Preparation method and application of titanium dioxide / egg white composite photocatalyst

Abstract

The invention discloses a preparation method and application of a titanium dioxide / egg white composite photocatalyst, and relates to the field of porous material preparation.The method comprises the steps that micro-nano titanium dioxide serves as an additive component to be dispersed in an egg white solution, gelation is conducted through a thermal induction technology, and the titanium dioxide / egg white composite photocatalyst is obtained; further freeze-drying to obtain a composite sponge with a microporous structure; by adjusting the size and morphology of titanium dioxide and the concentration of the egg white solution, the pore diameter, pore structure and porosity of the composite photocatalyst can be regulated and controlled, and the research result opens up a new direction for the field of preparation of novel photocatalysis by combining natural polymers and inorganic materials; besides, the preparation method is simple, the raw material egg white is a natural polymer, and titanium dioxide is non-toxic, so that the photocatalyst is a green photocatalyst, and has a good application prospect in the fields of dye sewage treatment, water treatment and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of composite photocatalytic material preparation, and specifically relates to a preparation method and application of a titanium dioxide / avian protein composite photocatalyst. Background Art

[0002] The development of industrialization has led to various environmental pollutions, especially water pollution, which has caused serious harm to human health. Printing and dyeing wastewater contains a large amount of organic pollutants, which are toxic and difficult to biodegrade, causing serious harm to human health and even the entire ecosystem. How to control organic pollutants in water has become one of the major issues facing human society.

[0003] Photocatalytic technology has a good degradation effect on organic dyes, so it has attracted much attention from scholars. Among many semiconductor catalysts, TiO2 has good catalytic effect, chemical stability, and low price. It is currently the most promising photocatalytic material. However, in actual use, TiO2 has problems such as easy agglomeration and difficult recycling. Therefore, the present invention adopts a one-step thermal solidification method to prepare titanium dioxide / poultry protein composite, and then freeze-drying titanium dioxide / poultry protein composite photocatalyst. The entire preparation process does not require the use of additional chemical cross-linking agents, and is an environmentally friendly preparation method. Therefore, the present invention uses natural poultry protein to load titanium dioxide to prepare a photocatalyst with high catalytic effect and easy recycling, which is of great significance.

[0004] Chinese patent CN 111375357A discloses a method for preparing a multifunctional nano-aerogel with amphiphilicity. Gelatin is a widely used biological protein. Gelatin is dissolved in water under continuous stirring conditions to obtain a uniform gelatin aqueous solution with a gelatin mass fraction of 4-8%. Nano-titanium dioxide and nano-silicon dioxide are then added to the prepared gelatin aqueous solution. A milky suspension is obtained after ultrasonic dispersion. The hydrogel is freeze-dried to obtain an ultra-light, porous and amphiphilic multifunctional nano-aerogel. The freeze-drying process is carried out under vacuum and the drying time is 24-48 hours. The method can treat oily wastewater with complex components. However, considering that an additional organic cross-linking agent is still required for cross-linking, the preparation process is likely to cause pollution to the environment, and the preparation technology is slightly insufficient.

[0005] Chinese patent CN109174204A discloses a method for preparing a high-efficiency photocatalytic composite material, wherein tryptone, yeast powder and mannitol are prepared into a nutrient solution in a mass ratio of 4.5:3:25.5; a circular melt-blown nonwoven fabric sample is immersed in a nano-TiO2 suspension for a period of time, washed with deionized water and placed in a freeze dryer for freeze drying for 19-24 hours, and finally a high-efficiency photocatalytic composite material is obtained. However, considering that the preparation process requires sodium hydroxide for alkaline boiling, a large amount of alkaline wastewater will be generated in the subsequent washing process, and the preparation technology is slightly insufficient. Summary of the invention

[0006] In view of the shortcomings of organic pollutants in existing composite photocatalytic material technology, which are toxic and difficult to biodegrade, and TiO2 that is easy to agglomerate and difficult to recycle, the present invention provides a preparation method and application of a titanium dioxide / avian protein composite photocatalyst.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] A method for preparing a titanium dioxide / avian protein composite photocatalyst comprises the following steps:

[0009] Step 1: Clean the eggs, crack the shells, and separate the poultry protein;

[0010] Step 2: The poultry protein is dispersed in deionized water to form a poultry protein solution;

[0011] Step 3: Titanium dioxide is evenly dispersed in the protein solution by ultrasonic treatment to obtain a titanium dioxide / poultry protein solution;

[0012] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and obtain a titanium dioxide / poultry protein gel after heat treatment;

[0013] Step 5: freeze-dry the titanium dioxide / poultry protein gel, and demould to obtain the titanium dioxide / poultry protein composite photocatalyst.

