Inorganic doped surface grafting demulsification functional layer oil-water separation microsphere resin coalescing material and preparation method

Abstract

This invention discloses an inorganic-doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material and its preparation method. The invention uses diallyl phthalate-acrylate highly absorbent resin as a substrate, and simultaneously introduces a certain proportion of hydrophilic monomers to form a synergistic effect. Through multi-level structural design, surface phosphonation modification is initiated, and chemically grafted demulsification functional molecular chain matrix and -Si-O-P-inorganic nanoparticles are constructed on the resin surface. This creates a four-in-one micro-nano multi-level rough structure integrating "highly absorbent substrate-phosphine coordination interface-micro-nano rough structure-demulsification functional layer," possessing both demulsification and agglomeration adsorption functions. This invention achieves the coupling of demulsification and agglomeration adsorption functions at the molecular scale, exhibiting highly efficient separation performance for emulsified oily wastewater. It realizes integrated and efficient separation of emulsified oily wastewater through demulsification-agglomeration-adsorption, and possesses excellent cyclic regeneration stability.

Description

Technical Field

[0001] This invention relates to the field of oil-water separation technology, and in particular to an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material and its preparation method. Background Technology

[0002] Oily wastewater is one of the main pollutants generated by industries such as petroleum extraction, refining, machinery processing, and textile printing and dyeing. Its treatment is extremely difficult, especially emulsified oily wastewater. As one of the world's largest industrial countries, China generates hundreds of millions of tons of oily wastewater annually, with emulsified oil accounting for as much as 30-50%, making its treatment extremely urgent. The oil droplets in emulsified oily wastewater are typically less than 10 μm in size and exhibit high stability. This stability stems from two factors: first, the rigid interfacial film formed by surfactants at the oil-water interface prevents oil droplet aggregation; second, the electrostatic repulsion of the double electric layer on the oil droplet surface. This stability makes it difficult to separate emulsified oil using conventional physical methods (such as gravity sedimentation and flotation), making it a key and challenging aspect of oily wastewater treatment. If discharged directly without effective treatment, emulsified oil will clog soil pores, form oil films that hinder water reoxygenation, poison aquatic organisms, and may accumulate through the food chain, endangering human health. Therefore, developing efficient, economical, and recyclable emulsified oil-water separation technologies is of great strategic significance for environmental protection, resource recovery, and sustainable industrial development.

[0003] Currently, oil-water separation technologies are mainly divided into three categories: physical separation methods, including gravity sedimentation, centrifugal separation, filtration, and membrane separation. Their advantages lie in simple operation and the absence of chemical additives, but they have low removal rates for stable emulsions (especially submicron-sized droplets), and the filter membranes / cartridges are easily clogged by oil, resulting in high operating costs. Chemical demulsification methods involve adding inorganic coagulants (such as Al2(SO4)3, FeCl3) or organic demulsifiers (such as polyethers and quaternary ammonium salts). Although demulsification is fast, it suffers from problems such as reagent residues, secondary pollution, and large sludge volumes, and cannot simultaneously achieve oil phase recovery. Functional material adsorption / separation methods utilize the differences in surface wettability of porous polymers, carbon-based materials, or ceramic materials to achieve selective oil-water separation, and have become a research hotspot in recent years. Among them, resin-based coalescing materials exhibit unique applicability in industrial fixed-bed reactors due to their high mechanical strength, controllable specific surface area, ease of modular packing, absence of chemical additives, and lack of secondary pollution.

[0004] In the application of resin materials, existing technologies mainly develop along two paths: (1) High oil-absorbing resin: It uses cross-linked polystyrene (PS), polyacrylate (PAA) or porous polyvinyl alcohol (PVA) as the matrix and relies on hydrophobic micropores to adsorb oil droplets. For example, Chinese invention patent CN101967212A discloses an acrylate polymer high oil-absorbing resin and its preparation method and uses. It uses acrylate and styrene as the main monomers and prepares a high oil-absorbing gel resin by free radical polymerization. It relies on hydrophobic micropores to adsorb oil droplets. It can absorb a variety of oil types (including aromatic hydrocarbons, chlorinated hydrocarbons, ketones, acetates and alkanes), with an oil absorption rate of 10-50 g / g and a mechanical oil retention rate of ≥90%. However, it is almost ineffective for O / W emulsions because it cannot destroy the emulsion droplet interface film. The oil droplets are completely wrapped outside the resin channels, resulting in low actual separation efficiency and difficulty in regeneration. This resin can be used to absorb floating oil on the sea surface, spilled oil, cooling emulsified oil, oil in industrial wastewater, etc.

