Composite water purifying agent for sewage purification and preparation process thereof

Abstract

The invention discloses a composite water purifying agent for sewage purification and a preparation process thereof, and the composite water purifying agent comprises: a metal-based coagulating sedimentation core composed of a ferric salt precursor; the self-adaptive response structure contains temperature and pH sensitive polymer microcapsules or magnetic response particles and is used for releasing or triggering active substances when the quality of the sewage changes; the bridged polymeric flocculant is used for enhancing the combination of a floc structure and the fiber / colloidal particles; the recycling structure is in a carrier form capable of being magnetically separated or floated, so that the water purifying agent can be recycled, dehydrated and regenerated after being used; after being added into the papermaking wastewater, charge neutralization and bridging flocculation are firstly realized, then the reinforcing agent is released or the recovery structure is started through the response structure according to the water quality change, and finally water purification, sedimentation, dehydration and recycling are realized. According to the recycling structure, the water purifying agent can be recycled, dehydrated and reused after being used, and the operation cost, the residual metal amount and the sludge treatment load are reduced.

Description

Technical Field

[0001] This invention relates to the technical field of wastewater treatment, and in particular to a composite water purification agent for wastewater purification and its preparation process. Background Technology

[0002] Wastewater from the papermaking industry typically contains large amounts of suspended solids (such as fibers and pulp debris), filler / auxiliary agent residues (such as calcium carbonate, talc, diatomaceous earth, and dyeing auxiliaries), colloids, colored organic matter, and bleaching agent residues. While traditional coagulants / flocculators (such as iron salts and aluminum salts) or single polymeric flocculants can remove some suspended solids or reduce turbidity, they still have the following shortcomings: In papermaking wastewater with high fiber, high filler, and high color, the removal efficiency is low and the floc settling speed is slow. High levels of residual metal ions or additives, large amounts of sludge, and high costs for subsequent dewatering treatment; The dosage is often difficult to adjust in real time due to fluctuations in water quality, resulting in waste or unstable effects.

[0003] Therefore, the present invention aims to provide an improved water purification agent and its preparation process to solve the above-mentioned defects. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above-mentioned composite water purification agents and their preparation processes for wastewater purification, this invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a composite water purification agent for wastewater purification and its preparation process. Its recyclable structure allows the water purification agent to be recycled, dehydrated, and reused after use, thereby reducing operating costs, residual metal content, and sludge treatment load.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a composite water purification agent for wastewater purification, comprising: Metal-based concrete settling cores are composed of iron salt precursors; An adaptive response structure containing temperature- or pH-sensitive polymer microcapsules or magnetically responsive particles is used to release or trigger active substances when wastewater quality changes. Bridging polymeric flocculants are used to enhance the bonding between floc structure and fiber / colloidal particles; The recyclable structure is in the form of a magnetically separable or floatable carrier, which allows the water purification agent to be recycled, dehydrated, and regenerated after use. The metal-based coagulation sedimentation core, the adaptive response structure, and the bridging polymer flocculant work synergistically to first achieve charge neutralization and bridging flocculation after being added to papermaking wastewater. Then, the response structure releases an enhancer or activates a recovery structure based on changes in water quality, ultimately achieving water purification, sedimentation, dewatering, and recycling.

[0008] As a preferred embodiment of the composite water purification agent for wastewater purification described in this invention, the iron salt precursor is a trivalent iron salt or hydrolyzed polyferric salt, and the iron content of the iron salt precursor is 20%-35% (by mass).

[0009] As a preferred embodiment of the composite water purification agent for wastewater purification described in this invention, the adaptive response structure is selected from temperature-sensitive polymer microcapsules, pH-sensitive microcapsules, or magnetically responsive microparticles, and the structure releases internal additives when the wastewater temperature changes by ≥5℃ or the pH changes by ≥0.5.

[0010] As a preferred embodiment of the composite water purification agent for wastewater purification described in this invention, the bridging polymeric flocculant is cationic polyacrylamide or cationic cellulose, and its solid content is 1.0%-3.0% (by mass).

[0011] As a preferred embodiment of the composite water purification agent for wastewater purification described in this invention, the recyclable structure is a magnetically responsive microparticle carrier or a flotation aid carrier, and can be reused as a filler or papermaking aid after being recycled and dehydrated.

