Silver sulfate silver ion slow-release compound as well as preparation method and application thereof

Abstract

The invention discloses a silver sulfate silver ion slow-release compound as well as a preparation method and application thereof, and belongs to the technical field of chemical materials and slow release. According to the preparation method of the silver sulfate silver ion slow-release compound, a modified porous material is selected as a slow-release carrier, silver sulfate is accurately loaded through an impregnation or coprecipitation method, a gradient density regulation and control layer is constructed by utilizing a high-molecular polymer, and an environment-responsive additive can be introduced to dynamically adjust the release rate of silver ions. The problems that an existing silver sulfate solution is too fast in silver ion release, large in concentration fluctuation and incapable of meeting complex scene requirements are solved, and the silver sulfate solution has the advantages of being high in release controllability, wide in adaptation range and low in cost and is suitable for various fields such as medical antibiosis and water quality purification.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical materials and slow-release technology, and particularly relates to a silver sulfate silver ion slow-release compound, a preparation method and an application thereof. BACKGROUND

[0002] In many fields, silver ions play an important role due to their unique chemical properties. For example, in the medical field, silver ions have antibacterial properties and can effectively inhibit the growth of various bacteria, helping to heal wounds and prevent infection. In the field of water purification, silver ions are widely used in drinking water disinfection, swimming pool water treatment and household water filter cartridges due to their high efficiency, broad-spectrum bactericidal ability and sustained disinfection effect, which can effectively inactivate bacteria and viruses in water and significantly improve the biological safety of the water. Silver sulfate is a common silver salt and is often used to prepare silver ion solutions. However, there are many problems with the release of silver ions in silver sulfate solutions. On the one hand, the release rate of silver ions is difficult to accurately control, and the initial release rate is too fast, resulting in rapid consumption of effective ingredients and the inability to maintain a stable effective concentration for a long time. On the other hand, traditional methods cannot flexibly adjust the release rate of silver ions according to actual needs, making it difficult to fully utilize the optimal performance of silver ions in different application scenarios. In the prior art, some methods add slow-release agents through simple physical mixing, but cannot accurately control the release of silver ions. Some methods use complex microcapsule technology, which is costly and complex, and is not suitable for large-scale application. Therefore, there is an urgent need for a silver sulfate silver ion slow-release compound and a preparation method thereof that can effectively maintain the slow release of silver ions in silver sulfate solutions, are accurately controllable, have low cost and are easy to implement on a large scale. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a preparation method of a silver sulfate silver ion slow-release compound, which aims to solve the problems of uncontrollable release rate of silver ions in existing silver sulfate solutions, poor environmental adaptability and insufficient carrier compatibility.

[0004] The embodiments of the present application are implemented as follows: a preparation method of a silver sulfate silver ion slow-release compound, comprising the following steps: Selecting a porous material as a carrier material and pretreating the carrier material; Loading silver sulfate onto the pretreated carrier material by using an impregnation method or a co-precipitation method; Constructing a gradient density polymer as a control layer on the surface of the silver sulfate loaded carrier material; According to the application scenario, introducing an environmental responsiveness additive on the surface of the control layer to adapt to the environment, and forming a final silver sulfate silver ion slow-release compound.

[0005] Further, the porous material is one or more of silica, hydroxyapatite or chitosan microspheres; or, the porous material is one or more of silica, hydroxyapatite or chitosan microspheres with hierarchical pore structure.

[0006] Further, the pretreatment of the carrier material is soaking the carrier material in an acid or alkali solution, then washing with deionized water until neutral, and then drying.

[0007] Further, the operation condition of the impregnation method is that the concentration of silver sulfate solution is 0.1-1 mol / L, the mass / volume ratio of carrier material to solution is 1:5-1:20, the constant temperature oscillation is at 25-40℃ for 6-16 hours, and the oscillation rate is 150-300 r / min. The operation condition of the co-precipitation method is that the silver nitrate solution and the ammonium sulfate solution are mixed according to the molar ratio of silver ions to sulfate ions of 1:1-1:1.2, the pretreated carrier material is added, the pH is adjusted to 4-6, and the stirring reaction is carried out at 30-50℃ for 2-4 hours.

