CN113979526A

CN113979526A - Preparation method and application of recyclable material loaded with nano metal

Info

Publication number: CN113979526A
Application number: CN202111112630.4A
Authority: CN
Inventors: 邱峻; 贺盟
Original assignee: Yancheng Institute of Technology
Current assignee: Yancheng Institute of Technology
Priority date: 2021-09-09
Filing date: 2021-09-09
Publication date: 2022-01-28

Abstract

The invention relates to a preparation method and application of a recyclable material loaded with nano metal. The metal nano particles have small volume, large specific surface area and unique physical and chemical properties, and have great application value in the fields of catalysis, antibiosis and the like. But it is extremely easy to agglomerate during use and is easy to leak into the environment to cause pollution. The invention takes sponge as a carrier, modifies a polydopamine coating on the surface of the sponge, adsorbs metal ions by utilizing polydopamine and reduces the metal ions into a nano metal simple substance in situ, so that the nano metal is firmly and uniformly adhered to the sponge in a dispersed manner. The material can be used for catalytic reduction of organic matters such as p-nitrophenol (amine) in industrial wastewater and as an antibacterial material. The invention has the advantages of simple preparation process, low cost, no need of adding a reducing agent to cause secondary pollution, good effect after repeated recycling, and effective solution of the problems of easy agglomeration and easy leakage of nano metal particles.

Description

Preparation method and application of recyclable material loaded with nano metal

Technical Field

The invention relates to the field of catalytic reduction technology and antibacterial materials of nitro-containing aromatic organic matters, in particular to a preparation method and application of a recyclable material loaded with nano-metal.

Background

The metal nanoparticles have small volume, large specific surface area and unique physical and chemical properties, have great application value in the fields of catalysis, antibiosis and the like, are used for efficiently catalyzing various homogeneous and multiphase chemical reactions at present, and are also taken as ideal candidates of novel antibacterial medical materials. However, since metal nanoparticles have high specific surface area and surface energy, they are highly susceptible to agglomeration during use, which greatly limits the applications of metal nanoparticles. In addition, metal nanoparticles are prone to leakage into the environment during use, causing contamination. For this reason, metal nanoparticles are generally surface-modified and loaded into various carriers to prevent their agglomeration and to limit their leakage. However, this method will reduce the surface activity and catalytic performance of the metal nanoparticles, or the preparation process is complicated and costly, which is not conducive to the industrial application. Most of the existing reports require complex modification of a substrate material, and then further adding a reducing agent and a surface modifier to prepare the metal nanoparticles.

Patent CN103460243A discloses a preparation method of a temperature-sensitive microgel asymmetric supported nano-silver catalyst. In the process of catalytic reduction of p-nitrophenol, the catalytic reaction efficiency is simultaneously regulated and controlled by the temperature and the temperature sensitivity of the microgel, and the good catalytic activity is shown. However, the raw material N-isopropylacrylamide used in the method is expensive, so that the industrial application of the method is limited.

Patent CN108404992A discloses a preparation method and application of a PVA sponge loaded nano-silver material.

Firstly, self-made PVA sponge is soaked in dopamine solution, and then is further soaked in silver nitrate solution after being taken out; and finally, soaking the PVA sponge in a sodium borohydride solution, cleaning and drying to obtain the PVA sponge-loaded nano silver material. The sponge used in the method is self-made, the process is complex, the industrialization is not facilitated, and the prepared PVA sponge is very hard in a dry state and is inconvenient to use. Meanwhile, in the method, a reducing agent sodium borohydride is also needed to be added in the process of reducing silver ions into nano silver. The whole process is complicated.

Patent CN112375250A discloses a nano-silver modified chitosan-polyvinyl alcohol antibacterial composite sponge and a preparation method thereof. The antibacterial composition is composed of chitosan, polyvinyl alcohol, silver nitrate, glutaraldehyde, glycerol, tannic acid, curcumin, ferric chloride, dimethyl sulfoxide and bovine serum albumin, and the preparation process is complex.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method and application of a recyclable material loaded with nano metal, so as to overcome the defects in the prior art.

The scheme for solving the technical problems is as follows: a preparation method and application of a recyclable material loaded with nano-metal specifically comprise the following steps: washing commercially available sponge with ethanol and deionized water; preparing a Tris buffer solution, adjusting the pH value to 7.5-9.5, and adding a proper amount of dopamine hydrochloride to ensure that the concentration of the dopamine solution is 2-10 g/L; placing the sponge into a dopamine solution and oscillating for 12-36 hours in an oscillator; and continuously putting the sponge loaded with the polydopamine into a solution with the concentration of 0.05-0.5mol/L metal ions, oscillating for 1-8 hours in an oscillator, cleaning and drying to obtain the material loaded with the nano metal. The material can be used for catalytic reduction of organic matters such as p-nitrophenol in industrial wastewater and as an antibacterial material, does not cause secondary pollution, and can still keep good effect after being recycled for many times.

