A core-shell structured packing material for treating high-salt wastewater, its preparation method and application

Abstract

This invention discloses a core-shell structured high-salt wastewater treatment packing material, its preparation method, and its application. The packing material is a core-shell composite structure, consisting of a core and a shell layer covering the surface of the core. The core is a salt-resistant porous carrier, and the shell layer includes a salt-resistant binder, functional components, and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier. The preparation method includes the following steps: core pretreatment, shell slurry preparation, core-shell composite formation, and curing. The prepared core-shell structured high-salt wastewater treatment packing material can be used for biological or adsorption treatment of high-salt wastewater. Through the synergistic design of the core-shell structure, multiple functions such as salt resistance and stability, microbial immobilization, and pollutant adsorption are integrated, improving the treatment efficiency of high-salt wastewater, extending the service life of the packing material, and reducing treatment costs.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, specifically to a core-shell structured high-salt wastewater treatment packing material, its preparation method, and its application. Background Technology

[0002] High-salinity wastewater refers to wastewater with a total salt content greater than 1.0 wt%. It is widely derived from industries such as chemical, printing and dyeing, coal chemical, and pharmaceutical. Its composition is complex, containing not only large amounts of inorganic salts (such as Na+) + Ca 2+ Cl - SO4 2- High-salinity wastewater often contains recalcitrant organic matter and heavy metal ions, making it extremely difficult to treat. Currently, the main methods for treating high-salinity wastewater include physical, physicochemical, and biological methods. Among these, the biological method utilizes microorganisms (mainly salt-tolerant or halophilic bacteria) to degrade organic pollutants in the wastewater. Due to its advantages such as low cost and environmental friendliness without secondary pollution, it has become one of the mainstream technologies for treating high-salinity wastewater. Packing materials, as the core carrier in biological treatment, provide a substrate for microorganisms to attach and grow, thereby forming a biofilm within the reactor. The performance of the packing materials directly determines the wastewater treatment efficiency and system stability.

[0003] Existing packing materials for treating high-salinity wastewater are mostly single-structure materials, such as zeolite, activated carbon, and ceramic packing materials, which have several drawbacks. Firstly, single-structure packing materials lack sufficient salt tolerance, easily leading to structural damage and performance degradation in high-salinity environments, resulting in a shortened service life. Secondly, single-structure packing materials have limited functions, either serving only as microbial carriers or achieving simple adsorption, failing to simultaneously meet the multiple requirements of microbial immobilization, pollutant adsorption, and salt tolerance stability, resulting in low wastewater treatment efficiency and difficulty in adapting to the complex water quality conditions of high-salinity wastewater. Furthermore, some packing materials suffer from small specific surface area, insufficient porosity, and weak biofilm adhesion, leading to slow microbial biofilm formation and low biomass, further affecting the treatment effect of high-salinity wastewater.

[0004] Core-shell structured materials, due to the synergistic effect of the core and shell, can achieve multiple functional integrations by controlling the composition and structure of the core and shell, showing promising application prospects in the field of wastewater treatment. However, existing core-shell structured packings are mostly used in energy storage, nanofiltration membranes, and other fields. Packings used for wastewater treatment are mostly single-structure or simple composite structures. For example, patent application CN 206359304U discloses a biofilm packing for purifying high-salt wastewater, which adopts a three-dimensional mesh honeycomb structure. Although it can provide attachment sites for microorganisms, it lacks salt-resistant modification and functional integration, and its stability and treatment efficiency in high-salt environments still need to be improved. Patent application CN 113104959A discloses a magnetic packing material for wastewater treatment and its preparation method. It uses modified Fe3O4@SiO2 composite magnetic microspheres as the magnetic core and porous polymers as the coating layer material. The coating layer material is coated onto the modified Fe3O4@SiO2 composite magnetic microspheres to form a modified Fe3O4@SiO2-PS magnetic packing material for wastewater treatment. The modified Fe3O4@SiO2 composite magnetic microspheres are obtained by using Fe3O4 magnetic particles as raw materials and SiO2 as the surface coating with mesopores, after acid activation and surface modification. Although this improves the biofilm formation effect, it still suffers from problems such as single function, loss of magnetism, short service life, and high cost. To address these issues, there is an urgent need to develop a core-shell structure high-salt wastewater treatment packing material that integrates multiple functions, including excellent salt resistance, pollutant adsorption, and microbial immobilization. Summary of the Invention

[0005] To address the existing technical problems, this invention provides a core-shell structured high-salt wastewater treatment packing material, its preparation method, and its application. Through the synergistic design of the core-shell structure, multiple functions such as salt resistance and stability, microbial immobilization, and pollutant adsorption are integrated, thereby improving the treatment efficiency of high-salt wastewater, extending the service life of the packing material, and reducing treatment costs.

[0006] The technical solution of the present invention is as follows: a core-shell structured high-salt wastewater treatment packing, wherein the packing is a core-shell composite structure, consisting of a core and a shell layer covering the surface of the core; the core is a salt-resistant porous carrier, and the shell layer includes a salt-resistant binder, functional components and additives, wherein the functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier.

[0007] The shell and the core are bonded together by chemical bonds or physical anchoring to form a dense core-shell structure.

[0008] Furthermore, the shell layer comprises the following components in weight percentage: 40%-60% salt-resistant binder, 30%-50% functional components, and 5%-10% additives.

[0009] Furthermore, in the functional components, the mass ratio of salt-tolerant adsorbent to salt-tolerant microbial immobilization carrier is (1-2):1.

[0010] The mass ratio of salt-tolerant adsorbent to microbial immobilization carrier can ensure the bonding strength, functionality, and stability of the shell, achieving synergistic optimization of functions such as salt tolerance, microbial immobilization, and adsorption.

[0011] Furthermore, the filler has a particle size of 0.5mm-5mm and a specific surface area of ​​150m². 2 / g-500m 2 / g, with a porosity of 60%-85%; the core has a particle size of 0.4-4.8 mm and a porosity of 65%-90%; the shell has a thickness of 0.05 mm-0.2 mm.

[0012] The shell thickness is controlled at 0.05-0.2 mm to ensure the density and stability of the shell without blocking the pores of the core.

