A new inorganic antibacterial agent (AgLaMo2O8) and a preparation method thereof

Abstract

The application relates to the field of antibacterial materials, in particular to a novel inorganic antibacterial agent (AgLaMo2O8) and a preparation method thereof. 24 The application uses silver nitrate, lanthanum nitrate and (NH4)6Mo7O 24 as raw materials, citric acid as a complexing agent, and ammonia water as a pH regulator, and through control of the citric acid dosage and self-ignition ignition temperature and time, AgLaMo2O8 superfine powder with different particle sizes is synthesized at low temperature in one step. The application provides a method for synthesizing AgLaMo2O8 superfine powder with a tetragonal crystal system at low temperature in one step, and the method is applied to the antibacterial field for the first time. The method has the advantages of short reaction time, simple process, convenient operation, high purity yield, low cost and easy scale production. The obtained AgLaMo2O8 superfine powder has better high-temperature stability and bacteriostatic performance, the high-temperature application advantage is more obvious, and the application field is more extensive.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of antibacterial materials, and particularly relates to a novel inorganic antibacterial agent (AgLaMo2O8) with high-temperature application advantages and a preparation method thereof. BACKGROUND

[0002] With the improvement of living standards, people pay more and more attention to the influence of the surrounding life supplies on their health. Bacteria, molds, viruses and other pathogens can be contaminated and proliferated on the surface of many products, affecting people's health. Ceramics are necessities of daily life, and antibacterial ceramics gradually enter the public's field of vision and are recognized as daily necessities by people. People urgently need the emergence of various high-performance antibacterial agents for ceramics.

[0003] Antibacterial agents include organic antibacterial agents and inorganic antibacterial agents, but only inorganic antibacterial agents can be used for high-temperature ceramics. Inorganic antibacterial agents are divided into two categories: metal ion type and photocatalytic type. The bactericidal ability of silver ions is the strongest among metal ion type antibacterial agents (Ag + >Cu 2+ >Fe 3+ =Sn 2+ >A1 3+ >Zn 2+ >Co 2+ >Ni + Research shows that as long as there is one hundred thousandth mass fraction of silver, sterilization can be achieved. Currently, silver ion inorganic antibacterial agents are mainly obtained by Ag + doping, through physical adsorption and other effects, Ag + is fixed on the surface or channel of porous materials such as zeolite, silica gel, titanium oxide and zirconium phosphate, and then a material with antibacterial properties is obtained. Ag + doping or physical adsorption and other effects to obtain antibacterial materials have relatively poor high-temperature stability, and a large amount of Ag + is rapidly released in a short period of time, which has many negative effects, such as poor safety, fast antibacterial decay, and also affects the quality of ceramics.

[0004] Photocatalytic antibacterial agents mostly belong to n-type semiconductor compounds such as TiO2, ZnO, CdS, WO3, Fe2O3, PnS, SnO2, ZnS, SiO2, etc. Current research shows that TiO2 nanoparticles with anatase structure have high photocatalytic activity, and are acid-resistant, alkali-resistant, light-chemical corrosion-resistant, low-cost and non-toxic. However, anatase structure TiO2 can only exist stably below 700℃, and when the temperature is higher than 700℃, the anatase structure is destroyed, and the photocatalytic activity, i.e. the antibacterial performance, is greatly attenuated, which limits its application in high-temperature ceramics.

[0005] In summary, although antibacterial materials have been greatly developed in the past few decades, the existing various antibacterial agents have some or other deficiencies, especially high-temperature stability, and in order to meet the requirements of upgrading of various products, a new type of antibacterial agent with high performance and high-temperature stability is particularly urgent.

[0006] Lanthanum silver molybdate (AgLaMo2O8) belongs to a tetragonal sheet silicate structure and is a new type of inorganic compound, and people have little research on it, and there are few related literatures, which are only reflected in solid phase preparation and rare earth fluorescence excitation.