[0008] Further, the construction of the high-molecular polymer with gradient density as the control layer on the surface of the silver sulfate-loaded carrier material is by multi-layer coating or in-situ polymerization; the specific high-molecular polymer is one or more of polyethylene glycol, polyvinyl alcohol, polylactic acid or polyacrylic acid; Further, the construction of the high-molecular polymer with gradient density as the control layer by multi-layer coating is that the silver sulfate-loaded carrier material is sequentially soaked in high-molecular polymer solutions with increasing concentration layer by layer, and drying is carried out between each layer to construct a control layer with gradient density; The concentration of high-molecular polymer increases by 3%-10% layer by layer; the number of layers of multi-layer coating is 2-5, and the drying is carried out at 60-80℃ for 1-2 hours after each layer of coating; The construction of the high-molecular polymer with gradient density as the control layer by in-situ polymerization is that the monomer concentration is increased layer by layer or the polymerization conditions are changed, and the polymerization is carried out for multiple rounds on the carrier material that has already loaded silver sulfate, so that the monomer directly polymerizes in the interior and on the surface of the carrier material to generate high-molecular polymer, and each round of polymerization is carried out on the basis of the polymer layer formed in the previous round, thereby constructing a gradient structure with density from low to high; The monomer concentration increases by 3%-10% round by round; the amount of initiator is 0.5%-2% of the mass of monomer; and the change in polymerization conditions is the change in initiator concentration, polymerization temperature or polymerization time, etc.

[0009] Further, the environmental responsive additive is one or more of pH-responsive carboxymethyl chitosan, temperature-responsive poly-N-isopropyl acrylamide or ion-responsive sodium alginate.

[0010] Further, the performing environment-responsive adaptation to form the final silver sulfate silver ion slow-release composite is: soaking the carrier material in a 0.5%-5% environment-responsive additive solution for 1-3 hours, and forming a composite control structure after freeze-drying.

[0011] Another purpose of the embodiment of the present application is to provide a silver sulfate silver ion slow-release composite prepared according to the preparation method of the silver sulfate silver ion slow-release composite of any one of the above.

[0012] Another purpose of the embodiment of the present application is to provide a use of a silver sulfate silver ion slow-release composite in preparing a medical wound antibacterial dressing or in preparing a water quality purification material, the silver sulfate silver ion slow-release composite being prepared according to the preparation method of the silver sulfate silver ion slow-release composite of any one of the above.

[0013] Advantages of the present application The present application discloses a silver sulfate silver ion slow-release composite, a preparation method and a use thereof, and belongs to the field of chemical materials and slow-release technology. The preparation method of the silver sulfate silver ion slow-release composite of the present application selects a modified porous material as a slow-release carrier, precisely loads silver sulfate through impregnation or co-precipitation, constructs a gradient density control layer by using a high molecular polymer, and can introduce an environment-responsive additive to dynamically adjust the silver ion release rate. The present application solves the problems of existing silver sulfate solution, such as fast silver ion release, large concentration fluctuation, and inability to adapt to complex scene requirements, and has the characteristics of strong controllability, wide adaptation range and low cost, and is suitable for various fields such as medical antibacterial and water quality purification. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The present application is a preferred embodiment of a silver sulfate silver ion slow-release composite preparation method flow chart. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. In order to facilitate the description, only the parts related to the embodiments of the present application are shown. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0016] The application discloses a silver ion slow-release compound of silver sulfate, a preparation method and application thereof, and belongs to the technical field of chemical materials and slow-release.

[0017] Figure 1 The application discloses a silver ion slow-release compound of silver sulfate, a preparation method and application thereof, and belongs to the technical field of chemical materials and slow-release. S101, a porous material is selected as a carrier material, and the carrier material is pretreated; The porous material is one or more of silica, hydroxyapatite or chitosan microspheres; In order to be suitable for high-end scenes requiring long-acting, stable, high-loading and intelligent response, in another embodiment of the application, the porous material is a porous material with a hierarchical pore structure, and the hierarchical pore structure is a hierarchical pore structure with the synergistic effect of macropores and mesopores; more specifically, the porous material is one or more of silica, hydroxyapatite or chitosan microspheres with a hierarchical pore structure; In the embodiment of the application, the preparation methods of silica, hydroxyapatite and chitosan microspheres with a hierarchical pore structure can respectively adopt the industry general technology, and will not be described here. In the embodiment of the application, only the porous material with a hierarchical pore structure is selected as the carrier material, and the porous material with a hierarchical pore structure is not prepared.

