Sludge conditioner as well as preparation method and application thereof

Abstract

The invention discloses a sludge conditioner, which belongs to the technical field of sludge conditioners and comprises a component A and a component B, the component A comprises the following components in parts by weight: 5-15 parts of a biological surfactant, 2-8 parts of a pH regulator, 3-10 parts of a calcium activator and 60-85 parts of a dispersion carrier; the component B is prepared from the following components in parts by weight: 15 to 35 parts of modified nano cellulose, 15 to 30 parts of a flocculating agent and 15 to 40 parts of bimetallic loaded zeolite; the biological surfactant is a compound of rhamnolipid and sophorolipid; the modified nanocellulose is nanocellulose grafted with a cationic quaternary ammonium salt group. The preparation method of the sludge conditioner comprises the following steps: mixing according to a required formula to respectively prepare the component A and the component B; after the sludge conditioner is used for conditioning the sludge, the water content and the COD content in the sludge can be effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of sludge conditioners, and in particular relates to a sludge conditioner and a preparation method and application thereof. Background Art

[0002] Sludge dewatering is a critical step in the wastewater treatment process, determining the cost and efficiency of subsequent disposal. Unconditioned sludge typically has a moisture content of 95% to 99%, resulting in a bulky structure. Whether transported to landfill, incinerated, or composted, high transportation and disposal costs significantly increase operational burdens. Therefore, developing efficient, economical, and environmentally friendly sludge dewatering and conditioning technologies is crucial.

[0003] The role of conditioning agents can be summarized as a four-step synergistic mechanism of "destabilization - flocculation - filtration aid - skeleton": first, through electrical neutralization and oxidation, the extracellular polymers (EPS) are broken down and the double layer is compressed to convert bound water into free water. Commonly used destabilizing agents include FeCl3, PAC, Fenton reagent or ozone; secondly, high molecular weight flocculants such as cationic PAM use adsorption and bridging effects to aggregate fine particles into millimeter-sized flocs; then, rigid filter aids such as lime, fly ash, diatomaceous earth or sawdust build a skeleton in the mud cake, reduce its compressibility, and maintain a permeable channel; finally, a stable structure of "water is easy to flow and mud is easy to compress" is formed, creating favorable conditions for mechanical dehydration.

[0004] However, the current traditional conditioning system, represented by iron salts, aluminum salts, and lime, has exposed obvious flaws during operation: Fe(OH)3 and Al(OH)3 generated during the destabilization phase, and the subsequent CaCO3 formed by reaction with lime, are easily deposited on filter cloths, diaphragms, and pipe walls, causing blockages. Blockages not only cause a sudden increase in filtration resistance and a decrease in dewatering efficiency, but also force frequent system shutdowns for cleaning, resulting in reduced effective chemical utilization and increased operating costs. How to fundamentally avoid sedimentation blockage while maintaining the complete functions of "destabilization - flocculation - filtration aid - skeleton" has become a core bottleneck that urgently needs to be overcome in current sludge deep dewatering technology. Summary of the Invention

[0005] In order to overcome the above technical problems, the present invention provides a sludge conditioner and its preparation method and application. After the sludge conditioner of the present invention is applied, the water content and COD content in the sludge can be effectively reduced.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] A sludge conditioner, consisting of component A and component B; Calculated by mass, the component A comprises: 5 to 15 parts of a biosurfactant, 2 to 8 parts of a pH regulator, 3 to 10 parts of a calcium activator, and 60 to 85 parts of a dispersion carrier; Preferably, the component A comprises: 8 to 10 parts of a biosurfactant, 3 to 4 parts of a pH regulator, 5 to 6 parts of a calcium activator, and 70 to 75 parts of a dispersion carrier; Calculated by mass fraction, the component B comprises: 15 to 35 parts of modified nanocellulose, 15 to 30 parts of flocculant, and 15 to 40 parts of bimetallic loaded zeolite; Preferably, the component B comprises: 20-30 parts of modified nanocellulose, 20-25 parts of flocculant, and 30-40 parts of bimetallic loaded zeolite; The biosurfactant is a complex of rhamnolipid and sophorolipid; wherein rhamnolipid can destroy the protein hydrogen bonds in EPS, and sophorolipid can dissolve lipid substances; The modified nanocellulose is nanocellulose grafted with cationic quaternary ammonium salt groups; wherein, sludge colloidal particles are usually negatively charged, and the nanocellulose grafted with cationic quaternary ammonium salt groups reduces electrostatic repulsion through charge neutralization.