[0007] In the field of antibacterial materials, a large number of studies have shown that Ag + , MoO3 has good antibacterial activity, however, the details of the antibacterial activity of the composite oxide including Mo have not been studied; hydrophobic materials can inhibit the contact and diffusion of bacteria, hinder the reproduction of bacteria, and the strong hydrophobicity of the surface of rare earth oxides is also proved by a large number of studies. Under this research background, the application provides a method for synthesizing AgLaMo2O8 ultrafine powder with a tetragonal sheet silicate structure and first applied in the antibacterial field, the method is simple in process, convenient in operation, high in purity and yield, low in cost and easy to scale production; the obtained AgLaMo2O8 ultrafine powder has better high-temperature stability and antibacterial performance, the high-temperature application advantage is more obvious, and the application field is more extensive. SUMMARY

[0008] The application aims to provide a new type of inorganic antibacterial agent (AgLaMo2O8) and a preparation method thereof, the AgLaMo2O8 ultrafine powder has good high-temperature stability, excellent antibacterial performance, high-temperature application advantage, and a wider application field; the preparation method is simple in process, convenient in operation, high in purity and yield, low in cost and easy to scale production.

[0009] The technical solution of the application is as follows.

[0010] A preparation method of AgLaMo2O8 ultrafine powder with a tetragonal sheet silicate structure, which is performed according to the following steps.

[0011] Step 1: a certain mass of lanthanum nitrate, silver nitrate, citric acid and (NH4)6Mo7O 24 are weighed and sequentially put into three different beakers (the citric acid and (NH4)6Mo7O 24 are put into the same beaker), and a proper amount of deionized water is added into the three beakers, and after stirring and dissolving, the lanthanum salt solution and the silver salt solution are sequentially added dropwise into the (NH4)6Mo7O 24 , citric acid solution, the pH value is adjusted by using ammonia water, and the colorless sol is obtained by continuously stirring at (70±5) ℃.

[0012] Step 2: After the colorless sol of step (1) is stirred magnetically, it is placed in a drying oven at a set temperature for drying, and after the dry gel is formed, the dry gel is ground into powder.

[0013] Step 3: The dry gel powder of step (2) is placed in a high-temperature furnace at a set temperature to induce spontaneous combustion, and the dry gel burns from the surface to the inside in a self-sustaining manner to form fluffy dendritic powder. After the combustion product is cooled and ground, a new type of inorganic (AgLaMo2O8) superfine antibacterial powder is obtained.

[0014] In the above technical solution, the AgNO3, La(NO3)3 and (NH4)6Mo7O 24 The molar ratio of citric acid to NO3 - is controlled to be between 0.5 and 2, and the pH is adjusted to about 2.0 with ammonia.

[0015] In the above technical solution, in step (2), the drying temperature of the blast dryer is 80-120°C, and the drying time is about 12-24h.

[0016] In the above technical solution, in step (3), the set temperature for inducing spontaneous combustion of the high-temperature furnace is 350-1500°C, that is, after the high-temperature furnace is heated to the set temperature, the dry gel is placed in the furnace for spontaneous combustion and is retained for 2-20min.

[0017] The beneficial effects of the present application are as follows.

[0018] The present application adopts a sol-gel spontaneous combustion method, uses silver nitrate, lanthanum nitrate and (NH4)6Mo7O 24 as raw materials, citric acid as a complexing agent, and ammonia as a pH adjuster, and by controlling the amount of citric acid and the ignition temperature and time of spontaneous combustion, a low-temperature one-step synthesis of lanthanum molybdate silver (AgLaMo2O8) superfine powder with different particle sizes is achieved and is first applied in the antibacterial field. Lanthanum molybdate silver (AgLaMo2O8) belongs to a tetragonal sheet molybdate structure, has good high-temperature stability, and has excellent antibacterial performance, and is a new type of inorganic compound. Up to now, people have not done much research on it, and there are few related literatures, which are only reflected in solid-phase high-temperature synthesis. The solid-phase reaction sintering temperature is high, the time is long, the purity is low, and it is also difficult to obtain superfine powder. The present application provides a low-temperature one-step synthesis method of AgLaMo2O8 superfine powder, which has short reaction time, simple process, easy operation, high purity yield, low cost, and is suitable for popularization and use in industry. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced as follows. Obviously, the drawings described in the following embodiments are only a part of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of the provided drawings.

[0020] Figure 1 is the XRD pattern of the product prepared in Example 1, Example 2 and Example 3 of the present application.

