CN111668500A

CN111668500A - Method for enhancing biocompatibility by coating carbon on surface of stainless steel wire

Info

Publication number: CN111668500A
Application number: CN202010383116.3A
Authority: CN
Inventors: 程浩毅; 王爱杰; 许德春; 王鸿程; 翟思媛; 刘成岩; 张博
Original assignee: Research Center for Eco Environmental Sciences of CAS
Current assignee: Research Center for Eco Environmental Sciences of CAS
Priority date: 2020-05-08
Filing date: 2020-05-08
Publication date: 2020-09-15
Anticipated expiration: 2040-05-08
Also published as: CN111668500B

Abstract

The invention discloses a method for enhancing biocompatibility by coating carbon on the surface of a stainless steel wire. The carbon coating method has simple process, low cost and high preparation efficiency, and the product prepared by the carbon coating method has excellent biocompatibility and electrogenesis performance, is expected to realize the large-scale production and application of the carbon coating method and promote the conversion of the bioelectrochemistry technology to the waste (sewage) water treatment and application of actual engineering scale.

Description

Method for enhancing biocompatibility by coating carbon on surface of stainless steel wire

Technical Field

The invention belongs to the field of sewage (waste water) purification treatment of a bioelectrochemical system, and particularly relates to a method for enhancing biocompatibility by coating carbon on the surface of a stainless steel wire mesh electrode applied to the bioelectrochemical system.

Background

With the rapid development of economy and society in China, the problem of environmental water pollution is increasingly severe. The biological electrochemical system is a sewage treatment technology with low energy consumption and environmental protection. The bioelectrochemical system can separately carry out the oxidation-reduction reaction of pollutants in the sewage, and in the anode chamber, the electrogenesis microorganisms attached to the anode electrode are utilized to catalyze the oxidation reaction of organic pollutants in the wastewater to convert the pollutants into CO₂At the same time, the process generates electrons, and the electrogenic microorganisms transfer the electrons to the anode; the electrons obtained from the anode are transferred to the cathode of the cathode chamber through an external circuit lead, and the electrons on the cathode are transferred to oxygen and H in the sewage by the electrogenic microorganisms⁺And the electron acceptor is subjected to reduction reaction. In the oxidation-reduction reaction of the whole pollutant, the directional transfer of electrons between the cathode and the anode forms current to generate electric energy. The more the pollutant is degraded and the degradation rate is faster, the more the generated electrons are generated and the faster the electrons are transferred, the larger the obtained current density and power density is, namely the bioelectrochemical electricity generation capacity is in positive correlation with the pollutant degradation efficiency, the better the electricity generation performance is, and the better the degradation efficiency of the pollutant in the sewage is. The bioelectrochemical system can effectively treat sewage and can generate bioelectricity at the same time, and is one of the research hotspots of the current water treatment technology. However, the application of the current bioelectrochemical system is still at the laboratory level, and the technical problems of insufficient electricity generation capacity, high amplification application cost and the like restrict organismsThe popularization of the electrochemical technology to the practical engineering application level. The electrode is a core component of a bioelectrochemical system, is a carrier attached to the growth of the electrogenic microorganisms and is an electron acceptor (donor) interface carrier in the system, and the selection of the electrode material can influence the electrogenic performance and the construction cost of the bioelectrochemical system to a great extent. Therefore, the development of low-cost and high-yield electrode materials is crucial to promote the practical engineering-scale application of bioelectrochemical technology.

Carbon-based materials and metal-based materials are currently commonly used as the electrodes of the bioelectrochemical system. Although the carbon-based material has stable chemical property and better biocompatibility, the carbon-based material is favorable for the attachment growth of electrogenic microorganisms and has good electrogenesis property. However, carbon-based materials have the main problems of poor conductivity, large ohmic loss during scale-up application, and poor mechanical properties, and require additional support materials to maintain the electrode configuration during scale-up application, resulting in high construction cost. Therefore, the carbon-based material is mostly used for laboratory small-scale experimental research and is difficult to be used in a bioelectrochemical system with actual engineering scale-up. The metal material is more conductive and excellent in mechanical properties than the carbon-based material, but many metals are excluded because the anode material for the bio-electrochemical system is required to have good corrosion resistance. Researches find that the stainless steel material is very suitable for being used as an electrode of an actual amplification scale bioelectrochemical system, has the advantages of low cost, strong corrosion resistance, high mechanical strength and the like, and is easy to produce and manufacture an application type electrode of an amplification scale engineering. However, compared with carbon-based materials, the surface of the stainless steel material is smooth, so that the adhesion and colonization of electrogenic microorganisms are not facilitated, the electron transfer between the electrode and the electrogenic active microorganisms is hindered, higher current and power density cannot be realized, and the electrogenic performance of a bioelectrochemical system is influenced. By utilizing the advantage of high biocompatibility of the carbon-based material, the stainless steel is subjected to carbon coating modification, so that the biocompatibility of the stainless steel material can be effectively enhanced, and the attachment amount of the electrogenic microorganisms is increased, thereby improving the electrogenesis performance of the stainless steel electrode, and enabling the stainless steel electrode to be more suitable for being applied to a bioelectrochemical system of an actual engineering scale in an amplification manner.