[0008] The mass ratio of the rhamnolipid to the sophorolipid is 1:1-2, preferably 1:1-1.5.

[0009] According to some embodiments of the present invention, the pH regulator is a sodium citrate and sodium bicarbonate buffer pH regulator, and the pH of the pH regulator is 6 to 8. According to some embodiments of the present invention, the calcium activator is calcium chloride, calcium citrate or calcium gluconate; wherein, Ca 2+ -COO of polysaccharides in EPS - Combination can break the gel structure.

[0010] According to some embodiments of the present invention, the dispersion carrier is diatomaceous earth, bentonite, activated carbon or biochar; According to some embodiments of the present invention, the flocculant is polyacrylamide, polyethyleneimine or a chitosan derivative; According to some embodiments of the present invention, the bimetallic loaded zeolite is Al 3+ and Fe 3+ Loaded zeolite; wherein Fe 3+ Provides strong charge neutralization ability, Al 3+ It is relatively weak, but it can adjust the hydrolysis rate to avoid a sudden drop in pH; zeolite nanopores act as "water molecule channels" to accelerate water seepage.

[0011] According to some embodiments of the present invention, the fiber diameter of the nanocellulose is ≤100 nm.

[0012] According to some embodiments of the present invention, the zeolite is a natural zeolite.

[0013] A method for preparing a sludge conditioner comprises the following steps: S1. Preparation of modified nanocellulose: hydrolyzing nanocellulose and then adding ammonium salt for grafting reaction; S2. Preparation of bimetallic loaded zeolite: The zeolite was crushed and acidified, and then impregnated with Al 3+ and Fe 3+ In the mixed solution, finally roasting; S3. Prepare component A and component B respectively by mixing according to the required formula.

[0014] In S1, the hydrolysis is carried out at 40-60° C. in a 2-5 mol / L sulfuric acid solution for 30-50 min; In S1, the hydrolyzed nanocellulose is washed with water until neutral, and then the hydrolyzed nanocellulose is prepared into a 5-20 wt% suspension; In S1, the mass ratio of the nanocellulose to the ammonium salt is 10:1-4, preferably 10:2-3.

[0015] In S1, the ammonium salt is CHPTAC (3-chloro-2-hydroxypropyltrimethylammonium chloride), GTMAC (glycidyltrimethylammonium chloride), EPTAC (2,3-epoxypropyltrimethylammonium chloride), DMC (methacryloyloxyethyltrimethylammonium chloride) or DADMAC (diallyldimethylammonium chloride); In S1, the grafting reaction is carried out at a pH of 10-11 and a temperature of 50-65° C. for 3-5 hours, and then washed to neutrality.

[0016] In S2, the zeolite is crushed and passed through a 100-200 mesh sieve; In S2, the acidification is carried out by treating with a 0.5-1.5 mol / L hydrochloric acid solution for 1-3 hours; In S2, the Al 3+ and Fe 3+ Fe in mixed solution 3+ The concentration is 0.2~0.3mol / L, Al 3+ The concentration is 0.1~0.2mol / L; In S2, the immersion time is 2 to 5 hours; In S2, the calcination is performed by aging at 70-90°C for 5-8 hours and then calcining at 450-500°C for 1.5-2.5 hours.

[0017] An application of a sludge conditioner comprises the following steps: Step 1: Prepare the reagent: dissolve component A in water to prepare 5-8 wt% of liquid A; dissolve component B in water to prepare 3-5 wt% of liquid B; Step 2: Add Liquid A to the sludge conditioning tank and stir for 5-20 minutes, adding 10-14L of Liquid A per ton of sludge; then add Liquid B and stir for 40-100 minutes, adding 23-50L of Liquid B per ton of sludge; Step 3: The sludge treated in step 2 is subjected to filter pressing and centrifugal dehydration to obtain filter cake and filtrate respectively.

