CN114644474A

CN114644474A - Method for recycling waste masks

Info

Publication number: CN114644474A
Application number: CN202111553259.5A
Authority: CN
Inventors: 陈新杰; 谢嘉璇; 张海生; 郑波; 储洪强; 杨晓星; 毛东建
Original assignee: Jiangsu Fangce Construction Engineering Technology Co ltd; Hohai University HHU
Current assignee: Jiangsu Fangce Construction Engineering Technology Co ltd; Hohai University HHU
Priority date: 2021-12-17
Filing date: 2021-12-17
Publication date: 2022-06-21
Anticipated expiration: 2041-12-17
Also published as: CN114644474B

Abstract

The invention discloses a method for recycling and treating waste masks, which comprises the steps of respectively placing waste medical masks in a roughening solution, a sensitizing solution and a palladium chloride solution for ultrasonic treatment; then, the treated waste medical mask is placed in a metal plating solution for soaking, and then the waste medical mask with the surface containing a metal coating is obtained through vacuum drying treatment; and finally, cutting the waste medical mask with the plated layer on the surface into mask fibers, and mixing and stirring the mask fibers, the cement, the river sand and the water to obtain the mask fiber mortar. The method can effectively kill bacteria remained on the waste mask, improve the adhesive property of the mask and a mortar matrix, improve the fracture resistance and the crack resistance of the mortar, improve the antimicrobial corrosion resistance of the mortar, and realize the reutilization of waste resources by using waste materials.

Description

Method for recycling waste masks

Technical Field

The invention belongs to the field of fiber material recycling, and particularly relates to a method for recycling a waste mask and improving the performance of mortar.

Background

The main component of Disposable Medical Masks (DMMs) is polypropylene PP which is a high molecular material, and the disposable medical masks with a large amount of waste can be produced due to the increasing dependence on medical masks. However, the disposable medical mask belongs to dry garbage, and is generally disposed by landfill and incineration, and there is almost no suitable method for recycling the dry garbage, which causes great pressure on the environment, so that a method for efficiently recycling the discarded disposable mask needs to be developed.

Mortar is one of the most widely used building materials and is mainly used in the internal and external plastering construction of building walls, however, the common mortar has the defects of low tensile strength, small elongation and the like, which causes the quality problems of projects, such as cracking, hollowing, dropping and the like, and can seriously cause the phenomena of water leakage, water seepage and the like, which has become a common problem in the building projects. The polypropylene fiber can effectively prevent the surface of the mortar from losing water and shrinking in volume, and inhibit the appearance of surface cracks, however, no research is available for preparing the fiber from waste polypropylene products for preparing the mortar to improve the crack resistance of the mortar.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a method for improving the crack resistance of mortar by using a waste disposable medical mask.

The technical scheme is as follows: the invention discloses a method for recycling a waste mask, which comprises the following steps:

(1) respectively placing the waste medical mask in a roughening solution, a sensitizing solution and a palladium chloride solution for ultrasonic treatment;

(2) soaking the treated waste medical mask in a metal plating solution, and then carrying out vacuum drying treatment to obtain the waste medical mask with a metal coating on the surface;

(3) cutting the waste medical mask with the plating layer on the surface into mask fibers, and mixing and stirring the mask fibers, the cement, the river sand and the water to obtain the mask fiber mortar.

Further, in the step (2), the metal plating solution is a nickel-containing solution or a copper-containing solution; the nickel-containing solution comprises 11-15 parts of nickel sulfate, 25-40 parts of sodium citrate, 3-5 parts of sodium hydroxide, 0.3-1 part of thiourea, 15-25 parts of sodium hypophosphite and 7-15 parts of cobalt sulfate; the copper-containing solution comprises 5-10 parts of copper sulfate, 20-30 parts of trisodium citrate, 20-30 parts of sodium hypophosphite, 30-40 parts of boric acid, 1 part of nickel sulfate, 0.4 part of thiourea and 10 parts of sodium hydroxide.

Further, in the step (3), the volume mixing amount of the mask fiber is 0.5-1.5%.

Further, in the step (3), the mortar-to-mortar ratio of the mask fiber mortar is 1: 2-3; the water-cement ratio is 0.5-1: 1.

further, in the step (1), the coarsening liquid is formed by mixing 90-110 parts of concentrated sulfuric acid, 100-130 parts of ammonium persulfate and 900-1000 parts of water. The preferable roughening liquid comprises 100 parts of concentrated sulfuric acid and 100 parts of ammonium persulfate.