[0005] (2) Functionalized modified resins: These resins are given demulsifying or agglomerating capabilities through surface modification. For example, Chinese invention patent CN114316244A uses octylphenol resin as an initiator and grafts propylene oxide and ethylene oxide to form a block copolymer demulsifier with a demulsification rate of over 98%. However, this material is a soluble demulsifier, which enters the aqueous phase after use and cannot be recycled. Furthermore, the phenolic structure poses environmental risks. Zhou Yanbo et al. (Study on the treatment of emulsified oil wastewater with quaternary ammonium salt modified resin [J]. China Water & Wastewater, 2008, 24(3):60-63.) used long-branched alkyl quaternary ammonium salts as modifiers and prepared a quaternary ammonium salt modified resin that can demulsify emulsified oil wastewater by grafting it onto polystyrene cation exchange resin through ion exchange. The modified resin can separate emulsified oil by demulsifying the emulsified oil itself without the need to add surfactants to the wastewater. However, the removal effect is better under alkaline conditions of influent, and the removal rate of emulsified oil reaches 82.1%. Chinese invention patents with publication numbers CN108607520A and CN108299827A construct micro-nano structure aggregate materials on the surface of stainless steel mesh and sponge through SiO2 nanoparticle self-assembly and sol-gel method, which can improve the oil-water separation efficiency to more than 99%. However, such materials lack chemical demulsification function, have limited effect on treating highly stable emulsions, and the surface modification layer of the hydrophobic mesh has poor wear resistance, is prone to failure, and has insufficient cycle stability.

[0006] A comprehensive analysis of the above technologies reveals that existing grafted demulsifiers and superabsorbent resins have certain advantages in the field of oil-water separation, but the following key technical bottlenecks exist: (1) Demulsification and coalescence functions are disconnected: Demulsifiers are dispersed in the bulk phase or uniformly cover the surface, and cannot accumulate active sites in the capillary hot spots (such as the tips of micron protrusions) where oil droplets are most likely to coalesce. This results in demulsifiers having no oil absorption function, requiring multi-stage processing, which is complex and costly.

[0007] (2) Poor stability: physical coating or weak bond bonding, easy to fall off, loss of functional layer, short lifespan, and secondary pollution.

[0008] (3) Poor recycling performance: High operating costs for single use or recycling, and large amount of solid waste.

[0009] (4) Simple structure: lacks the synergy between micro-nano rough structure and chemical demulsification function, resulting in low mass transfer efficiency and insufficient mechanical oil-locking ability.

[0010] Although coalescing resin materials have shown certain advantages in oil-water separation, their separation efficiency still falls short of practical application requirements for oily wastewater with high emulsification levels, low oil droplet concentrations, or complex compositions. When treating high-concentration emulsified oily wastewater, some coalescing resin materials exhibit slow coalescence rates and insufficient ability to capture small-diameter oil droplets, resulting in effluent oil content failing to meet stringent discharge standards. In complex wastewater environments and during long-term operation, coalescing resin materials are susceptible to clogging by oil, chemical corrosion, and mechanical wear, leading to a gradual decline in performance and a shortened service life. Most coalescing resin materials are difficult to effectively clean and regenerate after use, typically requiring periodic replacement. This not only increases treatment costs but may also generate large amounts of waste coalescing material, causing new environmental pollution problems. Summary of the Invention

[0011] This invention addresses the technical problems of existing oil-water separation resins, such as the disconnect between demulsification and coalescence functions in the treatment of emulsified oil in wastewater, poor cycle stability, and a simple structure. It provides an inorganic-doped surface-grafted demulsification functional layer oil-water separation microsphere resin coalescing material and its preparation method. The method utilizes techniques such as chemical grafting, followed by organosilane coupling and phosphorous acid surface modification, to crosslink specific functional groups and nanomaterials onto the surface of the coalescing resin material. Simultaneously, demulsifier molecules and nano-oxide particles are fixed at specific sites, constructing a quaternary spatially coupled micro / nano structure of "high oil-absorbing substrate - chemical coordination interface - micro / nano rough structure - demulsification functional molecular layer." This achieves precise synergy between the demulsification reaction and capillary coalescence adsorption within the resin structure, realizing integrated demulsification and oil absorption. Furthermore, the demulsification layer is non-lossable and continuously regenerable, allowing the oil-water mixture to flow more uniformly within the coalescing material, ensuring sufficient contact with the material, improving the coalescence adsorption effect, and effectively achieving high oil absorption capacity, selective separation of oil-water mixtures, and material recycling.

[0012] In a first aspect, the present invention provides a method for preparing an inorganic doped surface-grafted demulsifying functional layer oil-water separation microsphere resin agglomeration material, which is achieved by the following technical solution.