[0018] According to some embodiments of the present invention, the water content of the sludge is ≥80%.

[0019] According to some embodiments of the present invention, the filtration time is ≤3 min, preferably 1-2 min; and the sludge dewatering efficiency is faster after being treated with the sludge conditioner of the present invention.

[0020] According to some embodiments of the present invention, the water content of the filter cake treated with the sludge conditioner is 48-60%, preferably 48-57%.

[0021] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0022] Compared with the prior art, the present invention has the following beneficial effects: In terms of technology, component A is added first to complete cell wall disruption, and then component B is introduced under optimal conditions to enhance flocculation.

[0023] Component A, a composite biosurfactant composed of rhamnolipids and sophorolipids, synergistically disrupts extracellular polymers (EPS). A calcium-based activator promotes colloidal particle aggregation through a bridging effect. The dispersing carrier provides both support and sustained-release functions, enabling controlled release of the active ingredient. Component A, acting as a wall-breaking agent, avoids the corrosion and precipitation issues associated with traditional acid / base destabilization.

[0024] Component B consists of surface-cationized nanocellulose, bimetallic-loaded zeolite, and an organic polymer flocculant. The cationic nanocellulose neutralizes the electrostatic repulsion of sludge colloids, improving particle dispersibility through gentle charge neutralization. The bimetallic zeolite creates a rigid framework with low metal precipitation, minimizing the impact on the plating environment. The organic flocculant acts as a bridging flocculation agent. Component B replaces traditional dense flocs as a flocculant.

[0025] After treatment with the sludge conditioner, the dehydration rate is high, with the water content in the filter cake being ≤60%. Furthermore, the dehydration efficiency is faster, and the filtration time is shortened, with rapid dehydration being completed within 3 minutes. DETAILED DESCRIPTION

[0026] To facilitate understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with preferred embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0027] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0028] The "ranges" disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit, and the selected lower and upper limits define the boundaries of the particular range. Ranges defined in this manner can be inclusive or exclusive of the end values ​​and can be combined in any manner, i.e., any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values ​​listed are 1 and 2, and if the maximum range values ​​listed are 3, 4, and 5, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this disclosure, unless otherwise indicated, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed herein, and "0-5" is merely an abbreviation for these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0029] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0030] Unless otherwise specified, all technical features and optional technical features of the present invention can be combined with each other to form a new technical solution.

[0031] Unless otherwise specified, all steps of the present invention may be performed sequentially or randomly, preferably sequentially. For example, "the method includes steps (a) and (b)" indicates that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, "the method may further include step (c)" indicates that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0032] Unless otherwise specified, the terms "include" and "comprising" used in the present invention may be open-ended or closed-ended. For example, "include" and "comprising" may mean that other components not listed may also be included or that only the listed components are included.

[0033] Unless otherwise specified, the term "or" is inclusive in this disclosure. For example, the phrase "A or B" means "A, B, or both A and B." More specifically, the condition "A or B" is satisfied if any of the following conditions are met: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0034] The raw material information used in the following examples is as follows: Nanocellulose was purchased from Nanjing Tianlu Nanotechnology Co., Ltd. Nanocellulose TL-013 with a solid content of 6.0–10.0% and a fiber diameter of ≤100 nm; Polyacrylamide (non-ionic), Mn is 40,000; Polyethyleneimine, Mw is 70,000; Including but not limited to the above manufacturers and models.

[0035] [Sludge conditioner and preparation method thereof] Example 1 The sludge conditioner consists of component A and component B; Calculated by mass, component A: 10 parts of biosurfactant, 3 parts of pH regulator, 5.5 parts of calcium activator (calcium citrate), 70.2 parts of dispersion carrier (diatomaceous earth); By mass fraction, component B: 30 parts of modified nanocellulose, 25 parts of flocculant (polyacrylamide), 33.2 parts of bimetallic loaded zeolite; In this embodiment, the biosurfactant is a complex of rhamnolipid and sophorolipid, and the mass ratio of rhamnolipid to sophorolipid is 1:1.5; In this embodiment, the modified nanocellulose is nanocellulose grafted with cationic quaternary ammonium salt groups; In this embodiment, the pH regulator is a buffered pH regulator of sodium citrate and sodium bicarbonate, and its pH is 7.5.

