CN101133743A - A kind of preparation method of photocatalytic bactericidal antibacterial agent under visible light - Google Patents

Abstract

The invention discloses a preparation method of a photocatalytic bactericidal and antibacterial agent under visible light, relating to a bactericidal and antibacterial agent. Provide a method for preparing a photocatalytic bactericidal and antibacterial agent under visible light using a perovskite-type inorganic bactericidal and antibacterial material by reducing the rare earth perovskite in a reducing atmosphere to obtain moderate oxygen vacancies. The prepared bactericidal and antibacterial agent is used in It has bactericidal and antibacterial activity under normal indoor lighting. Prepare lanthanum nitrate, strontium nitrate and cobalt nitrate in a molar ratio (1-X): X: 1 to make a 0.05-0.1M solution; 1.2), the complexing agent and the prepared nitrate solution are mixed to form a sol, and dried to form a gel; the gel is pre-calcined, and then calcined to obtain perovskite La _1-x Sr _x CoO ₃ ; the calcined The obtained perovskite is placed in a reducing atmosphere furnace and treated with reducing gas to obtain the product.

Description

A kind of preparation method of photocatalytic bactericidal antibacterial agent under visible light

technical field

The invention relates to a bactericidal and antibacterial agent, in particular to a method for preparing the photocatalytic bactericidal and antibacterial agent under visible light using a perovskite-type inorganic bactericidal and antibacterial material.

Background technique

Since the discovery of the photocatalytic phenomenon of titanium dioxide, patents on the use of titanium dioxide to photocatalytically degrade wastewater, purify air, and kill bacteria have appeared one after another. Chinese patent ZL02119304.5 discloses a preparation method of mesoporous titanium dioxide film with high bactericidal photoactivity, which is used for the sterilization of seawater, tap water and other water quality, but the bactericidal and antibacterial process must be realized under the action of ultraviolet light. Chinese patent ZL02154431.X discloses a nano-photocatalyst antibacterial composition for antibacterial method, using nano-composite TiO ₂ containing rutile and anatase to make the antibacterial composition produce higher photocatalytic activity under sunlight to improve antibacterial Function, and by adding silver and zinc ions to the surface treatment composite _TiO2 , it also has antibacterial effect when there is no light. However, this method only uses titanium dioxide as a photocatalyst. Due to the limitation of its semiconductor band gap, it can only absorb 4% of the ultraviolet light of sunlight, and cannot use visible light with longer wavelengths. At the same time, silver and zinc ions are introduced into the photocatalyst. It may cause discoloration of inorganic materials and other phenomena.

In recent years, rare earth perovskite-type composites have been widely used in photocatalytic degradation of organic dye wastewater under visible light. Yang Qiuhua et al. used rare earth perovskite _LaCoO3 to degrade organic dyes under visible light (>410nm) and sunlight. Kang Zhenjin et al. prepared oxygen-deficient La _1-x Sr _x CoO _3-δ by doping modification, which can improve the photocatalytic efficiency, but excessive doping will reduce the photocatalytic efficiency, and the preparation conditions are difficult to control.

Contents of the invention

The purpose of the present invention is to provide a method for preparing a photocatalytic bactericidal antibacterial agent under visible light using a perovskite-type inorganic bactericidal antibacterial material by reducing the rare earth perovskite under a reducing atmosphere to obtain moderate oxygen vacancies. The prepared bactericidal and antibacterial agent has bactericidal and antibacterial activity under normal indoor lighting sources.

The preparation method of photocatalytic bactericidal antibacterial agent under visible light of the present invention comprises the following steps:

1) Prepare lanthanum nitrate, strontium nitrate and cobalt nitrate in a molar ratio (1-X): X: 1 to prepare a 0.05-0.1M solution, wherein 0≤X≤0.1;

2) According to the metal nitrate total molar ratio and the complexing agent molar ratio 1: (0.6～1.2), the complexing agent is mixed with the nitrate solution prepared in step 1 to form a sol, and then dried into a gel;

3) Pre-calcining the gel obtained in step 2 at 400-500°C for 2-3 hours, and further calcining at 750-850°C for 4-5 hours to obtain perovskite La _1-x Sr _x CoO ₃ ;

4) Put the perovskite obtained after calcination into a reducing atmosphere furnace, and treat it with reducing gas at 500-600°C for 4-6 hours, and the product is a composite rare earth perovskite-type material La ₁ with bactericidal and antibacterial activity _-x Sr _x CoO _3-y (0≤X≤0.1; 0<Y≤0.025).

