Treatment process of heavy metal polluted sludge

Abstract

The invention discloses a treatment process of heavy metal polluted sludge, and belongs to the technical field of sludge treatment. The invention provides a systematic heavy metal polluted sludge treatment process which comprises the following steps: S1, collecting river sludge, placing the river sludge in a stacking tank, screening to remove large-particle impurities, concentrating the river sludge by adopting a concentration process to obtain slurry, adding tween-80 into the slurry, uniformly mixing and stirring, then adding polyaluminum sulfate and a heavy metal treating agent, and uniformly mixing and stirring to obtain a slurry A; after uniformly mixing and stirring, standing until the sludge is obviously layered up and down, and separating supernatant and lower precipitate; s2, the sediment is dried, smashed and sieved, and sludge powder is prepared; s3, uniformly mixing and stirring sludge powder, fly ash and quicklime to form a mixture, then adding the supernatant separated in the step S1, uniformly mixing and stirring, and then transferring into a mold for natural curing, so that efficient treatment is realized through a physical and chemical synergistic effect, heavy metal ions in the sludge can be efficiently complexed and fixed, migration and secondary pollution of the heavy metal ions can be reduced, and the treatment effect is good. The method is suitable for large-scale treatment of heavy-metal-polluted sludge.

Description

Technical Field

[0001] The present invention relates to the technical field of sludge treatment, and particularly relates to a treatment process for heavy metal contaminated sludge. Background Art

[0002] With the rapid development of industrialization and urbanization, the problem of heavy metal pollution in sludge has become increasingly serious due to the discharge of a large amount of industrial wastewater and domestic sewage. Heavy metals (such as lead, cadmium, chromium, mercury, etc.) pose a serious threat to the ecological environment and human health due to their toxicity, persistence, and bioaccumulation. Traditional sludge treatment methods (such as landfill, incineration, etc.) have problems such as secondary pollution, resource waste, and high treatment costs, and are difficult to meet the modern environmental protection requirements. Therefore, the development of an efficient, economical, and environmentally friendly treatment process for heavy metal contaminated sludge has become a research hotspot.

[0003] Chinese patent document CN11909848A discloses a method for repairing heavy metal contaminated sludge, including: using an iridium-tantalum coated titanium electrode as the anode and a conductive electrode as the cathode, adding a complexing agent to the soft soil contaminated with heavy metals, placing one end of the anode and the cathode in the soft soil contaminated with heavy metals, and connecting the other ends together to be electrically connected to a power source, then adopting a vacuum combined intermittent multi-stage stepwise pressure electroosmosis technology to perform soil body repair and soil body reinforcement on the soft soil contaminated with heavy metals; the vacuum combined intermittent multi-stage stepwise pressure electroosmosis technology is: under vacuum, applying voltage to the soft soil contaminated with heavy metals step by step through the power source, the anode, and the cathode, and performing electroosmosis by means of intermittent treatment of energization and power-off. This invention combines vacuum preloading, electroosmotic consolidation, and electrokinetic remediation to remove heavy metal ions from the soft soil contaminated with heavy metals and perform soil body reinforcement on the soft soil contaminated with heavy metals. This invention involves multiple technical means such as vacuum preloading, electroosmotic consolidation, and electrokinetic remediation, with a complex process, high equipment requirements, great operation difficulty, and high implementation costs, especially poor economy when treating heavy metal contaminated sludge on a large scale. Summary of the Invention

[0004] The main object of the present invention is to propose a treatment process for heavy metal contaminated sludge, which can effectively remove heavy metals from the sludge and is suitable for large-scale treatment of heavy metal contaminated sludge.

[0005] To achieve the above object, the present invention proposes a treatment process for heavy metal contaminated sludge, including the following steps:

[0006] S1. Collect the river sludge and place it in a stacking pool, screen out large particle impurities, concentrate the river sludge by a concentration process to obtain slurry, add Tween-80 to the slurry, mix and stir evenly, then add polyaluminum sulfate and a heavy metal treatment agent, mix and stir evenly and then let it stand, the sludge shows obvious upper and lower stratification, and separate the upper clear liquid and the lower precipitate;

[0007] S2. After drying, pulverizing, and sieving the precipitate, a sludge powder is obtained.