The current stainless steel electrode carbon-coating modification method and the technical defects comprise: (1) patent application CN104900889B describes a method for modifying a stainless steel electrode by polypyrrole-carbon nanotubes, wherein pyrrole monomers are added into a carbon nanotube mixed solution under the anaerobic protection and uniformly mixed, pyrrole is polymerized on stainless steel by electrochemical constant potential electroplating, and carbon nanotubes are fixed on the surface of the stainless steel to prepare the carbon-coated modified stainless steel electrode. The method has high electroplating energy consumption and a complex process, and the size of electroplating equipment cannot meet the requirement when the method is applied in an enlarged mode. (2) A modification process for the pyrolytic carbonization of glucose is described (Guo K, Hidalgo D, Tommasi T, et al, pyrolytic carbon-coated sheet steel felt as a high-performance and for bioelectrical systems [ J ]. Bioresource technology,2016, 211:664-668.https:// doi. org/10.1016/J. biortech.2016.03.161) by first soaking stainless steel in a glucose solution of stainless steel for 24 h. After being taken out, the graphite thin carbon layer can be deposited on the surface of the stainless steel net by caramelization for 24h under the vacuum condition of 185 ℃, and then pyrolysis for 2h under the condition of nitrogen flow at 800 ℃. The method has high energy consumption of high-temperature pyrolysis, and the modification equipment is a tubular furnace with limited size and is difficult to be popularized to the modification application of the electrode with enlarged size. (3) An binderless carbon black impregnation process is described (Zheng S, Yang F, Chen S, et al, binder-free carbon black/stainless step composite electrode for high-performance and in microbial fuel cells [ J ]. Journal of Power Sources,2015,284: 252-257.https:// doi.org/10.1016/j.jp rows.2015.03.014) by first acidifying a stainless steel, then immersing a dispersion of carbon black in ethanol followed by drying, and three cycles of immersion-drying to obtain a carbon black modified stainless steel mesh electrode. The carbon material loaded by the impregnation-drying method is poor in stability and easy to fall off, and the time is long, so that the method is not beneficial to large-scale application. (4) Patent CN106946362B describes a method for modifying a stainless steel electrode by a mesoporous carbon material, which comprises the steps of firstly adding ferric chloride hexahydrate, sodium acetate and polyvinylpyrrolidone into an ethylene glycol solution, uniformly mixing, then adding solution A and solution B, reacting for 20-40 min at the temperature of 2-6 ℃, then adding a frozen ammonium persulfate solution, uniformly mixing and sintering; rolling the prepared mesoporous carbon material on one side of stainless steel to form a carbon layer, and smearing the dispersion liquid of the mesoporous carbon material on the other side of the stainless steel to prepare the carbon-coated modified stainless steel electrode. The method has complex steps, complex process and high cost when being applied in an amplification way, and is not suitable for large-scale production and application. (5) Chapter (Lamp J L, Guest J S, NaHA S, et al. flame synthesis of carbon nanostructres on flame steels systems for use in microbial fuels cells [ J ]. Journal of Power sources,2011,196(14): 5829. mangc. 5834. https:// doi. org/10.1016/J. spowsour.2011.02.077) describes a flame-fired carbonized modified stainless steel using ethylene as fuel, mounted in a fixture of a co-current axisymmetric burner, held 5mm above the bottom of the non-premixed flame, flame-fired carbonized for 3min, effective to form carbon nanoparticles on the stainless steel. The method is limited by the size of the flame, and when the flame is scaled up, the flame temperature is difficult to keep consistent, so that the decoration is uneven and time is consumed, and the method is not easy to be applied in a large scale. In conclusion, the current carbon-coating modification method carries out secondary reprocessing modification on the basis of finished stainless steel, has high energy consumption and cost and poor stability, and the reprocessing modification process is complicated and is not suitable for large-scale application.

Disclosure of Invention

Based on the above technical background, the present inventors have made a keen search and, as a result, have found that: in the process of drawing the stainless steel wire, the stainless steel and the carbon can be bonded through the action of the wire drawing die, so that a layer of carbon is firmly loaded on the surface of the stainless steel. The invention combines the stainless steel wire drawing process and the carbon loading process into a whole, simultaneously improves the carbon coating effect and the preparation efficiency of the surface of the stainless steel wire, and the product prepared by the carbon coating method has excellent biocompatibility and electrogenesis performance.

Specifically, the invention aims to provide a method for enhancing biocompatibility by coating carbon on the surface of a stainless steel wire, wherein stainless steel drawing is carried out in carbon milk, and carbon is coated on the surface of the stainless steel wire through a metal-oxygen-carbon bond.

The loading amount of carbon on the drawn carbon-coated stainless steel wire prepared by the method is 0.643-7.560 g.m^-2。

The carbon emulsion comprises a carbon source, a stabilizer, a thickening agent, a film forming aid and water;

the particle size of the carbon source is 0.1-5 mu m.

The method for enhancing biocompatibility by coating carbon on the surface of the stainless steel wire provided by the invention has the following advantages:

(1) the method for enhancing biocompatibility by coating carbon on the surface of the stainless steel wire integrates the stainless steel wire drawing process and the carbon loading process, and simultaneously improves the loading effect and the preparation efficiency;

(2) the method for enhancing the biocompatibility by coating carbon on the surface of the stainless steel wire obviously enhances the biocompatibility of the stainless steel material, and is more favorable for the attachment and value increase of electrogenesis microorganisms;

(3) the electrogenesis performance of the stainless steel electrode prepared by the method for enhancing the biocompatibility by coating carbon on the surface of the stainless steel wire is greatly improved;

(4) the method for enhancing the biocompatibility by coating carbon on the surface of the stainless steel wire reduces the production cost, simplifies the production process, can realize large-scale production and application, and promotes the conversion of the bioelectrochemical technology to the waste (sewage) treatment and application of actual engineering scale.

Drawings

FIG. 1 shows a schematic structural view of a water-tank type wire drawing machine according to a preferred embodiment of the present invention;

FIG. 2 is a schematic drawing of a wire drawing die and a wire drawing process according to a preferred embodiment of the present invention;

FIG. 3-a is a scanning electron micrograph showing the surface morphology of a sample prepared in example 4 of the present invention;

FIG. 3-b is a scanning electron micrograph showing the surface morphology of a stainless steel wire according to comparative example 1 of the present invention;

FIG. 4 shows an element energy spectrum (EDS) of the small box area of FIG. 3 according to the present invention;

FIG. 5 shows X-ray photoelectron spectroscopy (XPS) profiles of the surfaces of samples obtained in example 4 of the present invention and comparative example 1;

FIG. 6 is a graph showing the comparison of the electrode current curves with time for the samples obtained in example 4 of the present invention and comparative example 1.

Description of the reference numerals

1-a fine diameter stainless steel wire reel;

2-fine diameter stainless steel wire;

3-wire drawing machine cabinet;

4-driven pulley cone pulley;

5-carbon milk;

6-driving wheel cone pulley;

7-heavy diameter stainless steel wire;

8-a large diameter stainless steel wire reel;

9-steel frame;

10-a cone pulley motor;

11-drawing a wire mould;

12-placing the cantilever of the wire-drawing die;

13-winding motor.

Detailed Description

The present invention will be described in detail below, and features and advantages of the present invention will become more apparent and apparent with reference to the following description.

The invention provides a method for enhancing biocompatibility by coating carbon on the surface of a stainless steel wire, wherein stainless steel wire drawing is carried out in carbon milk, and carbon is coated on the surface of the stainless steel wire through a metal-oxygen-carbon bond.

The surface carbon loading amount of the drawn carbon-coated stainless steel wire prepared by the method is 0.643-7.560 g.m^-2Preferably, the loading amount of the carbon is 1.190 to 7.560 g.m^-2More preferably, the loading amount of the carbon is 4-7 g.m^-2. When the load of carbon is 4-7 g.m^-2When the method is used, the electrode prepared by drawing the carbon-coated stainless steel wire has the best electrogenesis performance.

The carbon loading amount refers to the loading mass of carbon-containing substances on the surface of the stainless steel wire in unit area.

The invention aims to integrate the stainless steel wire drawing process and the stainless steel wire surface carbon coating process into one, and selects carbon emulsion as a wire drawing lubricant in order to ensure that carbon materials are firmly loaded on the stainless steel during the wire drawing process of the stainless steel so as to realize the in-situ carbon coating modification of the stainless steel material.

In the present invention, the carbon emulsion includes a carbon source, a stabilizer, a thickener, a film-forming aid, and water.

