CN107649077B

CN107649077B - Haze-preventing porous hydrogel and preparation method and application thereof

Info

Publication number: CN107649077B
Application number: CN201710981419.3A
Authority: CN
Inventors: 王梓宁; 黄雅钦
Original assignee: Beijing University of Chemical Technology
Current assignee: Beijing University of Chemical Technology
Priority date: 2017-10-20
Filing date: 2017-10-20
Publication date: 2020-09-04
Anticipated expiration: 2037-10-20
Also published as: CN107649077A

Abstract

The invention relates to an anti-haze porous hydrogel and a preparation method and application thereof, wherein gelatin and rare earth are used as raw materials, the anti-haze porous hydrogel has a dense porous structure and good antibacterial property, and the water content is more than 95%. The blocking capability of the porous hydrogel to PM2.5 is obviously higher than that of the currently marketed anti-haze mask, the porous hydrogel is degradable and environment-friendly, is expected to realize high-efficiency anti-haze effect, is applied to the anti-haze mask for human bodies and the treatment device of automobile exhaust, and provides a high-quality new product for the healthy life of people.

Description

Haze-preventing porous hydrogel and preparation method and application thereof

Technical Field

The invention belongs to the technical field of hydrogel, and particularly relates to an anti-haze porous hydrogel and a preparation method and application thereof.

Background

With the development of society, China and even the world are facing a challenge of another environmental problem. In recent years, the most serious and most concerned problem in China is the haze problem, which has seriously affected our lives and health. Scientifically proven that the 'fierce' causing the haze problem is PM2.5, which refers to particulate matter with equivalent diameter less than or equal to 2.5 microns. The particle size is small, the specific surface area is large, and toxic and harmful substances in the air are easy to enrich, so that the particles can be inhaled by a human body and deposited in the upper respiratory tract, even go deep into bronchioles and alveoli, and the ventilation function of the lung is influenced. In addition, PM2.5 is carcinogenic to humans, causing difficult-to-cure symptoms of cardiovascular disease, respiratory disease, and lung cancer, among others. The death risk of the human body is improved. How to control haze is a problem to be solved urgently.

Therefore, various methods have been developed to control haze. Although achieving a certain result, the problem is not a simple problem which can be solved in a short time, so that the haze damage to the body in daily life needs to be avoided to the maximum extent possible. The most direct, simple and feasible method is to avoid the haze from being inhaled into the human body, and the harm of the haze to the human body is avoided to the greatest extent. In order to achieve the purpose, air purifiers, haze suction machines, haze prevention masks and other products are researched and developed on the market. Among them, the most widely used mask is the haze prevention mask. However, the antifog haze gauze mask that the material of selling on the existing market was for melting the non-woven fabrics still has some problems. Through national detection, the general overall protection level is low, one hundred percent of filtration cannot be achieved, and the leakage rate reaches 37.5%. Even more, the material is lost by the steal work, and the qualification rate is only 24.3%. Obviously, the mask on the market cannot meet the basic requirements of daily life of people. Therefore, the search for a new material to replace the melt-blown non-woven fabric is urgent.

The gelatin is prepared from by-products generated in the processing of food such as ox bone and pig bone. It has excellent physical and chemical performance, biocompatibility and sol-gel reversibility. The hydrogel prepared by the method has hydrophilicity and strong water-locking capacity. The hydrogel has good surface activity, can be used for preparing porous hydrogel, and the porous structure of the hydrogel greatly increases the specific surface area in the gel, so that more hydrophilic groups can be rapidly contacted with water molecules. Considering the excellent deposition capacity of water for PM 2.5. Therefore, water is expected to have good barrier capability to PM 2.5. Since gelatin is a macromolecular protein and is a good culture medium for bacteria, it is necessary to increase the antibacterial ability of the porous hydrogel. Cerium, a rare earth, has been attracting attention in recent years because of its good bacteriostatic properties. However, gelatin and rare earth have not been reported as haze prevention in the prior art.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides the haze-preventing porous hydrogel and the preparation method and the application thereof, the porous hydrogel is designed by adopting gelatin and rare earth as raw materials, a small amount of rare earth cerium is added into a gelatin system, so that the antibacterial effect can be achieved, a certain crosslinking effect can be achieved on gelatin molecules, the stability of the hydrogel is improved, and the porous hydrogel is used for protecting PM2.5, so that the breathing is not influenced, and the blocking capability is better than that of a general non-woven fabric.

In order to achieve the purpose, the invention adopts the following technical scheme: the haze-preventing porous hydrogel takes gelatin and rare earth as raw materials, has a dense porous structure and good antibacterial property, and has a water content of more than 95%.

