Environment-friendly aqueous film-forming foam extinguishing agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of fire extinguishing agents, in particular to an environment-friendly aqueous film-forming foam fire extinguishing agent and a preparation method and application thereof. The aqueous film-forming foam extinguishing agent is prepared from the following raw materials: a compound bio-based surfactant, compound bio-based polyol and a foam-stabilizing and anti-reburning nano-composite agent. According to the environment-friendly aqueous film-forming foam extinguishing agent disclosed by the invention, the easily biodegradable compound bio-based surfactant is used as a core component, and the freezing resistance, the antibacterial property and the environmental protection property are synergistically enhanced by utilizing the compound bio-based polyol; a foam-stabilizing anti-reburning nano-composite agent compounded based on layered iron-aluminum-magnesium trimetal hydroxide, nano magnesium aluminum silicate and hydrophobic nano silicon dioxide aerogel is introduced, the reburning resistance is remarkably improved through multiple mechanisms of physical foam stabilization, heat insulation and chemical flame retardance, all the raw materials are non-toxic and environmentally friendly, and the cost is low. The problem of pollution of a traditional fluorocarbon surfactant and the problems that a bio-based surfactant is poor in film-forming property and poor in burning resistance are solved, and the surfactant is suitable for fighting fire disasters caused by non-water-soluble combustible liquid.

Description

Technical Field

[0001] This invention relates to the field of fire extinguishing agent technology, and in particular to an environmentally friendly aqueous film-forming foam fire extinguishing agent, its preparation method, and its application. Background Technology

[0002] Aqueous film-forming foam (AFFF) is a high-efficiency foam extinguishing agent based on fluorocarbon and hydrocarbon surfactants. Its extinguishing mechanism is to reduce the surface tension of water and the interfacial tension between oil and water by fluorocarbon surfactants, driving the foam liquid to spread rapidly on the oil surface to form a dense water film. This water film not only isolates the fuel surface from oxygen but also cools the fuel surface and inhibits oil and gas volatilization, achieving a dual effect of "oxygen isolation and cooling". It can effectively extinguish fires of various non-water-soluble flammable liquids, including petroleum, diesel, aviation fuel, and transformer oil.

[0003] Traditional fire extinguishing fuel filters (AFFFs) primarily consist of two types of fluorocarbon surfactants: C8 perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These surfactants are characterized by high surface activity, strong stability, and hydrophobic and oleophobic properties, making them the best-performing surfactants to date. However, they are also among the most difficult organic pollutants to degrade, and due to their high toxicity, bioaccumulation, and environmental persistence, they have been listed as persistent organic pollutants (POPs) under the Stockholm Convention. To overcome environmental bottlenecks, some fluorocarbon surfactants developed based on short-chain technologies have become mainstream alternatives to PFOA and PFOS. Although short-chain fluorocarbon surfactants significantly reduce bioaccumulation and environmental hazards, their performance gradually declines as the fluorocarbon chain shortens, making it difficult to simultaneously achieve both environmental friendliness and fire extinguishing performance. Recent research has attempted to replace them with bio-based surfactants such as alkyl glycosides (APG) and betaine, but these methods suffer from poor film-forming properties and weak fire resistance.

[0004] Therefore, the development of environmentally friendly and efficient aqueous film-forming foam extinguishing agents remains an urgent need in the field of fire protection technology. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an environmentally friendly aqueous film-forming foam fire extinguishing agent, its preparation method and application, so as to at least solve the environmental hazard problem of fluorocarbon surfactants in existing AFFFs, and achieve effective control and efficient extinguishing of fires.

[0006] The following is a summary of this disclosure to provide a basic understanding of some aspects. This summary is not intended to identify key or important elements, nor is it intended to limit the implementation or any aspects of the claims. Furthermore, this summary provides a simplified overview of some aspects that can be described in more detail in other parts of this disclosure.

[0007] The present invention solves the above-mentioned technical problems through the following technical means:

[0008] In a first aspect, the present invention provides an environmentally friendly aqueous film-forming foam fire extinguishing agent, wherein the raw materials of the aqueous film-forming foam fire extinguishing agent include: compounded bio-based surfactants, compounded bio-based polyols, sodium benzoate and foam-stabilizing and anti-reignition nanocomposite agents; wherein the foam-stabilizing and anti-reignition nanocomposite agents include layered iron-aluminum-magnesium trimetallic hydroxide, nano-magnesium aluminum silicate and hydrophobic nano-silica aerogel.

[0009] In conjunction with the first aspect, in some embodiments, the raw materials of the aqueous film-forming foam fire extinguishing agent, by mass percentage, include: 10-15% of compounded bio-based surfactants, 8-12% of compounded bio-based polyols, 0.4-1.0% of foam-stabilizing and anti-reignition nanocomposite agents, 0.03-0.05% of sodium benzoate, and the balance being pure water.

[0010] In conjunction with the first aspect, in some embodiments, the compounded bio-based surfactant comprises, by mass percentage: 7-8% isooctyl glucoside, 2-4% rhamnolipid, and 1-3% sophorolipid.

[0011] The CAS number for isooctyl glucoside is 125590-73-0, and its chemical formula is C. 14 H 28 O6, possessing a high HLB value (13–15) and excellent surface activity, has short chains that tightly bind to water molecules via hydrogen bonds, forming a dense adsorption layer on the aqueous phase side of the interface. This significantly reduces the surface tension of water, promotes the rapid spreading of foam solutions, and facilitates the formation of a dense water film, effectively isolating oxygen. Rhamnose lipolipid has the CAS number 147858-26-2 and the molecular formula C2. 32 H 58 O 13 The two rhamnose groups in the molecule are linked by glycosidic bonds to form a rigid structure. Its long hydrophobic chain penetrates deep into the oil phase, tightly adsorbing oil molecules through hydrophobic interactions, reducing oil-water interfacial tension, increasing foaming ratio, and prolonging separation time. Its natural antibacterial activity inhibits microbial degradation of the foam structure, extending the shelf life and effectively reducing the amount of traditional preservatives used. Sophorolipid CAS number is 148409-20-5, and its molecular formula is C2. 34 H 56 O 14It is a lactone-type sophorolipid, composed of hydrophobic long-chain fatty acids linked to hydrophilic sophorose (a disaccharide) via glycosidic bonds. It interacts with both the aqueous and oil phases, exhibiting unique amphiphilic properties. Its ultra-low oil-water interfacial tension promotes oil emulsification into microdroplets, synergistically isolating oxygen and inhibiting combustion with the water film. Its antibacterial activity inhibits potentially proliferating microorganisms. When isooctyl glucoside, rhamnolipin, and sophorolipid are used in combination, the high hydrophilicity of isooctyl glucoside, the amphiphilicity of sophorolipid, and the high hydrophobicity of rhamnolipin complement each other structurally. Through directional adsorption at the interface, a gradient effect is generated, synergistically reducing surface tension, thereby shortening extinguishing time and enhancing anti-reignition performance.

[0012] In conjunction with the first aspect, in some embodiments, the compounded bio-based polyols, by mass percentage, comprise: 2-4% xylitol and 6-8% trehalose.

[0013] Xylitol has the CAS number 87-99-0 and the chemical formula C5H. 12 O5, trehalose, CAS 99-20-7, chemical formula C 12 H 22 O 11 The combination of these two ingredients exhibits significant synergistic advantages. Xylitol forms a hydrogen bond network through its five hydroxyl groups, working synergistically with the rigid glassy structure of trehalose to lower the freezing point to below -30°C, achieving stable foaming in low-temperature environments while inhibiting ice crystals from puncturing the foam film. Xylitol and trehalose complement the hydrophobic chains of rhamnolipids, enhancing emulsifying ability, while the glucose ring of isooctyl glucoside binds to the hydroxyl groups of trehalose, alleviating the problem of viscosity increase at low temperatures and maintaining foaming performance under low-temperature conditions. As natural polyols, rhamnolipids and trehalose also possess environmentally friendly and biodegradable properties. Through antifreeze synergy, functional complementarity, and environmental enhancement, they significantly improve the overall fire extinguishing performance of the fire extinguishing agent.

[0014] In conjunction with the first aspect, in some embodiments, the foam-stabilizing and anti-reignition nanocomposite agent comprises, by mass percentage: 0.2–0.4% of layered iron-aluminum-magnesium trimetallic hydroxide, 0.1–0.3% of nano-magnesium aluminum silicate, and 0.1–0.3% of hydrophobic nano-silica aerogel.