[0013] A method for preparing an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material includes the following steps: S1. Preparation of high oil-absorbing resin substrate: A mixture of oil phase containing 4-vinylbenzyl chloride, sodium p-styrene sulfonate, a bifunctional crosslinking agent, C12-C18 alkyl acrylate, a pore-forming agent, and an initiator was dispersed in an aqueous phase. Porous, highly oil-absorbent resin microspheres were prepared via suspension polymerization. The resulting microspheres had a particle size of 300-500 μm and a surface area of ​​800-1000 m². 2 / g, with an average pore size of 8-15nm, providing sufficient and uniform reaction sites for its subsequent surface functionalization; wherein, the mass ratio of 4-vinylbenzyl chloride, sodium p-styrene sulfonate, bifunctional crosslinking agent, C12-C18 alkyl acrylate, porogen, and initiator is (5-15):(20-60):(10-25):(25-40):(50-280):(0.2-5); S2. Grafting polymerization of surface demulsification functional layer: After the resin microspheres obtained in step S1 are swollen, they are mixed with ethanol, triethylamine and polyether block demulsifier solution, and refluxed at 60℃-80℃ for 4-6 hours for coupling grafting. After filtration, washing, drying and sieving, the surface-grafted demulsifying functional layer resin is obtained; wherein, the mass ratio of resin microspheres, ethanol, triethylamine and polyether block demulsifier is 1:(2-6):(0.005-0.02):(0.03-0.2). S3. Surface coordinating groups are fixed: The resin microspheres obtained in step S2 were dispersed in a mixed solution containing silane coupling agent and phosphorous acid, and reacted at 40-70℃ for 4-8 h. This allowed the silanol generated from the hydrolysis of silane to condense with the hydroxyl groups on the resin surface, while the phosphorous acid and silanol underwent PO-Si co-condensation to form a -Si-OP(=O)(OH)-phosphonic acid anchoring layer. After cooling and washing, a resin matrix with phosphonic acid modification on the surface was obtained. The phosphonic acid groups provide rigid, high-density anchoring sites for subsequent nanoparticle coordination. The mass ratio of resin microspheres, silane coupling agent, and phosphorous acid was 1:(0.05-0.65):(0.03-0.25). S4. Construction of micro / nano structures: The resin matrix obtained in step S3 was dispersed in a colloidal solution containing inorganic nano-oxides and refluxed at pH 4.5-5.5 and 60-80℃ for 4-6 h, allowing the nanoparticles to undergo chemical coordination grafting with phosphonic acid groups. This resulted in the growth of 200-500 nm sheet-like, spherical, rod-like, or irregular multi-level rough protrusion structures on the resin surface. The mixture was then filtered, washed, and dried to obtain a polymerized material with a micro / nano-demulsification spatial coupling synergistic structure. The resulting polymerized material with micro / nano and demulsification structures achieves spatial coupling between demulsification and micro / nano structures, increasing the surface area to 1000-1300 m². 2 / g, with an average pore size of 5-9nm, enables the composite material to have high oil absorption capacity, selectively separate oil-water mixtures, and recycle the material.

[0014] Furthermore, in step S1, the difunctional crosslinking agent is selected from diallyl phthalate or ethylene glycol diacrylate, preferably diallyl phthalate.

[0015] Furthermore, in step S1, the C12-C18 alkyl acrylate is preferably the C14-C18 alkyl acrylate, and the C14-C18 alkyl acrylate is preferably the hexadecyl methacrylate or octadecyl methacrylate.

[0016] Furthermore, in step S1, the pore-forming agent is a mixture of n-heptane and xylene in a mass ratio of 2:1; the initiator is AIBN.

[0017] Preferably, in step S1, the mass ratio of 4-vinylbenzyl chloride, sodium p-styrene sulfonate, bifunctional crosslinking agent, C12-C18 alkyl acrylate, porogen, and initiator is (10-15):(35-50):(10-20):(25-35):(50-150):(0.2-3).

[0018] Furthermore, in step S1, the aqueous phase contains polyvinyl alcohol, and the concentration of polyvinyl alcohol in the aqueous phase is 0.2%-1.0%, preferably 0.2%-0.6%.

[0019] Furthermore, in step S1, the mass ratio of the aqueous phase to the oil phase is 3-5:1, preferably 4-5:1.

[0020] Furthermore, in step S1, the suspension polymerization reaction temperature is 60-80℃, preferably 65-75℃, and the polymerization time is 7-12h, preferably 7-8h.

[0021] Furthermore, in step S2, the resin microspheres obtained in step S1 are swollen with ethanol.

[0022] Furthermore, in step S2, the polyether block demulsifier is selected as a polyether amine modified with terminal amino groups.

[0023] Preferably, in step S2, the mass ratio of resin microspheres, ethanol, triethylamine, and polyether block demulsifier is 1:(2-4):(0.005-0.01):(0.03-0.15).

[0024] Preferably, in step S2, the reaction temperature is 60-70℃ and the time is 4-5h.

[0025] Furthermore, in step S3, the silane coupling agent is selected from one or more of γ-chloropropyltrimethoxysilane, γ-bromopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane, preferably γ-chloropropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

[0026] Preferably, in step S3, the mass ratio of resin microspheres, silane coupling agent, and phosphorous acid is 1:(0.11-0.20):(0.03-0.20).