[0013] Furthermore, the salt-resistant porous carrier includes at least one of modified zeolite, modified diatomite, and modified porous ceramic.

[0014] Furthermore, the modified zeolite and the modified porous ceramic are modified with at least one of hydrochloric acid, nitric acid or sulfuric acid; the modified diatomite is modified with a silane coupling agent; and the porous ceramic is sintered from alumina and zirconium oxide.

[0015] Modified zeolites and modified porous ceramics are modified with one or more mixed acids, such as hydrochloric acid, nitric acid, or sulfuric acid, which can enhance their salt resistance and pore structure; modified diatomaceous earth is modified with silane coupling agents, which can improve its bonding force with the shell; porous ceramics are sintered from alumina and zirconium oxide as raw materials, and have excellent mechanical strength and salt resistance stability, and can be used as a supporting skeleton for fillers.

[0016] Furthermore, the salt-resistant binder is at least one of polyvinylidene fluoride (PVDF) and modified epoxy resin; the salt-resistant adsorbent includes at least one of activated carbon, mesoporous silica, and molecular sieve; and the salt-resistant microbial immobilization carrier includes at least one of polyvinyl alcohol microspheres and nano-silica modified polylactic acid microspheres.

[0017] The bonding of the core-shell structure is achieved by using PVDF or modified epoxy resin as a continuous phase skeleton. After curing, the entire shell and core are firmly bonded together through chemical bonds or physical anchoring.

[0018] The salt-resistant binder possesses excellent salt resistance, corrosion resistance, and bonding properties, ensuring a strong bond between the shell and the core. The salt-resistant adsorbent has a high specific surface area and strong adsorption capacity, enabling targeted and efficient adsorption of heavy metal ions and recalcitrant organic matter in high-salt wastewater. The salt-resistant microbial immobilization carrier promotes the attachment and proliferation of salt-resistant microorganisms, shortening the biofilm formation time. Carriers such as polyvinyl alcohol microspheres and nano-silica modified polylactic acid microspheres exhibit good biocompatibility, salt resistance, and thermal stability (withstanding temperatures below 150℃), effectively immobilizing salt-resistant microorganisms and preventing microbial loss. The dispersant ensures uniform dispersion of the shell components, preventing aggregation, while the antioxidant delays shell aging and extends the packing's service life.

[0019] Furthermore, the additives include at least one of a dispersant and an antioxidant, wherein the dispersant is polyethylene glycol or sodium dodecylbenzenesulfonate, and the antioxidant is di-tert-butyl-p-cresol or vitamin E.

[0020] This invention provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, comprising the following steps:

[0021] S1. Core pretreatment: The salt-tolerant porous carrier is crushed and sieved to obtain core particles with a particle size of 0.4-4.8 mm; the core particles are immersed in a modified solution while being stirred; after immersion, they are washed and dried to obtain the pretreated core.

[0022] Further, the modified solution in S1 is an acid solution with a mass concentration of 5%-15% or a silane coupling agent solution with a mass concentration of 1%-5%, the soaking time is 2h-6h, the stirring speed is 100r / min-300r / min, the drying temperature is 80℃-120℃, and the drying time is 2h-4h.

[0023] By modifying the kernel particles, impurities on the surface of the kernel particles can be completely removed, enhancing the salt resistance and bonding force between the kernel particles and the shell. The drying process ensures that the kernel is completely dry, avoiding any impact on the shell coating effect.

[0024] S2. Preparation of shell slurry: Weigh out the salt-resistant binder, functional components and additives by mass percentage. First, add the salt-resistant binder to the solvent and stir until the salt-resistant binder is completely dissolved. Then add the functional components and additives, stir evenly and then ultrasonically disperse to obtain a uniform shell slurry.

[0025] Furthermore, the solid content of the shell slurry in S2 is 15%-25%, and the viscosity is 200-500 mPa·s.

[0026] Further, the solvent in S2 is at least one of N-methylpyrrolidone, acetone and ethanol; the ultrasonic dispersion time is 20-40 min and the ultrasonic power is 200-400 W.

[0027] Ultrasonic dispersion treatment can effectively break up component agglomeration and ensure that the shell slurry is uniform and fine.

[0028] Furthermore, when the salt-resistant binder in S2 is polyvinylidene fluoride, it is heated to 50-60°C and stirred; when the salt-resistant binder is modified epoxy resin, it is stirred at room temperature.

[0029] S3. Core-shell composite: The pretreated core is placed in the shell slurry, and the shell slurry is uniformly coated on the core surface by dip-coating or spraying. The shell thickness is controlled to be 0.05-0.2 mm to obtain coated particles.

[0030] Furthermore, in the S3 method, the immersion time is 10-30 s, the lifting speed is 2-5 cm / min, and after lifting, the product is hung to drip dry at room temperature for 5-10 min; in the spraying method, the spray gun pressure is 0.2-0.3 MPa, the spraying distance is 15-20 cm, the product is sprayed in 2-3 coats, and each coat dries for 2-3 min.

[0031] The dip-coating method is simple to operate, produces uniform coating, and is suitable for mass production, while the spraying method allows for precise control of the shell thickness.

[0032] S4. Curing and molding: The coated particles are placed in a curing oven, heated and cured in stages, cooled to room temperature, and then sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 0.5mm-5mm.

[0033] Furthermore, the segmented heating and curing step in S4 is as follows: first, keep at 60-80 ℃ for 1-2 h, then keep at 100-120 ℃ for 1-2 h, and finally keep at 130-150 ℃ for 2-3 h; the cooling rate after curing is 5-10 ℃ / min.

[0034] Staged heating and curing prevents the shell from cracking due to excessively rapid heating, and also avoids burning of functional components at high temperatures. The first stage of heating slowly evaporates the solvent; the second stage of heating further cross-links the material; the final stage of heating fully cures the salt-resistant binder, ensuring a strong bond between the shell and the core; and the cooling rate after curing prevents damage to the filler structure due to excessively rapid cooling.