The carbon source is first comminuted, preferably in a pulverizer. The pulverization time is not limited, and the particle size of the carbon source after pulverization is 0.1 to 5 μm, preferably 0.5 to 2 μm, and more preferably 0.55 to 1 μm.

The inventor finds that the particle size of the carbon source influences the sedimentation degree of the carbon source in the carbon milk, the larger the particle size of the carbon source in the carbon milk is, the larger the sedimentation degree is, and the smaller the particle size is, the smaller the particle size of the carbon source particles are converged into large particles to be sedimented, and the content of the carbon source in the carbon milk is also reduced. Tests show that when the particle size of the carbon source is 0.1-5 mu m, the carbon source is stably distributed in the carbon emulsion, the sedimentation degree is low, the carbon coverage rate of the surface of the prepared stainless steel wire is high, and the wire drawing lubrication effect on the stainless steel is good.

The carbon source is selected from one or more of graphite, carbon black, graphene, activated carbon and carbon nanotubes; preferably, the carbon source is selected from one or more of graphite, graphene and carbon nanotubes; more preferably, the carbon source is graphite.

In the test process, the carbon source is found to have better lubrication effect on stainless steel wire drawing when graphite is selected as the carbon source, and the prepared carbon emulsion has better carbon coating effect on the surface of the stainless steel wire and higher carbon coating rate when the graphite is selected as the carbon source, so that the carbon load on the surface of the stainless steel wire is firmer, which is probably because when the stainless steel wire passes through a die in the wire drawing process, the friction between the stainless steel wire and the die generates a large amount of heat to promote the graphite and the stainless steel wire to form stronger metal-oxygen-carbon coordination bonds, thereby enabling the graphite carbon to be firmly loaded on the stainless steel. Meanwhile, the drawn carbon-coated stainless steel wire prepared by taking graphite as a carbon source has better biocompatibility and better electrogenesis performance, and the reason that the surface of the stainless steel wire is modified by graphite carbon is probably that attachment sites of electrogenesis microorganisms are increased, the formation of an electrochemical active biomembrane is promoted, the biomass attached to a carbon-coated modified electrode is obviously increased, and thus the electrogenesis performance of the stainless steel electrode organism is greatly improved.

The stabilizer can increase the chemical stability of the solution and reduce the surface tension. The inventors of the present invention have found that when a stabilizer is added to carbon emulsion, the degree of sedimentation of carbon source particles is reduced, the degree of lubrication of the carbon emulsion is improved, the amount of carbon coating on the surface of the produced drawn carbon-coated stainless steel wire is increased, and the electrogenesis performance of the electrode produced therefrom is improved.

In the invention, the stabilizer is selected from one or more of ferric hydroxide, zinc hydroxide, ferrous hydroxide and ammonia water; preferably, the stabilizer is selected from one or more of ferric hydroxide and ammonia water; more preferably, the stabilizer is ammonia. When ammonia water is used as a stabilizer, the carbon source in the carbon milk has better dispersibility.

The thickening agent is a rheological additive, and can adjust the rheological property after being added, so that the liquid phase viscosity of the preparation can be improved, and the dispersed phase can play a good suspension role in water. The inventor finds that carbon source particles in the carbon milk have hydrophobic property, and particularly carbon source particles with smaller particle size have larger cohesive force and are difficult to disperse, so that a plurality of carbon source particles are often aggregated together to be in a large particle state, and are coagulated and settled, so that the content of the carbon source in the carbon milk is insufficient, the performance of lubrication and the like is poor, the diameter uniformity of a stainless steel wire after being drawn is poor, the carbon coverage rate of the surface of the stainless steel wire is reduced, and the electricity production performance of the stainless steel wire as an electrode is reduced.

The inventor adds the thickening agent into the carbon milk to greatly improve the suspension dispersibility of the carbon source in the carbon milk, and simultaneously finds that the carbon coverage rate of the surface of the stainless steel wire and the biocompatibility and the electrogenesis performance of the electrode prepared by the stainless steel wire are greatly improved due to the addition of the thickening agent, probably because the thickening agent reduces the coagulation sedimentation degree of carbon source particles and improves the content of the carbon source in the carbon milk, thereby increasing the carbon coverage rate of the surface of the stainless steel wire, and simultaneously, the biocompatibility and the electrogenesis performance of the prepared electrode are improved due to the improvement of the carbon coverage rate.

The thickening agent is selected from one or more of cellulose ether, Arabic gum, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide and polyurethane; preferably, the thickening agent is selected from one or more of carboxymethyl cellulose, Arabic gum, polyvinyl alcohol and polyvinyl pyrrolidone; more preferably, the thickener is carboxymethyl cellulose.

In the invention, when the thickening agent is carboxymethyl cellulose, the carbon coverage rate of the surface of the prepared drawn carbon-coated stainless steel wire, the biocompatibility of the prepared electrode and the electricity generation performance are all higher, because the carboxymethyl cellulose has good emulsification stability and extremely excellent emulsification performance, and the carbon emulsion prepared by using the carboxymethyl cellulose as the thickening agent can form a homogeneous emulsion with stable performance.

The film-forming assistant can improve the film-forming mechanism of the emulsion and help to form a film. After the film-forming auxiliary agent is added into the carbon milk, the film-forming drying rate of the carbon milk is improved, and meanwhile, the carbon coverage rate of the surface of the stainless steel wire is increased due to the addition of the film-forming auxiliary agent.

The film-forming aid is selected from one or more of benzyl alcohol, ethylene glycol butyl ether and ethylene glycol, and preferably, the film-forming aid is ethylene glycol. Experiments show that when ethylene glycol is selected as a film forming aid, the liquid phase density can be effectively adjusted, and meanwhile, the dispersity of the carbon source in the carbon milk is improved.

The inventor finds that the dosage of each component in the carbon milk is closely related to the performance of the finally prepared drawn carbon-coated stainless steel wire, and the final performance of the stainless steel wire is influenced by too much or too little dosage. The amount of each component is controlled within a suitable range.

When the carbon source accounts for 15-36% of the total mass of the carbon milk, the carbon source has better suspension dispersity in the carbon milk and less coagulation sedimentation. If the amount of the carbon source added is too small (less than 15%), the content of the carbon source in the carbon emulsion decreases, and the stainless steel wire produced therefrom is poor in diameter uniformity, and the carbon coverage on the surface of the stainless steel wire decreases, and the electrode produced therefrom is low in power generation performance. If the addition amount of the carbon source is too large (higher than 36%), a plurality of carbon source particles aggregate into a large particle state, and the carbon source particles aggregate and precipitate, so that the content of the carbon source in the carbon milk is insufficient, and the carbon coverage rate of the surface of the stainless steel wire is also reduced.