[0036] In this embodiment, the bimetallic loaded zeolite is Al 3+ and Fe 3+ Loaded zeolite.

[0037] The preparation method of the sludge conditioner of this embodiment comprises the following steps: S1. Preparation of modified nanocellulose: The nanocellulose was hydrolyzed in a 2.5 mol / L sulfuric acid solution at 50°C for 30 minutes, washed with water until neutral, and then prepared into a 17% suspension. Ammonium salt was added to the nanocellulose at a mass ratio of 10:3 to carry out a grafting reaction. The grafting reaction was carried out at pH 10 and 60°C for 3 hours. After the grafting reaction, the solution was washed until neutral.

[0038] S2. Preparation of bimetallic loaded zeolite: The zeolite was crushed and passed through a 150 mesh sieve, and then treated with 1.0 mol / L hydrochloric acid solution for 2 h for acid treatment activation; 3+ and Fe 3+ In the mixed solution (pH 2, aqueous solution of ferric sulfate and aluminum sulfate), Fe 3+ The concentration is 0.25mol / L, Al 3+ The concentration is 0.15 mol / L; finally, it is aged at 80°C for 6 h and then calcined at 500°C for 2 h.

[0039] S3. Prepare component A and component B respectively by mixing the raw materials according to the above formula.

[0040] Example 2 The difference between this embodiment and embodiment 1 is that: The mass ratio of rhamnolipid to sophorolipid was 1:1.0; Other raw materials, steps and parameters are the same as in Example 1.

[0041] Example 3 The difference between this embodiment and embodiment 1 is that: The mass ratio of rhamnolipid to sophorolipid was 1:2.5; Other raw materials, steps and parameters are the same as in Example 1.

[0042] Example 4 The difference between this embodiment and embodiment 1 is that: Component B: 20 ​​parts of modified nanocellulose, 20 parts of flocculant (polyacrylamide) and 40 parts of bimetallic loaded zeolite; Other raw materials, steps and parameters are the same as in Example 1.

[0043] Example 5 The difference between this embodiment and embodiment 1 is that: Component B: 25 parts of modified nanocellulose, 25.3 parts of flocculant (polyethyleneimine) and 30 parts of bimetallic loaded zeolite; Other raw materials, steps and parameters are the same as in Example 1.

[0044] Example 6 The difference between this embodiment and embodiment 1 is that: The nanocellulose was hydrolyzed in a 2 mol / L sulfuric acid solution at 60°C for 45 min, washed with water until neutral, and the hydrolyzed nanocellulose was prepared into a 10% suspension; the mass ratio of nanocellulose to ammonium salt (CHPTAC) was 10:7; Other raw materials, steps and parameters are the same as in Example 1.

[0045] Example 7 The difference between this embodiment and embodiment 1 is that: Calcination in S2 was carried out at 600 °C for 1.5 h; Other raw materials, steps and parameters are the same as in Example 1.

[0046] Comparative Example 1 The difference between this comparative example and Example 1 is: This comparative example does not contain component A; Other raw materials, steps and parameters are the same as in Example 1.

[0047] Comparative Example 2 The difference between this comparative example and Example 1 is: This comparative example does not contain component B; Other raw materials, steps and parameters are the same as in Example 1.

[0048] Comparative Example 3 The difference between this comparative example and Example 1 is: Component A does not contain biosurfactants; Other raw materials, steps and parameters are the same as in Example 1.

[0049] Application Examples Step 1: dissolve the component A prepared in the above examples and comparative examples in water to prepare a 5 wt% solution A, and dissolve the component B in water to prepare a 3 wt% solution B; Step 2: Add liquid A to the sludge conditioning tank and stir for 10 minutes, adding 12L of liquid A per ton of sludge; then add liquid B and stir for 50 minutes, adding 30L of liquid B per ton of sludge; Step 3: The sludge treated in step 2 was filtered (pressure 1.0 MPa, time 1 min) and centrifuged for dehydration to obtain filter cake and filtrate respectively. The water content of the filter cake is shown in Table 1. The control group is the sludge before the conditioning agent treatment.