[0008] S3. Mix the sludge powder, fly ash, and quicklime evenly, form a mixture, then add the supernatant separated in step S1, mix and stir evenly, and then transfer it to a mold for natural curing.

[0009] Preferably, in step S1, the concentration process is to concentrate the volume of the river sludge to 1 / 4 - 1 / 3 of the original volume.

[0010] Preferably, in step S1, the addition amount of Tween - 80 is 2 - 4% of the total mass of the slurry.

[0011] Preferably, in step S1, the addition amount of polyaluminum sulfate is 1 - 2% of the total mass of the slurry.

[0012] Preferably, in step S1, the addition amount of the heavy metal treatment agent is 1 - 2% of the total mass of the slurry, and its preparation method includes the following steps:

[0013] 1) Add zinc salt and organic ligand to N,N - dimethylformamide, mix evenly, then add zeolite, disperse evenly and heat for reaction. After the reaction is completed, filter, wash, and dry to obtain the MOF - zeolite composite material.

[0014] 2) Add the MOF - zeolite composite material to water, adjust the pH value to weakly acidic, then add maleic anhydride, heat for reaction, and after the reaction is completed, filter, wash, and dry to obtain the functionalized zeolite.

[0015] 3) Add the functionalized zeolite to toluene, add initiator and 2 - acrylamide - 2 - methylpropanesulfonic acid, heat for reaction, cool, filter, collect the solid and dry to obtain the heavy metal treatment agent.

[0016] More preferably, in step 1), the zinc salt is at least one of zinc nitrate, zinc acetate, zinc sulfate, and zinc chloride.

[0017] More preferably, in step 1), the organic ligand is at least one of 2,5 - diamino pyridine, 2 - aminopyridine - 3 - carboxylic acid, and 2 - amino - 4 - thiazole acetic acid.

[0018] More preferably, in step 1), the mass ratio of the zinc salt, organic ligand, and zeolite is 6 - 10:4 - 6:15 - 20, the heating temperature is 120 - 150 °C, and the heating time is 3 - 6 h.

[0019] In this step, an organic heterocyclic ligand containing active amino, carboxyl, pyridyl, and thiazolyl groups is used to prepare a zinc-based MOF material, which increases the active adsorption sites of the zinc-based MOF material. Then, the zinc-based MOF material is loaded onto the surface of zeolite. The introduction of the zinc-based MOF material not only significantly increases the specific surface area of the zeolite, but also, through the synergistic effect of the zinc-based MOF material and the zeolite, significantly improves the adsorption capacity for heavy metal ions and organic pollutants in the sludge.

[0020] Preferably, the zeolite is at least one of 3A zeolite, 4A zeolite, 5A zeolite, and 13X zeolite.

[0021] More preferably, the mass ratio of the MOF-zeolite composite material to maleic anhydride in step 2) is 3 - 5:0.5 - 1.5.

[0022] In this step, the amino group on the MOF-zeolite composite material reacts with maleic anhydride, introducing both carbon-carbon double bonds and active carboxyl groups at the same time. The introduction of the carbon-carbon double bonds is beneficial for subsequent reactions, and the introduction of the active carboxyl groups helps to further improve the adsorption performance of the heavy metal treatment agent.

[0023] More preferably, the mass ratio of the functionalized zeolite, initiator, and 2-acrylamido-2-methylpropanesulfonic acid in step 3) is 2 - 4:0.3 - 0.5:1 - 3; the initiator is one of azobisisobutyronitrile, ammonium persulfate, and benzoyl peroxide; the heating temperature is 60 - 80°C, and the heating time is 5 - 8 h.