[0035] This invention also provides an application of core-shell structured high-salt wastewater treatment packing material, which is used for biological or adsorption treatment of high-salt wastewater. The packing density of the core-shell structured high-salt wastewater treatment packing material in the wastewater treatment device is 50%-75%, and the packing method adopts a gradient packing from the inlet end to the outlet end, with denser packing at the beginning and sparser packing at the end, and coarser packing at the beginning and finer packing at the end.

[0036] The packing material can serve as a carrier for salt-tolerant microorganisms, promoting microbial biofilm formation and proliferation, thereby degrading organic matter in high-salt wastewater; the adsorption treatment is used to remove heavy metal ions (such as Cr) from high-salt wastewater. 3+ Pb 2+ (etc.) and recalcitrant organic compounds (such as phenols, dyes, etc.).

[0037] Furthermore, the salt content of the high-salinity wastewater is 3%-20% by mass.

[0038] Furthermore, the biological treatment includes aerobic biological treatment and anaerobic biological treatment.

[0039] Furthermore, the gradient filling is specifically as follows: the filling density at the inlet end is 70%-75%, and the packing pore size is 6-8 mm; the filling density at the middle end is 60%-70%, and the packing pore size is 4-6 mm; the filling density at the outlet end is 50%-60%, and the packing pore size is 3-4 mm.

[0040] The inlet-end filling can cope with the high load and high suspended solids water quality characteristics of the inlet end, reducing clogging; the middle-end filling can achieve further degradation and adsorption of pollutants; the outlet-end filling can achieve deep treatment, ensuring that the effluent meets the standards, while reserving sufficient mass transfer space to avoid clogging caused by excessive biofilm thickness.

[0041] Furthermore, the core-shell structure high-salt wastewater treatment packing material can be regenerated and reused. The specific steps of the regeneration method include: soaking the core-shell structure high-salt wastewater treatment packing material that is saturated with adsorption or aged by biofilm in a regeneration solution for 2-4 hours, washing and drying it, and then it can be put into use again; the regeneration solution is a hydrochloric acid solution with a mass concentration of 5%-10% or a sodium hydroxide solution with a mass concentration of 2%-5%.

[0042] The regeneration method can effectively desorb pollutants adsorbed on the surface of the packing material, restore the adsorption performance and microbial adhesion ability of the packing material, and reduce treatment costs.

[0043] By adopting the above technical solution, the beneficial effects achieved by the present invention are as follows:

[0044] (1) The present invention adopts a core-shell composite structure design. The core serves as a supporting skeleton and has excellent salt resistance and mechanical strength, which can ensure the structural stability of the core-shell structure high-salt wastewater treatment packing in a high-salt environment. The shell layer serves as a functional layer, integrating salt resistance adsorption and microbial fixation functions, realizing the synergistic effect of multiple functions of "support-salt resistance-adsorption-biological purification", solving the problems of single function and poor salt resistance of existing packings, and extending the service life of the packing.

[0045] (2) This invention enhances the bonding force between the core and the shell by modifying the core. The shell and the core are bonded together by chemical bonds or physical anchoring to form a dense structure, preventing the shell from falling off and extending the service life of the core-shell structure high-salt wastewater treatment packing. At the same time, the core-shell structure high-salt wastewater treatment packing has a high specific surface area (150-500 m²). 2 With its high porosity (60%-85%) and high density ( / g), it can provide sufficient microbial attachment sites and pollutant adsorption channels, accelerate the microbial biofilm formation rate, and improve pollutant removal efficiency.

[0046] (3) The core-shell structure high-salt wastewater treatment packing of the present invention has excellent salt resistance and can be adapted to high-salt wastewater with a salt content of 3wt%-20wt%. Furthermore, through the gradient filling method, the packing distribution can be optimized according to the water quality load characteristics of high-salt wastewater to avoid clogging and ensure the stable operation of the wastewater treatment device. The packing can be repeatedly regenerated and reused, which reduces the cost of wastewater treatment and has good economic efficiency and practicality.

[0047] (4) The preparation method of the core-shell structure high-salt wastewater treatment packing of the present invention is simple to operate and the process is controllable. It adopts a reasonable solid content and viscosity range, and achieves core-shell composite by impregnation-pulling method or spraying method. The segmented low-temperature curing ensures structural stability and does not damage functional components. It is suitable for mass production and can be widely used in the treatment of high-salt wastewater in chemical, printing and dyeing, coal chemical and other industries. It has broad application prospects.

[0048] (5) The core-shell structure high-salt wastewater treatment packing of the present invention can be regenerated and reused. After three regeneration cycles, the treatment efficiency of the packing can still maintain more than 70% of the initial efficiency, and it has good reusability. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the core-shell structure high-salt wastewater treatment packing material of the present invention;

[0050] Figure 2 The figures show the COD degradation effect of the core-shell structure high-salt wastewater treatment packing materials in Examples 1 and 3.

[0051] Figure 3The graphs show the NH3-N degradation effect of the core-shell structure high-salt wastewater treatment packing materials in Examples 1 and 3.

[0052] Figure 4 This is an adsorption kinetic diagram of the core-shell structure high-salt wastewater treatment packing material of Example 2.

[0053] In the figure, 1 is a salt-resistant porous carrier; 2 is a shell layer; 3 is activated carbon; 4 is mesoporous silica; 5 is a molecular sieve; 6 is a salt-resistant microbial immobilization carrier; and 7 is a salt-resistant binder. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to specific embodiments.

[0055] Example 1

[0056] like Figure 1 As shown, a core-shell structured high-salt wastewater treatment packing material is provided. The packing material is a core-shell composite structure, consisting of a core and a shell layer 2 covering the surface of the core. The core is a salt-resistant porous carrier 1, and the shell layer 2 includes a salt-resistant binder 7, functional components and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier 6.

[0057] Preferably, the shell comprises the following components in weight percentage: 750% salt-resistant binder, 25% salt-resistant adsorbent, 15% salt-resistant microbial immobilization carrier, and 10% additives.

[0058] Preferably, the salt-resistant binder 7 is polyvinylidene fluoride, the salt-resistant adsorbent is activated carbon 3, the salt-resistant microbial immobilization carrier 6 is polyvinyl alcohol (PVA) microspheres, the additive is polyethylene glycol 400 (PEG400), and the salt-resistant porous carrier 1 is modified zeolite.