According to a preferred embodiment of the present invention, the carbon source accounts for 20% to 30% of the total mass of the carbon milk. According to a further preferred embodiment of the present invention, the carbon source accounts for 26% of the total mass of the carbon milk. When the carbon source accounts for 26 percent of the total mass of the carbon emulsion, the surface carbon coating rate of the prepared stainless steel wire is the highest, and the electricity generating performance is optimal.

In the invention, when the stabilizer accounts for 2-4% of the total mass of the carbon emulsion, the surface of the prepared stainless steel wire has higher carbon loading rate and has excellent biocompatibility and electrogenesis performance. Preferably, the percentage of the stabilizer in the total mass of the carbon milk is 2.5-3.5%, and more preferably 3%.

Too high or too low addition of the thickener affects the carbon coating amount on the surface of the stainless steel wire, and further affects the electricity generation performance of the stainless steel wire. The thickener accounts for 16-25% of the total mass of the carbon emulsion, preferably 19-23%, and more preferably 20%. If the amount of the thickener is too small, the suspension effect of the thickener on a carbon source in carbon milk is reduced, the content of the carbon source in the carbon milk is reduced, the carbon coating amount on the surface of the stainless steel wire is reduced, and if the amount of the thickener is too large, the carbon coating rate on the surface of the stainless steel wire is also reduced, so that the power generation performance of an electrode prepared from the stainless steel wire is reduced.

When the film-forming additive accounts for 4-9% of the total mass of the carbon emulsion, the surface of the stainless steel wire has higher carbon coating amount, and the electrode prepared from the stainless steel wire has higher electrogenesis performance. Preferably, the percentage of the film-forming aid in the total mass of the carbon emulsion is 6-8%, and more preferably 7%. The rest is water.

The carbon emulsion further comprises a dispersant, and the dispersant has the functions of reducing the dispersing time and energy required by the dispersing process, stabilizing the dispersed dispersion, modifying the surface property of the particles, adjusting the mobility of the particles, and preventing the particles from flocculating and settling.

In the test process, the dispersing agent is added into the carbon milk, so that the flocculation and sedimentation of carbon source particles can be further reduced, the carbon source particles can be more stably dispersed in the carbon milk, the surface carbon coating rate of the stainless steel wire is improved, and the electricity generation performance of the stainless steel wire as an electrode is improved.

The dispersing agent is selected from one or more of glyceryl tristearate, butyl stearate, calcium stearate and methylene dinaphthalene sulfonate, preferably, the dispersing agent is glyceryl tristearate or methylene dinaphthalene sulfonate, and more preferably, the dispersing agent is methylene dinaphthalene sulfonate.

The addition amount of the dispersing agent is controlled within a proper range, when the addition amount of the dispersing agent is too low, the dispersing effect on carbon source particles is not obvious, and the carbon coating rate on the surface of the stainless steel wire is not obviously improved.

Tests show that when the dispersant accounts for 0.1-5% of the total mass of the carbon emulsion, the carbon source is well dispersed in the carbon emulsion, the carbon coverage rate on the surface of the stainless steel wire is high, preferably, the dispersant accounts for 0.5-3% of the total mass of the carbon emulsion, and more preferably, the dispersant accounts for 0.7-2% of the total mass of the carbon emulsion.

And mixing weighed and crushed carbon source, pure water and stabilizer, stirring, wherein the stirring is mechanical stirring, preferably in a stirring kettle, after the stirring is uniform, adding weighed thickener and film-forming assistant into the uniformly stirred mixed solution for dispersing, wherein the dispersing is preferably performed in a high-speed disperser, and the dispersing time is not limited as long as the dispersing is uniform.

In the present invention, the stainless steel drawing process is performed in a drawing machine filled with carbon emulsion.

The wire drawing machine comprises a fine-diameter stainless steel wire reel 1, a wire drawing machine case 3, a driven wheel cone pulley 4, carbon emulsion 5, a driving wheel cone pulley 6, a coarse-diameter stainless steel wire reel 8, a steel frame 9, a cone pulley motor 10, a wire drawing die 11, a cantilever 12 for placing the wire drawing die and a winding motor 13. The carbon milk 5 is the carbon milk provided by the invention.

In the invention, the wire drawing machine case 3 is positioned between the small-diameter stainless steel wire reel 1 and the large-diameter stainless steel wire reel 8, the carbon emulsion 5 is arranged in the wire drawing machine case 3, the driven wheel cone 4, the driving wheel cone 6, the wire drawing die 11 and the suspension arm 12 for placing the wire drawing die are all positioned in the wire drawing machine case 3, and the device structure arranged in the wire drawing machine case 3 is completely immersed in the carbon emulsion 5. The carbon emulsion is mainly used for carbon coating of steel wires and lubrication in the stainless steel wire drawing process.

The driven wheel cone pulley 4 is close to the small-diameter stainless steel wire reel 1, the driving wheel cone pulley 6 is close to the large-diameter stainless steel wire reel 8, the wire drawing die 11 and the cantilever 12 for placing the wire drawing die are located between the driven wheel cone pulley 4 and the driving wheel cone pulley 6, and the cantilever 12 for placing the wire drawing die is mainly used for placing the wire drawing die 11.

This action wheel cone pulley 6 links to each other with cone pulley motor 10, and cone pulley motor 10 drive action wheel cone pulley 6 rotates, rolling motor 13 links to each other with thin diameter stainless steel wire spool 1, and rolling motor 13 is used for driving thin diameter stainless steel wire spool 1 to carry out the receipts of stainless steel wire and rolls up.

The wire drawing die 11 is mainly used for the wire drawing process of the stainless steel wire with the large diameter, a through hole is formed in the wire drawing die 11 and comprises a thick end and a thin end, the thick end is close to the driving wheel cone pulley 6 and located at the end where the stainless steel wire with the large diameter enters the die, the thin end is close to the driven wheel cone pulley 4 and located at the end, after the stainless steel wire with the large diameter is drawn, of the wire drawing die 11, an aperture transition area is arranged between the thick end and the thin end, and the diameter of the aperture transition area is continuously reduced from the thick end to the thin end.

The diameter of the thick end is larger than that of the stainless steel wire with the thick diameter entering the wire drawing die 11, and the diameter of the thin end is smaller than that of the stainless steel wire with the thick diameter entering the wire drawing die 11. Thus, the stainless steel wire with the large diameter can smoothly enter the wire drawing die 11, and is drawn out from the thin end of the wire drawing die after being drawn to be thin.

In the invention, the aperture transition area of the wire drawing die 11 provides a buffer area for the wire drawing process, so that the mechanical property reduction caused by sudden diameter reduction of the wire in the wire drawing process and the unstable device and damage to a wire drawing machine caused by the 'pulling and kicking' phenomenon in the whole wire drawing process are avoided. The longer this aperture transition zone is, the smoother the drawing process of the steel wire through the drawing die 11 is, and the central axes of the aperture transition zone, the thick end and the thin end are all located on the same straight line.