[0015] Layered iron-aluminum-magnesium trimetallic hydroxide is a layered inorganic nanomaterial prepared by a hydrothermal method using aluminum nitrate (Al(NO3)3·9H2O), magnesium nitrate (Mg(NO3)2·6H2O), and iron nitrate (Fe(NO3)3·9H2O) as raw materials. Its specific composition can be represented as: [Mg...] 2+ 1-x-y Al 3+ x Fe 3+ y (OH) - 2](x+y)+ [A n- ] (x+y) / n ·ZH2O, where A n- It is an n-valent anion, and x represents Al. 3+ The mole fraction, y represents Fe 3+ The mole fraction, 1-xy represents Mg 2+ The mole fraction of this layered iron-aluminum-magnesium trimetallic hydroxide can reduce the critical micelle concentration of compounded bio-based surfactants, significantly reduce the surface tension of aqueous film-forming foam solutions, and accelerate its spreading on fuel surfaces. Its nanosheets, interspersed within the foam liquid film, can enhance the mechanical strength of the liquid film, delay foam separation and rupture, extend the separation time by 25%, and improve foam stability. Upon thermal decomposition, it releases water of crystallization, CO2, and generates metal oxides (Al2O3, MgO, Fe2O3). CO2 and H2O can dilute combustible gases and O2, reducing the surface temperature of the combustible material; the metal oxides cover the fuel surface to form a porous carbon layer, blocking oxygen and heat conduction; Fe... 3 + It catalytically decomposes H· and OH· free radicals in the flame at high temperatures, inhibiting the gas-phase combustion chain reaction, thereby shortening the extinguishing time and enhancing the anti-reignition performance.

[0016] The CAS number of nano-magnesium aluminum silicate is 71205-22-6, and its chemical formula is Al2MgO8Si2. It can rapidly expand in water and form a three-dimensional network-like gel structure, which endows the system with excellent thixotropy and suspension stability. It can effectively prevent foam drainage and aggregation, prolong the foam coverage time, and ensure that the solid components, including layered iron-aluminum-magnesium trimetallic hydroxide and hydrophobic nano-silica aerogel, are uniformly suspended, preventing sedimentation and maintaining the stability of the fire extinguishing agent performance.

[0017] Hydrophobic nano-silica aerogel, CAS 68611-44-9, chemical formula C2H6Cl2O2Si2, possesses extremely high porosity, a large specific surface area, and extremely low thermal conductivity. It effectively blocks the transfer of flame heat to the depths of the foam layer and the fuel surface, protecting the foam structure. Its superhydrophobicity allows it to firmly adsorb at the gas-liquid interface of the foam, significantly enhancing the elasticity and mechanical strength of the liquid film. Its low density and nanoscale characteristics make it easy to disperse in the liquid phase and resistant to sedimentation. A combination of layered iron-aluminum-magnesium trimetallic hydroxide, nano-magnesium aluminum silicate, and hydrophobic nano-silica aerogel significantly improves the overall performance of the compounded bio-based surfactant through multiple synergistic mechanisms: nano-magnesium aluminum silicate acts as a bulk "skeleton," providing three-dimensional network support to ensure the suspension and stability of all components; the hydrophobic nano-silica aerogel acts as an interfacial "patch," enhancing the liquid film strength and thermal insulation; and the layered iron-aluminum-magnesium trimetallic hydroxide provides chemical flame retardancy and a high-temperature barrier, decomposing and absorbing heat to inhibit the combustion reaction. The three components work synergistically to provide comprehensive protection for the compounded bio-based surfactant, from physical foam stabilization and heat insulation to chemical flame retardancy. All components are non-toxic and harmless, meeting the requirements for fluorine-free environmental protection, and significantly improving the stability, anti-reignition ability, and environmental friendliness of aqueous film-forming foam fire extinguishing agents.

[0018] Secondly, the present invention provides a method for preparing an environmentally friendly aqueous film-forming foam fire extinguishing agent, comprising the following steps:

[0019] Prepare the following raw materials by weight percentage: 10-15% compound bio-based surfactant, 8-12% compound bio-based polyol, 0.4-1.0% foam-stabilizing and anti-reignition nanocomposite agent, 0.03-0.05% sodium benzoate, and the balance being water; the foam-stabilizing and anti-reignition nanocomposite agent includes layered iron-aluminum-magnesium trimetallic hydroxide, nano-magnesium aluminum silicate, and hydrophobic nano-silica aerogel;

[0020] The compounded bio-based polyol was added to the compounded bio-based surfactant under stirring and stirred until homogeneous to obtain mixed solution one; the foam-stabilizing and anti-reignition nanocomposite agent was added to mixed solution one under stirring and stirred until homogeneous to obtain mixed solution two; sodium benzoate was fully dissolved in water to obtain sodium benzoate solution; the sodium benzoate solution was added to mixed solution two under stirring and stirred until homogeneous for 60-100 minutes to obtain aqueous film-forming foam fire extinguishing agent.

[0021] In conjunction with the second aspect, in some embodiments, the compounded bio-based surfactant comprises, by weight percentage of the total raw materials of the aqueous film-forming foam extinguishing agent, 7-8% isooctyl glucoside, 2-4% rhamnolipid and 1-3% sophorolipid; and the compounded bio-based polyol comprises 2-4% xylitol and 6-8% trehalose.

[0022] In conjunction with the second aspect, in some embodiments, the preparation method of the foam-stabilizing and anti-reignition nanocomposite agent is as follows:

[0023] Based on the total mass percentage of the raw materials for the aqueous film-forming foam fire extinguishing agent, the following raw materials are prepared: 0.2-0.4% of layered iron-aluminum-magnesium trimetallic hydroxide, 0.1-0.3% of nano-magnesium aluminum silicate, and 0.1-0.3% of hydrophobic nano-silica aerogel.

[0024] The layered iron-aluminum-magnesium trimetallic hydroxide was mixed with pure water and stirred at 7000-8500 rpm for 20-40 min in a high-shear dispersing emulsifier to obtain a nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension.

[0025] The nano-magnesium aluminum silicate is mixed with pure water and stirred at 7000-8500 rpm for 20-40 min in a high-shear dispersing emulsifier to obtain a nano-magnesium aluminum silicate suspension.

[0026] The hydrophobic nano-silica aerogel was mixed with pure water and stirred at 7000-8500 rpm for 20-40 min in a high-shear dispersing emulsifier to obtain a hydrophobic nano-silica aerogel suspension.

[0027] The nanolayered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano magnesium-aluminum silicate suspension, and the hydrophobic nano silica aerogel suspension were mixed and stirred at 7000-8500 rpm for 15-40 min, and then treated under ultrasound at a power of 500-600 W and a frequency of 80-120 kHz for 5-15 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0028] In conjunction with the second aspect, in some embodiments, the preparation method of the layered iron-aluminum-magnesium trimetallic hydroxide includes the following steps:

[0029] According to Fe 3+ Al 3+ Mg 2+ The molar ratio of ferric nitrate, aluminum nitrate, and magnesium nitrate is 1:(2~3):(6~8). Ferric nitrate, aluminum nitrate, and magnesium nitrate are weighed and dissolved in pure water to obtain a mixed metal salt solution with a total metal concentration of 0.3~0.6mol / L. A sodium hydroxide solution with a concentration of 2~3mol / L is prepared. A carbonate mixed solution with pH = 10.0±0.1 is prepared by mixing 0.1mol / L Na2CO3 solution and 0.1mol / L NaHCO3 solution.

[0030] Under continuous stirring at 500–600 rpm, a mixed metal salt solution and a sodium hydroxide solution were slowly added dropwise to the carbonate mixture. The sodium hydroxide solution was added at a rate of 0.5–1 mL / min, and the pH value was maintained at 10.0 ± 0.1. After the addition was completed, the resulting mixed reaction solution was transferred to a high-pressure reactor, sealed, and reacted at 120℃ ± 5℃ for 8.5–11 h. After natural cooling to room temperature, the reaction solution was removed and centrifuged at 8000–10000 rpm for 25–40 min. Then, it was washed with pure water until the conductivity of the washing solution was <100 μS / cm. The precipitate was vacuum dried at 40–50℃ for 20–30 h, and then vacuum dried at 50–60℃ for 45–50 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

[0031] Thirdly, the present invention also provides the application of the aqueous film-forming foam extinguishing agent described in the first aspect above, or the aqueous film-forming foam extinguishing agent prepared by the preparation method described in the second aspect above, in fire extinguishing applications, wherein the aqueous film-forming foam extinguishing agent is mixed with water at a volume ratio of 6:94 before use.