[0059] Preferably, the particle size of the polyvinyl alcohol microspheres is 10-30 μm.

[0060] Preferably, the shell thickness is 0.1 mm; the core particle size is 0.4-0.6 mm, and the porosity is 75%; the filler particle size is 0.6-0.8 mm, and the specific surface area is 220 m². 2 / g, with a porosity of 68%.

[0061] This embodiment 1 provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, which includes the following steps:

[0062] S1. Core pretreatment: Natural zeolite is crushed and sieved to obtain core particles with a particle size of 0.4-0.6 mm; the core particles are placed in a 10% hydrochloric acid solution and soaked for 4 hours while stirring at a speed of 200 r / min. After soaking, the core particles are washed with deionized water until neutral and dried at 100℃ for 3 hours to obtain the pretreated modified zeolite core.

[0063] S2. Preparation of shell slurry: Weigh 50g PVDF, 25g activated carbon, 15g PVA microspheres and 10g PEG400. First, add PVDF to 150mL N-methylpyrrolidone (NMP) and heat and stir at 55℃ until PVDF is completely dissolved. Then add activated carbon, PVA microspheres and PEG400, stir evenly and then ultrasonically disperse for 30 min with an ultrasonic power of 300W to obtain a uniform shell slurry. The solid content of the shell slurry is 20% and the viscosity is 350mPa·s.

[0064] S3. Core-shell composite: The pretreated modified zeolite core is placed in the shell slurry. The impregnation-pulling method is used, with an impregnation time of 20s and a pulling speed of 4cm / min, so that the shell slurry is uniformly coated on the core surface. The core is then suspended and dripped at room temperature for 8min, and the shell thickness is controlled to be 0.1 mm to obtain the coated particles.

[0065] S4. Curing and Molding: The coated particles are placed in a curing oven and cured by staged heating. The staged heating and curing steps are as follows: first, keep at 70℃ for 1.5h, then keep at 110℃ for 1.5h, and finally keep at 140℃ for 2.5h. The cooling rate after curing is 8℃ / min. After cooling to room temperature, the particles are sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 0.6-0.8mm.

[0066] This embodiment 1 also provides an application of a core-shell structured high-salt wastewater treatment packing material. The core-shell structured high-salt wastewater treatment packing material is used for the biological treatment of dyeing and printing wastewater with a salt content of 8wt%. The packing method adopts a gradient packing, specifically: the packing density at the inlet end is 70% with a packing pore size of 6-8mm; the packing density in the middle is 65% with a packing pore size of 4-6mm; and the packing density at the outlet end is 55% with a packing pore size of 3-4mm. It is used for aerobic biological treatment, such as... Figure 2 The COD concentration in the effluent shown in Figure (a) remained stable at 30-50 mg·L⁻¹ for a long period. -1 The COD degradation rate only decreased slightly in the later stages of operation, and the overall effluent quality remained good. The COD degradation rate consistently remained around 80%, even approaching 90% in the later stages, indicating that the core-shell structured high-salt wastewater treatment packing material in Example 1 had high organic matter removal efficiency and exhibited good stability during the 40-day operating cycle, without significant performance degradation. Figure 3 The effluent NH3-N concentration shown in (c) remained at 5-10 mg·L⁻¹ for an extended period. -1 The overall treatment effect was good. Even when the influent NH3-N concentration decreased in the later stage, it was still able to maintain a high degradation rate. The NH3-N degradation rate was stable at about 80% in the early stage of operation and above 60% in the late stage of operation. This shows that the core-shell structure high-salt wastewater treatment packing material of Example 1 has a high overall removal efficiency of ammonia nitrogen, especially in the early stage of operation.

[0067] The biological treatment method in Example 1 is existing technology.

[0068] Example 2

[0069] like Figure 1 As shown, a core-shell structured high-salt wastewater treatment packing material is provided. The packing material is a core-shell composite structure, consisting of a core and a shell layer 2 covering the surface of the core. The core is a salt-resistant porous carrier 1, and the shell layer 2 includes a salt-resistant binder 7, functional components and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier 6.

[0070] Preferably, the shell comprises the following components in weight percentage: 45% salt-resistant binder, 30% salt-resistant adsorbent, 15% salt-resistant microbial immobilization carrier, and 10% additives.

[0071] Preferably, the salt-resistant binder 7 is a modified epoxy resin, the salt-resistant adsorbent is mesoporous silica 4, the salt-resistant microbial immobilization carrier 6 is nano-silica modified polylactic acid microspheres, the additive is sodium dodecylbenzenesulfonate, and the salt-resistant porous carrier 1 is a mixture of modified diatomaceous earth and modified porous ceramic, wherein the mass ratio of modified diatomaceous earth to modified porous ceramic is 1:1.

[0072] Preferably, the salt-tolerant microbial immobilization carrier 6 is a PVA microsphere (particle size 10-30 μm).

[0073] Preferably, the shell thickness is 0.15 mm; the core particle size is 2.0-2.4 mm, and the porosity is 80%; the filler particle size is 2.3-2.7 mm, and the specific surface area is 310 m². 2 / g, with a porosity of 72%.

[0074] This embodiment 2 provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, which includes the following steps:

[0075] S1. Core Pretreatment: Diatomaceous earth is pulverized and sieved to obtain diatomaceous earth particles with a particle size of 2.0-2.4 mm. The diatomaceous earth particles are placed in a 3% (w / w) silane coupling agent solution and soaked for 3 hours with stirring at a speed of 150 r / min. After soaking, the particles are washed with deionized water and dried at 100℃ for 3 hours to obtain modified diatomaceous earth particles. Alumina and zirconium oxide are mixed at a mass ratio of 2:1 and sintered to form porous ceramics. The ceramics are pulverized and sieved to obtain porous ceramic particles with a particle size of 2.0-2.4 mm. The porous ceramic particles are placed in a 15% (w / w) nitric acid solution and soaked for 2 hours with stirring at a speed of 300 r / min. After soaking, the particles are washed with deionized water until neutral and dried at 120℃ for 2 hours to obtain modified porous ceramic particles. The modified diatomaceous earth particles and the modified porous ceramic particles are mixed at a mass ratio of 1:1 to obtain the pretreated core.