[0027] Preferably, in step S3, the reaction temperature is 50-60℃ and the time is 5-7h.

[0028] Furthermore, in step S4, the mass ratio of inorganic nano-oxide to resin matrix is ​​(0.01-0.1):1, preferably (0.02-0.06):1.

[0029] Furthermore, in step S4, the nano-oxide is selected from one or more combinations of nano-zirconium phosphate, hydrotalcite, silica, zirconium oxychloride, and iron oxide inorganic nanoparticles.

[0030] Furthermore, in step S4, the colloidal solution is an ethanol solution containing 1-5 wt% hexadecyltrimethylammonium bromide, preferably an ethanol solution containing 2-5 wt% hexadecyltrimethylammonium bromide.

[0031] Preferably, in step S4, the reaction pH is 4.8-5.2, the temperature is 60-70℃, and the reaction time is 4-5h.

[0032] Secondly, the present invention provides an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material, which is achieved by the following technical solution.

[0033] An inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material prepared by the above preparation method.

[0034] Thirdly, the present invention provides an application of an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material, which is achieved by the following technical solution.

[0035] Application of the above-mentioned inorganic doped surface-grafted demulsifying functional layer oil-water separation microsphere resin agglomeration material in the treatment of wastewater containing ≤300ppm emulsified oil.

[0036] Furthermore, the wastewater includes oil-in-water (O / W) emulsions, surfactant-stabilized emulsions, or high-salt oily wastewater.

[0037] By adopting a technical solution, the material is filled into a fixed-bed reactor, and oily wastewater passes through at a flow rate of 5-10 BV / h. The demulsification time for O / W emulsions with a particle size of 0.5-5.0 μm is ≤12min, and the demulsification rate is >95%. The oil-water separation efficiency for oily wastewater with emulsified oil / dissolved oil content ≤300ppm is ≥98%, realizing integrated separation of demulsification-agglomeration-adsorption.

[0038] After the material is saturated, it is backwashed with 5% sulfuric acid solution for 6-10 hours. After 10 regenerations, the separation efficiency decreases by ≤9%.

[0039] This application has the following beneficial effects: The oil-water separation resin coalescing material prepared in this invention uses diallyl phthalate and C12-18 alkyl acrylate to endow the resin with a hydrophobic framework inside and a modifiable hydrophobic region on the surface. At the same time, a certain proportion of hydrophilic monomers are introduced to form a synergistic effect with sodium styrene sulfonate and hydrophobic monomers, adjusting the surface energy of the material to achieve oil droplet entry into the material with minimal resistance. Furthermore, through silane coupling agent and phosphorous acid surface modification, phosphonic acid groups are pre-modified on the surface of the resin matrix. Chemically grafted demulsifying functional molecular chain matrix and -Si-OP- nanoparticle rigid complex are constructed on the resin surface at specific sites, constructing a four-in-one micro-nano multi-level rough structure with dual functions of demulsification and coalescence adsorption, consisting of "high oil absorption substrate - phosphonic acid coordination interface - micro-nano rough structure - demulsification functional layer". The resin-polymerized material prepared by this process achieves efficient separation of emulsified oily wastewater through integrated demulsification-polymerization-adsorption, and possesses excellent cyclic regeneration stability. The results show that it has a stronger affinity for oil molecules than the high oil-absorbing polymer material obtained by copolymerizing simple lipophilic monomers. It breaks through the limit of demulsification and oil absorption rate of traditional oil-absorbing materials. The demulsification time for O / W emulsions with a particle size of 0.5-5.0μm is ≤12min, and the oil-water separation efficiency for oily wastewater with emulsified oil / dissolved oil content ≤300ppm is ≥98%. After 10 regenerations with 5% sulfuric acid backwashing, the separation efficiency decreases by ≤9%, and the performance is significantly improved compared with traditional polymerized materials. Attached Figure Description

[0040] Figure 1 This is a scanning electron microscope image of the surface of the product prepared in Embodiment 1 of the present invention. Detailed Implementation

[0041] The present patent application will be further described below with reference to the accompanying drawings and embodiments.

[0042] This invention uses diallyl phthalate-acrylate super-oil-absorbing resin as a base, and introduces a certain proportion of hydrophilic monomers to synergistically enhance the effects of sodium styrene sulfonate and hydrophobic monomers. Through multi-level structural design, surface phosphonation modification is initiated, and chemically grafted demulsification functional molecular chains and -Si-OP-inorganic nanoparticles are constructed on the resin surface. This creates a four-in-one micro-nano multi-level roughened structure integrating "super-oil-absorbing base - phosphonic acid coordination interface - micro / nano roughened structure - demulsification functional layer," achieving efficient separation of emulsified oily wastewater through demulsification, coalescence, and adsorption, while exhibiting excellent cyclic regeneration stability. The resin coalescing material prepared by this process meets the following key performance indicators: surface area increased to 1000-1300 m². 2 / g, average pore size 5-9nm, demulsification time for O / W emulsions with particle size 0.5-5.0μm ≤12min, oil-water separation efficiency for oily wastewater with emulsified oil / dissolved oil content <300ppm ≥98%, separation efficiency decreases ≤9% after 10 regenerations by backwashing with 5% sulfuric acid.