In order to ensure that the stainless steel wire can be more smoothly coated in the drawing process, the central axis of the through hole of the wire drawing die 11 and the lowest points of the driven wheel cone pulley 4 and the driving wheel cone pulley 6 are positioned on the same straight line.

The wire drawing die 11 is arranged in a cantilever 12 for placing the wire drawing die from top to bottom in sequence from large to small according to the diameter of a thin end, and the number of the wire drawing die 11 is the same as the number of stages of the driven wheel cone pulley 4 and the driving wheel cone pulley 6.

In the invention, the aperture difference value of the thin ends of the upper and lower adjacent wire drawing dies 11 is 0.01-0.1 mm, and the aperture difference value of the thin ends of the upper and lower adjacent wire drawing dies 11, namely the aperture difference value of the thick end and the thin end of the wire drawing dies 11, is the diameter reduction value of the stainless steel wire after passing through one wire drawing die. Preferably, the aperture difference is 0.02-0.07 mm, and more preferably, the aperture difference is 0.03-0.05 mm.

Tests show that the larger the aperture difference is, the higher the wire drawing efficiency of the stainless steel is, the expected diameter of the stainless steel wire can be obtained only by fewer dies, so that the working efficiency is greatly improved, but meanwhile, the interaction time of the stainless steel wire and the dies in the extension process is reduced only by fewer dies, the load rate of carbon on the surface of the stainless steel wire is reduced, the carbon coating effect of the carbon on the surface of the stainless steel wire is poor due to the fewer interaction of the stainless steel wire and the dies, the combination of the surface of the stainless steel wire and the carbon is not firm, the electricity production performance of the manufactured electrode is poor, and meanwhile, the phenomenon that the stainless steel wire deforms too much in the wire drawing process and even breaks occurs due to the overlarge aperture difference, and the smooth wire drawing process is influenced. Therefore, the smaller the aperture difference between the adjacent dies is, the more the stainless steel wire passes through the dies, the more the stainless steel wire interacts with the wire drawing die, and the more the carbon load rate and the carbon load effect on the surface of the stainless steel wire are increased, so that the electricity generation performance of the electrode manufactured by the stainless steel wire is improved. However, if the difference in pore diameter is too small, the number of required molds increases, which increases the complexity of production processes and operations, prolongs the preparation time, reduces the preparation efficiency, and increases the preparation cost.

In the process of drawing the stainless steel wires, according to the specific diameter of the stainless steel wires and the target diameter to be achieved, the diameter reduction value of the stainless steel wires is firstly determined, meanwhile, the size reduction value of the stainless steel wires passing through one drawing die is determined by referring to the aperture difference value of the thin ends of the adjacent drawing dies (namely the difference value of the thick ends and the thin ends of the drawing dies), and the number of the required drawing dies is calculated. If the diameter reduction value is 0.33mm when a thick-diameter stainless steel wire with an initial diameter of 0.55mm needs to be drawn and extended into a thin-diameter stainless steel wire with a diameter of 0.22mm, the difference of the pore diameters of the thin ends of the adjacent wire drawing dies provided by the invention is 0.01-0.1 mm, preferably 0.02-0.07 mm, and more preferably 0.03-0.05 mm. The number of the wire drawing dies 11 in the wire drawing machine is 4-33, preferably 5-17, and more preferably 7-11.

Before starting the wire drawing machine, the stainless steel wire needing to be extended and drawn is placed in the wire drawing machine, and the required wire drawing die is placed according to the diameter required by the stainless steel wire. And winding the large-diameter stainless steel wire from a large-diameter stainless steel wire reel 8 to a driving wheel cone pulley 6, entering a wire drawing die 11 from the driving wheel cone pulley 6, winding the stainless steel wire extending out of the wire drawing die 11 onto a driven wheel cone pulley 4, and finally winding onto a small-diameter stainless steel wire reel 1.

After the stainless steel wire is placed on a wire drawing machine, the wire drawing machine is started to draw wires, and a cone pulley motor 10 in the wire drawing machine starts to work after the wire drawing machine is started to drive a driving cone pulley 6 and a driven cone pulley 4 to start to run.

The large-diameter stainless steel wire reel 8 is arranged on a steel frame 9, the large-diameter stainless steel wire 7 on the large-diameter stainless steel wire reel 8 is pulled by the driving wheel cone pulley 6 and pulled into the wire drawing die 11 at a certain speed, under the pulling force of the cone pulley, the stainless steel wire 7 with the large diameter is pulled to pass through the wire-drawing die 11 in the cantilever 12 for placing the wire-drawing die, after passing through the wire-drawing die 11, the thick stainless steel wire 7 is drawn and extended into the thin stainless steel wire 2, if the diameter of the extended and drawn stainless steel wire does not reach the required diameter value, the stainless steel wire after being drawn thin continuously enters the driving wheel cone pulley 6, is drawn thin by the wire drawing die 11 and then enters the driven wheel cone pulley 4 until the stainless steel wire reaches the required diameter value, then the stainless steel wire 2 with the small diameter enters the stainless steel wire reel 1 from the driven wheel cone pulley 4 to finish the drawing process of the stainless steel wire.

In the wire drawing process, the winding motor 13 also works synchronously, the winding speed of the winding motor is matched with the wire drawing speed, and the stainless steel wire 2 with the small diameter is wound on the stainless steel wire reel 1 with the small diameter.

In the invention, the wire drawing speed is 0.1-5 m/s, preferably 0.5-2 m/s, and more preferably 1 m/s.

If the wire drawing speed is too fast, the soaking time of the stainless steel wire in the carbon emulsion is shortened, the carbon loading on the surface of the stainless steel wire is less, the improvement of the electricity generating performance is not facilitated, and meanwhile, the wire drawing speed is too fast, and the steel wire is easy to break. If the wire drawing speed is too slow, the wire drawing and carbon coating efficiency of the stainless steel wire is reduced.

The invention has the following beneficial effects:

(1) the method for enhancing biocompatibility by coating carbon on the surface of the stainless steel wire is characterized in that carbon and stainless steel are bonded and combined through the action of the wire drawing die in the process of drawing and extending the stainless steel wire from coarse thinning, a layer of carbon is firmly loaded on the surface of the stainless steel, the process of drawing the stainless steel wire and the process of loading the carbon are combined into a whole, the loading effect is good, and the preparation efficiency is improved;

(2) the wire-drawing carbon-coating modified stainless steel wire prepared by the method is woven into a stainless steel wire mesh or wound on an inert metal current collector to be used as an electrode, the wire-drawing carbon-coating modified stainless steel wire is applied to a bioelectrochemical system, attachment sites of electrogenesis microorganisms are increased due to the existence of carbon on the surface of the stainless steel, the formation of an electrochemical active biological film is promoted, the biomass attached to the carbon-coating modified electrode is obviously increased compared with an unmodified stainless steel electrode, and the wire-drawing carbon-coating modification obviously enhances the biocompatibility of the stainless steel material. The enhancement of biocompatibility is beneficial to the attachment and colonization of electrogenic microorganisms, so that the electrogenic performance of the stainless steel electrode organisms is greatly improved, and the density of the current generated on the stainless steel electrode after carbon coating is observed to be increased by dozens of times compared with that on the premise of modification;