Described complexing agent is citric acid.

The reducing gas contains 5%-10% of carbon monoxide or hydrogen, and the rest is nitrogen.

On the basis of the conventional method for preparing rare earth perovskite-type composite oxides (ABO3), the present invention performs moderate reduction treatment on the surface of the perovskite material under a reducing atmosphere, resulting in disordered oxygen vacancies on the surface of the perovskite, The ability of perovskite to absorb visible light is greatly improved, and at the same time, the photogenerated electrons and holes on the surface are effectively separated, thereby generating a large number of active groups such as hydroxyl radicals and oxygen radicals that can sterilize and antibacterial, and realize high-efficiency photocatalysis under conventional lighting sources. Sterilizing and antibacterial. Add the prepared composite rare earth perovskite material La _1-x Sr _x Co O _3-y into the solution containing Escherichia coli or Staphylococcus aureus, irradiate it under the fluorescent lamp for 15-30 minutes, take out the bacterial solution and cultivate it for 24 hours Calculate the change of bacterial concentration before and after sterilization, thus obtain the sterilization rate. Its bactericidal rate against Escherichia coli can reach 100%, and its bactericidal rate against Staphylococcus aureus can reach up to 97.0%. The prepared composite rare earth perovskite bactericidal and antibacterial material can be widely used in water quality sterilization, indoor air sterilization and self-cleaning and bactericidal building materials production.

Description of drawings

Fig. 1 is the XRD figure of the photocatalytic bactericidal antibacterial agent prepared by the embodiment. In Figure 1, the abscissa is 2theta. Curve a is La _0.9 Sr _0.1 O _2.975 ; Curve b is La _0.95 Sr _0.05 CoO _2.988 ; Curve c is LaCoO _2.975 .

Figure 2 is an ultraviolet-visible diffuse reflectance spectrum (UV-Vis DRS) figure of the photocatalytic bactericidal antibacterial agent prepared in the embodiment. In FIG. 2, the abscissa is the wavelength wavelength (nm), and the ordinate is the absorption intensity ABS. Curve a is La _0.9 Sr _0.1 CoO _2.975 ; Curve b is La _0.95 Sr _0.05 CoO _2.988 ; Curve c is LaCoO _2.975 .

Detailed ways

Below by embodiment the present invention will be further described.

Example 1: LaCoO _2.975

Weigh 8.64g of lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) and 5.81g of cobalt nitrate (Co(NO ₃ ) ₂ .6H ₂ O) at a molar ratio of 1:1, and prepare 200ml of a 0.1M solution , and then according to the total metal nitrate and citric acid molar ratio of 1:0.6, weigh 3.02g of citric acid (C ₆ H ₈ O ₇ .H ₂ O) and add it to the above solution to make a sol, and irradiate it under infrared light for 8h The gel was obtained, transferred to a muffle furnace for pre-calcination at 400°C for 3 hours, and finally calcined at 750°C for 5 hours to obtain 4.52g of LaCoO ₃ . Put 4.52g of LaCoO ₃ into an atmosphere furnace, act in a reducing atmosphere with 10% CO and the rest being N ₂ , and reduce at 500°C for 6 hours to obtain LaCoO _2.975 . It can be seen from the X-ray polycrystalline electron diffraction pattern in Figure 1 that the characteristic diffraction peak of the prepared bactericidal and antibacterial agent sample is a perovskite structure. It can be seen from Figure 2 that the bactericide has a very obvious absorption at 400-700nm, which shows that the perovskite treated with a reducing atmosphere has a good ability to absorb visible light.

After adding 0.005g of perovskite LaCoO _2.975 to 5ml of Escherichia coli or Staphylococcus aureus at a concentration of 10 ⁶ CFU/ml, irradiate for 15min under a 30W fluorescent lamp at a distance of 40cm from the lamp tube, and then take out 100 microliters of bacteria The solution was dispersed on a petri dish containing solid medium, and after 24 hours of cultivation, the number of bacteria in the original bacteria solution was obtained from the number of bacteria clusters on the glass slide, and the bactericidal rate was calculated from this. Escherichia coli is 100% bactericidal, and Staphylococcus aureus is 90.5% bactericidal.