[0012] A preparation process for a composite water purification agent for wastewater treatment includes the following steps: Step 1: Mix the carrier material and the responsive structural material in water and stir to disperse the responsive structural particles and form a carrier suspension; Step 2: Add iron salt precursor solution to the carrier suspension, control the temperature at 40-60°C, and stir for 30-60 minutes to allow the iron salt to be loaded onto the carrier surface to form metal-based coagulation sedimentation nuclei. Step 3: Add the bridging polymer flocculant to the above mixture and continue stirring for 10-30 minutes to allow the bridging polymer to combine with the carrier-metal core; Step 4: Adjust the mixture to a neutral pH (6.5-7.5) and allow it to stand for 1-3 hours to age, so that the structure can be stabilized; Step 5: Dehydrate, dry or granulate the aged material to obtain the final compound water purification agent that can be added.

[0013] As a preferred embodiment of the preparation process of the composite water purification agent for wastewater purification described in this invention, the iron salt precursor used in step two has an iron content of 20%-35%, and the solid content of the added bridging polymer flocculant is 1.0%-3.0%.

[0014] As a preferred embodiment of the preparation process of the composite water purification agent for wastewater purification described in this invention, the responsive structure is magnetically responsive microparticles, and the average particle size of the granulated particles obtained in step five is 50-150 µm, which is beneficial for subsequent magnetic recovery.

[0015] As a preferred embodiment of the preparation process of the composite water purification agent for wastewater purification according to the present invention, the method of using the composite water purification agent for wastewater purification includes the following steps: S1. Add the water purification agent to the papermaking wastewater. The dosage is determined based on the TSS (suspended solids) concentration, filler particle concentration, and color index of the wastewater. S2. After rapid mixing for 1-3 minutes, slow flocculation for 5-15 minutes is performed to form flocs. S3. Sedimentation or magnetic separation recovery of flocs, followed by dehydration treatment of the resulting precipitate; S4. Dehydrate, dry or granulate the recovered water purification agent carrier for reuse or use as a paper filling material.

[0016] In a preferred embodiment of the preparation process of the composite water purification agent for wastewater purification described in this invention, the dosage is determined by the metal-based coagulation sedimentation core in the water purification agent to be 0.1-0.4 kg / m³ based on the TSS concentration of the wastewater. 3 When the filler particle concentration exceeds 500 mg / L or the color exceeds 150 PCU, the adaptive response structure is triggered to release the additive or initiate the enhancement mode.

[0017] The beneficial effects of this invention are: The intelligent response structure enables the water purification agent to be automatically released or activated when water quality fluctuates (such as temperature, pH, and suspended solids concentration), thus improving the stability of the effect. The recycling structure allows the water purification agent to be recycled, dehydrated, and reused after use, reducing operating costs, residual metal content, and sludge treatment load. The overall formulation structure allows the metal matrix, bridging polymer, responsive structure, and carrier recovery to work together to improve floc formation rate, sedimentation rate, and dewatering efficiency. Detailed Implementation

[0018] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0020] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0021] A composite water purification agent for wastewater treatment, comprising: Metal-based concrete settling cores are composed of iron salt precursors; An adaptive response structure containing temperature- or pH-sensitive polymer microcapsules or magnetically responsive particles is used to release or trigger active substances when wastewater quality changes. Bridging polymeric flocculants are used to enhance the bonding between floc structure and fiber / colloidal particles; The recyclable structure is in the form of a magnetically separable or floatable carrier, which allows the water purification agent to be recycled, dehydrated, and regenerated after use. The metal-based coagulation sedimentation core, the adaptive response structure, and the bridging polymer flocculant work synergistically to first achieve charge neutralization and bridging flocculation after being added to papermaking wastewater. Then, the response structure releases an enhancer or activates a recovery structure based on changes in water quality, ultimately achieving water purification, sedimentation, dewatering, and recycling.

[0022] The iron salt precursor is a trivalent iron salt or hydrolyzed polyferric salt, and the iron content of the iron salt precursor is 20%-35% (by mass).