(3) the method integrates the carbon coating method of the stainless steel material into the production process of the stainless steel, replaces the original lubricant soap cream in the wire drawing process with the carbon cream, realizes in-situ carbon coating modification, increases the cost only for the consumption of the carbon cream, integrates the modification step into the production process, does not need to add an additional carbon coating modification process of the stainless steel, and in addition, the in-situ carbon coating modification based on the production process has no additional investment of new machines, fields, labor, power consumption and other costs, and the carbon cream lubricant is cheap and easy to obtain, thereby greatly reducing the cost of the carbon coating modification of the stainless steel;

(4) according to the carbon coating method, the carbon coating modification process is integrated into the production process, and the modified stainless steel wire serving as a raw material can be conveniently processed into various electrode configurations and sizes, so that the modification method can realize large-scale production and application, is different from the conventional carbon coating method based on secondary reprocessing modification treatment of stainless steel products, and can practically solve the technical problem that the conventional carbon coating method is difficult to realize large-scale production and application;

(5) the in-situ wire drawing carbon coating method is combined with actual production, carbon coating modification is completed at a stainless steel production end, industrial ecology is favorably changed, optimization and adjustment of a production structure are brought, product modification processing at a downstream end of a stainless steel material industrial chain is transferred to an upstream end of the industrial chain, and large-scale production and application of a stainless steel electrode are expected to be realized in future, and the transformation of a bioelectrochemistry technology to waste (sewage) water treatment and application of an actual engineering scale is promoted.

Examples

The invention is further illustrated by the following specific examples, which are intended to be illustrative only and not limiting to the scope of the invention.

Example 1

Filling the carbon emulsion with 26% of graphite content uniformly stirred and dispersed to a position 10cm above a cone pulley, wherein the carbon emulsion comprises the following components: 26% by mass of graphite particles (particle diameter of 0.6 μm), 3% by mass of ammonia water, 20% by mass of carboxymethyl cellulose, 7% by mass of ethylene glycol, and the balance of pure water. Then 1 wire drawing die (the size of the die hole at the thin end of the wire drawing die is 0.22mm) is placed on a cantilever where the wire drawing die is placed, a wire drawing machine is started, under the drive of a driving wheel cone pulley 6, a stainless steel wire with the thick diameter (0.25mm) is pulled by the driving wheel cone pulley 6 to pass through a wire drawing die 11, and the stainless steel wire with the thick diameter (0.25mm) is drawn and stretched into a stainless steel wire with the thin diameter (0.22 mm). At the same time, the winding motor 13 winds the stainless steel wire with a small diameter on the stainless steel wire reel 1 at a speed of 1m/s (the winding speed is the same as the wire drawing speed of the whole wire drawing process). Graphite carbon is firmly loaded on the stainless steel wire in the wire drawing process, so that in-situ carbon coating modification of the stainless steel wire is realized.

Example 2

The specific procedure was the same as in example 1, except that: the number of dies used in the wire drawing process is increased to 3 (the sizes of die holes on a cantilever 12 for placing the wire drawing dies are respectively 0.28mm, 0.25mm and 0.22mm from top to bottom, the sizes of the die holes are the sizes of the thin ends of the wire drawing dies), the stainless steel wire with the thick diameter (0.31mm) is pulled by a cone pulley to pass through the wire drawing dies 11, the stainless steel wire with the thick diameter (0.31mm) is pulled and extended into the stainless steel wire with the thin diameter (0.22mm) after the wire drawing of 3 dies for 1 time, and the wire drawing speed is unchanged (the wire drawing speed is 1 m/s).

Example 3

The specific procedure was the same as in example 1, except that: the number of dies used in the wire drawing process is increased to 5 (the sizes of die holes on a cantilever 12 for placing the wire drawing dies from top to bottom are respectively 0.35mm, 0.31mm, 0.28mm, 0.25mm and 0.22mm, the sizes of the die holes are the sizes of the fine ends of the wire drawing dies), the stainless steel wire with the coarse diameter (0.39 mm) is pulled by a cone pulley to pass through the wire drawing dies, the stainless steel wire with the coarse diameter (0.39 mm) is drawn and extended into the stainless steel wire with the fine diameter (0.22mm) after the stainless steel wire passes through 1 die for each time, and the wire drawing speed is unchanged (the wire drawing speed is 1 m/s).

Example 4

The specific procedure was the same as in example 1, except that: the number of dies used in the wire drawing process is increased to 8 (the sizes of die holes of the wire drawing dies arranged on a cantilever 12 for placing the wire drawing dies from top to bottom are respectively 0.48mm, 0.43mm, 0.39mm, 0.35mm, 0.31mm, 0.28mm, 0.25mm and 0.22mm, the sizes of the die holes are the sizes of the thin ends of the wire drawing dies), a thick-diameter (0.55mm) stainless steel wire is pulled to pass through the wire drawing dies by a cone pulley, the diameter of the stainless steel wire passing through 1 die is drawn for 1 time, until the thick-diameter (0.55mm) stainless steel wire is drawn and stretched into a thin-diameter (0.22mm) stainless steel wire after the wire drawing of 8 dies, and the wire drawing speed is not changed (the wire drawing speed is 1 m/s).

Comparative example

Comparative example 1

The specific procedure was the same as in example 1, except that: the carbon milk is replaced by soap milk, namely the soap milk is used as a lubricant to carry out a wire drawing experiment.

Examples of the experiments

Experimental example 1 scanning Electron microscope test

Scanning electron microscope tests were performed on the carbon-coated stainless steel wires obtained in example 4 and comparative example 1, respectively, and the results are shown in fig. 3-a and 3-b, respectively.

As can be seen from FIG. 3-a, the surface of the carbon-coated stainless steel wire obtained in example 4 was deposited with a thin layer of material, and the surface was rough. As can be seen from fig. 3-b, the stainless steel wire manufactured in comparative example 1 has a smooth surface with fine scratches.

EXAMPLE 2 elemental Spectroscopy (EDS)

The surfaces of the stainless steel wires prepared in example 4 and comparative example 1 were subjected to X-ray energy spectrometer tests, respectively, to characterize the substances on the surface of example 4, and the results are shown in fig. 4. Wherein the red part indicates the elements and contents on the surface of the stainless steel wire obtained in example 4, and the black part exposed above red in the figure indicates that the contents of the elements on the surface of the stainless steel wire obtained in comparative example 1 are greater than the values of the elements contents on the surface of the stainless steel wire obtained in example 4.