Example 2: La _0.9 Sr _0.1 CoO _2.975

Weigh lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) 7.78g, strontium nitrate (Sr(NO ₃ ) ₂ ) 0.42g, cobalt nitrate Co(NO ₃ ) ₂ .6H at a molar ratio of 0.9:0.1:1 ₂ O5.81g was made into 400ml of 0.05M solution, and 6.05g of citric acid was weighed according to the molar ratio of total metal nitrate and citric acid 1:1.2 and added to the above solution to make a sol, and then acted under an infrared lamp for 12h to make a gel, and then Precalcined at 500° C. for 2 hours, and calcined at 850° C. for 4 hours to obtain 4.56 g of the photocatalytic bactericidal material La _0.9 Sr _0.1 CoO ₃ . Put 4.56g of La _0.9 Sr _0.1 CoO ₃ into an atmosphere furnace, under the action of 30ml/min (10% H ₂ and the rest N ₂ ), hold at 600°C for 4 hours to obtain La _0.9 Sr _0.1 CoO _2.975 .

Add 0.015g perovskite La _0.9 Sr _0.1 CoO _2.975 catalyst to 5ml culture solution containing Escherichia coli or Staphylococcus aureus at a concentration of 10 ⁶ CFU/ml and irradiate for 30 minutes, and evaluate the bactericidal effect according to the method in Example 1. The results are shown in Table 1 and Table 2.

The bactericidal performance (%) of table 1 photocatalytic bactericidal antibacterial agent to escherichia coli

Example Bactericidal and antibacterial agents Sterilization rate comparative example Bactericidal and antibacterial agents Sterilization rate 1 LaCoO _2.975 100 1' LaCoO ₃ 94.5 2 La _0.9 Sr _0.1 CoO _2.975 100 2' La _0.9 Sr _0.1 CoO ₃ 98.0 3 La _0.92 Sr _0.08 CoO _2.995 100 3' La _0.92 Sr _0.08 CoO ₃ 97.0 4 La _0.95 Sr _0.05 CoO _2.988 100 4' La _0.95 Sr _0.05 CoO ₃ 98.0 5 La _0.97 Sr _0.03 CoO _2.985 99.5 5' La _0.97 Sr _0.03 CoO ₃ 96.0

The bactericidal performance (%) of table 2 photocatalytic bactericidal antibacterial agent to Staphylococcus aureus

Example Bactericidal and antibacterial agents Sterilization rate comparative example Bactericidal and antibacterial agents Sterilization rate 1 LaCoO _2.975 90.5 1' LaCoO ₃ 87.5 2 La _0.9 Sr _0.1 CoO _2.975 97.0 2' La _0.9 Sr _0.1 CoO ₃ 89.0 3 La _0.92 Sr _0.08 CoO _2.995 91.0 3' La _0.92 Sr _0.08 CoO ₃ 87.0 4 La _0.95 Sr _0.0.5 CoO _2.988 93.0 4' La _0.95 Sr _0.05 CoO ₃ 89.5 5 La _0.97 Sr _0.03 CoO _2.985 91.0 5' La _0.97 Sr _0.03 CoO ₃ 86.0

Example 3: La _0.92 Sr _0.08 CoO _2.995

Weigh lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) 8.41g, strontium nitrate (Sr(NO ₃ ) ₂ ) 0.34g, cobalt nitrate Co(NO ₃ ) ₂ .6H at a molar ratio of 0.92:0.08:1 ₂ O5.81g was made into 250ml of 0.08M solution, and 4.03g of citric acid was weighed according to the molar ratio of total metal nitrate and citric acid 1:0.8 and added to the above solution to make a sol, and then acted under an infrared lamp for 10h to make a gel. Then precalcined at 450° C. for 2.5 hours, and calcined at 800° C. for 4 hours to obtain 4.47 g of the photocatalytic bactericidal material La _0.92 Sr _0.08 CoO ₃ . Put 4.47g of La _0.92 Sr _0.08 CoO ₃ into an atmosphere furnace, and reduce at 500°C for 5 hours under the action of 30ml/min (7% H ₂ and the rest is N ₂ ), to obtain La _0.92 Sr _0.08 CoO _2.995 .

Measure the bactericidal rate by the method of embodiment 1, the results are shown in Table 1 and Table 2.