[0050]

[0051] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in the present invention can be purchased from the market or prepared by existing methods. The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A sludge conditioner, characterized in that: It is composed of component A and component B; Calculated by mass, the component A comprises: 5 to 15 parts of a biosurfactant, 2 to 8 parts of a pH regulator, 3 to 10 parts of a calcium activator, and 60 to 85 parts of a dispersion carrier; Calculated by mass fraction, the component B comprises: 15-35 parts of modified nanocellulose, 15-30 parts of flocculant, and 15-40 parts of bimetallic loaded zeolite; The biosurfactant is a complex of rhamnolipid and sophorolipid; The modified nanocellulose is nanocellulose grafted with cationic quaternary ammonium salt groups.

2. The sludge conditioner according to claim 1, wherein The mass ratio of the rhamnolipid to the sophorolipid is 1:1-2.

3. The sludge conditioner according to claim 1, wherein Meet at least one of the following conditions a to e: a. The pH adjusting agent is sodium citrate and sodium bicarbonate buffer pH adjusting agent; b. The calcium activator is calcium chloride, calcium citrate or calcium gluconate; c. The dispersion carrier is diatomaceous earth, bentonite, activated carbon or biochar; d. The flocculant is polyacrylamide, polyethyleneimine or a chitosan derivative; e. The bimetallic loaded zeolite is Al 3+ and Fe 3+ Loaded zeolite.

4. The sludge conditioner according to claim 1, wherein At least one of the following conditions a~b is met: a. The nanocellulose fiber diameter is ≤100nm; b. The zeolite is natural zeolite.

5. A method for preparing a sludge conditioner, characterized in that: The following steps are involved: S1. Preparation of modified nanocellulose: hydrolyzing the nanocellulose and then adding ammonium salt for grafting reaction; S2. Preparation of bimetallic loaded zeolite: The zeolite was crushed and acidified, and then impregnated with Al 3+ and Fe 3+ In the mixed solution, finally roasting; S3. Prepare component A and component B respectively by mixing according to the required formula.

6. The method for preparing the sludge conditioner according to claim 5, wherein: Meet at least one of the following conditions a to e: a. The hydrolysis is carried out in a 2 to 5 mol / L sulfuric acid solution at 40 to 60 ° C for 30 to 50 min; b. After the hydrolysis, the mixture was washed with water until neutral, and then the hydrolyzed nanocellulose was configured into a 5 to 20 wt% suspension; c. The mass ratio of the nanocellulose: the ammonium salt is 10:1~4; d. The ammonium salt is CHPTAC, GTMAC, EPTAC, DMC or DADMAC; e. The grafting reaction is carried out at a pH of 10-11 and a temperature of 50-65°C for 3-5 hours, followed by washing to neutrality.

7. The method for preparing the sludge conditioner according to claim 5, wherein: Meet at least one of the following conditions a to c: a. The zeolite is crushed and passed through a 100~200 mesh sieve; b. The acidification is carried out by treating with 0.5~1.5mol / L hydrochloric acid solution for 1~3h; c. the Al 3+ and Fe 3+ Fe in mixed solution 3+ The concentration is 0.2~0.3mol / L, Al 3+ The concentration is 0.1~0.2mol / L; d. The immersion time is 2 to 5 hours; e. The calcination is performed by aging at 70-90°C for 5-8 hours and then calcining at 450-500°C for 1.5-2.5 hours.

8. An application of a sludge conditioner, characterized in that: The following steps are involved: Step 1: Prepare the reagent: dissolve component A in water to prepare 5-8 wt% of liquid A; dissolve component B in water to prepare 3-5 wt% of liquid B; Step 2: Add liquid A to the sludge conditioning tank and stir for 5-20 minutes. Add 10-14L of liquid A per ton of sludge. Then add B solution and stir for 40-100 minutes, adding 23-50L B solution per ton of sludge; Step 3: The sludge treated in step 2 is subjected to filter pressing and centrifugal dehydration to obtain filter cake and filtrate respectively.

9. The use of the sludge conditioner according to claim 8, characterized in that: The water content of the sludge is ≥80%.

10. The use of the sludge conditioner according to claim 8, characterized in that: The water content of the filter cake treated with the sludge conditioner is 47-58%.

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