[0018] In the embodiment of the application, the pretreatment of the carrier material is that the carrier material is soaked in an acid or alkali solution, then washed with deionized water until neutral, and then dried. The surface charge and pore size of the carrier material are adjusted through acid and alkali treatment, so as to optimize the loading performance of silver sulfate.

[0019] For example, in an embodiment of the application, the pretreatment of the carrier material is that the chitosan microspheres with a hierarchical pore structure are soaked in a silane coupling agent solution with a mass fraction of 5%-15% for 2-6 hours, washed with deionized water, and then dried at 80-120 DEG C for 3-5 hours.

[0020] For example, in another embodiment of the present application, the pretreatment of the carrier material is as follows: the silica with hierarchical pore structure is soaked in a dilute hydrochloric acid solution for 2-4 hours, then washed with deionized water until neutral, and then dried at 100-120 DEG C for 4-6 hours, so that the surface silicon hydroxyl is fully exposed, and the binding sites with silver sulfate are increased.

[0021] S102, silver sulfate is loaded on the pretreated carrier material by impregnation or co-precipitation method; The operation conditions of the impregnation method are as follows: the concentration of silver sulfate solution is 0.1-1 mol / L, the mass / volume ratio of carrier material to solution is 1:5-1:20, the constant temperature oscillation is carried out at 25-40 DEG C for 6-16 hours, and the oscillation rate is 150-300 r / min, so that the silver sulfate fully enters the pores of the carrier material.

[0022] The operation conditions of the co-precipitation method are as follows: the silver nitrate solution and the ammonium sulfate solution are mixed according to the molar ratio of silver ion to sulfate ion of 1:1-1:1.2, the pretreated carrier material is added, the pH is adjusted to 4-6, and the stirring reaction is carried out at 30-50 DEG C for 2-4 hours, so that the silver sulfate is precipitated and separated out on the surface and in the pores of the carrier material.

[0023] S103, a high molecular polymer with gradient density is constructed on the surface of the carrier material loaded with silver sulfate as a control layer; The construction of the high molecular polymer with gradient density on the surface of the carrier material loaded with silver sulfate as a control layer is carried out by multi-layer coating or in-situ polymerization; the specific high molecular polymer is one or more of polyethylene glycol, polyvinyl alcohol, polylactic acid or polyacrylic acid; The high molecular polymer with gradient density is constructed as a control layer by multi-layer coating: the carrier material loaded with silver sulfate is sequentially soaked in high molecular polymer solutions with increasing concentration layer by layer, and drying is carried out between each layer, so as to construct a control layer with gradient density.

[0024] In the embodiment of the present application, the concentration of the high molecular polymer increases by 3%-10% layer by layer; the number of layers of the multi-layer coating is 2-5 layers, and the drying is carried out at 60-80 DEG C for 1-2 hours after each layer of coating; The high molecular polymer with gradient density is constructed as a control layer by in-situ polymerization: the monomer concentration is gradually increased or the polymerization conditions are changed, and the polymerization is carried out for multiple rounds on the carrier material loaded with silver sulfate, so that the monomer directly polymerizes in the interior and on the surface of the carrier material, and the high molecular polymer is generated, and each round of polymerization is carried out on the basis of the polymer layer formed in the previous round, so as to construct a gradient structure with density from low to high.

[0025] In the embodiment of the present application, the monomer concentration is increased by 3-10% in each round; the amount of initiator is 0.5-2% of the mass of the monomer; and the polymerization conditions are changed, such as the concentration of initiator, the polymerization temperature, or the polymerization time.