Further, in the step (1), the sensitizing solution is prepared by mixing 20-30 parts of stannous chloride, 10-20 parts of hydrochloric acid and 950-1000 parts of water.

Further, in the step (1), the palladium chloride solution is formed by mixing 0.3-0.5 part of palladium chloride and 100 parts of water, and the pH value of the palladium chloride solution is 2-4.

Further, in the step (1), the ultrasonic treatment time is 5-10 min, the ultrasonic treatment temperature is 20-40 ℃, and the ultrasonic power is 180-240W.

Further, in the step (3), the length of the mask fiber is 15-35 mm, and the width of the mask fiber is 2-3 mm.

The recovery treatment process comprises the steps of firstly carrying out metallization treatment on the surface of the waste medical mask and then adding the metallized surface into concrete for performance improvement; because the waste medical mask carries bacteria after being used, the metallization treatment on the surface can sterilize the waste mask on one hand; on the other hand, after nickel plating and copper plating treatment, the hydrophilic performance of the surface of the mask can be improved, the hydrophilic surface is favorable for improving the cohesiveness and compatibility with a mortar matrix, and the mechanical property of the mortar is integrally improved; in addition, due to the existence of the metal coating, after the mask fiber is added into the mortar matrix, the mortar is endowed with certain antibacterial and bactericidal capacity, and the antimicrobial corrosion performance of the mortar is improved.

Has the beneficial effects that: compared with the prior art, the invention has the following remarkable advantages: (1) the invention can effectively kill the residual bacteria on the waste mask and reduce the risk of disease transmission of the waste mask; (2) compared with the existing method, the waste mask treatment method provided by the invention can effectively recycle the waste mask and reduce the environmental pollution; (3) the method for adding the simply treated mask fibers into the mortar can improve the bonding property of the mask and a mortar matrix and improve the fracture resistance and crack resistance of the mortar; (4) the waste material is used, so that the cost for improving the crack resistance of the mortar can be obviously reduced, the waste resource can be recycled, and the resource is saved; (5) the mask fiber mortar provided by the invention can improve the antimicrobial corrosion resistance of the mortar.

Drawings

FIG. 1 is a microstructure of the mask after nickel plating treatment in example 1;

FIG. 2 is an EDS test of a nickel-plated mask;

FIG. 3 is a schematic view of the mask fibers doped with mortar;

FIG. 4 is a microstructure of the mask after copper plating treatment according to example 2;

FIG. 5 is an EDS test of a copper-plated mask;

FIG. 6 shows the effect of pretreatment of the fibers of the mask on the mechanical properties of the mortar;

FIG. 7 shows the effect of the doping amount of the fibers in the mask on the mechanical properties of the mortar;

FIG. 8 is the effect of the length of the fibers of the mask on the mechanical properties of the mortar;

FIG. 9 is a pH change curve of a bacterial solution of sulfate oxidizing bacteria.

Detailed Description

The technical solution of the present invention is further described in detail with reference to the accompanying drawings and examples.

The experimental methods described in this example are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

The nose bridge of the discarded mask and the peripheral bonding part were removed, and the remaining part was cut into mask fibers having a length of 15mm and a width of 2 mm. Then sequentially putting the mask fiber into a coarsening solution, a sensitizing solution and a palladium chloride solution with the pH value of 2 to perform ultrasonic treatment for 10min respectively, wherein the ultrasonic power is 240W and the ultrasonic temperature is 30 ℃. The coarsening liquid comprises 90 parts of concentrated sulfuric acid, 100 parts of ammonium persulfate and 1000 parts of water; the components of the sensitizing solution are 20 parts of stannous chloride, 15 parts of hydrochloric acid and 980 parts of water; the palladium chloride solution was 0.3 part of palladium chloride and 100 parts of water.

And (3) treating the treated mask fiber in a plating solution, placing the plating solution in a constant-temperature water bath at the temperature of 60 ℃ for 10min, taking out the mask, and placing the mask in a vacuum drying oven at the temperature of 50 ℃ for drying for 1 h. The components of the plating solution are 15 parts of nickel sulfate, 40 parts of sodium citrate, 5 parts of sodium hydroxide, 1 part of thiourea, 25 parts of sodium hypophosphite and 1000 parts of water.

Pouring the weighed cement into a mortar stirrer, wherein the cement is P.O 42.5 grade cement, adjusting the stirrer to a slow gear, slowly pouring mask fiber with the volume addition of 0.5%, referring to a figure 3, pouring river sand after stirring for 60s, stirring for 30s, pouring water, stirring for 90s after 30s, and changing to a fast gear. The glue-sand ratio of the raw materials of the mask fiber mortar is 1: 2.5, the water-cement ratio is 0.5. Finally, mask fiber mortar Y1 is obtained.