[0032] This invention relates to an environmentally friendly aqueous film-forming foam (AFFF) fire extinguishing agent. Firstly, it combines three bio-based surfactants—isooctyl glucoside, rhamnolipid, and sophorolipid—to reduce interfacial tension and improve foam spreading speed, coverage uniformity, and stability. All three bio-based surfactants are derived from renewable resources and have good biodegradability, replacing fluorocarbon surfactants and fundamentally solving the ecological hazards caused by fluorocarbon surfactants in traditional AFFFs. Secondly, it combines two bio-based polyols—xylitol and trehalose—to bind water molecules through multiple hydrogen bonds, reducing water activity and inhibiting ice crystal formation. Their natural antibacterial properties help inhibit microbial growth during storage, reducing the amount of traditional preservatives required. The synergistic effect of xylitol and trehalose significantly improves the antifreeze properties and stability of the bio-based surfactants, further enhancing the environmental friendliness and safety of the AFFF. On the other hand, the environmentally friendly aqueous film-forming foam fire extinguishing agent of the present invention introduces a foam-stabilizing and anti-reignition nanocomposite agent. Through the synergistic effect of layered iron-aluminum-magnesium trimetallic hydroxide, nano magnesium aluminum silicate, and hydrophobic nano silica aerogel, the overall performance of the compounded bio-based surfactant is comprehensively improved from physical foam stabilization and heat insulation to chemical flame retardancy. This solves the bottleneck problems of poor film-forming properties and weak fire resistance that are common in bio-based surfactants. Moreover, all components are non-toxic and harmless, which significantly improves the stability, anti-reignition ability, and environmental friendliness of the aqueous film-forming foam fire extinguishing agent.

[0033] The environmentally friendly aqueous film-forming foam fire extinguishing agent of this invention uses easily biodegradable bio-based surfactants as core components. By compounding bio-based polyols and foam-stabilizing and anti-reignition nanocomposite agents, it achieves effective fire control and efficient fire extinguishing while avoiding the biological risks and environmental problems caused by traditional aqueous film-forming foam fire extinguishing agents, providing an efficient and safe alternative to fire extinguishing agents for the fire protection field.

[0034] The preparation method of the environmentally friendly aqueous film-forming foam fire extinguishing agent of the present invention is simple in steps and mild in reaction conditions. Detailed Implementation

[0035] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0036] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0037] The environmentally friendly aqueous film-forming foam extinguishing agent of this application uses easily biodegradable bio-based surfactants as the core component. By compounding bio-based polyols and foam-stabilizing and anti-reignition nanocomposite agents, it can effectively control and extinguish fires while avoiding the biological risks and environmental problems caused by traditional aqueous film-forming foam extinguishing agents, providing an efficient and safe alternative to fire extinguishing agents for the fire protection field.

[0038] Specifically, the raw materials of the environmentally friendly aqueous film-forming foam fire extinguishing agent of this application include: a compounded bio-based surfactant, a compounded bio-based polyol, sodium benzoate, and a foam-stabilizing and anti-reignition nanocomposite agent; the foam-stabilizing and anti-reignition nanocomposite agent includes layered iron-aluminum-magnesium trimetallic hydroxide, nano-magnesium aluminum silicate, and hydrophobic nano-silica aerogel. The raw materials of the aqueous film-forming foam fire extinguishing agent include: 10–15 wt% compounded bio-based surfactant, 8–12 wt% compounded bio-based polyol, 0.4–1.0 wt% foam-stabilizing and anti-reignition nanocomposite agent, 0.03–0.05 wt% sodium benzoate, and the balance being pure water. Based on the total mass percentage of raw materials in the film-forming foam extinguishing agent, the compounded bio-based surfactant includes 7-8% isooctyl glucoside, 2-4% rhamnolipid, and 1-3% sophorolipid; the compounded bio-based polyol includes 2-4% xylitol and 6-8% trehalose; the foam-stabilizing and anti-reignition nanocomposite agent includes 0.2-0.4% layered iron-aluminum-magnesium trimetallic hydroxide, 0.1-0.3% nano-magnesium aluminum silicate, and 0.1-0.3% hydrophobic nano-silica aerogel.

[0039] The preparation method of the environmentally friendly aqueous film-forming foam fire extinguishing agent of this application includes the following steps:

[0040] S1. Prepare the following raw materials by mass percentage: 10-15% compound bio-based surfactant, 8-12% compound bio-based polyol, 0.4-1.0% foam stabilizer and flame retardant nanocomposite agent, 0.03-0.05% sodium benzoate, and the balance is water;

[0041] S2. Under continuous stirring at a speed of 200-300 rpm, slowly add the compound bio-based polyol to the compound bio-based surfactant. After the addition is complete, continue stirring for no less than 10 minutes until the mixture is uniform, and obtain mixed solution one.

[0042] S3. Under continuous stirring at a speed of 500-600 rpm, slowly add the foam-stabilizing and anti-reignition nanocomposite agent to the first mixed solution. After the addition is complete, continue stirring for no less than 10 minutes until the mixture is uniform, to obtain the second mixed solution.

[0043] S4. Mix sodium benzoate and water at a mass ratio of 1:10 and dissolve them completely to obtain a sodium benzoate solution;

[0044] S5. Under continuous stirring at a speed of 500-600 rpm, slowly add sodium benzoate solution to mixed solution two, and add the remaining pure water to the specified total amount. Continue stirring for no less than 60 minutes to obtain aqueous film-forming foam fire extinguishing agent.

[0045] The following examples 1-4 will provide a detailed description of the environmentally friendly aqueous film-forming foam fire extinguishing agent of this application, its preparation method, and its application.

[0046] Example 1

[0047] The environmentally friendly aqueous film-forming foam fire extinguishing agent of this embodiment comprises the following raw materials by mass percentage: 8% isooctyl glucoside, 4% rhamnolipid, 3% sophorolipid, 4% xylitol, 8% trehalose, 0.4% layered iron-aluminum-magnesium trimetallic hydroxide, 0.3% nano-magnesium aluminum silicate, 0.3% hydrophobic nano-silica aerogel, 0.03% sodium benzoate, and 71.97% pure water.

[0048] The preparation method of the environmentally friendly aqueous film-forming foam fire extinguishing agent in this embodiment is as follows:

[0049] (1) Preparation of compound bio-based surfactants

[0050] 24% of the total mass of the aqueous film-forming foam extinguishing agent raw materials were dissolved in pure water. Isooctyl glucoside was added to the 24% pure water, and the mixture was slowly heated to 45°C while continuously stirred until completely dissolved to obtain an isooctyl glucoside solution. Rhamnolipin was added to 12% pure water, and the mixture was slowly heated to 45°C while continuously stirred until completely dissolved to obtain a rhamnolipin solution. Sophorolipid was added to 9% pure water, and the mixture was slowly heated to 45°C while continuously stirred until completely dissolved to obtain a sophorolipid solution. The isooctyl glucoside solution, rhamnolipin solution, and sophorolipid solution were thoroughly mixed and allowed to cool naturally to room temperature to obtain a compound bio-based surfactant.

[0051] (2) Preparation of compound bio-based polyols

[0052] Take 4% pure water by weight of the total mass of the aqueous film-forming foam extinguishing agent raw materials, add xylitol to the 4% pure water, slowly heat to 40°C, and continue stirring at this temperature until completely dissolved to obtain a xylitol solution; add trehalose to 8% pure water, slowly heat to 40°C, and continue stirring at this temperature until completely dissolved to obtain a trehalose solution; mix the xylitol solution and the trehalose solution thoroughly, and allow to cool naturally to room temperature to obtain a compound bio-based polyol.