[0024] In this step, the carbon-carbon double bond on the functionalized zeolite reacts with 2-acrylamido-2-methylpropanesulfonic acid under the action of the initiator, and 2-acrylamido-2-methylpropanesulfonic acid can be grafted onto the functionalized zeolite. The amide group and the strongly electronegative sulfonic acid group on 2-acrylamido-2-methylpropanesulfonic acid can complex metal elements in the river sludge, and can also improve the hydrophilicity of the functionalized zeolite, making its dispersibility better in the aqueous phase system, thereby increasing the contact area with heavy metal ions in the river sludge and further enhancing the adsorption efficiency.

[0025] Preferably, the mass ratio of the sludge powder, fly ash, quicklime, and supernatant in step S3 is 3 - 4:1 - 3:0.8 - 1:5 - 10.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] (1) The present invention provides a systematic treatment process for heavy metal - contaminated sludge, which achieves efficient treatment through the synergistic action of physical and chemical methods. Through screening and concentration processes, large - particle impurities and excess water in river sludge are removed, significantly reducing the treatment volume in subsequent processes and improving the process efficiency. After adding Tween - 80 to the slurry, it can effectively disperse the particulate matter in the slurry, release the bound water in the sludge cells, and also release the heavy metals present on the surface or in the particle structure of the sludge, changing the water distribution and heavy - metal distribution in the sludge, reducing the intermolecular forces between particles, improving the fluidity and stratification effect of the slurry, and laying a foundation for the subsequent in - depth treatment of heavy metals. By adding heavy - metal treatment agents and polyaluminum sulfate, the flocculation of the slurry is further promoted, and the adsorption and solidification ability of heavy - metal ions in the sludge are improved, reducing the secondary release of heavy metals and ensuring that the treated sludge meets the environmental protection discharge standards. There is no discharge of high - concentration wastewater or waste gas during the treatment process, meeting the requirements of green environmental protection. Moreover, the solidified body can be used as building materials, reducing the pressure of solid - waste landfill and creating significant economic benefits;

[0028] (2) By adding heavy - metal treatment agents with multifunctional adsorption sites, the present invention significantly improves the adsorption ability of heavy - metal ions and organic pollutants in the sludge. The zinc - based MOF material is loaded on the surface of zeolite, significantly increasing the specific surface area. At the same time, the synergistic effect enhances the adsorption efficiency. The carboxyl, amide, sulfonic acid groups, etc. in the functionalized zeolite act synergistically to efficiently complex and fix heavy - metal ions in the sludge, reducing their migration and secondary pollution, and avoiding the inhibition of cement hydration reaction by heavy - metal ions, which in turn affects the mechanical properties of the solidified soil. Compared with the physical mixture of MOF materials, maleic anhydride, 2 - acrylamide - 2 - methylpropanesulfonic acid and zeolite, the present invention improves the zeolite through chemical reactions, significantly enhancing the stability and adsorption ability of the heavy - metal treatment agent, while enhancing the dispersibility of the heavy - metal treatment agent in the aqueous phase system, thereby further improving the contact efficiency with heavy - metal ions in the sludge, and finally achieving the efficient adsorption and solidification of heavy - metal ions, ensuring that the treated sludge can meet the requirements of environmental protection discharge or resource utilization, and avoiding the reaction of heavy - metal ions with Ca 2+ 、SiO 4 4- etc. to form insoluble compounds, thereby reducing the effective components participating in the gelling reaction and resulting in a decrease in the strength of the gelling product, which is beneficial to improving the mechanical properties and durability of the solidified body. Detailed implementation methods

[0029] To avoid repetition, unless otherwise specified, the items used in the following examples are all commercially available products, and the methods used are all conventional methods unless otherwise specified.

[0030] The sources of some raw materials used in the present invention are as follows:

[0031] Zeolite, 5A clinoptilolite, was purchased from Shanghai Jiading Zhengda Molecular Sieve Co., Ltd.

[0032] Poly aluminum sulfate, flaky, with alumina content ≥ 16.13%, was purchased from Zibo Guangzheng Aluminum Salt Chemical Co., Ltd.