[0076] S2. Preparation of shell slurry: Weigh 45g of modified epoxy resin, 30g of mesoporous silica, 15g of nano-silica modified polylactic acid microspheres and 10g of sodium dodecylbenzenesulfonate. First, add the modified epoxy resin to 120mL of acetone and stir at room temperature until the modified epoxy resin is completely dissolved. Then add the mesoporous silica, nano-silica modified polylactic acid microspheres and sodium dodecylbenzenesulfonate, stir evenly, and ultrasonically disperse for 25 min at an ultrasonic power of 350 W to obtain a uniform shell slurry. The solid content of the shell slurry is 22% and the viscosity is 280 mPa·s.

[0077] S3. Core-shell composite: The pretreated core is placed in the shell slurry and sprayed. The spray gun pressure is 0.25 MPa and the spraying distance is 18 cm. The coating is done in 3 coats. Each coat is dried at room temperature for 3 min after spraying. The shell thickness is controlled to be 0.15 mm to obtain coated particles.

[0078] S4. Curing and Molding: The coated particles are placed in a curing oven and cured by staged heating. The staged heating and curing steps are as follows: first, keep at 80℃ for 1 hour, then keep at 120℃ for 1 hour, and finally keep at 145℃ for 2 hours. The cooling rate after curing is 6℃ / min. After cooling to room temperature, the particles are sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 2.3-2.7mm.

[0079] This embodiment 2 also provides an application of a core-shell structured high-salt wastewater treatment packing material. The core-shell structured high-salt wastewater treatment packing material is used for the adsorption treatment of coal chemical high-salt wastewater with a salt content of 12wt%. A gradient packing method is adopted: the packing density at the inlet end is 72%, and the packing pore size is 6-8 mm; the packing density in the middle end is 62%, and the packing pore size is 4-6 mm; the packing density at the outlet end is 52%, and the packing pore size is 3-4 mm. Used for adsorption treatment, Cr...3+ The removal rate reached over 88%, and the specific adsorption kinetics were as follows: Figure 4 As shown in the diagram. After four months of use, the core-shell structure high-salt wastewater treatment packing material is regenerated and reused. The specific steps of the regeneration method include: immersing the saturated core-shell structure high-salt wastewater treatment packing material in a 3% sodium hydroxide solution for 3 hours, washing, and drying it before reuse. The adsorption performance of the regenerated core-shell structure high-salt wastewater treatment packing material recovers to more than 73% of its initial performance.

[0080] The adsorption treatment method in Example 2 is existing technology.

[0081] Example 3

[0082] like Figure 1 As shown, a core-shell structured high-salt wastewater treatment packing material is provided. The packing material is a core-shell composite structure, consisting of a core and a shell layer 2 covering the surface of the core. The core is a salt-resistant porous carrier 1, and the shell layer 2 includes a salt-resistant binder 7, functional components and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier 6.

[0083] Preferably, the shell comprises the following components by weight percentage: 55% salt-resistant binder, 30% salt-resistant adsorbent, 8% salt-resistant microbial immobilization carrier, and 7% additives.

[0084] Preferably, the salt-resistant binder 7 is PVDF, the salt-resistant adsorbent is a mixture of activated carbon 3 and molecular sieve 5, the mass ratio of activated carbon 3 to molecular sieve 5 is 1:1, the salt-resistant microbial immobilization carrier 6 is PVA microspheres, the additive is PEG400, and the salt-resistant porous carrier 1 is modified porous ceramic.

[0085] Preferably, the salt-tolerant microbial immobilization carrier 6 is a PVA microsphere (particle size 10-30 μm).

[0086] Preferably, the shell thickness is 0.1 mm; the core particle size is 4.0-4.8 mm, and the porosity is 85%; the filler particle size is 4.2-5.0 mm, and the specific surface area is 400 m². 2 / g, with a porosity of 78%.

[0087] This embodiment 3 provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, which includes the following steps:

[0088] S1. Core pretreatment: Alumina and zirconium oxide are mixed at a mass ratio of 3:1 and sintered to form porous ceramics. The ceramics are then crushed and sieved to obtain porous ceramic particles with a particle size of 4.0-4.8 mm. The porous ceramic particles are placed in a 15% nitric acid solution and soaked for 2 hours while being stirred at a stirring speed of 300 r / min. After soaking, the particles are washed with deionized water until neutral and dried at 120℃ for 2 hours to obtain the pretreated core.

[0089] S2. Preparation of shell slurry: Weigh 55g PVDF, 15g activated carbon, 15g molecular sieve, 8g PVA microspheres and 7g PEG400. First, add PVDF to 180mL NMP and heat and stir at 60℃ until PVDF is completely dissolved. Then add activated carbon, molecular sieve, PVA microspheres and PEG400, stir evenly, and ultrasonically disperse for 35 min at an ultrasonic power of 400 W to obtain a uniform shell slurry. The solid content of the shell slurry is 18% and the viscosity is 400 mPa·s.

[0090] S3. Core-shell composite: The pretreated core is placed in the shell slurry and the immersion-pulling method is used. The immersion time is 15 s and the pulling speed is 3 cm / min, so that the shell slurry is uniformly coated on the surface of the core. The core is suspended and dripped at room temperature for 10 min, and the shell thickness is controlled to be 0.1 mm to obtain the coated particles.

[0091] S4. Curing and Molding: The coated particles are placed in a curing oven and cured in stages. The staged curing steps are as follows: first, keep at 60℃ for 2 hours, then keep at 100℃ for 2 hours, and finally keep at 150℃ for 2 hours. The cooling rate after curing is 10℃ / min. After cooling to room temperature, the particles are sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 4.2-5.0mm.

[0092] This embodiment 3 also provides an application of core-shell structured high-salt wastewater treatment packing material. The packing material is used for the biological treatment of pharmaceutical high-salt wastewater with a salt content of 18 wt%, employing a gradient packing method: 75% packing density and 6-8 mm pore size at the inlet, 70% packing density and 4-6 mm pore size in the middle, and 60% packing density and 3-4 mm pore size at the effluent. For anaerobic biological treatment, the COD removal rate reaches over 80%, and the heavy metal ion removal rate reaches over 90%. After 5 months of use, the packing material is regenerated and reused. The regeneration method includes immersing the aged biofilm packing material in a 10% hydrochloric acid solution for 4 hours, followed by washing and drying before reuse. The regenerated packing material's adsorption performance recovers to over 74% of its initial performance.