[0026] In the embodiment of the present application, the in-situ polymerization method can make the polymer chains inside the carrier material relatively sparse, and the polymer chains outside the carrier material more dense and cross-linked. This gradient structure increases the diffusion resistance of silver ions layer by layer, and realizes precise slow-release control. For example, in a preferred embodiment of the present application (Example 1), three layers of coating are performed using a polyethylene glycol (PEG) solution: First layer: 5% concentration of polyethylene glycol PEG solution, forming a porous and loose film; Second layer: 10% concentration of polyethylene glycol PEG solution, forming a relatively dense intermediate layer; Third layer: 15% concentration of polyethylene glycol PEG solution, forming a very dense outer layer;

[0028] In this way, from inside to outside, the density and thickness of the polymer network gradually increase, forming a gradient. For example, in another embodiment of the present application, the specific implementation method for constructing a gradient density control layer by in-situ polymerization of acrylic monomers is as follows: Step 1: Carrier preparation and pretreatment: The carrier material (such as aminated silica) that has completed silver sulfate loading is vacuum dried to remove internal moisture, ensuring that the monomer solution can fully penetrate;

[0029] The carrier material is dispersed in an inert organic solvent (such as toluene or ethanol) and nitrogen is introduced to exclude oxygen (oxygen will inhibit free radical polymerization). Step 2: First round of in-situ polymerization (forming a low-density inner layer): Prepare the first round of reaction solution: add the first portion of acrylic monomer to the above system so that its concentration in the system is 3% (v / v). At the same time, add 1.0% of the mass of this portion of monomer as an initiator (such as azobisisobutyronitrile, AIBN); Initiate polymerization: slowly heat the system to 65-70°C and maintain constant temperature stirring at this temperature for 2 hours. At this time, the acrylic monomer polymerizes inside the pores and on the surface of the carrier, forming a first layer of low molecular weight, relatively loose polyacrylic acid film;

[0030] Washing and preliminary stabilization: after the reaction is completed, centrifugal separation is performed, and the carrier is quickly rinsed with the inert organic solvent to remove unreacted monomers and homopolymers, and then briefly dried at low temperature (such as 40°C) to stabilize the structure. Third step: Second round of in-situ polymerization (forming a medium-density middle layer): Change the reaction medium and add the second round of monomers: Re-disperse the material after the first round of polymerization in fresh inert organic solvent (such as toluene or ethanol). Add the second portion of acrylic acid monomer, increasing its concentration to 6% (v / v), and supplement the corresponding amount of initiator; Continue polymerization: Perform the second round of polymerization under the same reaction conditions; The newly added acrylic acid monomer not only polymerizes in the blank areas on the surface of the carrier, but also continues to grow and graft onto the already existing first layer of polyacrylic acid PAA, forming a thicker, more cross-linked second layer of polymer network. Due to the higher monomer concentration, this layer has a significantly increased density.

[0031] Fourth step: Third round of in-situ polymerization (forming a high-density outer layer): Add the third round of high-concentration monomers: Separate the material again and disperse it in fresh inert organic solvent (such as toluene or ethanol), with the concentration of acrylic acid monomer further increased to 9% (v / v), and supplement the corresponding amount of initiator; Final polymerization: Complete the last polymerization under the same conditions. At this time, a layer of polyacrylic acid "sealing layer" with the highest molecular weight, maximum cross-linking density, and most compact structure is formed on the outermost layer.

[0032] Fifth step: Post-processing and functionalization: Thorough cleaning and drying: After polymerization is complete, repeatedly clean the material with solvent to completely remove all unreacted monomers and impurities; pH adjustment and activation: Soak the obtained composite material in a dilute alkali solution (such as NaOH) to convert the carboxyl groups (-COOH) on the PAA chains into carboxylate groups (-COO⁻); This step will make the polymer chains stretch due to electrostatic repulsion and fully expose their ion exchange sites, preparing for subsequent controlled release of silver ions.

[0033] S104, according to the application scenario, introducing an environmentally responsive additive on the surface of the control layer to form a final silver sulfate silver ion slow-release composite; The environmentally responsive additive is one or more of pH-responsive carboxymethyl chitosan, temperature-responsive poly-N-isopropyl acrylamide, or ion-responsive sodium alginate.

[0034] The environmentally responsive adaptation is performed by soaking the carrier material in a 0.5%-5% environmentally responsive additive solution for 1-3 hours, and then freeze-drying to form a silver sulfate silver ion slow-release composite.