[0053] (3) Preparation of layered iron-aluminum-magnesium trimetallic hydroxide powder

[0054] According to Fe 3+ Al 3+ Mg 2+The molar ratio of ferric nitrate (Fe(NO3)3·9H2O), aluminum nitrate (Al(NO3)3·9H2O), and magnesium nitrate (Mg(NO3)2·6H2O) were weighed and dissolved in pure water to prepare a mixed metal salt solution. The total metal concentration in the mixed metal salt solution was controlled at 0.3 mol / L. 0.1 mol / L Na2CO3 and 0.1 mol / L NaHCO3 were mixed in a volume ratio of 3:7 to prepare a carbonate mixed solution with a pH of 10.0 ± 0.1. A sodium hydroxide (NaOH) solution with a concentration of 2 mol / L was prepared. A mixed metal salt solution was slowly added dropwise to a carbonate mixture under continuous stirring at 600 rpm, while NaOH solution was added dropwise at a rate of 1 mL / min. The pH of the reaction system was controlled at 10.0 ± 0.1. After the addition was complete, the mixture was transferred to a high-pressure reactor, sealed, and reacted at 120 ± 5 °C for 10 h. After natural cooling to room temperature, the reaction solution was removed and centrifuged at 8000 rpm for 30 min to remove unreacted impurities. The solution was then washed with pure water until the conductivity of the washing solution was <100 μS / cm. The resulting precipitate was vacuum dried at 50 °C for 24 h, and then vacuum dried at 60 °C for 48 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

[0055] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0056] Add 2% pure water (by weight of the total raw material mass of aqueous film-forming foam fire extinguishing agent) to the 2% pure water, then add layered iron-aluminum-magnesium trimetallic hydroxide and rapidly stir at 8000 rpm for 20 minutes using a high-shear dispersion emulsifier to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension. Add 1.5% pure water to nano-magnesium aluminum silicate and rapidly stir at 8000 rpm for 20 minutes using a high-shear dispersion emulsifier to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Add hydrophobic nano-silica aerosol... The adhesive was mixed with 1.5% pure water and rapidly stirred at 8000 rpm for 20 minutes using a high-shear dispersion emulsifier to form a uniform and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed for 15 minutes using a high-shear dispersion emulsifier at 8000 rpm, and then ultrasonically treated at 500W power and 120kHz frequency for 5 minutes to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0057] (5) Preparation of aqueous film-forming foam fire extinguishing agent

[0058] Take 0.3% pure water by weight of the total raw materials of the aqueous film-forming foam fire extinguishing agent, weigh out sodium benzoate and mix it with 0.3% pure water, and fully dissolve it to obtain a sodium benzoate solution. Adjust the mixer speed to 200 rpm, and while continuously stirring, slowly add the compounded bio-based polyol to the compounded bio-based surfactant. After the addition is complete, continue stirring for 10 minutes to obtain mixed solution one. Adjust the mixer speed to 600 rpm, and while continuously stirring, slowly add the foam-stabilizing and anti-reignition nanocomposite agent to mixed solution one. After the addition is complete, continue stirring for 10 minutes to obtain mixed solution two. While continuously stirring at 600 rpm, slowly add the sodium benzoate solution to mixed solution two, and finally add the remaining 9.67% pure water, and continue stirring for 60 minutes to obtain the environmentally friendly aqueous film-forming foam fire extinguishing agent.

[0059] Comparative Example 1

[0060] Compared to Example 1, the raw materials for preparing the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example have reduced the proportion of isooctyl glucoside and increased the proportions of rhamnolipid and sophorolipid. Specifically, the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example comprises the following raw materials by mass percentage: 5% isooctyl glucoside, 5% rhamnolipid, 5% sophorolipid, 4% xylitol, 8% trehalose, 0.4% layered iron-aluminum-magnesium trimetallic hydroxide, 0.3% nano-magnesium aluminum silicate, 0.3% hydrophobic nano-silica aerogel, 0.03% sodium benzoate, and 71.97% pure water.

[0061] (1) Preparation of compound bio-based surfactants

[0062] Take 15% of the total mass of the raw materials for the aqueous film-forming foam extinguishing agent as pure water, add isooctyl glucoside to the 15% pure water, slowly heat to 45°C, and continuously stir at this temperature until completely dissolved to obtain an isooctyl glucoside solution; add rhamnolipin to 15% pure water, slowly heat to 45°C, and continuously stir at this temperature until completely dissolved to obtain a rhamnolipin solution; add sophorolipid to 15% pure water, slowly heat to 45°C, and continuously stir at this temperature until completely dissolved to obtain a sophorolipid solution; thoroughly mix the isooctyl glucoside solution, rhamnolipin solution, and sophorolipid solution, and allow to cool naturally to room temperature to obtain a compound bio-based surfactant.

[0063] (2) Prepare compound bio-based polyols, the same as in Example 1.

[0064] (3) Prepare layered iron, aluminum and magnesium trimetallic hydroxide powder, the same as in Example 1.

[0065] (4) Prepare foam-stabilizing and anti-reignition nanocomposite agent, the same as in Example 1.

[0066] (5) Prepare aqueous film-forming foam fire extinguishing agent. This step is the same as in Example 1. Finally, aqueous film-forming foam fire extinguishing agent is obtained.

[0067] Example 2

[0068] The environmentally friendly aqueous film-forming foam fire extinguishing agent of this embodiment comprises the following raw materials by mass percentage: 7% isooctyl glucoside, 4% rhamnolipid, 2% sophorolipid, 2% xylitol, 8% trehalose, 0.2% layered iron-aluminum-magnesium trimetallic hydroxide, 0.2% nano-magnesium aluminum silicate, 0.3% hydrophobic nano-silica aerogel, 0.05% sodium benzoate, and 76.25% pure water.

[0069] The preparation method of the environmentally friendly aqueous film-forming foam fire extinguishing agent in this embodiment is as follows:

[0070] (1) Preparation of compound bio-based surfactants

[0071] Take 21% pure water by mass of the total raw materials of the aqueous film-forming foam extinguishing agent. Add isooctyl glucoside to the 21% pure water, slowly heat to 50°C, and stir continuously at this temperature until completely dissolved to obtain an isooctyl glucoside solution. Add rhamnolipin to 12% pure water, slowly heat to 50°C, and stir continuously at this temperature until completely dissolved to obtain a rhamnolipin solution. Add sophorolipid to 6% pure water, slowly heat to 50°C, and stir continuously at this temperature until completely dissolved to obtain a sophorolipid solution. Thoroughly mix the isooctyl glucoside solution, rhamnolipin solution, and sophorolipid solution, and allow to cool naturally to room temperature to obtain a compound bio-based surfactant.

[0072] (2) Preparation of compound bio-based polyols

[0073] Take 2% pure water by weight of the total mass of the aqueous film-forming foam extinguishing agent raw materials, add xylitol to the 2% pure water, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved to obtain a xylitol solution; add trehalose to 8% pure water, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved to obtain a trehalose solution; mix the xylitol solution and the trehalose solution thoroughly and cool naturally to room temperature to obtain a compound bio-based polyol.

[0074] (3) Preparation of layered iron-aluminum-magnesium trimetallic hydroxide powder

[0075] According to Fe 3+ Al 3+ Mg 2+The molar ratio of ferric nitrate (Fe(NO3)3·9H2O), aluminum nitrate (Al(NO3)3·9H2O), and magnesium nitrate (Mg(NO3)2·6H2O)) was weighed out and dissolved in pure water to prepare a mixed metal salt solution. The total metal concentration in the mixed metal salt solution was controlled at 0.6 mol / L. 0.1 mol / L Na2CO3 and 0.1 mol / L NaHCO3 were mixed in a volume ratio of 3:7 to prepare a carbonate mixed solution with a pH of 10.0 ± 0.1. A sodium hydroxide (NaOH) solution with a concentration of 3 mol / L was prepared. A mixed metal salt solution was slowly added dropwise to a carbonate mixture under continuous stirring at 500 rpm, while NaOH solution was added dropwise at a rate of 0.5 mL / min. The pH of the reaction system was controlled at 10.0 ± 0.1. After the addition was complete, the mixture was transferred to a high-pressure reactor, sealed, and reacted at 120℃ ± 5℃ for 8.5 h. After natural cooling to room temperature, the reaction solution was centrifuged at 9000 rpm for 25 min to remove unreacted impurities. The solution was then washed with pure water until the conductivity of the washing solution was <100 μS / cm. The resulting precipitate was vacuum dried at 40℃ for 20 h, and then vacuum dried at 50℃ for 48 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

[0076] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0077] 1% pure water was added to the total mass of the aqueous film-forming foam extinguishing agent raw materials. Layered iron-aluminum-magnesium trimetallic hydroxide was added to this 1% pure water, and the mixture was rapidly stirred at 8000 rpm for 20 minutes using a high-shear dispersion emulsifier to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension. Nano-magnesium aluminum silicate was added to this 1% pure water, and the mixture was rapidly stirred at 8000 rpm for 20 minutes using a high-shear dispersion emulsifier to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Hydrophobic nano-silica aerogel was then added... Add 1.5% pure water and use a high-shear dispersion emulsifier to rapidly stir at 8000 rpm for 20 minutes to form a uniform and stable hydrophobic nano-silica aerogel suspension. Mix the nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension, first stir at high speed for 15 minutes using a high-shear dispersion emulsifier at 8000 rpm, and then sonicate at 600W power and 80kHz frequency for 5 minutes to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0078] (5) Preparation of aqueous film-forming foam fire extinguishing agent

[0079] Take 0.5% pure water by weight of the total raw materials of the aqueous film-forming foam extinguishing agent, weigh out sodium benzoate and mix it with 0.5% pure water, and fully dissolve it to obtain a sodium benzoate solution. Adjust the mixer speed to 300 rpm, and while continuously stirring, slowly add the compounded bio-based polyol to the compounded bio-based surfactant. After the addition is complete, continue stirring for 10 minutes to obtain mixed solution one. Adjust the mixer speed to 500 rpm, and while continuously stirring, slowly add the foam-stabilizing and anti-reignition nanocomposite agent to mixed solution one. After the addition is complete, continue stirring for 10 minutes to obtain mixed solution two. While continuously stirring at 500 rpm, slowly add the sodium benzoate solution to mixed solution two, and finally add the remaining 23.25% pure water, and continue stirring for 65 minutes to obtain the environmentally friendly aqueous film-forming foam extinguishing agent.