Example 4: La _0.95 Sr _0.05 CoO _2.988

Weigh lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) 8.23g, strontium nitrate (Sr(NO ₃ ) ₂ ) 0.21g, cobalt nitrate Co(NO ₃ ) ₂ .6H at a molar ratio of 0.9:0.05:1 ₂ O5.81g was made into 285ml of 0.07M solution, and 5.04g of citric acid was weighed according to the molar ratio of total metal nitrate and citric acid 1:1 and added to the above solution to make a sol, and then acted under an infrared lamp for 10h to make a gel. Then precalcined at 500° C. for 2 hours, and calcined at 850° C. for 4.5 hours to obtain 4.34 g of the photocatalytic bactericidal material La _0.95 Sr _0.05 CoO ₃ . Put 4.34g of La _0.95 Sr _0.05 CoO ₃ into an atmosphere furnace, and reduce it at 500°C for 4.5 hours under the action of 30ml/min (7% CO and the rest is N ₂ ), to obtain La _0.95 Sr _0.05 CoO _2.988 , which contains Escherichia coli in 5ml Or add 0.015g of perovskite La _0.95 Sr _0.05 CoO _2.988 catalyst to the culture solution of Staphylococcus aureus with a concentration of 10 ⁶ CFU/ml and irradiate for 30 minutes, and evaluate the bactericidal effect according to the method of Example 1 for the rest. The results are shown in Table 1 and Table 2.

Example 5: La _0.97 Sr _0.03 CoO _2.985

Weigh lanthanum nitrate (La(NO ₃ ) ₃ .6H ₂ O) 8.40g, strontium nitrate (Sr(NO ₃ ) ₂ ) 0.13g, cobalt nitrate Co(NO ₃ ) ₂ .6H at a molar ratio of 0.97:0.03:1 ₂ O 5.81g was made into 665ml of 0.03M solution, and 4.53g of citric acid was weighed according to the molar ratio of total metal nitrate and citric acid 1:0.9 and added to the above solution to make a sol, and then acted under an infrared lamp for 10 hours to make a gel. Then precalcine at 430° C. for 2 hours, and calcined at 850° C. for 4 hours to obtain 4.27 g of the photocatalytic bactericidal material La _0.97 Sr _0.03 CoO ₃ . Put 4.27 g of La _0.97 Sr _0.03 CoO ₃ into an atmosphere furnace, and under the action of 30ml/min (5% CO and the rest is N ₂ ), reduce at 550°C for 5 hours to obtain La _0.97 Sr _0.03 CoO _2.985 , according to the method of Example 1 Determination of bactericidal rate, the results are shown in Table 1 and Table 2.

Comparative example 1-5

The bactericidal rate of the photocatalytic bactericidal materials without final reduction treatment in the preparation of Examples 1-5 was measured according to the same bactericidal evaluation method, and the results are shown in Table 1 and Table 2. From the comparison results, it can be seen that the bactericidal activity of the material that caused oxygen vacancies on the surface of the perovskite after reduction treatment was significantly improved compared with the untreated material.

Claims (3)

1. the preparation method of a visible light photocatalysis sterilization antimicrobials agent is characterized in that may further comprise the steps:

1) lanthanum nitrate, strontium nitrate and cobalt nitrate are measured than (1-X): X by mole: 1 is mixed with the solution of 0.05～0.1M, wherein 0≤X≤0.1;

2) press metal nitrate total mole number and complexing agent mole ratio 1: (0.6～1.2), the nitrate solution with complexing agent and step 1 preparation is mixed into colloidal sol earlier, is dried to gel then;

3) the pre-calcination 2～3h under 400～500 ℃ of gel elder generation that step 2 is obtained further at 750～850 ℃ of following calcination 4～5h, obtains perovskite La _1-xSr _xCoO ₃

4) perovskite that obtains after the calcination is put into the reducing atmosphere stove, adopt reducibility gas to handle 4～6h at 500～600 ℃, product is the compound rare-earth perovskite-type material La with sterilization antibacterial activity _1-xSr _xCoO _3-y, 0≤X≤0.1 wherein; 0＜Y≤0.025.

2. the preparation method of a kind of visible light photocatalysis sterilization antimicrobials agent as claimed in claim 1 is characterized in that described complexing agent is a citric acid.

3. the preparation method of a kind of visible light photocatalysis sterilization antimicrobials agent as claimed in claim 1 is characterized in that containing in the described reducibility gas 5%～10% carbon monoxide or hydrogen, and all the other are nitrogen.

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