[0035] In the specific embodiment, when the environmental pH value or temperature changes, the structure of the environmentally responsive additive changes, thereby affecting the permeability of the regulation layer and achieving dynamic adjustment of the silver ion release rate. For example, in a wound healing application, due to the generally acidic pH value at the wound, the introduced pH-responsive carboxymethyl chitosan is protonated in the acidic environment, the regulation layer pore is increased, the silver ion release is accelerated, and the antibacterial effect is enhanced.

[0036] For example, in preferred embodiment 1 of the application, the preparation method of the silver sulfate silver ion slow-release composite is as follows: 1. Selection and pretreatment of carrier material: Selected material: macroporous-mesoporous hierarchical structure silica, which is a special type prepared by a bimodal template method. The structure has both through macropores (50-200 nm) and ordered mesopores (about 8 nm, >600 m² / g); The role of this hierarchical structure: macropores ensure low mass transfer resistance during loading and release, mesopores provide high loading capacity and primary slow-release effect, and the two work together to lay a physical foundation for long-acting slow release.

[0037] Pretreatment steps: Acid washing activation: take 5.0 grams of the above hierarchical structure silica and place it in 250 mL of 0.1 mol / L dilute hydrochloric acid solution, oscillate and soak at room temperature for 3 hours. This step aims to clean the surface, remove impurities, and fully expose the surface silicon hydroxyl groups (-Si-OH); Rinse and dry: rinse the material with deionized water repeatedly until the filtrate is neutral, and then dry it in an oven at 110°C for 4 hours to obtain the activated silica carrier material; Surface amination: immerse the activated silica in 100 mL of 10% (3-aminopropyl) triethoxysilane (APTES) ethanol solution at room temperature for 4 hours, so that APTES is fully grafted to the surface of the carrier. After the reaction is completed, rinse repeatedly with deionized water until neutral to remove physically adsorbed coupling agents; Finally, place the carrier material in a 100°C oven and dry for 4 hours to obtain a modified carrier with amino functional groups (-NH2) on the surface. The introduction of amino groups provides more sites for subsequent electrostatic binding with silver sulfate.

[0038] 2. Loading of silver sulfate: Loading method: use the impregnation method, the specific operation is as follows: Prepare 100 mL of 0.5 mol / L silver sulfate aqueous solution. Add the pretreated amino-functionalized hierarchical silica (5.0 g) to the silver sulfate solution (mass-to-volume ratio of support to solution is 1:20). Place the mixed system in a constant-temperature shaker and shake at 200 r / min for 10 hours at 30°C to ensure that the silver sulfate is fully dispersed and adsorbed inside the hierarchical pores; After loading is complete, separate the solid product by centrifugation and wash it with a small amount of deionized water 2-3 times to remove the salt attached to the surface. Dry the washed material at 60°C under vacuum for 2 hours to obtain the "silver sulfate-hierarchical silica" composite.

[0039] 3. Construct a gradient density high polymer control layer: Method: Use a multi-layer coating method to construct a gradient density, and the high polymer is polyethylene glycol (PEG-4000). The specific operation is as follows: Prepare three PEG aqueous solutions with increasing concentrations: First layer solution: 5% polyethylene glycol PEG solution by mass fraction; Second layer solution: 10% polyethylene glycol PEG solution by mass fraction (concentration increased by 5%); Third layer solution: 15% polyethylene glycol PEG solution by mass fraction (concentration increased by 5% again).

[0040] Divide the "silver sulfate-hierarchical silica" composite into three equal parts; First layer coating: soak one part of the composite in a 5% PEG solution for 30 minutes with slow stirring. After taking it out, dry it at 70°C for 1.5 hours; Second layer coating: take out the material coated in the first layer, soak it in a 10% PEG solution for 30 minutes, and also dry it at 70°C for 1.5 hours; Third layer coating: repeat the above operation, use a 15% PEG solution for coating and drying; Finally, mix the three parts of the support material that have completed three layers of gradient coating respectively to obtain the "PEG gradient-coated silver sulfate-hierarchical silica" composite. This gradient density structure means that from the inside to the outside, the density of the polymer network gradually increases, thereby achieving step-by-step precise control over the diffusion rate of silver ions.