As can be seen from fig. 4, the elements on the surface of the carbon-coated stainless steel wire obtained in comparative example 1 were mainly Fe (65.34%), Cr (18.39%), Ni (7.98%), C (3.62%), O (4.66%), and the balance trace elements (<2 atomic%) (the surface element contents of the stainless steel wire were atomic percentages), such as Si, Mn, Mo.

In example 4, the surface element content of the stainless steel wire prepared by carbon emulsion wire drawing and carbon coating is mainly C accounting for 82.15%, and the balance is Fe (10.67%), Cr (3.13%), O (3.03%) and Ni (1.02%) (the surface element content of the stainless steel wire is atomic percentage). The significant increase in carbon content indicates that the material observed in the SEM photograph is graphitic carbon, and also indicates that the content detected decreases because graphitic carbon covers a portion of the stainless steel surface, so that other elements (Fe, Cr, Ni) on the stainless steel are mostly occluded.

The characterization test results of SEM and EDS fully show that the wire drawing carbon coating treatment of the invention can effectively load graphite carbon on the surface of the stainless steel wire.

Experimental example 3X-ray photoelectron spectroscopy test

To further characterize the carbon-coated bonding force of the surface of the final material, X-ray photoelectron spectroscopy (XPS) was performed on the surface of the carbon-coated stainless steel wire obtained in example 4, and the results are shown in fig. 5.

The fitting result of fig. 5 shows that an obvious metal-oxygen-carbon bond appears on the stainless steel wire subjected to wire drawing treatment in example 4, which indicates that a coordination bond is formed between graphite carbon and stainless steel due to high temperature generated by frictional heat between a die and the stainless steel wire during wire drawing, which indicates that the wire drawing carbon-coating treatment of the present invention can firmly load graphite carbon on the stainless steel wire, and simultaneously indicates that the carbon-coated stainless steel material prepared by the wire drawing carbon-coating modification method of the present invention has good stability and firm bonding between graphite carbon and the stainless steel wire.

Experimental example 4 graphite carbon loading test

The carbon-coated stainless steel wires prepared in examples 1 to 4 were subjected to a graphite carbon loading test, which comprises the following steps: 2.8M of the carbon-coated stainless steel wire prepared in examples 1 to 4 was weighed and recorded as M1, and then the stainless steel wire was thoroughly cleaned by ultrasonic cleaning and dried and weighed and recorded as M2, so that the graphite carbon loading w of the stainless steel wire per unit mass was (M1-M2)/M2, and all measurements were performed three times or more, and the results were averaged.

The amount of graphite carbon loaded on the drawn carbon-coated stainless steel wires prepared in examples 1 to 4 was calculated to be 0.643. + -. 0.076 g.m^-2(example 1,1 die drawing treatment result), 1.190. + -. 0.202 g.m^-2(results of wire drawing in examples 2 and 3 pieces of die), 2.269. + -. 0.144 g.m^-2(results of wire drawing in examples 3 and 5 dies) and 4.260. + -. 0.256 g.m^-2(example 4, 8 pieces of die drawing results).

As can be seen from the above, the larger the number of drawing dies, the larger the amount of graphite carbon supported. According to the XPS analysis result (as shown in FIG. 5), in the process of drawing and extending the stainless steel wire from the rough thinning, under the combined action of extrusion and friction heat of the die, the graphite carbon and the stainless steel form coordination bonding, and the graphite carbon is continuously and firmly bonded on the surface of the stainless steel, so that the more the number of the die is, the better the graphite carbon loading is.

Experimental example 5 Electricity Generation Performance test

The stainless steel wires prepared in example 4 and comparative example 1 were tested for electrode biocompatibility and electrogenesis performance, respectively, by taking 2.8m each of the stainless steel wires prepared in example 4 and comparative example 1, and uniformly winding the wire on a titanium mesh sheet of 1.0cm × 3.0.0 cm to prepare an electrode, ultrasonically cleaning the titanium mesh sheet in an ethanol acetone 1:1 solution for 5 minutes before use, placing the prepared electrode in a waste (sewage) water treatment reactor of a bioelectrochemical system for constant potential culture and acclimation, wherein the constant potential is-0.20V (vs Ag/AgCl), the reference electrode in the reactor was selected as a saturated Ag/AgCl electrode (0.197V vs SHE), the auxiliary electrode was a stainless steel brush electrode, adding 100mL of artificially synthesized wastewater into the reactor, and inoculating 10mL of anolyte (the acclimated effluent of the reactor of the artificially synthesized wastewater treatment plant for 6 months) and 5mL of sludge in a secondary sedimentation tank (Beijing high stele store). The formula of the artificially synthesized wastewater comprises the following components: (g/L): NaH₂PO₄·2H₂O(2.77)，Na₂HPO₄·12H₂O(11.55)， NH₄Cl(0.31),KCl(0.13)，MgSO₄·7H₂O (0.10), anhydrous sodium acetate (3.00), and then 12.50mL/L of trace element liquid and 12.50mL/L of vitamin liquid are added, wherein the formula of the trace element liquid is as follows: 10mg/L sodium selenite, 10mg/L nickel chloride hexahydrate, 10mg/L sodium tungstate dihydrate, 10mg/L copper sulfate pentahydrate, 10mg/L aluminum potassium sulfate dodecahydrate, 10mg/L boric acid, 10mg/L sodium molybdate monohydrate, 0.1g/L ferrous sulfate heptahydrate, 0.1g/L cobalt chloride hexahydrate, 0.1g/L calcium chloride, 0.1g/L zinc sulfate heptahydrate, 0.5g/L manganese sulfate monohydrate, 1g/L sodium chloride, 1.5g/L nitrilotriacetic acid and 3g/L manganese sulfate heptahydrate. The formula of the vitamin solution is as follows: 2mg/L vitamin H, 2mg/L folic acid, 10mg/L pyridoxine hydrochloride, 5mg/L vitamin B1, 5mg/L vitamin B2, 5mg/L nicotinic acid, 5mg/L calcium D-pantothenate, 0.1mg/L vitamin B12, 5mg/L p-aminobenzoic acid, and 5mg/L lipoic acid. For the bioelectrochemical system electrogenesis microorganism, the culture and domestication temperature is 30 ℃. The optimal growth environment of the electrogenesis microorganisms of the electrochemical system is anaerobic, oxygen is removed before the prepared artificial synthetic wastewater is used, and 99.999 percent of high-purity N is introduced₂Blowing off for 30min to remove dissolved oxygen, maintaining anaerobic environment to ensure optimal growth environment of the electrochemically generated microorganisms, culturing at 30 deg.C for acclimatization culture for 26 days, and finishing the culture. The biomass and current density on the electrode after acclimatization culture were observed, and the results are shown in FIG. 6.