The invention also provides a preparation method of the novel anti-haze porous hydrogel, which comprises the following steps:

(1) weighing a certain amount of gelatin powder, dissolving in distilled water, swelling at room temperature for 0.5-2h, dissolving in 50-70 deg.C water bath to obtain gelatin water solution with a certain mass fraction, and adjusting pH to 7;

(2) fully stirring in a water bath at the temperature of 20-25 ℃ to foam the gelatin solution, adding a cross-linking agent for cross-linking for 0.5-1h, then adding a rare earth salt solution, stirring, and filling the cross-linked foam solution into a mold for later use.

In a preferred embodiment of the invention, the gelatin powder is derived from waste of nature and food processing, more preferably waste animal bone.

In a preferred embodiment of the invention, the mass fraction of gelatin produced in step (1) is 2-10%.

In a preferred embodiment of the invention, the crosslinker is EDC, added in an amount of 0.5 wt.%.

In a preferred embodiment of the present invention, the rare earth salt solution is preferably a soluble cerium salt solution, preferably a cerium nitrate solution, more preferably a 0.1% cerium nitrate solution.

The invention also protects the application of the haze-preventing porous hydrogel in the preparation of haze-preventing products.

Compared with the prior art, the invention has the following advantages:

(1) the raw materials are taken from nature and waste (animal bones) of food processing, are nontoxic, have high safety, are easily obtained, have low cost and can realize effective utilization of resources.

(2) The raw material of the gelatin is macromolecular protein, has good compatibility with water, and is beneficial to the formation of porous hydrogel. The gelatin has surface activity, a foaming agent is not required to be added, and the porous hydrogel can be prepared by stirring and foaming, so that the effective prevention and control of haze can be realized.

(3) The combination of gelatin and rare earth cerium enables the porous hydrogel to have a good inhibition effect on escherichia coli and have rich pore structures, and comparative research shows that the blocking capability of the porous hydrogel on PM2.5 is obviously higher than that of the currently-sold anti-haze mask, the porous hydrogel has an excellent antibacterial effect, the inhibition effect on escherichia coli is particularly strong, and the porous hydrogel is expected to be applied to the inner layer of the anti-haze mask. Because the mask has high purification capacity, convenient preparation, easily available and cheap raw materials and simple and quick process, the mask is expected to become a new generation of high-performance anti-haze mask.

(4) The porous hydrogel can be degraded, is environment-friendly, is expected to realize the efficient haze prevention effect, is applied to a haze prevention mask for a human body and a treatment device for automobile exhaust, and provides a high-quality new product for the healthy life of people.

Drawings

The following further description is made with reference to the accompanying drawings:

FIG. 1 is a photograph of a porous hydrogel prepared in example 1;

wherein the inset is a photograph of the dried hydrogel;

FIG. 2 is a scanning electron micrograph of a sample prepared in example 1;

FIG. 3 is a graph showing the relationship between the weight and the water content of the porous hydrogel prepared in example 1;

FIG. 4 is a graph showing the relationship between the weight and the water content of the porous hydrogel prepared in example 1;

FIG. 5 is the effect of the water content of the porous hydrogel prepared in example 1 on the ability to resist PM 2.5;

FIG. 6 is a photograph showing the results and process of the test for the inhibition of E.coli by the porous hydrogel prepared in example 1.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described with the following specific examples, but the present invention is by no means limited to these examples.

The experimental apparatus used in the present invention comprises: a stirrer (type EURO-ST 20D S025 cantilever stirrer, ericka (guangzhou) instruments and equipment ltd), a vacuum freeze dryer (LGJ-12 type freeze dryer, produced by beijing pine source huaxing scientific and technological development ltd) and an analytical balance (MS 104S type electronic analytical balance, produced by mterler-toledo international trade (shanghai) ltd), as well as a beaker, a measuring cylinder, a pipette, a glass rod ash key.

The raw materials and reagents used in the present invention are as follows: gelatin (type B bone, rochelo (guangdong) gelatin limited), carbodiimide (99%, shanghai-sourced leaf biotechnology limited), cerium nitrate hexahydrate (analytically pure, produced by shanghai ziming reagent factory), distilled water, and the like.

Example 1

(1) Weighing a certain amount of gelatin powder, dissolving in distilled water, swelling at room temperature for 30min, dissolving in water bath at 60 deg.C to obtain 100ml gelatin water solution (mass fraction of 4%), and adjusting pH to 7;

(2) fully stirring in a water bath at 25 ℃ to foam the gelatin solution, adding 0.5wt% of EDC for crosslinking for 30min, then adding 0.1% of cerium nitrate, stirring, and filling the crosslinked foam solution into a mold for later use.