[0043] The 4-vinylbenzyl chloride (90% purity), diallyl phthalate (98% purity), hexadecyl methacrylate (90% purity), octadecyl methacrylate (96% purity), amino-terminated modified polyetheramine (EO / PO ratio: 33 / 10, HLB value: 13.8), and polyvinyl alcohol (type 1788) used in the following embodiments of this application were purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Example 1

[0044] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of hexadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 0.2g of initiator (AIBN) were dispersed in 590g of an aqueous phase containing 0.6% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​947 m². 2 / g, pore size 10.2 nm.

[0045] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 4 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0046] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 5.5 g of 3-aminopropyltriethoxysilane and 2.75 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0047] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium phosphate (3g) containing 2% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.0 with phosphoric acid, and the reaction was carried out at 70℃ for 5 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1250m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 6.9nm.

[0048] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <2.5 mg / L. The separation efficiency was 98.7%, the demulsification time was ≤10 min, and the separation efficiency was 92.1% after 10 cycles. Example 2

[0049] Preparation of the highly oil-absorbent resin substrate: 7.5 g of 4-vinylbenzyl chloride, 25 g of sodium p-styrene sulfonate, 5 g of diallyl phthalate, 17.5 g of hexadecyl methacrylate, 55 g of porogen (n-heptane:xylene = 2:1), and 0.75 g of initiator (AIBN) were dispersed in 450 g of an aqueous phase containing 0.6% polyvinyl alcohol, and suspended at 65 °C for 7 h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 427 μm and a specific surface area of ​​802 m². 2 / g, pore size 14.6 nm.

[0050] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 200 g of ethanol, 0.5 g of triethylamine and 1.5 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0051] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 5.5 g of 3-aminopropyltriethoxysilane and 2.75 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0052] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium phosphate (5g) containing 2% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.0 with phosphoric acid, and the reaction was carried out at 70℃ for 5 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1120 m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 5.9nm.

[0053] Performance test: In a packed fixed bed (Φ25×300 mm), with an O / W emulsion containing 300 mg / L of condensate oil, the emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <5.0 mg / L, the separation efficiency was 98.2%, the demulsification time was ≤12 min, and the separation efficiency was 91.8% after 10 cycles. Example 3

[0054] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 25g of hexadecyl methacrylate, 150g of porogen (n-heptane:xylene = 2:1), and 3g of initiator (AIBN) were dispersed in 960g of an aqueous phase containing 0.6% polyvinyl alcohol, and the mixture was suspended and polymerized at 75℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The resulting microspheres had a particle size of 385 μm and a specific surface area of ​​815 m². 2 / g, pore size 14.2 nm.

[0055] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.25 g of triethylamine and 4 g of polyetheramine with terminal amino modification, reflux at 60 °C for 5 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0056] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 5.5 g of 3-aminopropyltriethoxysilane and 1.5 g of phosphorous acid. React at 50 °C for 7 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0057] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium phosphate (0.5g) containing 5% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 4.8 with phosphoric acid. The reaction was carried out at 60℃ for 4 hours, filtered, washed with deionized water, and dried at 60℃ to obtain an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1090 m². The micro / nano-level rough structure of zirconium phosphate forms a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 8.5nm.

[0058] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <5.0 mg / L. The separation efficiency was 98.2%, the demulsification time was ≤12 min, and the separation efficiency was 91.4% after 10 cycles. Example 4

[0059] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of octadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 1.5g of initiator (AIBN) were dispersed in 735g of an aqueous phase containing 0.6% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​923 m². 2 / g, pore size 9.3 nm.

[0060] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 7.5 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0061] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 10 g of 3-aminopropyltriethoxysilane and 10 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0062] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium phosphate (5g) containing 2% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.2 with phosphoric acid, and the reaction was carried out at 70℃ for 4 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1297m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 5.5nm.

[0063] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <2 mg / L. The separation efficiency was 99.3%, the demulsification time was ≤10 min, and the separation efficiency was 91.2% after 10 cycles. Example 5

[0064] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of octadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 1.5g of initiator (AIBN) were dispersed in 735g of an aqueous phase containing 0.2% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​906 m². 2 / g, pore size 9.5 nm.

