

[0028] This embodiment provides a sludge cell disruptor, comprising a solid carrier and a surface-active component, wherein the mass ratio of the solid carrier to the surface-active component is 65:35. The solid carrier is a porous diatomaceous earth matrix grafted with nano-zinc oxide, and the particle size of the porous diatomaceous earth matrix is ​​150 μm. The surface-active component comprises an amphoteric surfactant and an anionic polymer. The amphoteric surfactant is cocamidopropyl betaine, and the anionic polymer is hydrolyzed polymaleic anhydride, wherein the mass ratio of the amphoteric surfactant to the anionic polymer is 2:1.

[0029] The application of sludge cell wall disruptors in sludge drying includes the following specific steps:

[0030] S1: The porous diatomaceous earth matrix was pre-ground, acid-leached, and then the solid was removed and dried to obtain pre-treated diatomaceous earth. Zinc nitrate, citric acid, and water were mixed, and then anhydrous ethanol was added. The mass ratio of zinc nitrate to water and anhydrous ethanol was 1:10:10 to form a reaction solution. Ammonia was added to the reaction solution to adjust the pH to 10. Polyethylene glycol (PEG400) was then added dropwise to the reaction solution. The mass ratio of zinc nitrate to polyethylene glycol was 1:0.5. After ultrasonic dispersion, the mixture was heated to 85°C in a water bath. Finally, the pre-treated porous diatomaceous earth matrix was added to the reaction solution and mixed. The mass ratio of porous diatomaceous earth matrix, zinc nitrate, citric acid, and polyethylene glycol was 10:10:1:0.5. The mixture was vacuum reacted for 2 hours. After standing, the product was dried, ground, and calcined to obtain a grafted composite of nano-zinc oxide-porous diatomaceous earth matrix, which is a solid carrier with an aspect ratio of 13:1.

[0031] S2: The solid carrier is mixed with amphoteric surfactants and anionic polymers to form a sludge cell disruptor. The sludge cell disruptor is mixed with sludge at a weight ratio of 1%, and then a liquid deodorizing additive of 1‰ of the sludge weight is sprayed on. The liquid deodorizing additive is sodium hypochlorite. Finally, 30% of the sludge weight of recycled fuel additive, which is straw powder, is added. The mixture is stirred evenly to obtain sludge recycled fuel. The sludge drying process is completed by turning, drying and collecting the material.

[0032] Example 2

[0033] The difference between Example 2 and Example 1 is that the mass ratio of the solid carrier to the surfactant component is 60:40.

[0034] Example 3

[0035] The difference between Example 3 and Example 1 is that the mass ratio of the solid carrier to the surfactant component is 70:30.

[0036] Example 4

[0037] The difference between Example 4 and Example 1 is that the mass ratio of zwitterionic surfactant and anionic polymer in the surfactant component raw material is 4:1.

[0038] Example 5

[0039] The difference between Example 5 and Example 1 is that the mass ratio of porous diatomaceous earth matrix, zinc nitrate, citric acid and polyethylene glycol in the solid carrier raw material is 10:12:2:0.8.

[0040] Example 6

[0041] The difference between Example 6 and Example 1 is that the amount of sludge cell wall disruptor added in the sludge drying application is 0.8% of the sludge weight.

[0042] Example 7

[0043] The difference between Example 7 and Example 1 is that the amount of sludge cell wall disruptor added in the sludge drying application is 1.2% of the sludge weight.

[0044] Example 8

[0045] The difference between Example 8 and Example 1 is that the amount of liquid deodorizing additive added in the sludge cell wall breaking agent in sludge drying application is 1.2‰ of the sludge weight, and the amount of recycled fuel additive added is 30% of the sludge weight.

[0046] Example 9

[0047] The difference between Example 9 and Example 1 is that the amount of liquid deodorizing additive added in the sludge cell wall breaking agent in sludge drying application is 0.8‰ of the sludge weight, and the amount of recycled fuel additive added is 50% of the sludge weight.

[0048] Comparative Example 1

[0049] The difference between Comparative Example 1 and Example 1 is that anionic polymers are not used in the raw materials of the sludge cell wall disruptor.

[0050] Comparative Example 2

[0051] The difference between Comparative Example 2 and Example 1 is that the solid carrier in the sludge cell wall breaking agent raw material is a porous diatomaceous earth matrix.

[0052] The application of sludge cell wall disruptors in sludge drying includes the following specific steps:

[0053] A solid carrier is mixed with amphoteric surfactants and anionic polymers to form a sludge cell-wall breaking agent. The sludge cell-wall breaking agent is mixed with sludge at a weight ratio of 1%, and then a liquid deodorizing additive of 1‰ of the sludge weight (sodium hypochlorite) is sprayed on. Finally, 30% of the sludge weight of recycled fuel additive (straw powder) is added and stirred evenly to obtain sludge recycled fuel. The sludge drying process is completed by turning, drying and collecting the material.

[0054] According to Examples 1-9 and Comparative Examples 1-2 of this application, sludge cell-wall breaking agents and their applications in sludge drying were provided, and the following performance tests were conducted. The specific test results are shown in Table 1.