[0041] 4. Environmental response adaptation: Application scenario: medical wound antibacterial dressing; the wound environment is usually weakly acidic (pH decreases) when infected, therefore, introduce a pH-responsive material to accelerate the release of silver ions when infected (low pH) and release steadily during the healing period (neutral pH); Responsive additive: carboxymethyl chitosan (CMCS), which is protonated under acidic conditions, the molecular chain shrinks, the pore size increases, and the release is accelerated.

[0042] Specific operation: prepare a 2% mass fraction carboxymethyl chitosan aqueous solution. Soak the "PEG gradient coated silver sulfate-silica" composite in the solution, and gently oscillate for 2 hours. Take out the material, quickly freeze in liquid nitrogen, and then place it in a freeze dryer for 24 hours to form the final environmentally responsive silver ion release composite of silver sulfate.

[0043] Performance verification: Test method: The prepared silver ion release composite of silver sulfate is placed in a simulated wound exudate phosphate buffer solution (PBS) and oscillated at 37°C. Regular sampling and atomic absorption spectrometry are used to detect silver ion concentration.

[0044] Verification results: Release period: Silver ion release can last for more than 21 days, fully covering the high-risk period of wound infection; Release stability: The fluctuation range of daily silver ion release amount is ≤12% during the entire release period, showing excellent stability, effectively avoiding initial "burst release" and later "cliff-like" decline; Environmental responsiveness: When the environmental pH decreases from 7.4 (normal) to 6.0 (infection), the daily release rate of silver ions can increase by about 40%, proving its good intelligent response bactericidal capacity.

[0045] For example, in a preferred embodiment (Example 2) of the present application, a method for preparing a silver ion release composite of silver sulfate is: 1. Selection and pretreatment of carrier material: Take 10g of mesoporous silica (particle size 50-100μm, specific surface area 800m² / g) and place it in a 500mL beaker. Add 200mL of 10% silane coupling agent (γ-aminopropyl triethoxysilane) ethanol solution and seal for 4 hours at room temperature, stirring every 30 minutes. After soaking, rinse the mesoporous silica with deionized water until the pH of the rinse solution is neutral (pH=7.0), then collect the solid by filtration. Place the collected mesoporous silica in a vacuum drying oven at 100°C for 4 hours, and cool to room temperature before use. Record as "modified mesoporous silica carrier".

[0046] 2. Directional loading of silver sulfate: Prepare a 0.5mol / L silver sulfate solution: weigh 24.9g of silver sulfate and add 200mL of deionized water. Stir until completely dissolved in a 30°C water bath, then cool to 200mL. Into a 250 mL conical flask, add 10 g of "modified mesoporous silica carrier", then add 100 mL of the above 0.5 mol / L silver sulfate solution (mass-volume ratio of carrier to solution is 1:10, g:mL); Place the conical flask in a constant temperature shaker, set the temperature to 30°C and the shaking rate to 200 r / min, and constant temperature shake for 12 hours; After the shaking is completed, filter and collect the solid, rinse the surface with a small amount of deionized water to remove the unloaded silver sulfate, and then dry in a vacuum drying oven at 60°C for 2 hours, and record it as "silver sulfate-carrier composite".

[0047] 3. Gradient control layer construction: Prepare gradient concentration polyethylene glycol solution: prepare 5%, 10%, 15% (mass fraction) polyethylene glycol aqueous solution respectively, each 100 mL, and stir until completely dissolved; Spread the "silver sulfate-carrier composite" evenly in a culture dish (thickness about 2 mm), and evenly spray 5% polyethylene glycol solution with a sprayer, the spraying amount is 5 mL / g of composite, and after spraying, place it in a 70°C air-drying oven for 1.5 hours; After drying, repeat the above spraying operation: spray 10% polyethylene glycol solution (spraying amount 5 mL / g of composite, 70°C drying for 1.5 hours) and 15% polyethylene glycol solution (spraying amount 5 mL / g of composite, 70°C drying for 1.5 hours) in turn, to form three layers of gradient control layer, and record it as "gradient control composite".