[0023] Specifically, the adaptive response structure is selected from temperature-sensitive polymer microcapsules, pH-sensitive microcapsules, or magnetically responsive microparticles, and the structure releases internal additives when the wastewater temperature changes by ≥5℃ or the pH changes by ≥0.5; the bridging polymer flocculant is cationic polyacrylamide or cationic cellulose, with a solid content of 1.0%-3.0% (by mass); the recycling structure is a magnetically responsive microparticle carrier or a flotation aid carrier, and can be reused as a filler or papermaking additive after recycling and dewatering.

[0024] A preparation process for a composite water purification agent for wastewater treatment includes the following steps: Step 1: Mix the carrier material and the responsive structural material in water and stir to disperse the responsive structural particles and form a carrier suspension; Step 2: Add iron salt precursor solution to the carrier suspension, control the temperature at 40-60°C, and stir for 30-60 minutes to allow the iron salt to be loaded onto the carrier surface to form metal-based coagulation sedimentation nuclei. Step 3: Add the bridging polymer flocculant to the above mixture and continue stirring for 10-30 minutes to allow the bridging polymer to combine with the carrier-metal core; Step 4: Adjust the mixture to a neutral pH (6.5-7.5) and allow it to stand for 1-3 hours to age, so that the structure can be stabilized; Step 5: Dehydrate, dry or granulate the aged material to obtain the final compound water purification agent that can be added.

[0025] In step two, the iron salt precursor contains 20%-35% iron, and the added bridging polymeric flocculant has a solid content of 1.0%-3.0%. The response structure is a magnetically responsive microparticle, and the average particle size after granulation in step five is 50-150µm, which is beneficial for subsequent magnetic recovery.

[0026] The method of using the compound water purification agent for wastewater purification includes the following steps: S1. Add the water purification agent to the papermaking wastewater. The dosage is determined based on the TSS (suspended solids) concentration, filler particle concentration, and color index of the wastewater. S2. After rapid mixing for 1-3 minutes, slow flocculation for 5-15 minutes is performed to form flocs. S3. Sedimentation or magnetic separation recovery of flocs, followed by dehydration treatment of the resulting precipitate; S4. Dehydrate, dry or granulate the recovered water purification agent carrier for reuse or use as a paper filling material.

[0027] Specifically, the dosage is determined by the concentration of metal-based coagulation sedimentation cores in the water treatment agent, based on the TSS concentration of the wastewater, to be 0.1-0.4 kg / m³. 3 When the filler particle concentration exceeds 500 mg / L or the color exceeds 150 PCU, the adaptive response structure is triggered to release the additive or initiate the enhancement mode.

[0028] Example 1 Formulation and Preparation Carrier material: Magnetic responsive microparticle carrier (such as silanized Fe3O4 microparticles), accounting for approximately 15% of the total dose (by mass). Iron salt precursor: FeCl3·6H2O, with an iron content of approximately 30% (by mass). Bridged polymeric flocculant: cationic polyacrylamide (CPAM), solids content approximately 2.0% (by weight). Response structure: Temperature-sensitive polymeric microcapsules (chitosan-acrylamide copolymer) that release additives when the water temperature rises by ≥5°C. Preparation steps The magnetically responsive microparticle carrier was suspended in deionized water, stirred until dispersed, and the pH was adjusted to approximately 6.5.

[0029] Iron salt precursor solution was slowly added to the carrier suspension, the temperature was controlled at 45°C, and the mixture was stirred for 45 minutes to allow the iron salt to deposit on the surface of the particles.

[0030] Add CPAM solution to the mixture and continue stirring for 20 minutes to bridge the polymer adsorbent support-metal core structure.

[0031] Adjust the pH to approximately 7.0 and allow it to stand for 2 hours to age.

[0032] The mixture is dehydrated and dried to a moisture content of <5% or granulated (average particle size of about 100µm) to become the final water purification product.

[0033] How to use The water purification agent was added to the pretreatment tank before the effluent from the paper mill, with the dosage set at 0.15 kg / m³ based on the TSS concentration. 3 After rapid mixing for 2 minutes, slow flocculation was carried out for 8 minutes, followed by sedimentation for 10 minutes. The settled sediment was separated by magnetic separation, and the carrier was dewatered and could be reused as a paper filling material.