[0093] The core-shell structured high-salinity wastewater treatment packing material of Example 3 was used for the biological treatment of high-salinity coal chemical wastewater with a salt content of 12 wt%. A gradient packing method was adopted: the packing density at the inlet was 72% with a pore size of 6-8 mm; the packing density in the middle was 62% with a pore size of 4-6 mm; and the packing density at the effluent was 52% with a pore size of 3-4 mm. It was used for aerobic biological treatment. Figure 2 Results in (b) show that during the 40-day operation period, the COD removal rate was approximately 90% in the initial startup phase, indicating a microbial acclimatization and adaptation stage. As the biofilm matured, the COD removal rate stabilized at around 95%, demonstrating that the gradient packing structure created a decreasing pore size gradient along the water flow direction within the packing layer, balancing the anti-clogging capability at the inlet and the deep treatment effect at the outlet. This illustrates that the core-shell structure high-salinity wastewater treatment packing material of Example 3 exhibits extremely high efficiency in treating organic matter under high salinity (12wt%) conditions and demonstrates excellent stability. Figure 3 The results in (d) show that the NH3-N degradation rate fluctuates between 60% and 80%, indicating that the core-shell structure high-salt wastewater treatment packing material of Example 3 has a high overall removal efficiency for ammonia nitrogen and high stability.

[0094] The biological treatment method and the adsorption treatment method in Example 3 are existing technologies.

[0095] Example 4

[0096] like Figure 1 As shown, a core-shell structured high-salt wastewater treatment packing material is provided. The packing material is a core-shell composite structure, consisting of a core and a shell layer 2 covering the surface of the core. The core is a salt-resistant porous carrier 1, and the shell layer 2 includes a salt-resistant binder 7, functional components and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier 6.

[0097] Preferably, the shell comprises the following components in weight percentage: 60% salt-resistant binder, 15% salt-resistant adsorbent, 15% salt-resistant microbial immobilization carrier, and 10% additives.

[0098] Preferably, the salt-resistant binder 7 is polyvinylidene fluoride, the salt-resistant adsorbent is activated carbon 3, the salt-resistant microbial immobilization carrier 6 is polyvinyl alcohol (PVA) microspheres, the additive is polyethylene glycol 400 (PEG400), and the salt-resistant porous carrier 1 is modified zeolite.

[0099] Preferably, the salt-tolerant microbial immobilization carrier 6 is a PVA microsphere (particle size 10-30 μm).

[0100] Preferably, the shell thickness is 0.05 mm; the core particle size is 4.6-4.8 mm, and the porosity is 90%; the filler particle size is 4.7-4.9 mm, and the specific surface area is 500 m². 2 / g, with a porosity of 85%.

[0101] This embodiment 4 provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, which includes the following steps:

[0102] S1. Core pretreatment: Natural zeolite was crushed and sieved to obtain core particles with a particle size of 4.6-4.8 mm; the core particles were placed in a 5% hydrochloric acid solution and soaked for 6 hours while stirring at a speed of 100 r / min. After soaking, the core particles were washed with deionized water until neutral and dried at 80℃ for 4 hours to obtain the pretreated modified zeolite core.

[0103] S2. Preparation of shell slurry: Weigh 60g PVDF, 15g activated carbon, 15g PVA microspheres and 10g PEG400. First, add PVDF to 180mL N-methylpyrrolidone (NMP) and heat and stir at 50℃ until PVDF is completely dissolved. Then add activated carbon, PVA microspheres and PEG400, stir evenly and then ultrasonically disperse for 40 min with an ultrasonic power of 200W to obtain a uniform shell slurry. The solid content of the shell slurry is 25% and the viscosity is 200mPa·s.

[0104] S3. Core-shell composite: The pretreated modified zeolite core is placed in the shell slurry. The impregnation-pulling method is used, with an impregnation time of 30s and a pulling speed of 2cm / min, so that the shell slurry is uniformly coated on the core surface. The core is then suspended and dripped at room temperature for 5min, and the shell thickness is controlled to be 0.05 mm to obtain coated particles.

[0105] S4. Curing and Molding: The coated particles are placed in a curing oven and cured by staged heating. The staged heating and curing steps are as follows: first, keep at 70℃ for 1 hour, then keep at 110℃ for 1.5 hours, and finally keep at 130℃ for 3 hours. The cooling rate after curing is 5℃ / min. After cooling to room temperature, the particles are sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 4.7-4.9mm.

[0106] This embodiment 4 also provides an application of core-shell structured high-salt wastewater treatment packing material. The core-shell structured high-salt wastewater treatment packing material is used for the aerobic biological treatment of dyeing and printing wastewater with a salt content of 20wt%. The packing method adopts a gradient packing: the packing density at the inlet is 70% with a packing pore size of 6-8 mm; the packing density in the middle is 70% with a packing pore size of 4-6 mm; and the packing density at the outlet is 55% with a packing pore size of 3-4 mm. After 5 months of use, the core-shell structured high-salt wastewater treatment packing material is regenerated and reused. The specific steps of the regeneration method include: soaking the biofilm-aged core-shell structured high-salt wastewater treatment packing material in a 5% hydrochloric acid solution for 4 hours, washing, and drying before reuse.

[0107] The aerobic biological treatment method in Example 4 is existing technology.

[0108] Example 5

[0109] like Figure 1 As shown, a core-shell structured high-salt wastewater treatment packing material is provided. The packing material is a core-shell composite structure, consisting of a core and a shell layer 2 covering the surface of the core. The core is a salt-resistant porous carrier 1, and the shell layer 2 includes a salt-resistant binder 7, functional components and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier 6.

[0110] Preferably, the shell comprises the following components by weight percentage: 40% salt-resistant binder, 25% salt-resistant adsorbent, 25% salt-resistant microbial immobilization carrier, and 10% additives.