[0080] Comparative Example 2

[0081] Compared to Example 2, the raw materials for preparing the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example have reduced the proportion of xylitol and increased the proportion of trehalose. Specifically, the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example comprises the following raw materials by mass percentage: 7% isooctyl glucoside, 4% rhamnolipid, 2% sophorolipid, 1% xylitol, 9% trehalose, 0.2% layered iron-aluminum-magnesium trimetallic hydroxide, 0.2% nano-magnesium aluminum silicate, 0.3% hydrophobic nano-silica aerogel, 0.05% sodium benzoate, and 76.25% pure water.

[0082] (1) Prepare compound bio-based surfactants, the same step as in Example 2.

[0083] (2) Preparation of compound bio-based polyols

[0084] Take 1% pure water by mass of the total raw materials of the aqueous film-forming foam extinguishing agent, add xylitol to the 1% pure water, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved to obtain a xylitol solution; add trehalose to 9% pure water, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved to obtain a trehalose solution; mix the xylitol solution and the trehalose solution thoroughly, and let them cool naturally to room temperature to obtain a compound bio-based polyol.

[0085] (3) Prepare layered iron, aluminum and magnesium trimetallic hydroxide powder, the same as in Example 2.

[0086] (4) Prepare foam-stabilizing and anti-reignition nanocomposite agent, the same as in Example 2.

[0087] (5) Prepare aqueous film-forming foam fire extinguishing agent. This step is the same as in Example 2. Finally, aqueous film-forming foam fire extinguishing agent is obtained.

[0088] Example 3

[0089] The environmentally friendly aqueous film-forming foam fire extinguishing agent of this embodiment comprises the following raw materials by mass percentage: 7% isooctyl glucoside, 2% rhamnolipid, 1% sophorolipid, 4% xylitol, 7% trehalose, 0.3% layered iron-aluminum-magnesium trimetallic hydroxide, 0.1% nano-magnesium aluminum silicate, 0.1% hydrophobic nano-silica aerogel, 0.04% sodium benzoate, and 78.46% pure water.

[0090] The preparation method of the environmentally friendly aqueous film-forming foam fire extinguishing agent in this embodiment is as follows:

[0091] (1) Preparation of compound bio-based surfactants

[0092] Take 21% of the total mass of the aqueous film-forming foam extinguishing agent raw materials in pure water, add isooctyl glucoside to the 21% pure water, slowly heat to 48°C, and continuously stir at this temperature until completely dissolved to obtain an isooctyl glucoside solution; add rhamnolipin to 6% pure water, slowly heat to 48°C, and continuously stir at this temperature until completely dissolved to obtain a rhamnolipin solution; add sophorolipid to 3% pure water, slowly heat to 48°C, and continuously stir at this temperature until completely dissolved to obtain a sophorolipid solution; thoroughly mix the isooctyl glucoside solution, rhamnolipin solution, and sophorolipid solution, and allow to cool naturally to room temperature to obtain a compound bio-based surfactant.

[0093] (2) Preparation of compound bio-based polyols

[0094] Take 4% pure water by mass of the raw materials of aqueous film-forming foam fire extinguishing agent, add xylitol to the 4% pure water, slowly heat to 42°C, and continue stirring at this temperature until completely dissolved to obtain a xylitol solution; add trehalose to 7% pure water, slowly heat to 42°C, and continue stirring at this temperature until completely dissolved to obtain a trehalose solution; mix the xylitol solution and the trehalose solution thoroughly, and cool naturally to room temperature to obtain a compound bio-based polyol.

[0095] (3) Preparation of layered iron-aluminum-magnesium trimetallic hydroxide powder

[0096] According to Fe 3+ Al 3+ Mg 2+The molar ratio of ferric nitrate (Fe(NO3)3·9H2O), aluminum nitrate (Al(NO3)3·9H2O), and magnesium nitrate (Mg(NO3)2·6H2O)) was weighed out and dissolved in pure water to prepare a mixed metal salt solution. The total metal concentration in the mixed metal salt solution was controlled at 0.5 mol / L. 0.1 mol / L Na2CO3 and 0.1 mol / L NaHCO3 were mixed in a volume ratio of 3:7 to prepare a carbonate mixed solution with a pH of 10.0 ± 0.1. A sodium hydroxide (NaOH) solution with a concentration of 2.5 mol / L was prepared. A mixed metal salt solution was slowly added dropwise to a carbonate mixture under continuous stirring at 550 rpm, while NaOH solution was added dropwise at a rate of 0.6 mL / min. The pH of the reaction system was controlled at 10.0 ± 0.1. After the addition was complete, the mixture was transferred to a high-pressure reactor, sealed, and reacted at 120℃ ± 5℃ for 11 h. After natural cooling to room temperature, the reaction solution was centrifuged at 10000 rpm for 40 min to remove unreacted impurities. The solution was then washed with pure water until the conductivity of the washing solution was <100 μS / cm. The resulting precipitate was vacuum dried at 45℃ for 30 h, and then vacuum dried at 55℃ for 45 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

[0097] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0098] Add 1.5% pure water (by weight of the total raw materials of the aqueous film-forming foam fire extinguishing agent) to the 1.5% pure water. Then, add layered iron-aluminum-magnesium trimetallic hydroxide to the 1.5% pure water and use a high-shear dispersion emulsifier to rapidly stir at 7000 rpm for 40 minutes to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension. Add nano-magnesium aluminum silicate to 0.5% pure water and use a high-shear dispersion emulsifier to rapidly stir at 7000 rpm for 40 minutes to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Add hydrophobic nano-silica... Aerogel was added to 0.5% pure water and rapidly stirred at 7000 rpm for 40 min using a high-shear dispersion emulsifier to form a uniform and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed of 8500 rpm for 20 min using a high-shear dispersion emulsifier, and then ultrasonically treated at 500W power and 80kHz frequency for 10 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0099] (5) Preparation of aqueous film-forming foam fire extinguishing agent

[0100] 0.4% of the total mass of the aqueous film-forming foam (AFCF) fire extinguishing agent raw materials were dissolved in pure water. Sodium benzoate was weighed and mixed with 0.4% pure water to obtain a sodium benzoate solution. The mixer speed was adjusted to 240 rpm, and the compounded bio-based polyol was slowly added to the compounded bio-based surfactant while continuously stirring. After the addition was completed, stirring was continued for 10 minutes to obtain mixed solution one. The mixer speed was adjusted to 550 rpm, and the foam-stabilizing and anti-reignition nanocomposite agent was slowly added to mixed solution one while continuously stirring. After the addition was completed, stirring was continued for 10 minutes to obtain mixed solution two. The sodium benzoate solution was slowly added to mixed solution two while continuously stirring at 500 rpm. Finally, the remaining 34.56% pure water was added, and stirring was continued for 60 minutes to obtain the environmentally friendly aqueous film-forming foam fire extinguishing agent.

[0101] Comparative Example 3

[0102] Compared to Example 3, the raw materials for preparing the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example have reduced the proportions of nano-magnesium aluminum silicate and hydrophobic nano-silica aerogel. Specifically, the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example comprises the following raw materials by mass percentage: 7% isooctyl glucoside, 2% rhamnolipid, 1% sophorolipid, 4% xylitol, 7% trehalose, 0.3% layered iron-aluminum-magnesium trimetallic hydroxide, 0.05% nano-magnesium aluminum silicate, 0.05% hydrophobic nano-silica aerogel, 0.04% sodium benzoate, and 78.56% pure water.