[0048] 4. Environmental response adaptation: Application scenario: water purification; Responsive additive: carboxymethyl chitosan; Specific operation: prepare 2% (mass fraction) carboxymethyl chitosan aqueous solution: weigh 2 g of carboxymethyl chitosan, add 100 mL of deionized water, and stir in a 40°C water bath until completely dissolved, and cool to room temperature; add the "gradient control composite" to the above carboxymethyl chitosan solution, soak at room temperature for 2 hours, and stir gently every 20 minutes during the soaking; after soaking, filter and collect the solid, and transfer it to a freeze dryer, and freeze dry at -50°C and a vacuum degree of 10 Pa for 8 hours to obtain the final product "silver sulfate silver ion slow-release composite".

[0049] Performance verification: Test method: weigh 1 g of silver sulfate silver ion slow-release composite, place it in 500 mL of deionized water (simulated water environment), and soak it statically at 25°C, replace all the soaking liquid every day, and use inductively coupled plasma emission spectrometer ICP-OES to determine the silver ion concentration in the daily soaking liquid, and calculate the daily release amount; Test results: silver ion release period: 21 days (silver ion release concentration decreased to below 0.1 mg / L on the 21st day, which is considered as the end of release); Daily release amount: 1.2 mg / g on the 1st day, 1.1 mg / g on the 7th day, 1.0 mg / g on the 14th day, and 0.1 mg / g on the 21st day, with a fluctuation range of daily release amount ≤12%.

[0050] The preferred embodiment of the present application also provides a silver ion sustained-release compound of silver sulfate, which is prepared according to the preparation method of the silver ion sustained-release compound of silver sulfate of any one of the above embodiments.

[0051] The preferred embodiment of the present application also provides a use of a silver ion sustained-release compound of silver sulfate in the preparation of a medical wound antibacterial dressing; the silver ion sustained-release compound of silver sulfate is prepared according to the preparation method of the silver ion sustained-release compound of silver sulfate of any one of the above embodiments.

[0052] For example, the silver ion sustained-release compound of silver sulfate prepared in the embodiment 1 of the present application can be used in the field of medical wound antibacterial dressing; Performance verification: Test method: the prepared silver ion sustained-release compound of silver sulfate is placed in a phosphate buffer solution (PBS) simulating wound exudate, and is oscillated at 37℃, and silver ion concentration is detected by atomic absorption spectrometry by regularly sampling.

[0053] Verification results: release period: silver ion release can last for more than 21 days, which completely covers the high-risk period of wound infection.

[0054] Release stability: during the entire release period, the fluctuation range of daily silver ion release amount is ≤12%, which shows excellent stability, effectively avoiding initial “burst release” and later “cliff-type” decline.

[0055] Environmental responsiveness: when the environmental pH decreases from 7.4 (normal) to 6.0 (infection), the daily release rate of silver ions can increase by about 40%, which proves the good intelligent response bactericidal capacity.

[0056] The preferred embodiment of the present application also provides a use of a silver ion sustained-release compound of silver sulfate in the preparation of water purification materials. The silver ion sustained-release compound of silver sulfate is prepared according to the preparation method of the silver ion sustained-release compound of silver sulfate of any one of the above embodiments.

[0057] For example, the silver ion sustained-release compound of silver sulfate prepared in the embodiment 2 of the present application can be used in the field of environmental water purification; Performance verification: Test method: 1 g of silver sulfate silver ion slow-release compound was weighed and placed in 500 mL of deionized water (simulated water environment), and was soaked statically at 25 DEG C, the whole soaking solution was replaced every day, the silver ion concentration in the daily soaking solution was determined by inductively coupled plasma emission spectrometer ICP-OES, and the daily release amount was calculated; Test result: silver ion release period: 21 days (the silver ion release concentration decreased to below 0.1 mg / L on the 21st day, and was regarded as the end of release); Daily release amount: the release amount on the 1st day was 1.2 mg / g, the release amount on the 7th day was 1.1 mg / g, the release amount on the 14th day was 1.0 mg / g, the release amount on the 21st day was 0.1 mg / g, and the fluctuation range of the daily release amount was ≤12%.