[0021] Figure 2 is the SEM photo of the product prepared in Example 1 of the present application.

[0022] Figure 3 is the SEM photo of the product prepared in Example 2 of the present application.

[0023] Figure 4 is the SEM photo of the product prepared in Example 3 of the present application.

[0024] Figure 5 is the bacteriostatic ring of the bacteriostatic experiment of the product prepared in Example 1, Example 2 and Example 3 of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application and the drawings of the specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without any creative effort belong to the protection scope of the present application.

[0026] The technical solutions of the present application will be further described in combination with specific embodiments.

[0027] Example 1.

[0028] ① 6.5g of La (NO3) 3·6H2O, 2.55g of AgNO3, 14.25g of citric acid and 5.30g of (NH4) 6Mo7O 24 ·4H2O were weighed into three different beakers (citric acid and (NH4) 6Mo7O 24 ·4H2O were placed in the same beaker), and 30ml, 30ml and 60ml of deionized water were added into the three beakers respectively. After stirring and dissolving, the lanthanum nitrate solution and the silver nitrate solution were added dropwise into the (NH4) 6Mo7O 24 and citric acid solution in sequence, the pH value was adjusted to about 2 by using ammonia water, and the colorless sol was obtained by continuously stirring at (70±5)℃;

[0029] ② The colorless sol was dried in a blast drying oven at 100°C for 16 hours after magnetic stirring. After the formation of the xerogel, the xerogel was ground into powder.

[0030] ③ The xerogel powder was placed in a high-temperature furnace whose temperature had been raised to 350°C to induce self-ignition, and was kept in the high-temperature furnace for 10 minutes. The xerogel burned from the surface to the inside in a self-sustaining manner, forming fluffy tree-like powder. The combustion product was cooled and ground to obtain the novel inorganic (AgLaMo2O8) superfine antibacterial powder.

[0031] The XRD pattern of Example 1 (attached Figure 1 , 350°C) is completely consistent with PDF (49-384), and is mainly AgLaMo2O8 with orthorhombic pyrochlore structure, with an average particle size of about 250 nm (attached Figure 2 ).

[0032] Example 2.

[0033] ① 6.5 g of La(NO3)3·6H2O, 2.55 g of AgNO3, 11.50 g of citric acid and 5.30 g of (NH4)6Mo7O 24 ·4H2O were weighed into three different beakers (the citric acid and (NH4)6Mo7O 24 ·4H2O were placed in the same beaker), and 30 ml, 30 ml and 60 ml of deionized water were added to the three beakers, respectively. After stirring and dissolving, the lanthanum nitrate solution and the silver nitrate solution were added dropwise to the (NH4)6Mo7O 24 and citric acid solutions, respectively, and the pH value was adjusted to about 2 with ammonia water, and the colorless sol was obtained by continuously stirring at (70±5) °C;

[0034] ② The colorless sol was dried in a blast drying oven at 80°C for 20 hours after magnetic stirring. After the formation of the xerogel, the xerogel was ground into powder.

[0035] ③ The xerogel powder was placed in a high-temperature furnace whose temperature had been raised to 500°C to induce self-ignition, and was kept in the high-temperature furnace for 20 minutes. The xerogel burned from the surface to the inside in a self-sustaining manner, forming fluffy tree-like powder. The combustion product was cooled and ground to obtain the novel inorganic (AgLaMo2O8) superfine antibacterial powder.

[0036] The XRD pattern of Example 2 (attached Figure 1 , 500°C) is consistent with PDF (49-384), and is mainly AgLaMo2O8 with orthorhombic pyrochlore structure, with an average particle size of about 600 nm (attached Figure 3 ).

[0037] Example 3.

[0038] ① Take 6.5g La(NO3)3·6H2O, 2.55g AgNO3, 8.55g citric acid and 5.30g (NH4)6Mo7O 24 24 24

[0039] ② After the colorless sol is magnetically stirred, it is moved to a drying oven at 90℃ for drying for 20h. After the dry gel is formed, the dry gel is ground into powder.