Referring to fig. 1, the microscopic morphology of the mask after nickel plating treatment, the surface morphology of the nickel-plated mask is respectively magnified 5000 times, 20000 times and 100000 times in the diagrams (a), (b) and (d) is the cross-sectional morphology magnified 5000 times; as can be seen, after the nickel plating pretreatment, a layer of metal nickel plating layer is obviously formed on the surface of the mask.

Fig. 2 shows the EDS test of the nickel-plated mask, indicating that the mask surface has a high content of nickel elements and no other impurities, indicating that the nickel-plating pretreatment attached nickel to the mask surface.

Example 2

The nose bridge of the discarded mask and the peripheral bonding part were removed, and the remaining part was cut into mask fibers having a length of 15mm and a width of 2 mm. Then sequentially putting the mask fiber into the coarsening solution, the sensitizing solution and the palladium chloride solution with the pH value of 2 for ultrasonic treatment for 5min respectively, wherein the ultrasonic power is 200W, and the ultrasonic temperature is 30 ℃. The coarsening liquid comprises 90 parts of concentrated sulfuric acid, 100 parts of ammonium persulfate and 1000 parts of water; the components of the sensitizing solution are 20 parts of stannous chloride, 15 parts of hydrochloric acid and 980 parts of water; the palladium chloride solution was 0.5 part of palladium chloride and 100 parts of water.

And (3) treating the treated mask fiber in a plating solution, placing the plating solution in a constant-temperature water bath at the temperature of 60 ℃ for 10min, taking out the mask, and placing the mask in a vacuum drying oven at the temperature of 50 ℃ for drying for 1 h. The components of the plating solution are 15 parts of copper sulfate, 40 parts of sodium citrate, 5 parts of sodium hydroxide, 1 part of thiourea, 25 parts of sodium hypophosphite, 1 part of nickel sulfate, 20 parts of boric acid and 1000 parts of water.

Pouring the weighed cement into a mortar stirrer, wherein the cement is P.O 42.5 grade cement, adjusting the stirrer to a slow speed, slowly pouring mask fiber with the volume doping amount of 0.5%, stirring for 60s, pouring river sand, stirring for 30s, pouring water, stirring for 30s, and changing to a high speed to stir for 90 s. The glue-sand ratio of the raw materials of the mask fiber mortar is 1: 2.5, the water-cement ratio is 0.5. Finally, mask fiber mortar C3 is obtained.

Referring to fig. 4, the microscopic morphology of the mask after the copper plating treatment is shown, wherein the surface morphology of the copper-plated mask in (a), (b) and (c) is respectively 5000 times, 20000 times and 100000 times larger than that of the copper-plated mask, and the cross-sectional morphology of the copper-plated mask in (d) is 5000 times larger than that of the copper-plated mask; as can be seen from the figure, after the nickel plating pretreatment, a layer of metal copper plating layer is obviously formed on the surface of the mask.

Fig. 5 is an EDS test of a copper-plated mask showing that the mask surface has a high level of elemental copper and no other impurities, indicating that the copper plating pretreatment attached copper to the mask surface.

Example 3

This example is the same as the preparation method of example 1, except that: the pH of the palladium chloride solution was 4, and finally mask fiber mortar Y2 was obtained.

Example 4

This example is the same as example 1, except that: the plating solution is 11 parts of nickel sulfate, 25 parts of sodium citrate, 3 parts of sodium hydroxide, 0.3 part of thiourea, 15 parts of sodium hypophosphite and 1000 parts of water, and finally the mask fiber mortar Y3 is obtained.

Example 5

This example is the same as example 1, except that: the length of the mask fiber is 25mm, and finally mask fiber mortar Y4 is obtained.

Example 6

This example is the same as example 1, except that: the length of the mask fiber is 35mm, and finally mask fiber mortar Y5 is obtained.

Example 7

This example is the same as example 1, except that: the volume mixing amount of the mask fiber is 1.00 percent, and finally the mask fiber mortar Y6 is obtained.

Example 8

This example is the same as example 1, except that: the volume mixing amount of the mask fiber is 1.50 percent, and finally the mask fiber mortar Y7 is obtained.

Comparative example 1

This comparative example differs from example 1 in that: no inlet cover fiber was added to the mortar, and a blank control mortar C1 was finally obtained.