[0058] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of preparing a silver sulfate silver ion slow release complex, characterized by, The method comprises the following steps: selecting a porous material as a carrier material and pretreating the carrier material; loading silver sulfate onto the pretreated carrier material by an impregnation method or a coprecipitation method; constructing a high-molecular polymer with gradient density on the surface of the carrier material loaded with silver sulfate as a control layer; introducing an environmental response additive on the surface of the control layer according to an application scenario, performing environmental response adaptation, and forming a final silver sulfate silver ion slow-release composite.

2. The method for preparing the silver sulfate-silver ion sustained-release complex according to claim 1, characterized in that, The porous material is one or more of silica, hydroxyapatite or chitosan microspheres; or the porous material is one or more of silica, hydroxyapatite or chitosan microspheres with a hierarchical pore structure.

3. The method for preparing the silver sulfate silver ion sustained-release complex according to claim 1, characterized in that, The pretreatment of the carrier material is soaking the carrier material in an acid or alkali solution, then rinsing with deionized water until neutral, and then drying.

4. The method for preparing the silver sulfate silver ion sustained-release complex according to claim 1, characterized in that, The operation conditions of the impregnation method are as follows: the concentration of the silver sulfate solution is 0.1-1 mol / L, the mass / volume ratio of the carrier material to the solution is 1:5-1:20, constant temperature oscillation is performed at 25-40 DEG C for 6-16 hours, and the oscillation rate is 150-300 r / min. The operation conditions of the coprecipitation method are as follows: mixing a silver nitrate solution and an ammonium sulfate solution at a molar ratio of silver ions to sulfate ions of 1:1-1:1.2, adding the pretreated carrier material, adjusting the pH to 4-6, and stirring the reaction at 30-50 DEG C for 2-4 hours.

5. The method for preparing the silver sulfate-silver ion sustained-release complex according to claim 1, characterized in that, The construction of the high-molecular polymer with gradient density on the surface of the carrier material loaded with silver sulfate as a control layer is performed by a multilayer coating or in-situ polymerization method; the high-molecular polymer is one or more of polyethylene glycol, polyvinyl alcohol, polylactic acid or polyacrylic acid.

6. The method of claim 5, wherein the silver sulfate silver ion releasing complex is prepared by the steps of: The construction of the high-molecular polymer with gradient density as a control layer by a multilayer coating method is as follows: the carrier material loaded with silver sulfate is sequentially soaked in high-molecular polymer solutions with increasing concentrations, and drying is performed between each layer to construct a control layer with gradient density. The concentration of the high-molecular polymer increases by 3%-10% for each layer; the number of layers of the multilayer coating is 2-5, and drying is performed at 60-80 DEG C for 1-2 hours after each layer is coated. The construction of the high-molecular polymer with gradient density as a control layer by an in-situ polymerization method is as follows: a plurality of rounds of polymerization are performed on the carrier material loaded with silver sulfate by gradually increasing the monomer concentration or changing the polymerization conditions, so that the monomers directly polymerize in the interior and on the surface of the carrier material to form a high-molecular polymer; each round of polymerization is performed on the basis of the polymer layer formed in the previous round, thereby constructing a gradient structure with density gradually increasing from low to high. The monomer concentration increases by 3%-10% for each round; the amount of initiator is 0.5%-2% of the mass of the monomers; and the change in the polymerization conditions is a change in the concentration of the initiator, the polymerization temperature or the polymerization time.

7. The method for preparing the silver sulfate-silver ion sustained-release complex according to claim 1, characterized in that, The environmental response additive is one or more of pH-responsive carboxymethyl chitosan, temperature-responsive poly-N-isopropyl acrylamide or ion-responsive sodium alginate.

8. The method for preparing the silver sulfate-silver ion sustained-release complex according to claim 1, characterized in that, The forming of the final silver sulfate silver ion slow-release composite through environmental response adaptation is: soaking the carrier material in a 0.5%-5% environmental response additive solution for 1-3 hours, and forming a composite control structure after freeze-drying.

9. A silver sulfate silver ion slow release complex characterized in that, The silver sulfate silver ion slow-release composite is prepared according to the preparation method of any one of claims 1-8.

10. The silver sulfate silver ion release complex of claim 9, wherein, The silver sulfate silver ion slow-release composite is suitable for preparing medical wound antibacterial dressings or water purification materials.

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