[0033] Example 1

[0034] A treatment process for heavy metal contaminated sludge, comprising the following steps:

[0035] S1. Collect the river sludge and place it in a stacking pool, screen out large particle impurities, concentrate the volume of the river sludge to 1 / 3 of the original volume using a concentration process to obtain slurry. Add Tween-80 to the slurry, with the addition amount of Tween-80 being 3% of the total mass of the slurry, mix and stir evenly, then add a heavy metal treatment agent and poly aluminum sulfate. The addition amount of poly aluminum sulfate is 1.5% of the total mass of the slurry, and the addition amount of the heavy metal treatment agent is 1.6% of the total mass of the slurry. After mixing and stirring evenly, let it stand, and obvious upper and lower stratification appears in the sludge. Separate the upper clear liquid and the lower precipitate;

[0036] S2. After drying, pulverizing, and sieving the precipitate, obtain sludge powder;

[0037] S3. Mix 350 g of sludge powder, 220 g of fly ash, and 95 g of quicklime evenly to form a mixture, then add 750 g of the supernatant separated in step S1, mix and stir evenly, and then evenly inject it into a mold with a diameter of 39.1 mm and a height of 80 mm, and cure naturally for 28 days, and demold to obtain sludge solidified soil.

[0038] The preparation method of the heavy metal treatment agent comprises the following steps:

[0039] 1) Add 75 g of zinc nitrate hexahydrate and 50 g of 2,5-diaminopyridine to 300 mL of N,N-dimethylformamide, mix evenly, then add 180 g of 5A zeolite, disperse evenly, and heat and react at 130 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain the MOF-zeolite composite material;

[0040] 2) Add 40 g of the MOF-zeolite composite material to 200 mL of water, adjust the pH value to 6, then add 10.2 g of maleic anhydride, heat and react at 70 °C for 4 h. After the reaction is completed, filter, wash, and dry to obtain the functionalized zeolite;

[0041] 3) Add 30 g of the functionalized zeolite to 200 mL of toluene, add 4.2 g of azobisisobutyronitrile and 22 g of 2-acrylamido-2-methylpropanesulfonic acid, heat and react at 70 °C for 6 h, cool, filter, collect the solid, and dry to obtain the heavy metal treatment agent.

[0042] Example 2

[0043] A treatment process for heavy metal - contaminated sludge includes the following steps:

[0044] S1. Collect the river sludge and place it in a stacking pool. Screen out large - particle impurities, and use a concentration process to concentrate the volume of the river sludge to 1 / 4 of the original volume to obtain slurry. Add Tween - 80 to the slurry, and the addition amount of Tween - 80 is 2% of the total mass of the slurry. Mix and stir evenly, then add a heavy - metal treatment agent and polyaluminum sulfate. The addition amount of polyaluminum sulfate is 1% of the total mass of the slurry, and the addition amount of the heavy - metal treatment agent is 1% of the total mass of the slurry. After mixing and stirring evenly, let it stand. The sludge shows obvious upper and lower stratification, and separate the upper clear liquid and the lower precipitate;

[0045] S2. Dry, crush, and sieve the precipitate to obtain sludge powder;

[0046] S3. Mix 300 g of sludge powder, 100 g of fly ash, and 80 g of quicklime evenly to form a mixture, then add 500 g of the supernatant separated in step S1. After mixing and stirring evenly, inject it evenly into a mold with a diameter of 39.1 mm and a height of 80 mm, and cure it naturally for 28 days, then demold to obtain solidified soil of sludge.

[0047] The preparation method of the heavy - metal treatment agent includes the following steps:

[0048] 1) Add 60 g of zinc acetate and 40 g of 2 - aminopyridine - 3 - carboxylic acid to 300 mL of N,N - dimethylformamide, mix evenly, then add 150 g of 5A zeolite. After dispersing evenly, heat - react at 120 °C for 6 h. After the reaction is completed, filter, wash, and dry to obtain the MOF - zeolite composite material;

[0049] 2) Add 30 g of the MOF - zeolite composite material to water, adjust the pH value to 5, then add maleic anhydride, and heat - react at 60 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain functionalized zeolite;

[0050] 3) Add 20 g of functionalized zeolite to 200 mL of toluene, add 3 g of benzoyl peroxide and 11 g of 2 - acrylamido - 2 - methylpropanesulfonic acid, heat - react at 60 °C for 8 h, cool, filter, collect the solid and dry to obtain the heavy - metal treatment agent.