Comparative example 2

This comparative example differs from example 1 in that: the mask is not subjected to nickel plating treatment, and is directly cut and added into a mortar matrix to finally obtain mask fiber mortar C2.

Experimental example 1

And (3) testing the sterilization rate: irradiating an unused mask under an ultraviolet lamp for 3 hours, then putting the unused mask into 200ml of escherichia coli bacterial liquid with the concentration of about 5 multiplied by 10^5CFU/ml, oscillating the unused mask in a constant-temperature water bath oscillation box with the temperature of 36 ℃ and the speed of 150r/min for 6 hours, taking the mask out, carrying out nickel plating sterilization treatment, putting the mask into 200ml of LB broth culture medium after the treatment is finished, oscillating the mask in a constant-temperature water bath oscillation box with the temperature of 36 ℃ and the speed of 150r/min for 0.5 hour, diluting the culture medium solution, and testing the bacterial concentration by using a plate counting method. The sterilization rate calculation method comprises the following steps:

R＝(N₀-N_R)/N₀×100％

wherein R represents the bactericidal rate; n0 shows the bacterial concentration after the mask soaked in the escherichia coli liquid is directly placed into an LB broth culture medium and oscillated for 0.5h without nickel plating sterilization treatment; concentration of bacteria after NR nickel plating sterilization treatment.

TABLE 1 Sterilization test results

As shown in Table 1, it can be seen that the mask treated by the methods of examples 1-4 has a great reduction in the residual bacteria, wherein the treatment methods of examples 1 and 2 have the best sterilization effect, and the sterilization rate reaches more than 99.99%.

Experimental example 2

And (3) testing mechanical properties: the fracture resistance and the compressive strength are tested by referring to GB/T17671-1999 cement mortar strength test method.

FIG. 6 shows the results of mechanical property tests on mask fiber mortar of C1, C2, C3 and Y1, wherein (a) shows flexural strength and (b) shows compressive strength; it can be seen that Y1 and C3 both improve the mechanical property of the mortar, and Y1 has a better effect on improving the mechanical property of the mortar. The reason is that the raw material of the mask is polypropylene, the surface of the mask is hydrophobic, the mask is poorer in bonding performance with a mortar matrix after mortar is added, and the nickel plating and copper plating treatment improve the hydrophilic performance of the surface of the mask and improve the bonding performance of the mask and the mortar matrix. And (4) combining the test result of the sterilization test, preferably selecting the mask fiber pretreatment mode as nickel plating sterilization treatment.

FIG. 7 shows the results of mechanical property tests of C1, C2, Y1, Y6 and Y7, wherein (a) shows flexural strength and (b) shows compressive strength; it can be seen that the anti-breaking strength of the mortar can be improved by doping the mask fibers, the effect of improving the anti-breaking strength of the mortar by the mask fibers can be improved by nickel plating, the adverse effect on the compressive strength of the mortar is reduced, and the 28d anti-breaking strength of Y1 in example 1 is improved by 7.85% compared with that of C2 in proportion 2. With the increase of the doping amount of the mask fibers, the promotion effect shows the tendency of increasing first and then decreasing, when the doping amount is 1.00%, the promotion effect on the breaking strength of mortar is the best, and the 28d breaking strength of Y6 is improved by 16.04% compared with that of C1 in the comparative ratio 1.

FIG. 8 shows the results of mechanical property tests of C1, Y1, Y4 and Y5, wherein (a) is the flexural strength and (b) is the compressive strength; the length of the mask fiber is increased to generate adverse effect on the mechanical property of the mortar, the improvement effect on the mortar mechanics is best when the length of the mask fiber is 15mm, and the 28d flexural strength and the compressive strength of the mask fiber are improved by 10.75 percent and 0.18 percent compared with C1 of comparative example 1. Therefore, the mask fiber length is preferably 15 mm.

Experimental example 3

And (3) testing the crack resistance: and after forming, filling the mortar into a crack resistance test mould with the thickness of 300mm multiplied by 30mm, irradiating by a tungsten lamp, blowing by a fan with the wind speed of 4m/s-5m/s to accelerate the hydration process, and stopping irradiating after irradiating for 4 hours by the tungsten lamp. And recording the length and width of the crack on the surface of the test piece after 24h, and calculating the crack index and the crack resistance by referring to JCT 951-.