[0014] Furthermore, the poultry eggs in the first step are one or more of chicken eggs, duck eggs and goose eggs.

[0015] Furthermore, the concentration of the poultry protein solution in the second step is 20 to 90 wt%.

[0016] Furthermore, in the third step, the titanium dioxide particle size is 10 nm-5 μm, the titanium dioxide concentration is 0.1-1000 mg / L, the ultrasonic treatment power is 80-2400 W, the ultrasonic time is 0.1-5 h, and the ultrasonic treatment temperature is 4-50° C.

[0017] Furthermore, the fourth step heat treatment temperature is 80-100° C., and the heat treatment time is 0.1-6 hours.

[0018] Furthermore, the freeze-drying temperature in the fifth step is -20 to -80°C, and the freeze-drying time is 12 to 48 hours.

[0019] Furthermore, the poultry protein can be replaced by other similar animal proteins or plant proteins, wherein the other similar animal proteins are one of whey protein, lactoferrin, fish protein or a mixture of the two; the plant protein is one of soy protein isolate, rice protein, cottonseed protein or a mixture of the two.

[0020] The application also discloses the use of the titanium dioxide / avian protein composite photocatalyst prepared by the above preparation method in the degradation of dyes or heavy metal ions.

[0021] Furthermore, the dye is one or more of methylene blue, rhodamine B, and methyl orange.

[0022] Furthermore, the heavy metal ion is Cr 6+ , Pb 2+ , Hg 2+ One or more of the .

[0023] Principle explanation: Titanium dioxide has good photocatalytic performance and good chemical stability. Protein molecules will be denatured after heat treatment to form a gel with a regular structure. After freeze-drying, a loose porous material with a large specific surface area can be obtained, which has good adsorption properties and is an ideal catalyst carrier. For this reason, nano-titanium dioxide and protein are selected as functional components to construct a porous foam structure with the dual advantages of interface effect and synergistic effect, which can improve the performance of the composite photocatalyst to obtain a photocatalytic material with excellent performance.

[0024] Compared with the prior art, the beneficial effects of the present invention include:

[0025] 1. The titanium dioxide / avian protein composite photocatalyst obtained by the present invention is used in dyes and other polluted water.

[0026] 2. The titanium dioxide / poultry protein composite photocatalyst obtained by the present invention has a good photocatalytic effect on methylene blue, and the degradation rate can reach 98%.

[0027] 3. The titanium dioxide / avian protein composite photocatalyst obtained by the present invention has a great influence on Cr 6+ , the photocatalytic effect is good, and the degradation rate can reach 95%.

[0028] 4. The titanium dioxide / poultry protein composite photocatalyst obtained by the present invention degrades methylene blue and can be reused 10 times, with the degradation rate still reaching 94% at the 10th time.

[0029] 5. Titanium dioxide / poultry protein composite photocatalyst obtained by the present invention for degradation of Cr6+ , reused 10 times, the degradation rate can still reach 92% on the 10th time. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a scanning electron microscope (SEM) image of the titanium dioxide / avian protein composite photocatalyst described in Example 1 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described below in conjunction with embodiments. The contents mentioned in the implementation modes are not intended to limit the present invention.

[0032] In the following examples, unless otherwise specified, "concentration" refers to mass percentage.

[0033] Example 1

[0034] A method for preparing a titanium dioxide / avian protein composite photocatalyst, comprising the following specific steps:

[0035] Step 1: Wash the eggs, crack the shells, and separate the egg whites;

[0036] Step 2: Take 50g of egg white and disperse it in 50g of deionized water to form an egg white solution with a concentration of 50%;

[0037] Step 3: Add 100 mg of titanium dioxide (particle size of 50-100 nm) to the chicken egg white solution and use an ultrasonic cleaning machine with a power of 800 W for 1 hour, and set the ultrasonic temperature to 25° C. to obtain a titanium dioxide / poultry protein solution;

[0038] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and heat treat at 90°C for 1 hour to obtain a titanium dioxide / poultry protein gel;

[0039] Step 5: freeze-dry the titanium dioxide / poultry protein gel at -80°C for 36 hours, and demould to obtain a titanium dioxide / poultry protein composite photocatalyst;

[0040] Step 6: Application of titanium dioxide / poultry protein composite photocatalyst in photocatalytic degradation of dye wastewater, the dye is methylene blue.