[0111] Preferably, the salt-resistant binder 7 is a modified epoxy resin, the salt-resistant adsorbent is mesoporous silica 4, the salt-resistant microbial immobilization carrier 6 is nano-silica modified polylactic acid microspheres, the additives are sodium dodecylbenzenesulfonate and di-tert-butyl-p-cresol, the mass ratio of sodium dodecylbenzenesulfonate and di-tert-butyl-p-cresol is 1:1, and the salt-resistant porous carrier 1 is modified diatomaceous earth.

[0112] Preferably, the particle size of the polyvinyl alcohol microspheres is 10-30 μm.

[0113] Preferably, the shell thickness is 0.2 mm; the core particle size is 1.0-1.4 mm, and the porosity is 65%; the filler particle size is 1.4-1.8 mm, and the specific surface area is 150 m². 2 / g, with a porosity of 60%.

[0114] This embodiment 5 provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, which includes the following steps:

[0115] S1. Core pretreatment: The diatomaceous earth is crushed and sieved to obtain diatomaceous earth particles with a particle size of 1.0-1.4 mm. The diatomaceous earth particles are placed in a 1% silane coupling agent solution and soaked for 3 hours while stirring at a speed of 150 r / min. After soaking, the particles are washed with deionized water and dried at 100℃ for 3 hours to obtain the pretreated core.

[0116] S2. Preparation of shell slurry: Weigh 40g modified epoxy resin, 25g mesoporous silica, 25g nano-silica modified polylactic acid microspheres, 5g sodium dodecylbenzenesulfonate and 5g di-tert-butyl-p-cresol. First, add the modified epoxy resin to 110mL acetone and stir at room temperature until the modified epoxy resin is completely dissolved. Then add the mesoporous silica, nano-silica modified polylactic acid microspheres and sodium dodecylbenzenesulfonate, stir evenly, and ultrasonically disperse for 20 min at an ultrasonic power of 350 W to obtain a uniform shell slurry. The solid content of the shell slurry is 15% and the viscosity is 500 mPa·s.

[0117] S3. Core-shell composite: The pretreated core is placed in the shell slurry and sprayed in two layers at a spray gun pressure of 0.2 MPa and a spraying distance of 15 cm. Each layer is dried at room temperature for 2 min after spraying, and the shell thickness is controlled to be 0.2 mm to obtain coated particles.

[0118] S4. Curing and Molding: The coated particles are placed in a curing oven and cured by staged heating. The staged heating and curing steps are as follows: first, keep at 80℃ for 1 hour, then keep at 120℃ for 1 hour, and finally keep at 145℃ for 2 hours. The cooling rate after curing is 6℃ / min. After cooling to room temperature, the particles are sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 1.4-1.8mm.

[0119] This embodiment 5 also provides an application of core-shell structured high-salt wastewater treatment packing material. The packing material is used for the adsorption treatment of coal chemical high-salt wastewater with a salt content of 3wt%, employing a gradient packing method: the packing density at the inlet is 72% with a pore size of 6-8 mm; the packing density in the middle is 60% with a pore size of 4-6 mm; and the packing density at the outlet is 50% with a pore size of 3-4 mm. After four months of use, the packing material is regenerated and reused. The specific steps of the regeneration method include: immersing the saturated packing material in a 5% sodium hydroxide solution for 2 hours, washing, and drying before reuse.

[0120] The adsorption treatment method in Example 5 is existing technology.

[0121] Example 6

[0122] like Figure 1 As shown, a core-shell structured high-salt wastewater treatment packing material is provided. The packing material is a core-shell composite structure, consisting of a core and a shell layer 2 covering the surface of the core. The core is a salt-resistant porous carrier 1, and the shell layer 2 includes a salt-resistant binder 7, functional components and additives. The functional components include a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier 6.

[0123] Preferably, the shell comprises the following components by weight percentage: 60% salt-resistant binder, 20% salt-resistant adsorbent, 15% salt-resistant microbial immobilization carrier, and 5% additives.

[0124] Preferably, the salt-resistant binder 7 is a modified epoxy resin, the salt-resistant adsorbent is mesoporous silica 4, the salt-resistant microbial immobilization carrier 6 is nano-silica modified polylactic acid microspheres, the additive is sodium dodecylbenzenesulfonate, and the salt-resistant porous carrier 1 is modified diatomaceous earth.

[0125] Preferably, the particle size of the polyvinyl alcohol microspheres is 10-30 μm.

[0126] Preferably, the shell thickness is 0.1 mm; the core particle size is 2.0-2.4 mm, and the porosity is 80%; the filler particle size is 2.2-2.6 mm, and the specific surface area is 400 m². 2 / g, with a porosity of 70%.

[0127] This embodiment 6 provides a method for preparing a core-shell structured high-salt wastewater treatment packing material, which includes the following steps:

[0128] S1. Core pretreatment: The diatomaceous earth is crushed and sieved to obtain diatomaceous earth particles with a particle size of 2.0-2.4 mm. The diatomaceous earth particles are placed in a 2% silane coupling agent solution and soaked for 3 hours. The stirring is carried out at a stirring speed of 150 r / min during soaking. After soaking, the particles are washed with deionized water and dried at 100℃ for 3 hours to obtain the pretreated core.

[0129] S2. Preparation of shell slurry: Weigh 60g of modified epoxy resin, 20g of mesoporous silica, 15g of nano-silica modified polylactic acid microspheres and 5g of sodium dodecylbenzene sulfonate. First, add the modified epoxy resin to 160mL of acetone and stir at room temperature until the modified epoxy resin is completely dissolved. Then add the mesoporous silica, nano-silica modified polylactic acid microspheres and sodium dodecylbenzene sulfonate, stir evenly, and ultrasonically disperse for 20 min at an ultrasonic power of 350 W to obtain a uniform shell slurry. The solid content of the shell slurry is 20% and the viscosity is 350 mPa·s.

[0130] S3. Core-shell composite: The pretreated core is placed in the shell slurry and sprayed in three layers at a spray gun pressure of 0.3 MPa and a spraying distance of 20 cm. Each layer is dried at room temperature for 3 min after spraying, and the shell thickness is controlled to be 0.2 mm to obtain coated particles.