[0065] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 7.5 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0066] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 10 g of 3-aminopropyltriethoxysilane and 10 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0067] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of hydrotalcite (0.5g) containing 2% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 4.8 with phosphoric acid, and the reaction was carried out at 70℃ for 4 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1021 m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 8.3nm.

[0068] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 8 BV / h. The oil content in the aqueous phase at the outlet was <6 mg / L. The separation efficiency was 98.0%, the demulsification time was ≤7.5 min, and the separation efficiency was 91.0% after 10 cycles. Example 6

[0069] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of octadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 1.5g of initiator (AIBN) were dispersed in 735g of an aqueous phase containing 0.2% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​941 m². 2 / g, pore size 9.4 nm.

[0070] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 7.5 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0071] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 10 g of 3-aminopropyltriethoxysilane and 10 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0072] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of silica (3g) containing 3% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 4.8 with phosphoric acid, and the reaction was carried out at 70℃ for 4 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a spherical micro / nano-level rough structure formed on the resin surface by nano-silica was obtained, with a specific surface area of ​​1222 m². 2 / g, average pore size 6.2nm.

[0073] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <4.5 mg / L. The separation efficiency was 98.5%, the demulsification time was ≤10 min, and the separation efficiency was 91.6% after 10 cycles. Example 7

[0074] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of octadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 1.5g of initiator (AIBN) were dispersed in 735g of an aqueous phase containing 0.2% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 8h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​928 m². 2 / g, pore size 9.5 nm.

[0075] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 7.5 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0076] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 10 g of 3-aminopropyltriethoxysilane and 10 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0077] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of 3g of iron oxide containing 3% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.0 with phosphoric acid, and the reaction was carried out at 70℃ for 4 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with rod-shaped micro / nano-level rough structure formed on the resin surface was obtained, with a specific surface area of ​​1261 m². 2 / g, average pore size 5.7nm.

[0078] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <5 mg / L. The separation efficiency was 98.2%, the demulsification time was ≤10 min, and the separation efficiency was 91.8% after 10 cycles. Example 8

[0079] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of hexadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 1.5g of initiator (AIBN) were dispersed in 735g of an aqueous phase containing 0.4% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 8h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​902 m². 2 / g, pore size 9.3 nm.

[0080] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 7.5 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0081] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 10 g of 3-aminopropyltriethoxysilane and 10 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0082] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium oxychloride (3g) containing 3% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.0 with phosphoric acid, and the reaction was carried out at 70℃ for 4 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1277m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 6.3nm.

[0083] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 6 BV / h. The oil content in the aqueous phase at the outlet was <5 mg / L. The separation efficiency was 98.2%, the demulsification time was ≤10 min, and the separation efficiency was 91.3% after 10 cycles. Example 9

[0084] Preparation of the highly oil-absorbent resin substrate: 10g of 4-vinylbenzyl chloride, 35g of sodium p-styrene sulfonate, 20g of diallyl phthalate, 32g of hexadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 2.0g of initiator (AIBN) were dispersed in 735g of an aqueous phase containing 0.4% polyvinyl alcohol, and the mixture was suspended and polymerized at 65℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​955 m². 2 / g, pore size 9.5 nm.

[0085] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.25 g of triethylamine and 3.5 g of polyetheramine with terminal amino modification, reflux at 60 °C for 5 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0086] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 7.5 g of γ-chloropropyltrimethoxysilane and 7.5 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0087] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium oxychloride (3g) containing 3% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.2 with phosphoric acid, and the reaction was carried out at 70℃ for 5 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1241 m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 6.2nm.

[0088] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 10 BV / h. The oil content in the aqueous phase at the outlet was <6 mg / L. The separation efficiency was 98.0%, the demulsification time was ≤6 min, and the separation efficiency was 91.7% after 10 cycles.

[0089] Comparative Example 1 Preparation of the high oil-absorbing resin substrate: 45g of styrene, 20g of diallyl phthalate, 32g of hexadecyl methacrylate, 50g of porogen (n-heptane:xylene = 2:1), and 0.2g of initiator (AIBN) were dispersed in 590g of an aqueous phase containing 0.6% polyvinyl alcohol, and suspension polymerization was carried out at 65℃ for 7h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 491μm and a specific surface area of ​​871m². 2 / g, pore size 9.9 nm.

[0090] Demulsification functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine and 4 g of polyetheramine with terminal amino modification, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsification functional layer resin.

[0091] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 5.5 g of 3-aminopropyltriethoxysilane and 2.75 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0092] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium phosphate (3g) containing 2% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.0 with phosphoric acid, and the reaction was carried out at 70℃ for 5 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1070 m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 7.2nm.

[0093] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 4 BV / h. The oil content in the aqueous phase at the outlet was <30 mg / L. The separation efficiency was 90%, the demulsification time was ≥12 min, and the separation efficiency was 78% after 10 cycles.