Example 2

(1) Weighing a certain amount of gelatin powder, dissolving in distilled water, swelling at room temperature for 1h, placing in 70 ℃ water bath for dissolution assistance, preparing 100ml (10%) of gelatin aqueous solution with a certain mass fraction, and adjusting the pH to 7;

(2) fully stirring in a water bath at 20 ℃ to foam the gelatin solution, adding 0.5wt% of EDC for crosslinking for 1h, then adding 0.1% of cerium nitrate, stirring, and filling the crosslinked foam solution into a mold for later use.

Example 3

1. Morphology of porous hydrogels

The photograph of the porous hydrogel is shown in fig. 1, and the antibacterial porous hydrogel has a dense porous structure and a high water content. The porous structure can be maintained after drying. And further carrying out scanning electron microscope test on the prepared sample, observing the surface of the sample by using the scanning electron microscope, spraying gold coating on the quenched natural section in liquid nitrogen by using an ion sputtering instrument, and observing the pore structure of the sample by using the scanning electron microscope.

As a result, as shown in FIG. 2, the sample has a rich porous structure, and the pores are through holes and have good mutual connectivity.

2. Testing of Water content of cellular hydrogels

Weighing a sample with a mass W₁Then dried and weighed as W₂Then the water content of the sample is calculated by the formula 3-1,

X %=(W₁–W₂) /W₁×100 %（3-1），

the relationship between the water content and the water holding capacity of the sample is shown in FIGS. 3 and 4. As can be seen from FIG. 3, as the weight of the porous hydrogel increases, the water content increases, and the increase is significant. It is further shown from FIG. 4 that the water content of the porous hydrogel remains substantially constant as its weight increases. The water content can reach more than 95 percent, which shows that the hydrogel has high pores.

3. Haze prevention Performance test of porous hydrogel

The prepared antibacterial porous hydrogel is detected by a microcomputer laser dust meter and compared with masks on the market. The results are shown in table 1 and fig. 5.

As can be seen from FIG. 5, the total average haze concentration tends to decrease with the increase of the water content of the porous hydrogel, which indicates that the larger the water content of the porous hydrogel is, the better the performance of blocking PM2.5 is. In the range of the invention, the prepared sample has strong haze barrier capability which is far lower than the PM2.5 concentration of air. Haze air is prevented from entering the human body. Therefore, the common masks in the market are tested for the haze prevention capability by the same method, and are compared with indoor pollution concentration, dry gel and high-water-content water-containing porous gel. The results are shown in Table 1.

TABLE 1 comparison List of haze Barrier Performance for several products

From table 1, the haze prevention ability of the high water content porous hydrogel is obviously superior to that of a common mask. After water in the hydrogel is removed, the haze protection capability of the hydrogel is greatly reduced, and the increased advantages of the porous hydrogel are illustrated.

4. Testing of the bacteriostatic Properties of porous hydrogels

The prepared sample is tested for its inhibitory ability against escherichia coli according to the following steps;

(1) mixing agar and nutrient broth with water at a certain ratio, and boiling;

(2) sterilizing in autoclave for about 20 min;

(3) inoculating the nutrient broth (Escherichia coli), mixing with agar, and making into culture medium;

(4) cutting the gelatin film into a wafer with the diameter of about 1cm, and placing the wafer on a culture medium;

(5) the culture medium is put into a constant temperature incubator to be cultivated for 24 hours at constant temperature, and then the result is observed.

The result is shown in fig. 6, the antibacterial ring around the porous hydrogel sample is obvious, which shows that the porous hydrogel has good inhibitory effect on escherichia coli, can meet the antibacterial requirement of human body, and can be used by human body.

While the present invention has been described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. An anti-haze porous hydrogel is characterized in that gelatin and rare earth are used as raw materials, the hydrogel has a dense porous structure and good antibacterial property, and the water content is more than 95%; the preparation method comprises the following steps:

2. The hydrogel according to claim 1, wherein said gelatin powder is derived from nature and food processing waste.

3. The hydrogel according to claim 2, wherein said gelatin powder is derived from waste animal bone.

4. The hydrogel according to claim 1, wherein the mass fraction of gelatin prepared in step (1) is 2-10%.

5. The hydrogel of claim 1, wherein the crosslinking agent is EDC and is added in an amount of 0.5 wt%.

6. The hydrogel of claim 1, wherein the rare earth salt solution is a soluble cerium salt solution.

7. The hydrogel of claim 6, wherein the rare earth salt solution is a cerium nitrate solution.

8. Use of the anti-haze porous hydrogel according to any one of claims 1 to 7 for preparing an anti-haze product.