Preferably, the sponge is polyurethane sponge, melamine sponge, cellulose sponge, and the pore size is 200-1000 nm.

Preferably, the solution containing metal ions comprises silver nitrate solution, silver ammonia solution, chloroauric acid solution, cuprous chloride ammonia solution.

The invention has the advantages that: the preparation process is simple and easy to implement, the cost is low, the agglomeration of metal nano particles is overcome, a reducing agent is not required to be added, and the preparation method can be recycled. The carrier for loading the nano metal particles is selected from commercially available sponge, is cheap, easy to use and easy to obtain, and can be cut into any required shape and size. Dopamine is polymerized into polydopamine on the surface and inside of the sponge, polydopamine particles can be tightly adhered to the surface and inside network of the sponge, and the structure of the polydopamine particles contains a large number of phenolic hydroxyl groups, amino groups, imino groups and other active groups, so that the polydopamine particles can be coordinated with metal ions and can be reduced into metal nanoparticles without adding a reducing agent. In particular, in the preparation of nano-copper, Cu is used in the literature²⁺Through reduction by a reducing agent, the cuprous ammonia chloride solution used in the invention only needs to reduce polydopamine, and does not need the polydopamineIt is a reducing agent. The attachment amount of the metal nanoparticles on the surface of the polydopamine can be controlled by adjusting the concentration and the reaction time of the metal ion solution. Meanwhile, both the poly dopamine is attached to the sponge and the nano metal particles are reduced in situ on the poly dopamine coating through chemical bonds, and the poly dopamine coating is not simple in physical adsorption, so that the poly dopamine coating is firmer. After 100 times of water absorption and extrusion, the same catalytic reduction effect and antibacterial performance can be still maintained. The invention not only solves the problem that the metal nano particles are easy to agglomerate, but also can prevent the metal nano particles from leaking to cause secondary pollution, and can be conveniently recycled.

The recyclable material loaded with the nano metal has excellent catalytic performance and antibacterial performance in the process of reducing p-nitrophenol and p-nitroaniline by using sodium borohydride.

Drawings

FIG. 1 is a scanning electron microscope picture of a PU sponge loaded with nano-silver prepared in example 1 of the present invention

FIG. 2 is a scanning electron microscope picture of the PU sponge loaded with nano-copper prepared in example 4 of the present invention

FIG. 3 is a UV-VIS spectrum of catalytic reduction of p-nitrophenol with a nano-silver loaded PU sponge prepared in example 1 of the present invention

Fig. 4 is a test chart of the bacteriostatic circle of the PU sponge loaded with nano silver prepared in example 1 and the PU sponge loaded with nano copper prepared in example 4.

Detailed Description

Example 1

100mL of Tris-HCl buffer solution having a pH of 8.5 was prepared, and 200mg of Dopamine (DA) hydrochloride was added. And (3) soaking the cleaned and dried Polyurethane (PU) sponge with the volume of 2 x 2cm into the dopamine solution, and placing the solution in a vibrator to vibrate and react for 24 hours to obtain the sponge covered with the Polydopamine (PDA) nano coating. The sponge is cleaned and dried, and then is immersed into 30mL of silver nitrate solution with the concentration of 0.25mol/L for reaction for 1h, and then is taken out, cleaned and dried to obtain the material which firmly adsorbs a large amount of silver nano particles.

Example 2

100mL of Tris-HCl buffer solution having a pH of 8.0 was prepared, and 200mg of Dopamine (DA) hydrochloride was added. Soaking cleaned and dried melamine sponge with 2 x 2cm into the dopamine solution, and placing the melamine sponge in a shaker for shaking reaction for 36 hours to obtain the sponge covered with the Polydopamine (PDA) nano coating. The sponge is cleaned and dried, and then is immersed into 30mL of silver nitrate solution with the concentration of 0.5mol/L for reaction for 1h, and then is taken out, cleaned and dried to obtain the material which firmly adsorbs a large amount of silver nano particles.

Example 3

100mL of Tris-HCl buffer solution having a pH of 8.0 was prepared, and 400mg of Dopamine (DA) hydrochloride was added. Soaking the cleaned and dried 2 x 2cm cellulose sponge into the dopamine solution, and placing the solution in a vibrator to vibrate and react for 30 hours to obtain the sponge covered with the Polydopamine (PDA) nano coating. The sponge is cleaned and dried, and then is immersed into 30mL of silver ammonia solution with the concentration of 0.25mol/L for reaction for 2h, and then the material is taken out, cleaned and dried to obtain the material which firmly adsorbs the silver nano particles.