[0051] Example 3

[0052] A treatment process for heavy metal - contaminated sludge includes the following steps:

[0053] S1. Collect the river silt and place it in a stacking pool. Screen out large particle impurities. Concentrate the volume of the river silt to 1 / 3 of its original volume using a concentration process to obtain slurry. Add Tween-80 to the slurry, and the addition amount of Tween-80 is 4% of the total mass of the slurry. Mix and stir evenly, then add a heavy metal treatment agent and polyaluminum sulfate. The addition amount of polyaluminum sulfate is 2% of the total mass of the slurry, and the addition amount of the heavy metal treatment agent is 2% of the total mass of the slurry. After mixing and stirring evenly, let it stand. The silt shows obvious upper and lower stratification, and separate the upper clear liquid and the lower precipitate;

[0054] S2. Dry, crush, and screen the precipitate to obtain silt powder;

[0055] S3. Mix 400 g of silt powder, 300 g of fly ash, and 100 g of quicklime evenly to form a mixture. Then add 100 g of the supernatant separated in step S1. After mixing and stirring evenly, inject it evenly into a mold with a diameter of 39.1 mm and a height of 80 mm, and cure naturally for 28 days, then demold to obtain silt solidified soil.

[0056] The preparation method of the heavy metal treatment agent includes the following steps:

[0057] 1) Add 100 g of zinc chloride and 60 g of 2-amino-4-thiazoleacetic acid to 300 mL of N,N-dimethylformamide, mix evenly, then add 180 g of 5A zeolite. After dispersing evenly, heat and react at 150 °C for 3 h. After the reaction is completed, filter, wash, and dry to obtain the MOF-zeolite composite material;

[0058] 2) Add 50 g of the MOF-zeolite composite material to 200 mL of water, adjust the pH value to 6, then add 15 g of maleic anhydride, and heat and react at 80 °C for 3 h. After the reaction is completed, filter, wash, and dry to obtain functionalized zeolite;

[0059] 3) Add 40 g of functionalized zeolite to 200 mL of toluene, add 5 g of ammonium persulfate and 30 g of 2-acrylamido-2-methylpropanesulfonic acid, heat and react at 80 °C for 5 h, cool, filter, collect the solid and dry to obtain the heavy metal treatment agent.

[0060] Comparative Example 1

[0061] A treatment process for heavy metal contaminated silt, which is similar to Example 1, except that the heavy metal treatment agent is functionalized zeolite, and specifically includes the following steps:

[0062] S1. Collect the river silt and place it in a stacking pool. Screen out large particle impurities. Concentrate the volume of the river silt to 1 / 3 of its original volume using a concentration process to obtain slurry. Add Tween-80 to the slurry, with the addition amount of Tween-80 being 3% of the total mass of the slurry. Mix and stir evenly, then add a heavy metal treatment agent and polyaluminum sulfate. The addition amount of polyaluminum sulfate is 1.5% of the total mass of the slurry, and the addition amount of the heavy metal treatment agent is 1.6% of the total mass of the slurry. After mixing and stirring evenly, let it stand. The silt shows obvious upper and lower stratification, and separate the upper clear liquid and the lower precipitate;

[0063] S2. Dry, crush, and screen the precipitate to obtain silt powder;

[0064] S3. Mix 350 g of silt powder, 220 g of fly ash, and 95 g of quicklime evenly to form a mixture. Then add 750 g of the supernatant separated in step S1. After mixing and stirring evenly, inject it evenly into a mold with a diameter of 39.1 mm and a height of 80 mm, and cure it naturally for 28 days, then demold to obtain silt solidified soil.