[0094] Results Analysis: Comparative analysis of Example 1 and Comparative Example 1 shows that Example 1, by introducing a copolymer system of 4-vinylbenzyl chloride and sodium p-styrenesulfonate into the polymer matrix, not only enhances the polarity and hydrophilic-lipophilic balance of the substrate but also promotes the effective grafting of subsequent functional layers and the orderly assembly of inorganic nanostructures. This is key to achieving efficient, rapid, and stable oil-water separation. Example 1 maintains high-efficiency separation at a high flow rate of 6 BV / h, achieving a separation efficiency of 98.7%; while Comparative Example 1 requires a flow rate reduction to 4 BV / h and a demulsification time ≥12 min, with a separation efficiency of 90%. This indicates that Example 1 has stronger demulsification and adsorption capabilities for O / W emulsions, resulting in more thorough purification, and the material exhibits superior mass transfer rate and channel permeability.

[0095] Comparative Example 2 Preparation of the highly oil-absorbent resin substrate: 10 g of 4-vinylbenzyl chloride, 35 g of sodium p-styrene sulfonate, 20.0 g of diallyl phthalate, 32 g of hexadecyl methacrylate, 50 g of porogen (n-heptane:xylene = 2:1), and 0.2 g of initiator (AIBN) were dispersed in 590 g of an aqueous phase containing 0.6% polyvinyl alcohol, and suspended at 65 °C for 7 h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​867 m². 2 / g, pore size 10.2 nm.

[0096] Demulsifying functional layer grafting: Take 50 g of the above microspheres, mix with 100 g of ethanol, 0.3 g of triethylamine, and 4 g of amino-terminated modified polyetheramine, reflux at 70 °C for 4 h, filter, wash with ethanol, and vacuum dry at 60 °C to obtain surface-grafted demulsifying functional layer resin with a specific surface area of ​​833 m². 2 / g, average pore size 9.7nm.

[0097] Performance test: A packed fixed bed (Φ25×300 mm) was used with an O / W emulsion containing 300 mg / L of condensate oil. The emulsion was passed through at a flow rate of 4 BV / h. The oil content in the aqueous phase at the outlet was <48 mg / L. The separation efficiency was 84%, the demulsification time was ≥15 min, and the separation efficiency was 63% after 10 cycles.

[0098] Results Analysis: Comparative analysis of Example 1 and Comparative Example 2 shows that the nano-zirconium phosphate sheet-like micro / nano-level rough structure on the surface of the material in Example 1 increases the contact area between the material and oil droplets, promoting oil droplet aggregation and separation. This structure also improves the material's anti-fouling ability and extends its service life. Surface phosphonation treatment introduces phosphonic acid groups, altering the surface charge properties and wettability, enhancing the material's adsorption and demulsification capabilities for oil droplets, and further improving oil-water separation efficiency. The synergistic effect of these two processes results in Example 1 material significantly outperforming Comparative Example 2 material, which only underwent demulsification functional layer grafting, in terms of both oil-water separation performance and cycle stability. Therefore, when preparing high-performance oil-water separation materials, a complete preparation process should be adopted to fully utilize the synergistic effects of each step to obtain materials with excellent performance.

[0099] Comparative Example 3 Preparation of the highly oil-absorbent resin substrate: 10 g of 4-vinylbenzyl chloride, 35 g of sodium p-styrene sulfonate, 20.0 g of diallyl phthalate, 32 g of hexadecyl methacrylate, 50 g of porogen (n-heptane:xylene = 2:1), and 0.2 g of initiator (AIBN) were dispersed in 590 g of an aqueous phase containing 0.6% polyvinyl alcohol, and suspended at 65 °C for 7 h. After filtration, removal of the porogen, and washing, polymer microspheres were obtained. The obtained microspheres had a particle size of 485 μm and a specific surface area of ​​947 m². 2 / g, pore size 10.2 nm.

[0100] Surface phosphonation: Take 50 g of the above microspheres and disperse them in a mixed solution containing 5.5 g of 3-aminopropyltriethoxysilane and 2.75 g of phosphorous acid. React at 60 °C for 5 h, cool, wash with water, and dry under vacuum at 60 °C to obtain the phosphonated matrix.

[0101] Micro / nanostructure construction: 50g of phosphonate matrix was dispersed in an ethanol solution of zirconium phosphate (3g) containing 2% hexadecyltrimethylammonium bromide. The pH of the solution was adjusted to 5.0 with phosphoric acid, and the reaction was carried out at 70℃ for 5 hours. After filtration, washing with deionized water, and drying at 60℃, an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin aggregate material with a specific surface area of ​​1160 m² was obtained, forming a sheet-like micro / nano-level rough structure on the resin surface. 2 / g, average pore size 7.8nm.