TABLE 2 mortar cracking results

	C1	C2	C3	Y1	Y6	Y7
							Total division of cracks	512	230	186	144	34	—
Total area of crack	266.32	104.7	88.68	64	14.62	—
							Index of cracking	195.5	87.5	73.5	52.5	8.5	—
Crack resistance	—	55.24％	62.40％	74.29％	95.65％	100％

The results of the early crack resistance test of the mortar are shown in table 2, compared with the C1 and C2 of the comparative examples, the early crack resistance of the mortar of example 1, Y1 and C3 of example 2 is improved, the effect of Y1 is better than that of C3, and the improvement effect is more obvious after the nickel plating sterilization treatment. Along with the increase of the doping amount of the mask fiber after nickel plating treatment, the anti-cracking performance is gradually improved, and the Y6 of example 7 is a test piece with the doping amount of 1.0 percent, and the anti-cracking performance is improved by 95.65 percent; y7 in example 8 is a test piece with a content of 1.5%, and no crack is generated on the surface after 24h of molding. In combination with the influence of the mask fibers on the mechanical property of the mortar, the preferred doping amount of the mask fibers is 1.00%.

Experimental example 4

Antibacterial property: the test pieces of C2, C3 and Y1 which are maintained for 28 days and have the size of 40X 40mm are respectively put into 150ml of sulfate oxidizing bacteria liquid with the pH value of about 1.5, and the pH values of the bacteria liquid are respectively tested for 6h, 12h and 24h in a room temperature environment.

A large amount of sulfate oxidizing bacteria exist at the top of the sewage pipeline, and can convert sulfides into sulfuric acid, and the sulfuric acid reacts with concrete to generate gypsum and ettringite, so that the concrete is cracked. The sulfate oxidizing bacteria liquid is acidic, after the sulfate oxidizing bacteria liquid is placed into a mortar test piece, alkaline substances in the mortar are continuously dissolved, the pH value of the bacteria liquid is increased, and when a bactericide is contained in the mortar, the sulfate oxidizing bacteria can be killed, the generation of sulfuric acid is reduced, and the pH value is increased more quickly. Fig. 9 is a pH change curve of the test pieces C2, C3, and Y1 after being put in the bacterial liquid of sulfate oxidizing bacteria, from which it can be seen that the pH of the bacterial liquid put in the test pieces C3 and Y1 rises faster, which indicates that the mask is sterilized by nickel plating and copper plating and then doped into mortar, and then the mortar is endowed with a certain sterilization capability.

Claims

1. A method for recycling and treating a waste mask is characterized by comprising the following steps:

2. The method for recycling and disposing a waste mask as claimed in claim 1, wherein: in the step (2), the metal plating solution is nickel-containing solution or copper-containing solution.

3. The method for recycling the waste masks according to claim 2, wherein: the nickel-containing solution comprises 11-15 parts of nickel sulfate, 25-40 parts of sodium citrate, 3-5 parts of sodium hydroxide, 0.3-1 part of thiourea, 15-25 parts of sodium hypophosphite and 7-15 parts of cobalt sulfate; the copper-containing solution comprises 5-10 parts of copper sulfate, 20-30 parts of trisodium citrate, 20-30 parts of sodium hypophosphite, 30-40 parts of boric acid, 1 part of nickel sulfate, 0.4 part of thiourea and 10 parts of sodium hydroxide.

4. The method for recycling the waste masks in the step (3), according to claim 1, wherein the volume content of the mask fibers is 0.5-1.5%.

5. The method for recycling the waste masks according to claim 1, wherein in the step (3), the mortar/mortar ratio of the mask fiber is 1: 2-3; the water-cement ratio is 0.5-1: 1.

6. the method according to claim 1, wherein the coarsening liquid in the step (1) is formed by mixing 90 to 110 parts of concentrated sulfuric acid, 100 to 130 parts of ammonium persulfate and 900 to 1000 parts of water.

7. The method for recycling the waste masks in the step (1), according to the claim 1, wherein the sensitizing solution is prepared by mixing 20-30 parts of stannous chloride, 10-20 parts of hydrochloric acid and 950-1000 parts of water.

8. The method for recycling and disposing a discarded mask as set forth in claim 1, wherein in the step (1), the palladium chloride solution is formed by mixing 0.3 to 0.5 part of palladium chloride and 100 parts of water, and has a pH of 2 to 4.

9. The method for recycling the waste masks according to claim 1, wherein in the step (1), the ultrasonic treatment time is 5-10 min, the ultrasonic treatment temperature is 20-40 ℃, and the ultrasonic power is 180-240W.

10. The method for recycling and disposing a waste mask as claimed in claim 1, wherein in the step (3), the length of the mask fiber is 15-35 mm, and the width is 2-3 mm.