[0065] The preparation method of the heavy metal treatment agent includes the following steps:

[0066] 1) Add 75 g of zinc nitrate hexahydrate and 50 g of 2,5-diaminopyridine to 300 mL of N,N-dimethylformamide, mix evenly, then add 180 g of 5A zeolite. After dispersing evenly, heat and react at 130 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain the MOF-zeolite composite material;

[0067] 2) Add 40 g of the MOF-zeolite composite material to 200 mL of water, adjust the pH value to 6, then add 10.2 g of maleic anhydride, heat and react at 70 °C for 4 h. After the reaction is completed, filter, wash, and dry to obtain the functionalized zeolite, that is, the heavy metal treatment agent.

[0068] Comparative Example 2

[0069] A treatment process for heavy metal contaminated silt, similar to Example 1, the difference is that the heavy metal treatment agent is the MOF-zeolite composite material, and it specifically includes the following steps:

[0070] S1. Collect the river silt and place it in a stacking pool. Screen out large particle impurities. Use a concentration process to concentrate the volume of the river silt to 1 / 3 of its original volume to obtain slurry. Add Tween-80 to the slurry, and the addition amount of Tween-80 is 3% of the total mass of the slurry. Mix and stir evenly, then add a heavy metal treatment agent and polyaluminum sulfate. The addition amount of polyaluminum sulfate is 1.5% of the total mass of the slurry, and the addition amount of the heavy metal treatment agent is 1.6% of the total mass of the slurry. After mixing and stirring evenly, let it stand. The silt shows obvious upper and lower stratification, and separate the upper clear liquid and the lower precipitate;

[0071] S2. After drying, crushing, and sieving the precipitate, obtain silt powder;

[0072] S3. Mix 350 g of silt powder, 220 g of fly ash, and 95 g of quicklime evenly to form a mixture. Then add 750 g of the supernatant separated in step S1. After mixing and stirring evenly, pour it evenly into a mold with a diameter of 39.1 mm and a height of 80 mm, and cure it naturally for 28 days, then demold to obtain silt solidified soil.

[0073] The preparation method of the heavy metal treatment agent includes the following steps:

[0074] Add 75 g of zinc nitrate hexahydrate and 50 g of 2,5-diaminopyridine to 300 mL of N,N-dimethylformamide, mix evenly, then add 180 g of 5A zeolite. After dispersing evenly, heat and react at 130 °C for 5 h. After the reaction is completed, filter, wash, and dry to obtain the MOF-zeolite composite material, that is, the heavy metal treatment agent.

[0075] Comparative Example 3

[0076] A treatment process for heavy metal contaminated silt, which is similar to Example 1, the difference is that no heavy metal treatment agent is added. The specific steps are as follows:

[0077] S1. Collect the river silt and place it in a stacking pool. Screen out large particle impurities. Use a concentration process to concentrate the volume of the river silt to 1 / 3 of its original volume to obtain slurry. Add Tween-80 to the slurry, and the addition amount of Tween-80 is 3% of the total mass of the slurry. Mix and stir evenly, then add polyaluminum sulfate. The addition amount of polyaluminum sulfate is 1.5% of the total mass of the slurry. After mixing and stirring evenly, let it stand. The silt shows obvious upper and lower stratification, and separate the upper clear liquid and the lower precipitate;

[0078] S2. After drying, crushing, and sieving the precipitate, obtain silt powder;

[0079] S3. Mix 350 g of silt powder, 220 g of fly ash, and 95 g of quicklime evenly to form a mixture. Then add 750 g of the supernatant separated in step S1, mix and stir evenly, and then pour it evenly into a mold with a diameter of 39.1 mm and a height of 80 mm. Cure it naturally for 28 days and demold to obtain silt solidified soil.