[0103] (1) Prepare compound bio-based surfactants, the same step as in Example 3.

[0104] (2) Prepare compound bio-based polyols, the same step as in Example 3.

[0105] (3) Prepare layered iron, aluminum and magnesium trimetallic hydroxide powder, the same as in Example 3.

[0106] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0107] Add 1.5% pure water (by weight of the total raw materials of the aqueous film-forming foam extinguishing agent) to the 1.5% pure water. Add layered iron-aluminum-magnesium trimetallic hydroxide to the 1.5% pure water and use a high-shear dispersion emulsifier to rapidly stir at 8000 rpm for 20 minutes to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension. Add nano-magnesium aluminum silicate to 0.25% pure water and use a high-shear dispersion emulsifier to rapidly stir at 8000 rpm for 20 minutes to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Add hydrophobic nano-silica... Aerogel was added to 0.25% pure water and rapidly stirred at 8000 rpm for 20 min using a high-shear dispersion emulsifier to form a uniform and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed for 15 min using a high-shear dispersion emulsifier at 8000 rpm, and then ultrasonically treated at 500W power and 100kHz frequency for 5 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0108] (5) Prepare aqueous film-forming foam fire extinguishing agent. This step is the same as in Example 3. Finally, the aqueous film-forming foam fire extinguishing agent is obtained.

[0109] Example 4

[0110] The environmentally friendly aqueous film-forming foam fire extinguishing agent of this embodiment comprises the following raw materials by mass percentage: 8% isooctyl glucoside, 3% rhamnolipid, 3% sophorolipid, 3% xylitol, 6% trehalose, 0.4% layered iron, aluminum, and magnesium trimetallic hydroxide, 0.3% nano-magnesium aluminum silicate, 0.2% hydrophobic nano-silica aerogel, 0.04% sodium benzoate, and 76.06% pure water.

[0111] The preparation method of the environmentally friendly aqueous film-forming foam fire extinguishing agent in this embodiment is as follows:

[0112] (1) Preparation of compound bio-based surfactants

[0113] Take 24% of the total mass of the aqueous film-forming foam extinguishing agent raw materials in pure water. Add isooctyl glucoside to the 24% pure water, slowly heat to 45°C, and continuously stir at this temperature until completely dissolved to obtain an isooctyl glucoside solution. Add rhamnolipin to 9% pure water, slowly heat to 45°C, and continuously stir at this temperature until completely dissolved to obtain a rhamnolipin solution. Add sophorolipid to 9% pure water, slowly heat to 45°C, and continuously stir at this temperature until completely dissolved to obtain a sophorolipid solution. Thoroughly mix the isooctyl glucoside solution, rhamnolipin solution, and sophorolipid solution, and allow to cool naturally to room temperature to obtain a compound bio-based surfactant.

[0114] (2) Preparation of compound bio-based polyols

[0115] Take 3% pure water by mass of the raw materials of aqueous film-forming foam fire extinguishing agent, add xylitol to the 3% pure water, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved to obtain a xylitol solution; add trehalose to 6% pure water, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved to obtain a trehalose solution; mix the xylitol solution and the trehalose solution thoroughly, and cool naturally to room temperature to obtain a compound bio-based polyol.

[0116] (3) Preparation of layered iron-aluminum-magnesium trimetallic hydroxide powder

[0117] According to Fe 3+ Al 3+ Mg 2+ The molar ratio of ferric nitrate (Fe(NO3)3·9H2O), aluminum nitrate (Al(NO3)3·9H2O), and magnesium nitrate (Mg(NO3)2·6H2O)) was weighed out and dissolved in pure water to prepare a mixed metal salt solution. The total metal concentration in the mixed metal salt solution was controlled at 0.4 mol / L. 0.1 mol / L Na2CO3 and 0.1 mol / L NaHCO3 were mixed in a volume ratio of 3:7 to prepare a carbonate mixed solution with a pH of 10.0 ± 0.1. A sodium hydroxide (NaOH) solution with a concentration of 2.0 mol / L was prepared. A mixed metal salt solution was slowly added dropwise to a carbonate mixture under continuous stirring at 550 rpm, while NaOH solution was added dropwise at a rate of 0.7 mL / min. The pH of the reaction system was controlled at 10.0 ± 0.1. After the addition was complete, the mixture was transferred to a high-pressure reactor, sealed, and reacted at 120℃ ± 5℃ for 10 h. After natural cooling to room temperature, the reaction solution was removed and centrifuged at 8000 rpm for 40 min to remove unreacted impurities. The solution was then washed with pure water until the conductivity of the washing solution was <100 μS / cm. The resulting precipitate was vacuum dried at 50℃ for 24 h, and then vacuum dried at 60℃ for 45 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

[0118] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0119] Add 2.0% pure water (by weight of the total raw materials of the aqueous film-forming foam fire extinguishing agent), add layered iron-aluminum-magnesium trimetallic hydroxide to the 2.0% pure water, and use a high-shear dispersion emulsifier to rapidly stir at 8500 rpm for 25 minutes to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension; add nano-magnesium aluminum silicate to 1.5% pure water, and use a high-shear dispersion emulsifier to rapidly stir at 8500 rpm for 25 minutes to form a homogeneous and stable nano-magnesium aluminum silicate suspension; add hydrophobic nano-silica gas... The gel was added to 0.5% pure water and rapidly stirred at 8500 rpm for 25 min using a high-shear dispersion emulsifier to form a uniform and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed for 40 min using a high-shear dispersion emulsifier at 8000 rpm, and then ultrasonically treated at 600W power and 100kHz frequency for 15 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0120] (5) Preparation of aqueous film-forming foam fire extinguishing agent

[0121] 0.4% of the total mass of the aqueous film-forming foam (AFCF) fire extinguishing agent raw materials were dissolved in pure water. Sodium benzoate was weighed and mixed with 0.4% pure water to obtain a sodium benzoate solution. The mixer speed was adjusted to 300 rpm, and the compounded bio-based polyol was slowly added to the compounded bio-based surfactant while continuously stirring. After the addition was completed, stirring was continued for 10 minutes to obtain mixed solution one. The mixer speed was adjusted to 550 rpm, and the foam-stabilizing and anti-reignition nanocomposite agent was slowly added to mixed solution one while continuously stirring. After the addition was completed, stirring was continued for 10 minutes to obtain mixed solution two. The sodium benzoate solution was slowly added to mixed solution two while continuously stirring at 500 rpm. Finally, the remaining 20.16% pure water was added, and stirring was continued for 65 minutes to obtain the environmentally friendly aqueous film-forming foam fire extinguishing agent.

[0122] Comparative Example 4

[0123] Compared to Example 4, the raw materials for preparing the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example have an increased proportion of layered iron-aluminum-magnesium trimetallic hydroxide. Specifically, the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example comprises the following raw materials by mass percentage: 8% isooctyl glucoside, 3% rhamnolipid, 3% sophorolipid, 3% xylitol, 6% trehalose, 0.5% layered iron-aluminum-magnesium trimetallic hydroxide, 0.3% nano-magnesium aluminum silicate, 0.2% hydrophobic nano-silica aerogel, 0.04% sodium benzoate, and 75.96% pure water.

[0124] (1) Prepare compound bio-based surfactants, the same step as in Example 4.

[0125] (2) Prepare compound bio-based polyols, the same step as in Example 4.

[0126] (3) Prepare layered iron, aluminum and magnesium trimetallic hydroxide powder, the same as in Example 4.

[0127] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0128] 2.5% of the total mass of the aqueous film-forming foam extinguishing agent raw materials were added to pure water. Layered iron-aluminum-magnesium trimetallic hydroxide was added to 1.5% pure water, and the mixture was rapidly stirred at 8000 rpm for 25 minutes using a high-shear dispersion emulsifier to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension. Nano-magnesium aluminum silicate was added to 1.5% pure water, and the mixture was rapidly stirred at 8000 rpm for 250 minutes using a high-shear dispersion emulsifier to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Hydrophobic nano-silica... Aerogel was added to 0.5% pure water and rapidly stirred at 8000 rpm for 25 min using a high-shear dispersion emulsifier to form a uniform and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed for 15 min using a high-shear dispersion emulsifier at 8000 rpm, and then ultrasonically treated at 600W power and 100kHz frequency for 5 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0129] (5) Prepare aqueous film-forming foam fire extinguishing agent. This step is the same as in Example 4. Finally, the aqueous film-forming foam fire extinguishing agent is obtained.