[0041] Example 2

[0042] A method for preparing a titanium dioxide / avian protein composite photocatalyst, comprising the following specific steps:

[0043] Step 1: Wash the eggs, crack the shells, and separate the egg whites;

[0044] Step 2: Disperse 40g of egg white in 60g of deionized water to form a 40% egg white solution;

[0045] Step 3: Add 100 mg of titanium dioxide (particle size of 50-100 nm) to the chicken egg white solution and use an ultrasonic cleaning machine with a power of 800 W for 1 hour, and set the ultrasonic temperature to 25° C. to obtain a titanium dioxide / poultry protein solution;

[0046] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and heat treat at 90°C for 1 hour to obtain a titanium dioxide / poultry protein gel;

[0047] Step 5: freeze-dry the titanium dioxide / poultry protein gel at -80°C for 36 hours, and demould to obtain a titanium dioxide / poultry protein composite photocatalyst;

[0048] Step 6: Application of titanium dioxide / poultry protein composite photocatalyst in photocatalytic degradation of dye wastewater, the dye is rhodamine B.

[0049] Example 3

[0050] A method for preparing a titanium dioxide / avian protein composite photocatalyst, comprising the following specific steps:

[0051] Step 1: Wash the eggs, crack the shells, and separate the egg whites;

[0052] Step 2: Disperse 30g of egg white in 70g of deionized water to form a 30% egg white solution;

[0053] Step 3: Add 100 mg of titanium dioxide (particle size of 50-100 nm) to the chicken egg white solution and use an ultrasonic cleaning machine with a power of 800 W for 1 hour, and set the ultrasonic temperature to 25° C. to obtain a titanium dioxide / poultry protein solution;

[0054] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and heat treat at 90°C for 1 hour to obtain a titanium dioxide / poultry protein gel;

[0055] Step 5: freeze-dry the titanium dioxide / poultry protein gel at -80°C for 36 hours, and demould to obtain a titanium dioxide / poultry protein composite photocatalyst;

[0056] Step 6: Application of titanium dioxide / poultry protein composite photocatalyst in photocatalytic degradation of dye wastewater, the dye is methyl orange.

[0057] Example 4

[0058] A method for preparing a titanium dioxide / avian protein composite photocatalyst, comprising the following specific steps:

[0059] Step 1: Wash the eggs, crack the shells, and separate the egg whites;

[0060] Step 2: Disperse 60g of egg white in 40g of deionized water to form an egg white solution with a concentration of 60%;

[0061] Step 3: Add 100 mg of titanium dioxide (particle size of 50-100 nm) to the chicken egg white solution and use an ultrasonic cleaning machine with a power of 800 W for 1 hour, and set the ultrasonic temperature to 25° C. to obtain a titanium dioxide / poultry protein solution;

[0062] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and heat treat at 90°C for 1 hour to obtain a titanium dioxide / poultry protein gel;

[0063] Step 5: freeze-dry the titanium dioxide / poultry protein gel at -80°C for 36 hours, and demould to obtain a titanium dioxide / poultry protein composite photocatalyst;

[0064] Step 6: Application of titanium dioxide / poultry protein composite photocatalyst in photocatalytic degradation of heavy metal ion wastewater, heavy metal ion is Cr 6+ .

[0065] Example 5

[0066] A method for preparing a titanium dioxide / avian protein composite photocatalyst, comprising the following specific steps:

[0067] Step 1: Wash the eggs, crack the shells, and separate the egg whites;

[0068] Step 2: Disperse 70g of egg white in 30g of deionized water to form an egg white solution with a concentration of 70%;

[0069] Step 3: Add 100 mg of titanium dioxide (particle size of 50-100 nm) to the chicken egg white solution and use an ultrasonic cleaning machine with a power of 800 W for 1 hour, and set the ultrasonic temperature to 25° C. to obtain a titanium dioxide / poultry protein solution;

[0070] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and heat treat at 90°C for 1 hour to obtain a titanium dioxide / poultry protein gel;

[0071] Step 5: freeze-dry the titanium dioxide / poultry protein gel at -80°C for 36 hours, and demould to obtain a titanium dioxide / poultry protein composite photocatalyst;

[0072] Step 6: Application of titanium dioxide / poultry protein composite photocatalyst in photocatalytic degradation of heavy metal ion wastewater, heavy metal ion is Pb 2+ .