[0040] ③ The dry gel powder is placed in a high temperature furnace whose temperature has been raised to 1300℃ to induce self-ignition, and is kept in the high temperature furnace for 20min. The dry gel burns from the surface to the inside by self-spread combustion, forming fluffy tree-like powder. After the combustion product is cooled and ground, a new type of inorganic (AgLaMo2O8) superfine antibacterial powder is prepared.

[0041] The XRD pattern of Example 3 (attached Figure 1 , 1300℃) is consistent with PDF (49-384), and is mainly AgLaMo2O8 with orthorhombic sheet structure, with an average particle size of about 15um (attached Figure 4 ).

[0042] Antibacterial performance detection:

[0043] The sterilized agar medium is poured into a culture dish to form a plate, and then 0.1mL of mixed bacteria solution is taken on the plate and uniformly coated with a spatula. The antibacterial material is made into a tablet (diameter 5mm, thickness 3mm), and then the culture dish is placed in a constant temperature incubator at 37℃. After 24h, the size of the antibacterial ring around the sample is measured (see attached Figure 5 ), and the average value of the diameter of the antibacterial ring is taken as the basis for evaluating the antibacterial performance of the material. The experimental results are shown in Table 1.

[0044] Table 1:

[0045] Test item Example 1 Example 2 Example 3 Bacteriostatic ring (mm) 23 21 19

[0046] The above experimental results show that the AgLaMo2O8 superfine powder with orthorhombic sheet structure prepared by the present application can exactly inhibit the growth of microorganisms, and has excellent antibacterial effect.

[0047] Bactericidal test

[0048] ​​​The test is carried out according to the national standard GB / T31402-2015, Escherichia coli is selected as a test strain, and the samples of examples 1, 2 and 3 are tested, and the results are shown in table 2.

[0049] Table 2:

[0050] Test item Example 1 Example 2 Example 3 Bacteriostatic rate >99％ >99％ >99％

[0051] As shown in table 2, the tetragonal sheet AgLaMo2O8 superfine powder prepared by the technical scheme has excellent sterilization effect.

[0052] The above is an exemplary description of the present application, it should be noted that without departing from the core of the present application, any simple modification, modification or other equivalent replacement which can not cost the creative labor of those skilled in the art falls within the protection scope of the present application.

Claims

1. A method for preparing an inorganic antibacterial agent AgLaMo2O8, characterized by, According to the following steps: (1) Take a certain amount of lanthanum nitrate, silver nitrate, citric acid and (NH4)6Mo7O 24 Into three different beakers in turn, citric acid and (NH4)6Mo7O 24 In the same beaker, and add an appropriate amount of deionized water to the three beakers, stir and dissolve, then add the lanthanum salt solution, silver salt solution to the (NH4)6Mo7O 24 solution drop by drop in turn, adjust the pH value with ammonia water and continuously stir at 70±5°C to obtain a colorless sol. (2) After magnetic stirring of the colorless sol in step (1), the sol is placed in a drying oven at a set temperature for drying. After the formation of a dry gel, the dry gel is ground into powder; (3) The dry gel powder in step (2) is placed in a high-temperature furnace at a set temperature to induce spontaneous combustion. The dry gel burns from the surface to the inside in a self-sustaining manner to form fluffy tree-like powder. The combustion product is cooled and ground to obtain inorganic AgLaMo2O8 ultra-fine antibacterial powder; AgNO3, La(NO3)3 and (NH4)6Mo7O 24 The molar ratio of the substances is 7:7:2, the molar ratio of citric acid to NO3- is controlled at 0.5-2, and the pH is adjusted to 2.0 with ammonia water; In step (2), the drying temperature is 80°C to 120°C, and the drying time is 12h to 24h; In step (3), the temperature for inducing spontaneous combustion is 350°C to 1500°C, and the dry gel is placed in the spontaneous combustion for 2 to 20min.

2. Application of the inorganic AgLaMo2O8 ultra-fine antibacterial powder prepared by the method of claim 1 in the field of antibacterial. 3.The application of the inorganic ultrafine powder AgLaMo 2O 8 in the field of antibiosis according to claim 2, characterized in that, The AgLaMo2O8 ultra-fine powder has excellent antibacterial performance. Due to its good high-temperature stability, it can be applied to medium-high temperature ceramics.

Images