[0055] I. Moisture content

[0056] The moisture content of the dried sludge in this application was determined using a moisture content meter.

[0057] Table 1: Performance Test Results Data Table

[0058]

[0059] Performance testing results show that the sludge cell disruptor prepared in this application can effectively disrupt the colloidal structure of sludge, effectively breaking down intracellular water into free water, which can then be easily removed through simple gravity settling or mechanical dewatering. This improves the sludge-water separation effect and sludge drying efficiency, resulting in a reduction of the moisture content of the dried sludge to within 20%. Furthermore, the entire sludge drying process is relatively simple, with no secondary pollution during production, thus improving resource utilization.

[0060] A comparison of Comparative Example 1 and Example 1 shows that Comparative Example 1 uses a single zwitterionic surfactant as the surface-active component, and the performance test results indicate that the sludge moisture content increases. This further illustrates that while zwitterionic surfactants can maintain a certain dewatering effect, the dehydrated sludge colloidal particles are prone to re-aggregation, re-encapsulating moisture, which is detrimental to subsequent sludge drying. This application employs the synergistic effect of zwitterionic surfactants and anionic polymers to dewater the sludge while reducing the re-aggregation of colloidal particles, thereby improving the sludge-water separation effect and sludge drying efficiency.

[0061] A comparison of Comparative Example 2 and Example 1 shows that, in Comparative Example 2, no surface grafting was performed on the diatomaceous earth matrix. Performance testing results indicate a significant increase in sludge moisture content and a decrease in sludge drying efficiency. This further demonstrates that a single diatomaceous earth matrix merely acts as a carrier and cannot disrupt the colloidal structure of the sludge. In contrast, this application employs a method that bonds nanomaterials to the specific surface area and pore walls of diatomaceous earth, increasing the adsorption sites and reactive sites of the solid carrier. Simultaneously, it forms a sharp, rough nanostructure on the surface of the diatomaceous earth matrix. Furthermore, the carrier's own spikes pierce the sludge colloidal structure, releasing interstitial water and capillary-bound water, achieving sludge-water separation and improving sludge drying efficiency.

[0062] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A sludge cell-wall breaking agent, characterized in that, The product comprises a solid carrier and a surface-active component, wherein the mass ratio of the solid carrier to the surface-active component is (60-70):(30-40). The solid carrier is a porous diatomaceous earth matrix grafted with nanomaterials. The surface-active component includes amphoteric surfactants and anionic polymers. The solid carrier is formed by grafting nano-zinc oxide onto the surface of the porous diatomaceous earth matrix. The amphoteric surfactant is cocamidopropyl betaine, and the anionic polymer is hydrolyzed polymaleic anhydride.

2. The sludge cell-wall breaking agent according to claim 1, characterized in that, The porous diatomaceous earth matrix surface is grafted with nano zinc oxide to form a solid carrier, and the aspect ratio of the solid carrier is (10-15):

1.

3. The sludge cell-wall breaking agent according to claim 2, characterized in that, The method for grafting nano-zinc oxide onto the surface of a porous diatomaceous earth matrix includes the following specific steps: the porous diatomaceous earth matrix is ​​pre-ground, acid-leached, and dried to obtain pre-treated diatomaceous earth; zinc nitrate, citric acid, water, and anhydrous ethanol are mixed to form a reaction solution; polyethylene glycol and ammonia are added dropwise to the reaction solution; after ultrasonic dispersion, the mixture is heated in a water bath; finally, the pre-treated porous diatomaceous earth matrix is ​​added to the reaction solution for mixing and reaction; after standing, the product is dried, ground, and calcined to obtain the grafted composite of nano-zinc oxide and porous diatomaceous earth matrix.

4. The sludge cell-wall breaking agent according to claim 3, characterized in that, The mass ratio of the porous diatomaceous earth matrix, zinc nitrate, citric acid, and polyethylene glycol is 10:(10-12):(1-2):(0.5-0.8).

5. The sludge cell-wall breaking agent according to claim 3, characterized in that, The water bath heating temperature is (80-90)℃.

6. The sludge cell-wall breaking agent according to claim 3, characterized in that, The porous diatomaceous earth matrix has a particle size of 50-200 μm.

7. The sludge cell-wall breaking agent according to claim 1, characterized in that, The mass ratio of the zwitterionic surfactant to the anionic polymer is (2-4):

1.

8. The application of a sludge cell-wall breaking agent as described in any one of claims 1-7 in sludge drying, characterized in that, The specific steps include: mixing solid carrier and surfactant components evenly to obtain sludge cell-wall breaking agent; mixing sludge cell-wall breaking agent with sludge; spraying and adding liquid deodorizing additive; finally adding recycled fuel additive and stirring evenly to obtain sludge recycled fuel; and collecting the material by turning, drying and sun-drying to complete the sludge drying treatment.

9. The application of the sludge cell wall disruptor according to claim 8 in sludge drying, characterized in that, The amount of sludge cell disruptor added is (0.8-1.2)% of the sludge weight, the amount of liquid deodorizing additive added is (0.8-1.2)‰ of the sludge weight, and the amount of recycled fuel additive added is (30-50)% of the sludge weight.

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