[0034] Preferred parameters —Iron content: Approximately 28-32% —CPAM solids content: approximately 1.5-2.5% —Carrier percentage: 12-18% —Average particle size after granulation: 50-150µm Effect Under these conditions, TSS decreased by approximately 90%, turbidity dropped to <30 NTU, and metal residue was significantly lower than that of traditional single-agent iron salt formulations.

[0035] Example 2 Preparation process variation In step two, the temperature is set to 50°C and the stirring time is 60 minutes.

[0036] The response structure uses magnetically responsive microparticles (such as Fe3O4 microparticles with surface cationization treatment) to give the final particles magnetically responsive characteristics.

[0037] The final average particle size was controlled at 80µm.

[0038] Preferred parameters —Iron content of iron salt precursors: approximately 25-35% —Bridging polymer solids content: approximately 1.0-3.0% —Particle size: 50-100µm (preferably 70-90µm) Effect The water purification agent prepared by this modification can be quickly recovered with the help of a magnetic field after use, the dehydrated solids are easier to dry, and the solid-liquid separation time is shortened by about 30%.

[0039] Example 3 Instructions for use Key indicators for online monitoring of wastewater from paper mills include: TSS, filler particle concentration, color, pH, and temperature.

[0040] When TSS > 2000 mg / L, filler particle concentration > 500 mg / L, or color > 150 PCU, activate the enhanced mode: use a water purification agent with a temperature / pH responsive structure, at a dosage of 0.30 kg / m³. 3 Otherwise, use the standard method, with a dosage of 0.10-0.20 kg / m³. 3 .

[0041] After addition, mix quickly for 1-3 minutes, flocculate slowly for 5-15 minutes, and allow to settle or separate magnetically for 10-20 minutes.

[0042] After the flocs are separated by sedimentation or magnetic separation, the water purification agent carrier is dehydrated and dried to a moisture content of <10% before being used as a paper filling agent or added again.

[0043] Preferred parameters —Enhanced mode activation threshold: filler particle size > 500 mg / L or color > 150 PCU —Standard dosage: 0.12-0.18 kg / m³ 3 —Enhanced dosage: 0.25-0.35 kg / m³ 3 Effect This method can cope with water quality fluctuations, maintain a TSS reduction of ≥85%, a color reduction of ≥70%, a significant reduction in residual iron in the water purification agent, and a recovery rate of >80%.

[0044] The beneficial effects of the present invention can be clearly seen from the above embodiments: The intelligent response structure enables the water purification agent to automatically increase or release its activity based on water quality conditions (temperature / pH / filler load), thereby improving treatment efficiency and reducing dosage waste; The recyclable structure allows the water purification agent to be dewatered by magnetic separation / flotation after use and reused or recycled through the packing material, reducing operating costs and the burden of metal residue and sludge treatment. The preparation process is simple and easy to scale up, and the optimized parameters are reasonably designed, making it easy to apply in paper mills. Compared with traditional single iron-based or polymeric water purifiers, this invention has higher treatment efficiency, less residue, and better recycling value when treating papermaking wastewater (high fiber, high filler, high color).

[0045] The specific implementation examples are compared in Table 1 below: Table 1 ; Specifically, the "enhanced mode activation condition" refers to the use of enhanced dosage mode when the residual filler or color in the papermaking wastewater reaches the threshold. In the table, “—” indicates that the item is not specifically limited in this embodiment or is a general state; Furthermore, the recommended optimal dosage under different water quality conditions (mainly based on three indicators: suspended solids (TSS), filler particle concentration, and color) is shown in Table 2: Table 2 ; The "dosage" in this table refers to the metal-based coagulation and sedimentation content of the water treatment agent, expressed as a percentage of wastewater volume (kg / m³). 3 ); "Filler particles" refers to the estimated concentration (mg / L) of mineral fillers, fiber residue fragments, and particulate colloids in papermaking wastewater; "Colorimetry" is measured in PCU (Platinum-Cobalt colorimetry unit); "Enhanced mode" refers to activating the adaptive response structure in the water purification agent to release the auxiliary agent, increasing the dosage, or initiating enhanced recovery, etc. The recommended dose ranges for each situation can be further optimized based on actual field measurements and test results; After addition, it is recommended to mix quickly for 1-3 minutes, flocculate slowly for 5-15 minutes, and allow to settle or separate magnetically for 10-20 minutes.