Example 4

100mL of Tris-HCl buffer solution having a pH of 8.8 was prepared, and 300mg of Dopamine (DA) hydrochloride was added. And (3) soaking the cleaned and dried Polyurethane (PU) sponge with the volume of 2 x 2cm into the dopamine solution, and placing the solution in a vibrator to vibrate and react for 20 hours to obtain the sponge covered with the Polydopamine (PDA) nano coating. The sponge is cleaned and dried, and then is immersed into 30mL cuprous chloride ammonia solution with the concentration of 0.15mol/L for reaction for 8h, and then the material is taken out, cleaned and dried to obtain the material which firmly adsorbs the copper nano particles.

Example 5

100mL of Tris-HCl buffer solution having a pH of 8.5 was prepared, and 500mg of Dopamine (DA) hydrochloride was added. Soaking cleaned and dried Polyurethane (PU) sponge with 2 x 2cm into the dopamine solution, and placing the solution in a vibrator to vibrate and react for 28 hours to obtain the sponge covered with the Polydopamine (PDA) nano coating. The sponge is cleaned and dried, and then is immersed into 30mL cuprous chloride ammonia solution with the concentration of 0.35mol/L for reaction for 8h, and then the material is taken out, cleaned and dried to obtain the material which firmly adsorbs the copper nano particles.

Commercially available sponges are usually cutThe test pieces are cut into 2 x 2cm, and after the test is finished, the test pieces are cut into a plurality of small pieces of 3 x 3mm or 3 x 5mm, and 1-4 pieces are taken for use when the performance test is carried out. Fig. 1 and fig. 2 are scanning electron microscope images of the PU sponges loaded with nano silver and nano copper in examples 1 and 4, respectively, and it can be seen from the images that nano silver and nano copper particles are uniformly distributed on the surfaces of the sponges. Sodium borohydride can reduce p-nitrophenol (4-NP) to p-aminophenol (4-AP), and FIG. 3 is a UV-vis spectrum reflecting the catalytic effect of the reaction by the nanosilver-loaded polyurethane sponge of example 1. From the time-dependent data of the absorbance at 400nm in FIG. 3 and the Langmuir-Hinshelwood equation, the apparent reaction rate constant k can be calculated_appHas a value of 0.216min^-1While the rate constant of the silver nano-particle catalyzed p-nitrophenol is 0.0456min^-1This shows that the nano silver particles uniformly loaded on the sponge have much better catalytic performance than the silver nano particles which are easy to agglomerate without the carrier. Fig. 4 is a test chart of the inhibition zone of the sponge loaded with nano silver and nano copper in example 1 and example 4 on escherichia coli. The upper part of the culture dish is provided with the sponge loaded with the nano silver, the lower part of the culture dish is provided with the sponge which is used as a reference and is only attached with the polydopamine and has no nano metal particles, the two sponges in the middle are loaded with the nano copper, the left side of the culture dish has lower nano copper content, and the right side of the culture dish has higher nano copper content.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Claims

1. A preparation method of a recyclable material loaded with nano-metal is characterized by comprising the following steps:

(1) selecting commercially available sponge, and cleaning and drying with ethanol and deionized water;

(2) placing the sponge into a Tris solution of dopamine hydrochloride to vibrate in a vibrator;

(3) and (3) placing the sponge loaded with the polydopamine into a solution containing metal ions, shaking in a shaker, cleaning and drying.

2. The method for preparing the nano-metal supported recyclable material as described in claim 1, wherein the sponge in (1) is commercially available sponge of various types including polyurethane sponge, melamine sponge, cellulose sponge, and the like.

3. The method for preparing the nano-metal supported recyclable material according to claim 1, wherein the dopamine solution in the step (2) has a pH value of 7.5-9.5.

4. The method for preparing the nano-metal-loaded recyclable material according to claim 1, wherein the concentration of the dopamine solution in the step (2) is 2g/L-10 g/L.

5. The method for preparing the nano metal-loaded recyclable material as described in claim 1, wherein the reaction time of the sponge in the dopamine solution in the step (2) is 12-36 h.

6. The method for preparing the nano-metal supported recyclable material as described in claim 1, wherein the solution containing metal ions in (3) comprises silver nitrate solution, silver ammonia solution, chloroauric acid solution, cuprous chloride ammonia solution.

7. The method for preparing the nanometal-loaded recyclable material according to claim 1, wherein the concentration of the solution containing the metal ions in the step (3) is 0.05 to 0.5 mol/L.

8. The method for preparing the nano-metal supported recyclable material according to claim 1, wherein the reaction time in the solution containing the metal ions in (3) is 1 to 8 hours.

9. The supported nano metal recyclable material prepared by the preparation method of any one of claims 1 to 8 is applied to catalytic reduction of p-nitrophenol and p-nitroaniline.

10. The nano metal-loaded recyclable material prepared by the preparation method according to any one of claims 1-8 is applied to materials for resisting coliform bacteria, staphylococcus aureus and the like.