[0073] Example 6

[0074] A method for preparing a titanium dioxide / avian protein composite photocatalyst, comprising the following specific steps:

[0075] Step 1: Wash the eggs, crack the shells, and separate the egg whites;

[0076] Step 2: Take 80g of egg white and disperse it in 20g of deionized water to form an egg white solution with a concentration of 80%;

[0077] Step 3: Add 100 mg of titanium dioxide (particle size of 50-100 nm) to the chicken egg white solution and use an ultrasonic cleaning machine with a power of 800 W for 1 hour, and set the ultrasonic temperature to 25° C. to obtain a titanium dioxide / poultry protein solution;

[0078] Step 4: Pour the titanium dioxide / poultry protein solution into a mold and heat treat at 90°C for 1 hour to obtain a titanium dioxide / poultry protein gel;

[0079] Step 5: freeze-dry the titanium dioxide / poultry protein gel at -80°C for 36 hours, and demould to obtain a titanium dioxide / poultry protein composite photocatalyst;

[0080] Step 6: Application of titanium dioxide / poultry protein composite photocatalyst in photocatalytic degradation of heavy metal ion wastewater, heavy metal ion is Hg 2+ .

[0081] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a titanium dioxide / avian protein composite photocatalyst, characterized in that: The following steps are involved: Step 1: Clean the eggs, crack the shells, and separate the poultry protein; Step 2: The poultry protein is dispersed in deionized water to form a poultry protein solution; Step 3: Titanium dioxide is evenly dispersed in the protein solution by ultrasonic treatment to obtain a titanium dioxide / poultry protein solution; Step 4: Pour the titanium dioxide / poultry protein solution into a mold and obtain a titanium dioxide / poultry protein gel after heat treatment; Step 5: freeze-dry the titanium dioxide / poultry protein gel, and demould to obtain the titanium dioxide / poultry protein composite photocatalyst.

2. The method for preparing the titanium dioxide / avian protein composite photocatalyst according to claim 1, characterized in that: In the first step, the poultry eggs are one or more of chicken eggs, duck eggs and goose eggs.

3. The method for preparing the titanium dioxide / avian protein composite photocatalyst according to claim 1, characterized in that: The concentration of the poultry protein solution in the second step is 20-90 wt%.

4. The method for preparing the titanium dioxide / avian protein composite photocatalyst according to claim 1, characterized in that: In the third step, the titanium dioxide particle size is 10nm-5μm, the titanium dioxide concentration is 0.1-1000mg / L, the ultrasonic treatment power is 80-2400W, the ultrasonic treatment time is 0.1-5h, and the ultrasonic treatment temperature is 4-50°C.

5. The method for preparing the titanium dioxide / avian protein composite photocatalyst according to claim 1, characterized in that: The fourth step heat treatment temperature is 80-100° C., and the heat treatment time is 0.1-6 hours.

6. The method for preparing the titanium dioxide / avian protein composite photocatalyst according to claim 1, characterized in that: The fifth step of freeze drying has a temperature of -20 to -80°C and a freeze drying time of 12 to 48 hours.

7. The method for preparing the titanium dioxide / avian protein composite photocatalyst according to claim 1, characterized in that: The poultry protein can be replaced by other similar animal proteins or plant proteins. The other similar animal proteins are one of whey protein, lactoferrin, fish protein or a mixture of the two; the plant protein is one of soy protein isolate, rice protein, cottonseed protein or a mixture of the two.

8. Use of a titanium dioxide / avian protein composite photocatalyst prepared by any preparation method according to any one of claims 1 to 7 in the degradation of dyes or heavy metal ions.

9. The use according to claim 8, characterized in that: The dye is one or more of methylene blue, rhodamine B and methyl orange.

10. The use according to claim 8, characterized in that: The heavy metal ion is Cr 6+ , Pb 2+ , Hg 2+ One or more of the .

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