[0131] S4. Curing and Molding: The coated particles are placed in a curing oven and cured by staged heating. The staged heating and curing steps are as follows: first, keep at 80℃ for 1 hour, then keep at 120℃ for 1 hour, and finally keep at 145℃ for 2 hours. The cooling rate after curing is 6℃ / min. After cooling to room temperature, the particles are sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 2.2-2.6mm.

[0132] This embodiment 6 also provides an application of a core-shell structured high-salt wastewater treatment packing material. The packing material is used for the adsorption treatment of coal chemical high-salt wastewater with a salt content of 9wt%, employing a gradient packing method: the packing density at the inlet is 72% with a pore size of 6-8 mm; the packing density in the middle is 65% with a pore size of 4-6 mm; and the packing density at the outlet is 55% with a pore size of 3-4 mm. After four months of use, the packing material is regenerated and reused. The specific steps of the regeneration method include: immersing the saturated packing material in a 2% sodium hydroxide solution for 4 hours, washing, and drying before reuse.

[0133] The adsorption treatment method in Example 6 is existing technology.

Claims

1. A core-shell structured packing material for treating high-salt wastewater, characterized in that: The filler is a core-shell composite structure, consisting of a core and a shell (2) covering the surface of the core; the core is a salt-resistant porous carrier (1), and the shell includes a salt-resistant binder (7), functional components and additives, the functional components including a salt-resistant adsorbent and a salt-resistant microbial immobilization carrier (6).

2. The core-shell structured high-salt wastewater treatment packing material according to claim 1, characterized in that: The shell (2) comprises the following components by mass percentage: 40%-60% salt-resistant binder (7), 30%-50% functional components, and 5%-10% additives.

3. The core-shell structured high-salt wastewater treatment packing material according to claim 1, characterized in that: In the functional components, the mass ratio of salt-tolerant adsorbent to salt-tolerant microbial immobilization carrier (6) is (1-2):

1.

4. The core-shell structured high-salt wastewater treatment packing material according to claim 1, characterized in that: The salt-resistant porous carrier (1) includes at least one of modified zeolite, modified diatomaceous earth and modified porous ceramic; the salt-resistant binder (7) is at least one of polyvinylidene fluoride and modified epoxy resin; the salt-resistant adsorbent includes at least one of activated carbon (3), mesoporous silica (4) and molecular sieve (5); the salt-resistant microbial immobilization carrier (6) includes at least one of polyvinyl alcohol microspheres and nano-silica modified polylactic acid microspheres.

5. The core-shell structured high-salt wastewater treatment packing material according to claim 1, characterized in that: The adjuvant includes at least one of a dispersant and an antioxidant, wherein the dispersant is polyethylene glycol or sodium dodecylbenzenesulfonate, and the antioxidant is di-tert-butyl-p-cresol or vitamin E.

6. A method for preparing a core-shell structured high-salt wastewater treatment packing material according to any one of claims 1-5, characterized in that: Includes the following steps: S1. Core pretreatment: The salt-tolerant porous carrier is crushed and sieved to obtain core particles with a particle size of 0.4-4.8 mm; the core particles are immersed in a modified solution while being stirred; after immersion, they are washed and dried to obtain the pretreated core. S2. Preparation of shell slurry: Weigh out the salt-resistant binder, functional components and additives by mass percentage. First, add the salt-resistant binder to the solvent and stir until the salt-resistant binder is completely dissolved. Then add the functional components and additives, stir evenly and then ultrasonically disperse to obtain a uniform shell slurry. S3. Core-shell composite: The pretreated core is placed in the shell slurry, and the shell slurry is uniformly coated on the surface of the core by dip-coating or spraying. The shell thickness is controlled to be 0.05-0.2 mm to obtain coated particles. S4. Curing and molding: The coated particles are placed in a curing oven, heated and cured in stages, cooled to room temperature, and then sieved to obtain core-shell structured high-salt wastewater treatment filler with a particle size of 0.5mm-5mm.

7. The method for preparing a core-shell structured high-salt wastewater treatment packing material according to claim 6, characterized in that: The modified solution in S1 is an acid solution with a mass concentration of 5%-15% or a silane coupling agent solution with a mass concentration of 1%-5%, with a soaking time of 2h-6h, a stirring speed of 100r / min-300r / min, a drying temperature of 80℃-120℃, and a drying time of 2h-4h; the solvent in S2 is at least one of N-methylpyrrolidone, acetone, and ethanol; the ultrasonic dispersion time is 20-40min, and the ultrasonic power is 200-400 W; when the salt-resistant binder in S2 is polyvinylidene fluoride, it is heated to 50-60℃ and stirred; when the salt-resistant binder is modified epoxy resin, it is stirred at room temperature.

8. The method for preparing a core-shell structured high-salt wastewater treatment packing material according to claim 6, characterized in that: The segmented heating and curing steps in S4 are as follows: first, maintain the temperature at 60-80 ℃ for 1-2 h, then maintain the temperature at 100-120 ℃ for 1-2 h, and finally maintain the temperature at 130-150 ℃ for 2-3 h; the cooling rate after curing is 5-10 ℃ / min.

9. The application of the core-shell structured high-salinity wastewater treatment packing prepared by the method described in any one of claims 6-8, characterized in that: The core-shell structure high-salt wastewater treatment packing is used for biological or adsorption treatment of high-salt wastewater. The packing density of the core-shell structure high-salt wastewater treatment packing in the wastewater treatment device is 50%-75%, and the packing method adopts a gradient packing from the inlet end to the outlet end, with denser packing at the beginning and sparser packing at the end, and coarser packing at the beginning and finer packing at the end.

10. The application of the core-shell structured high-salt wastewater treatment packing material according to claim 9, characterized in that... The core-shell structured high-salt wastewater treatment packing material can be regenerated and reused. The specific steps of the regeneration method include: soaking the core-shell structured high-salt wastewater treatment packing material that is saturated with adsorption or aged by biofilm in a regeneration solution for 2-4 hours, washing and drying it, and then it can be put into use again; the regeneration solution is a hydrochloric acid solution with a mass concentration of 5%-10% or a sodium hydroxide solution with a mass concentration of 2%-5%.

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