[0080] Performance test

[0081] Test of 28-day unconfined compressive strength: For the silt solidified soil obtained in Examples 1-3 and Comparative Examples 1-3, conduct tests according to the unconfined compressive strength test method in JTJ051-93 "Highway Geotechnical Test Procedures". The average value of the unconfined compressive strength of 3 test specimens is the unconfined compressive strength of the solidified soil. The test results are shown in Table 1:

[0082] Table 1 Test results of 28-day unconfined compressive strength of solidified soil

[0083]

[0084] Long-term locking effect on metal ions: At room temperature, soak the solidified soil prepared in Examples 1-3 and Comparative Examples 2-3 in a 30°C water bath for one month at a constant temperature. Use flame atomic absorption spectrometry to detect the absorbance of metal ions in the soaking solution. The specific data are shown in Table 2:

[0085] Table 2 Detection results of heavy metal ions in the soaking solution of solidified soil (unit: mg / kg)

[0086]

[0087]

[0088] It can be seen from the experimental results in Table 1 and Table 2 that using the treatment process of heavy metal contaminated silt of the present invention can effectively fix the heavy metal ions in the heavy metal contaminated silt, help reduce the leaching of heavy metal ions and improve the 28-day unconfined compressive strength of the solidified soil, which is beneficial to environmental protection.

[0089] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the patent protection scope of the present invention.

Claims

1. A process for treating heavy metal contaminated sludge, characterized in that: The steps include: S1. Collect river sludge and place it in a stacking pool, sieve to remove large particles of impurities, use a concentration process to concentrate the river sludge to obtain mud, add Tween-80 to the mud, mix and stir evenly, then add polyaluminum sulfate and heavy metal treatment agent, mix and stir evenly and let it stand until the sludge has obvious upper and lower stratification, and separate the upper clear liquid and the lower sediment; S2, drying, crushing and sieving the precipitate to obtain sludge powder; S3, the sludge powder, fly ash and quicklime are mixed and stirred evenly to form a mixture, and the supernatant separated in step S1 is added, the mixture is mixed and stirred evenly, and then transferred to a mold for natural curing.

2. The treatment process according to claim 1, characterized in that: The amount of Tween-80 added in step S1 is 2-4% of the total mass of the mud.

3. The treatment process according to claim 1, characterized in that: The amount of polyaluminium sulfate added in step S1 is 1-2% of the total mass of the mud.

4. The treatment process according to claim 1, characterized in that: The amount of heavy metal treatment agent added in step S1 is 1-2% of the total mass of the mud.

5. The treatment process according to claim 4, characterized in that: The preparation method of the heavy metal treatment agent comprises the following steps: 1) adding zinc salt and organic ligand to N,N-dimethylformamide, mixing evenly, then adding zeolite, dispersing evenly and heating to react, after the reaction is completed, filtering, washing and drying to obtain a MOF-zeolite composite material; 2) adding the MOF-zeolite composite material to water, adjusting the pH value to be weakly acidic, then adding maleic anhydride, heating to react, and filtering, washing, and drying after the reaction is completed to obtain a functionalized zeolite; 3) adding the functionalized zeolite into toluene, adding an initiator and 2-acrylamide-2-methylpropanesulfonic acid, heating for reaction, cooling, filtering, collecting solids, and drying to obtain a heavy metal treatment agent.

6. The treatment process according to claim 5, characterized in that: The zinc salt in step 1) is at least one of zinc nitrate, zinc acetate, zinc sulfate and zinc chloride.

7. The treatment process according to claim 5, characterized in that: In the step 1), the organic ligand is at least one of 2,5-diaminopyridine, 2-aminopyridine-3-carboxylic acid, and 2-amino-4-thiazoleacetic acid.

8. The treatment process according to claim 5, characterized in that: In the step 1), the mass ratio of zinc salt, organic ligand and zeolite is 6-10:4-6:15-20, the heating temperature is 120-150° C., and the heating time is 3-6 hours.

9. The treatment process according to claim 5, characterized in that: In the step 2), the mass ratio of the MOF-zeolite composite material to maleic anhydride is 3-5:0.5-1.

5.

10. The treatment process according to claim 5, characterized in that: In the step 3), the mass ratio of the functionalized zeolite, the initiator, and the 2-acrylamide-2-methylpropanesulfonic acid is 2-4:0.3-0.5:1-3.

Images