[0102] Performance test: Packed fixed bed (Φ25×300 mm), with O / W emulsion containing 300 mg / L of condensate oil, the emulsion was passed through at a flow rate of 4 BV / h, the oil content of the aqueous phase at the outlet was <30 mg / L, the separation efficiency was 90%, the demulsification time was ≥15 min, and the separation efficiency was 72% after 10 cycles.

[0103] Results Analysis: A comparative analysis of Example 1 and Comparative Example 3 reveals that the core difference lies in whether the material preparation process includes a demulsification functional layer grafting step. Comparative Example 3 did not perform demulsification functional layer grafting, only completing the three-step process of preparing the highly absorbent resin substrate, surface phosphonation, and micro / nanostructure construction. This difference in surface chemical composition directly affects the interaction between the material and oil and water droplets, thus impacting oil-water separation performance. The terminal amino-modified polyetheramine in the demulsification functional layer exhibits excellent demulsification properties, interacting with oil and water droplets, disrupting emulsion stability, and promoting oil droplet aggregation and separation. Simultaneously, the polyetheramine groups increase the hydrophilicity of the material surface, reducing oil droplet adsorption and improving the material's anti-fouling ability. The demulsification functional layer provides more active sites for subsequent surface modification, while surface phosphonation and micro / nanostructure construction further optimize the material's surface structure and properties. These three elements work together to improve the material's oil-water separation performance.

[0104] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an inorganic doped surface-grafted demulsification functional layer oil-water separation microsphere resin agglomeration material, characterized in that: Includes the following steps: S1. Preparation of high oil-absorbing resin substrate: A mixture of oil phase containing 4-vinylbenzyl chloride, sodium p-styrene sulfonate, a bifunctional crosslinking agent, C12-C18 alkyl acrylate, a porogen, and an initiator was dispersed in an aqueous phase and porous, highly oil-absorbing resin microspheres were prepared by suspension polymerization. The mass ratio of 4-vinylbenzyl chloride, sodium p-styrene sulfonate, bifunctional crosslinking agent, C12-C18 alkyl acrylate, porogen, and initiator was (5-15):(20-60):(10-25):(25-40):(50-280):(0.2-5). S2. Grafting polymerization of surface demulsification functional layer: After the resin microspheres obtained in step S1 are swollen, they are mixed with ethanol, triethylamine and polyether block demulsifier solution, and refluxed at 60℃-80℃ for 4-6 hours for coupling grafting. After filtration, washing, drying and sieving, the surface-grafted demulsifying functional layer resin is obtained; wherein, the mass ratio of resin microspheres, ethanol, triethylamine and polyether block demulsifier is 1:(2-6):(0.005-0.02):(0.03-0.2). S3. Surface coordinating groups are fixed: The resin microspheres obtained in step S2 were dispersed in a mixed solution containing silane coupling agent and phosphorous acid, and reacted at 40-70℃ for 4-8 h. After cooling, the mixture was washed to obtain a resin matrix with surface phosphonate modification. The mass ratio of resin microspheres, silane coupling agent and phosphorous acid was 1:(0.05-0.65):(0.03-0.25). S4. Construction of micro / nano structures: The resin matrix obtained in step S3 was dispersed in a colloidal solution containing inorganic nano-oxides and refluxed at pH 4.5-5.5 and 60-80℃ for 4-6 h. After filtration, washing and drying, a coalesced material with a micro-nano-demulsification spatial coupling synergistic structure was obtained.

2. The preparation method according to claim 1, characterized in that: In step S1, the difunctional crosslinking agent is selected from diallyl phthalate or ethylene glycol diacrylate.

3. The preparation method according to claim 1, characterized in that: In step S1, the C12-C18 alkyl acrylate is selected from hexadecyl methacrylate or octadecyl methacrylate.

4. The preparation method according to claim 1, characterized in that: In step S2, the polyether block demulsifier is selected from polyether amines modified with terminal amino groups.

5. The preparation method according to claim 1, characterized in that: In step S3, the silane coupling agent is selected from one or more of γ-chloropropyltrimethoxysilane, γ-bromopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

6. The preparation method according to claim 1, characterized in that: In step S4, the nano-oxide is selected from one or more combinations of nano-zirconium phosphate, hydrotalcite, silica, zirconium oxychloride, and iron oxide inorganic nanoparticles.

7. The preparation method according to claim 1, characterized in that: In step S4, the mass ratio of inorganic nano-oxide to resin matrix is ​​(0.01-0.1):

1.

8. The preparation method according to claim 1, characterized in that: In step S4, the colloidal solution is an ethanol solution containing 1-5 wt% hexadecyltrimethylammonium bromide.

9. An inorganic doped surface-grafted demulsifying functional layer oil-water separation microsphere resin agglomeration material prepared by any one of the preparation methods of claims 1-8.

10. The application of the inorganic doped surface-grafted demulsifying functional layer oil-water separation microsphere resin agglomeration material according to claim 9 in the treatment of wastewater containing ≤300ppm emulsified oil.

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