[0130] Comparative Example 5

[0131] Compared to Example 4, the raw materials for preparing the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example have a reduced proportion of layered iron-aluminum-magnesium trimetallic hydroxide. Specifically, the environmentally friendly aqueous film-forming foam fire extinguishing agent in this comparative example comprises the following raw materials by mass percentage: 8% isooctyl glucoside, 3% rhamnolipid, 3% sophorolipid, 3% xylitol, 6% trehalose, 0.1% layered iron-aluminum-magnesium trimetallic hydroxide, 0.3% nano-magnesium aluminum silicate, 0.2% hydrophobic nano-silica aerogel, 0.04% sodium benzoate, and 76.36% pure water.

[0132] (1) Prepare compound bio-based surfactants, the same step as in Example 4.

[0133] (2) Prepare compound bio-based polyols, the same step as in Example 4.

[0134] (3) Prepare layered iron, aluminum and magnesium trimetallic hydroxide powder, the same as in Example 4.

[0135] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0136] Add 0.5% pure water (by weight of the total raw materials of the aqueous film-forming foam fire extinguishing agent) to the layered iron-aluminum-magnesium trimetallic hydroxide. Then, use a high-shear dispersion emulsifier to rapidly stir at 8000 rpm for 25 minutes to form a homogeneous and stable nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension. Add 1.5% pure water to nano-magnesium aluminum silicate and use a high-shear dispersion emulsifier to rapidly stir at 8000 rpm for 250 minutes to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Add hydrophobic nano-silica... Aerogel was added to 0.5% pure water and rapidly stirred at 8000 rpm for 25 min using a high-shear dispersion emulsifier to form a uniform and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium-aluminum silicate suspension and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed for 15 min using a high-shear dispersion emulsifier at 8000 rpm, and then ultrasonically treated at 600W power and 100kHz frequency for 5 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0137] (5) Prepare aqueous film-forming foam fire extinguishing agent. This step is the same as in Example 4. Finally, the aqueous film-forming foam fire extinguishing agent is obtained.

[0138] Comparative Example 6

[0139] Compared to Example 4, the environmentally friendly aqueous film-forming foam fire extinguishing agent of this comparative example does not contain layered iron, aluminum, and magnesium trimetallic hydroxides. Specifically, the environmentally friendly aqueous film-forming foam fire extinguishing agent of this comparative example comprises the following raw materials by mass percentage: 8% isooctyl glucoside, 3% rhamnolipid, 3% sophorolipid, 3% xylitol, 6% trehalose, 0.3% nano-magnesium aluminum silicate, 0.2% hydrophobic nano-silica aerogel, 0.04% sodium benzoate, and 76.46% pure water.

[0140] (1) Prepare compound bio-based surfactants, the same step as in Example 4.

[0141] (2) Prepare compound bio-based polyols, the same step as in Example 4.

[0142] (3) Prepare layered iron, aluminum and magnesium trimetallic hydroxide powder, the same as in Example 4.

[0143] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0144] 1.5% pure water was added to the total mass of the aqueous film-forming foam extinguishing agent raw materials. Nano-magnesium aluminum silicate was added to the 1.5% pure water and rapidly stirred at 8000 rpm for 250 min using a high-shear dispersion emulsifier to form a homogeneous and stable nano-magnesium aluminum silicate suspension. Hydrophobic nano-silica aerogel was added to 0.5% pure water and rapidly stirred at 8000 rpm for 25 min using a high-shear dispersion emulsifier to form a homogeneous and stable hydrophobic nano-silica aerogel suspension. The nano-layered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano-magnesium aluminum silicate suspension, and the hydrophobic nano-silica aerogel suspension were mixed, first stirred at high speed at 8000 rpm for 15 min using a high-shear dispersion emulsifier, and then ultrasonically treated at 600W power and 100kHz frequency for 5 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0145] (5) Prepare aqueous film-forming foam fire extinguishing agent. This step is the same as in Example 4. Finally, the aqueous film-forming foam fire extinguishing agent is obtained.

[0146] Comparative Example 7

[0147] The difference between this comparative example of an environmentally friendly aqueous film-forming foam fire extinguishing agent and Example 1 is that isooctyl glucoside is replaced with alkyl glycoside APG1214 to form an aqueous film-forming foam fire extinguishing agent; otherwise, they are the same.

[0148] Comparative Example 8

[0149] The aqueous film-forming foam fire extinguishing agent of this comparative example comprises the following raw materials by mass percentage: 8% isooctyl glucoside, 4% rhamnolipid, 3% sophorolipid, 4% xylitol, 8% trehalose, 0.4% layered iron, aluminum, and magnesium trimetallic hydroxide, 0.3% nano-magnesium aluminum silicate, 0.3% hydrophobic nano-silica aerogel, 0.03% sodium benzoate, and 71.97% pure water.

[0150] The preparation method of the aqueous film-forming foam fire extinguishing agent in this comparative example is as follows:

[0151] (1) Preparation of compound bio-based surfactants

[0152] Take 45% of the total mass of the raw materials for the aqueous film-forming foam fire extinguishing agent as pure water, add isooctyl glucoside, rhamnolipin and sophorolipid to the 45% pure water in sequence, slowly heat to 45°C, and continue stirring at this temperature until completely dissolved. Let it cool naturally to room temperature to obtain a compound bio-based surfactant.

[0153] (2) Preparation of compound bio-based polyols

[0154] Take 12% of the total mass of the raw materials for the aqueous film-forming foam fire extinguishing agent as pure water, add xylitol and trehalose to the 12% pure water, slowly heat to 40°C, and continue stirring at this temperature until completely dissolved. Let it cool naturally to room temperature to obtain a compound bio-based polyol.

[0155] (3) Preparation of layered iron-aluminum-magnesium trimetallic hydroxide powder

[0156] According to Fe 3+ Al 3+ Mg 2+ A mixed metal salt solution was prepared by dissolving ferric nitrate (Fe(NO3)3·9H2O), aluminum nitrate (Al(NO3)3·9H2O), and magnesium nitrate (Mg(NO3)2·6H2O) in pure water at a molar ratio of 1:2:6, with the total metal concentration controlled at 0.3 mol / L. A carbonate mixture with pH = 10.0 was prepared by mixing 0.1 mol / L Na2CO3 and 0.1 mol / L NaHCO3 at a volume ratio of 3:7. A 2 mol / L sodium hydroxide (NaOH) solution was prepared. The mixed metal salt solution was slowly added dropwise to the carbonate mixture while continuously stirring at 600 rpm, simultaneously adding NaOH solution dropwise at a rate of 1 mL / min, controlling the pH of the reaction system at 10.0 ± 0.1. After the addition was complete, the mixture was transferred to a high-pressure reactor, sealed, and reacted at 120℃ ± 5℃ for 10 h, followed by natural cooling to room temperature. Then, centrifuge at 8000 rpm for 30 min to remove unreacted impurities. Wash with pure water until the conductivity of the washing solution is <100 μS / cm. Dry under vacuum at 50℃ for 24 h, then under vacuum at 60℃ for 48 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

[0157] (4) Preparation of foam-stabilizing and anti-reignition nanocomposite agent

[0158] 5% pure water was taken from the total mass of the raw materials of the aqueous film-forming foam fire extinguishing agent. Layered iron-aluminum-magnesium trimetallic hydroxide, nano magnesium aluminum silicate and hydrophobic nano silica aerogel were added to the 5% pure water. The mixture was first stirred at high speed for 15 minutes in a high-shear dispersion emulsifier at 8000 rpm, and then ultrasonically treated at 500W power and 120kHz frequency for 5 minutes to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

[0159] (5) Preparation of aqueous film-forming foam fire extinguishing agent

[0160] Take 0.3% pure water by weight of the total raw materials of the aqueous film-forming foam (AFCF) fire extinguishing agent. Mix sodium benzoate with 0.3% pure water and dissolve it completely to obtain a sodium benzoate solution. Adjust the mixer speed to 200 rpm and slowly add the compounded bio-based polyol to the compounded bio-based surfactant while continuously stirring. After the addition is complete, continue stirring for 10 minutes to obtain mixed solution one. Adjust the mixer speed to 600 rpm and slowly add the foam-stabilizing and anti-reignition nanocomposite agent to mixed solution one while continuously stirring. After the addition is complete, continue stirring for 10 minutes to obtain mixed solution two. Slowly add the sodium benzoate solution to mixed solution two while continuously stirring. Finally, add the remaining 9.67% pure water and continue stirring for 60 minutes to obtain the aqueous film-forming foam fire extinguishing agent.