As can be seen from FIG. 6, the stainless steel electrode of example 4, which is modified by wire drawing and carbon coating, starts up quickly, and a considerable increase in bioelectric current can be observed in about 24h, while the stainless steel electrode of comparative example 1 can observe a weak bioelectric current only after about 5 d. As can also be seen from FIG. 6, the maximum current density obtained on the electrode modified by wire drawing and carbon coating in example 4 can reach 1.924mA cm^-2While the maximum current density obtained by the stainless steel electrode of comparative example 1 was only 0.118mA cm^-2The method shows that the electrogenesis performance of the stainless steel electrode prepared by the wire drawing carbon-coating modification method is obviously enhanced.

Experimental example 6 electrode biocompatibility test

The final samples prepared in example 4 and comparative example 1 were subjected to the electrode biocompatibility test, respectively. After sufficient acclimation culture (see example 5 for acclimation culture procedure), biomass on the electrode was measured to characterize the change in biocompatibility of the stainless steel material. ATP provides energy to the viable cells, so the ATP content can be used to estimate the number of viable bacterial cells, and the biomass of the electricity-producing microorganisms on the electrodes can be estimated by measuring the ATP content on the electrodes. The test results are shown in table 1.

TABLE 1 electrode biocompatibility and electrogenesis Performance test results

	Biomass (ATP representation, 10)⁹cell·cm^-2)	Maximum current density (mA. cm)^-2)
			Comparative stainless steel electrode	0.529	0.118
EXAMPLE 4 stainless Steel electrode	3.757	1.924

As can be seen from Table 1, the ATP contents on the electrodes of example 4 and comparative example 1, which were modified by wire drawing and carbon coating, were 3.757 × 10⁹cell·cm^-2And 0.529 × 10⁹cell·cm^-2The electrode after carbon coating modification by the method of the inventionATP is increased by 7 times, which shows that the wire drawing carbon coating modification method can greatly improve the biocompatibility of the stainless steel, and is more favorable for enrichment and proliferation of electrogenesis microorganisms on the stainless steel electrode, thereby obviously enhancing the electrogenesis performance of the electrode.

The characterization results show that the method firmly loads carbon on the stainless steel through die wire drawing treatment, realizes in-situ carbon coating modification of the stainless steel material, and greatly improves the biocompatibility of the stainless steel, thereby obviously improving the electrogenesis performance of the electrode. The method has the advantages of simple operation, low modification cost and good material stability, is tightly combined with the production process, and is easy to realize large-scale production and application. The technical problems of high cost, poor stability and difficulty in large-scale production and application of the existing carbon coating technology can be practically solved. The carbon-coated stainless steel wire prepared by the method can be conveniently processed into various electrode configurations and sizes as a raw material, and the scale-up application of stainless steel electrodes is promoted.

The invention has been described in detail with reference to specific embodiments and illustrative examples, but the description is not intended to be construed in a limiting sense. It will be understood by those skilled in the art that various equivalent substitutions, modifications or improvements may be made in the technical solution of the present invention and the embodiments thereof without departing from the spirit and scope of the present invention, which fall within the scope of the present invention. The scope of the invention is to be determined by the appended claims.

Claims

1. A method for enhancing biocompatibility by coating carbon on the surface of a stainless steel wire is characterized in that stainless steel wire drawing is carried out in carbon milk, and carbon is coated on the surface of the stainless steel wire through a metal-oxygen-carbon bond.

2. The method of claim 1, wherein the carbon loading is 0.643-7.560 g-m^-2。

3. The method of claim 2,

the particle size of the carbon source is 0.1-5 mu m.

4. The method of claim 2,

the carbon source is selected from one or more of graphite, carbon black, graphene, activated carbon and carbon nanotubes;

the stabilizer is selected from one or more of ferric hydroxide, zinc hydroxide, ferrous hydroxide and ammonia water;

the thickening agent is selected from one or more of cellulose ether, Arabic gum, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide and polyurethane;

the film-forming assistant is selected from one or more of benzyl alcohol, ethylene glycol butyl ether and ethylene glycol, and is preferably ethylene glycol.

5. The method of claim 4,

the carbon source accounts for 15-36% of the total mass of the carbon emulsion, the stabilizer accounts for 2-4% of the total mass of the carbon emulsion, the thickening agent accounts for 16-25% of the total mass of the carbon emulsion, the film-forming assistant accounts for 4-9% of the total mass of the carbon emulsion, and the balance is water.

6. The method of claim 4,

the carbon emulsion also comprises a dispersing agent, wherein the dispersing agent is one or more selected from glyceryl tristearate, butyl stearate, calcium stearate and methylene dinaphthalene sulfonate, and preferably, the dispersing agent is glyceryl tristearate or methylene dinaphthalene sulfonate;

the dispersant accounts for 0.1 to 5 percent of the total mass of the carbon emulsion.

7. A method according to claim 2, characterized in that the stainless steel wire drawing is performed in a wire drawing machine filled with carbon milk,

the wire drawing machine comprises a small-diameter stainless steel wire reel (1), a wire drawing machine case (3), a driven wheel cone pulley (4), carbon emulsion (5), a driving wheel cone pulley (6), a large-diameter stainless steel wire reel (8), a steel frame (9), a cone pulley motor (10), a wire drawing die (11), a cantilever (12) for placing the wire drawing die and a winding motor (13);

the carbon emulsion (5) is arranged in the wire drawing machine case (3), and the driven wheel cone pulley (4), the driving wheel cone pulley (6), the wire drawing die (11) and the cantilever (12) for placing the wire drawing die are all arranged in the wire drawing machine case (3) and are completely immersed in the carbon emulsion (5);

driven wheel cone pulley (4) are close to thin diameter stainless steel wire reel (1), and action wheel cone pulley (6) are close to thick diameter stainless steel wire reel (8), wire drawing mould (11) and cantilever (12) of placing the wire drawing mould are located between driven wheel cone pulley (4) and action wheel cone pulley (6), and wire drawing mould (11) are arranged in cantilever (12) of placing the wire drawing mould.

8. The method of claim 7,

the wire drawing die (11) is provided with a through hole, the through hole comprises a thick end and a thin end, the thick end is close to the driving wheel cone pulley (6), the thin end is close to the driven wheel cone pulley (4), an aperture transition area is arranged between the thick end and the thin end, and the diameter of the aperture transition area is continuously reduced from the thick end to the thin end;

the central axes of the aperture transition area, the thick end and the thin end are all positioned on the same straight line.

9. The method of claim 7,

the central axis of the through hole of the wire drawing die (11) and the lowest point of the driven wheel cone pulley (4) and the driving wheel cone pulley (6) are positioned on the same straight line;

the wire drawing die (11) is arranged in a cantilever (12) for placing the wire drawing die from top to bottom in sequence from large to small according to the diameter of the through hole;

the aperture difference value of the thin ends of the upper and lower adjacent wire drawing dies (11) is 0.01-0.1 mm, preferably 0.02-0.07 mm, and more preferably 0.03-0.05 mm.

10. The method of claim 2,

the wire drawing speed is 0.1-5 m/s, preferably 0.5-2 m/s, and more preferably 1 m/s.