[0046] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A composite water purification agent for wastewater purification, characterized in that, include: Metal-based concrete settling cores are composed of iron salt precursors; An adaptive response structure containing temperature- or pH-sensitive polymer microcapsules or magnetically responsive particles is used to release or trigger active substances when wastewater quality changes. Bridging polymeric flocculants are used to enhance the bonding between floc structure and fiber / colloidal particles; The recyclable structure is in the form of a magnetically separable or floatable carrier, which allows the water purification agent to be recycled, dehydrated, and regenerated after use. The metal-based coagulation sedimentation core, the adaptive response structure, and the bridging polymer flocculant work synergistically to first achieve charge neutralization and bridging flocculation after being added to papermaking wastewater. Then, the response structure releases an enhancer or activates a recovery structure based on changes in water quality, ultimately achieving water purification, sedimentation, dewatering, and recycling.

2. The composite water purification agent for wastewater purification according to claim 1, characterized in that: The iron salt precursor is a trivalent iron salt or hydrolyzed polyferric salt, and the iron content of the iron salt precursor is 20%-35% (by mass).

3. The composite water purification agent for wastewater purification according to claim 2, characterized in that: The adaptive response structure is selected from temperature-sensitive polymer microcapsules, pH-sensitive microcapsules, or magnetically responsive microparticles, and the structure releases internal additives when the wastewater temperature changes by ≥5℃ or the pH changes by ≥0.

5.

4. The composite water purification agent for wastewater purification according to claim 3, characterized in that: The bridging polymeric flocculant is cationic polyacrylamide or cationic cellulose, with a solid content of 1.0%-3.0% (by mass).

5. The composite water purification agent for wastewater purification according to claim 4, characterized in that: The recyclable structure is a magnetically responsive microparticle carrier or a flotation aid carrier, and after recycling and dehydration, it can be reused as a filler or papermaking aid.

6. A preparation process for a composite water purification agent for wastewater purification, characterized in that: Includes the following steps: Step 1: Mix the carrier material and the responsive structural material in water and stir to disperse the responsive structural particles and form a carrier suspension; Step 2: Add iron salt precursor solution to the carrier suspension, control the temperature at 40-60°C, and stir for 30-60 minutes to allow the iron salt to be loaded onto the carrier surface to form metal-based coagulation sedimentation nuclei. Step 3: Add the bridging polymer flocculant to the above mixture and continue stirring for 10-30 minutes to allow the bridging polymer to combine with the carrier-metal core; Step 4: Adjust the mixture to a neutral pH (6.5-7.5) and allow it to stand for 1-3 hours to age, so that the structure can be stabilized; Step 5: Dehydrate, dry or granulate the aged material to obtain the final compound water purification agent that can be added.

7. The preparation process of the composite water purification agent for wastewater purification according to claim 6, characterized in that: The iron salt precursor used in step two has an iron content of 20%-35%, and the added bridging polymer flocculant has a solid content of 1.0%-3.0%.

8. The preparation process of the composite water purification agent for wastewater purification according to claim 6, characterized in that: The response structure is a magnetically responsive microparticle, and the average particle size after granulation in step five is 50-150 µm, which is beneficial for subsequent magnetic recovery.

9. The preparation process of the composite water purification agent for wastewater purification according to claim 6, characterized in that: The method of using the compound water purification agent for wastewater purification includes the following steps: S1. Add the water purification agent to the papermaking wastewater. The dosage is determined based on the TSS (suspended solids) concentration, filler particle concentration, and color index of the wastewater. S2. After rapid mixing for 1-3 minutes, slow flocculation for 5-15 minutes is performed to form flocs. S3. Sedimentation or magnetic separation recovery of flocs, followed by dehydration treatment of the resulting precipitate; S4. Dehydrate, dry or granulate the recovered water purification agent carrier for reuse or use as a paper filling material.

10. The preparation process of the composite water purification agent for wastewater purification according to claim 9, characterized in that: The dosage is 0.1-0.4 kg / m³ of metal-based coagulation sedimentation cores in the water treatment agent, calculated based on the TSS concentration of the wastewater. 3 When the filler particle concentration exceeds 500 mg / L or the color exceeds 150 PCU, the adaptive response structure is triggered to release the additive or initiate the enhancement mode.