[0161] Performance Testing: Aqueous film-forming foam extinguishing agents prepared in Examples 1-4 and Comparative Examples 1-8 were used as test samples and tested according to the national standard "Foam Extinguishing Agents" GB15308-2006. Three groups of each sample were taken for parallel experiments, and the average value of the experimental results was taken. The test results of various physicochemical properties and fire extinguishing performance of different aqueous film-forming foam extinguishing agents are shown in Table 1. Before the performance test, each sample was diluted and mixed with water at a volume ratio of 6:94.

[0162]

[0163]

[0164] Table 1

[0165] The data in Table 1 show that the environmentally friendly aqueous film-forming foam fire extinguishing agent provided in this application uses raw materials that do not cause pollution to the environment. Furthermore, through the synergistic effect of the components with specific contents, it has excellent foaming ability and foam stability. Its foaming ratio is 7.5 to 8.6, surface tension is 16.7 to 17.8 mN / m, 25% liquid separation time is 4.5 to 5.3 min, fire extinguishing time is 1.6 to 2.0 min, fire resistance time is 12.6 to 14.3 min, foaming height is 190 to 198 mm, and freezing point is -26 to -30℃.

[0166] Therefore, the aqueous film-forming foam extinguishing agent of this application can be used for fire extinguishing. Before using the aqueous film-forming foam extinguishing agent of this application, it should be mixed with water at a volume ratio of 6:94.

[0167] The foregoing description includes examples from this specification. Of course, for the purposes of describing this specification, it is impossible to describe every conceivable combination of components or methods; however, those skilled in the art will understand that many other combinations and arrangements are possible. Therefore, this specification is intended to cover all such changes, modifications, and variations that fall within the spirit and scope of the appended claims. Furthermore, with regard to the use of the term "comprising" in the detailed description or claims, the term is intended to be inclusive in a manner similar to the term "including," as interpreted when "comprising" is used as a transitional word in the claims.

[0168] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An environmentally friendly water-film forming foam extinguishing agent, characterized in that, The raw materials of the water film forming foam extinguishing agent include: compounded bio-based surfactant, compounded bio-based polyol, sodium benzoate and foam stabilizing anti-reburning nanocomposite; the foam stabilizing anti-reburning nanocomposite includes layered iron aluminum magnesium three-metal hydroxide, nano magnesium aluminum silicate and hydrophobic nano silicon dioxide aerogel.

2. The environmentally friendly water-film forming foam extinguishing agent according to claim 1, wherein, According to the mass percentage, the raw materials of the water film forming foam extinguishing agent include: 10-15% of compounded bio-based surfactant, 8-12% of compounded bio-based polyol, 0.4-1.0% of foam stabilizing anti-reburning nanocomposite, 0.03-0.05% of sodium benzoate, and the balance is pure water.

3. The environmentally friendly water-film forming foam extinguishing agent according to claim 1, wherein, According to the mass percentage, the compounded bio-based surfactant includes: 7-8% of isooctyl glucoside, 2-4% of rhamnolipid, and 1-3% of sophorolipid.

4. The environmentally friendly water-film forming foam extinguishing agent according to claim 1, wherein, According to the mass percentage, the compounded bio-based polyol includes: 2-4% of xylitol, and 6-8% of trehalose.

5. The environmentally friendly water-film forming foam extinguishing agent according to claim 1, wherein, According to the mass percentage, the foam stabilizing anti-reburning nanocomposite includes: 0.2-0.4% of layered iron aluminum magnesium three-metal hydroxide, 0.1-0.3% of nano magnesium aluminum silicate, and 0.1-0.3% of hydrophobic nano silicon dioxide aerogel.

6. A method of preparing an environmentally friendly water film forming foam extinguishing agent, characterized by, The method includes the following steps: According to the mass percentage, the following raw materials are prepared: 10-15% of compounded bio-based surfactant, 8-12% of compounded bio-based polyol, 0.4-1.0% of foam stabilizing anti-reburning nanocomposite, 0.03-0.05% of sodium benzoate, and the balance is water; the foam stabilizing anti-reburning nanocomposite includes layered iron aluminum magnesium three-metal hydroxide, nano magnesium aluminum silicate and hydrophobic nano silicon dioxide aerogel; The compounded bio-based polyol is added to the stirred compounded bio-based surfactant, stirred and uniformly mixed to obtain a mixed solution one; The foam stabilizing anti-reburning nanocomposite is added to the stirred mixed solution one, stirred and uniformly mixed to obtain a mixed solution two; The sodium benzoate is fully dissolved in water to obtain a sodium benzoate solution; After the sodium benzoate solution is added to the stirred mixed solution two, it is stirred and uniformly mixed for 60-100 min to obtain the water film forming foam extinguishing agent.

7. The production method according to claim 6, wherein According to the total mass percentage of the raw materials of the water film forming foam extinguishing agent, the compounded bio-based surfactant includes: 7-8% of isooctyl glucoside, 2-4% of rhamnolipid and 1-3% of sophorolipid; the compounded bio-based polyol includes: 2-4% of xylitol and 6-8% of trehalose.

8. The production method according to claim 6, wherein The preparation method of the foam stabilizing anti-reburning nanocomposite is as follows: According to the total mass percentage of the raw materials of the water film forming foam extinguishing agent, the following raw materials are prepared: 0.2-0.4% of layered iron aluminum magnesium three-metal hydroxide, 0.1-0.3% of nano magnesium aluminum silicate, and 0.1-0.3% of hydrophobic nano silicon dioxide aerogel; The layered iron aluminum magnesium three-metal hydroxide is mixed with pure water, stirred in a high shear dispersion emulsifier at 7000-8500 rpm for 20-40 min to obtain a nano layered iron aluminum magnesium three-metal hydroxide suspension; The nano-magnesium aluminum silicate is mixed with pure water and stirred at 7000-8500 rpm for 20-40 min in a high-shear dispersing emulsifier to obtain a nano-magnesium aluminum silicate suspension. The hydrophobic nano-silica aerogel was mixed with pure water and stirred at 7000-8500 rpm for 20-40 min in a high-shear dispersing emulsifier to obtain a hydrophobic nano-silica aerogel suspension. The nanolayered iron-aluminum-magnesium trimetallic hydroxide suspension, the nano magnesium-aluminum silicate suspension, and the hydrophobic nano silica aerogel suspension were mixed and stirred at 7000-8500 rpm for 15-40 min, and then treated under ultrasound at a power of 500-600 W and a frequency of 80-120 kHz for 5-15 min to obtain a foam-stabilizing and anti-reignition nanocomposite agent.

9. The production method according to claim 6, wherein The preparation method of the layered iron-aluminum-magnesium trimetallic hydroxide includes the following steps: According to the molar ratio of Fe 3+ , Al 3+ , Mg 2+ 1:(2-3):(6-8), the iron nitrate, aluminum nitrate and magnesium nitrate are weighed and added into pure water to dissolve, to obtain a mixed metal salt solution, wherein the total metal concentration in the mixed metal salt solution is 0.3-0.6 mol / L; Prepare a sodium hydroxide solution with a concentration of 2–3 mol / L; Prepare a carbonate mixture with pH = 10.0 ± 0.1 by mixing 0.1 mol / L Na₂CO₃ solution and 0.1 mol / L NaHCO₃ solution. Under continuous stirring at 500–600 rpm, a mixed metal salt solution and a sodium hydroxide solution were added dropwise to the carbonate mixture. The sodium hydroxide solution was added at a rate of 0.5–1 mL / min, and the pH value was maintained at 10.0 ± 0.

1. After the addition was completed, the resulting mixed reaction solution was transferred to a high-pressure reactor, sealed, and reacted at 120 ± 5 °C for 8.5–11 h. After natural cooling to room temperature, the reaction solution was removed and centrifuged at 8000–10000 rpm for 25–40 min. Then, it was washed with pure water until the conductivity of the washing solution was <100 μS / cm. The precipitate was vacuum dried at 40–50 °C for 20–30 h, and then vacuum dried at 50–60 °C for 45–50 h to obtain layered iron-aluminum-magnesium trimetallic hydroxide powder.

10. The aqueous film-forming foam extinguishing agent according to any one of claims 1 to 5, or the aqueous film-forming foam extinguishing agent prepared according to any one of claims 6 to 9 for use in fire extinguishing, characterized in that, In the fire extinguishing application, the aqueous film-forming foam extinguishing agent is mixed with water at a volume ratio of 6:94 before use.

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