KR100779882B1 - Electroless Copper Coated Pitch Based Activated Carbon Fiber with Excellent Nitrogen Monoxide Reduction Characteristics and Electroless Copper Coated Pitch Based Activated Carbon Fiber - Google Patents

Abstract

The present invention relates to a method for producing an electroless copper-coated pitch-based activated carbon fiber and an electroless copper-coated pitch-based activated carbon fiber, and more particularly, in the method for producing a pitch-based activated carbon fiber, (a) pitch system Providing an activated carbon fiber (110), (b) a degreasing process 120 for removing oil from the pitch-based activated carbon fiber, (c) an etching process 130 for improving hook effect and wettability, (d) a catering process 140 for supporting palladium, which is an active material for growing copper on the pitch-based activated carbon fiber surface, (e) a washing process 150 using water, and (f) the catering Acceleration process 160 to remove the tin (Sn) layer used to support the palladium (Pd) in the process, and (e) electroless copper coating on the pitch-based activated carbon fibers subjected to the acceleration process Configured to include an electroless copper coating process 170 Relates the features in the nitric oxide reduction characteristics are superior electroless copper coating a pitch-based activated carbon fiber production process, and the electroless copper coated pitch-based activated carbon fibers produced therefrom that.

Description

Electroless Copper-Coated Pitch-Based Activated Carbon Fiber with Excellent Nitrogen Monoxide Reduction Characteristics and Electroless Copper-Plated Activated Carbon Fibers

1 is a flowchart illustrating a method for producing an electroless copper coated pitch-based activated carbon fiber having excellent nitrogen monoxide reduction characteristics according to an embodiment of the present invention.

Figure 2 shows the experimental apparatus applied to the NO reduction test.

3 shows the shape of the ACF / Cu sample.

4 shows the results of X-ray diffractometry (XRD) analysis of FIG. 3.

Figure 5 shows the results of the 77K / N ₂ isotherm (adsorption isotherm) of ACF / Cu samples containing ACF / Pristine.

6A, 6B, 6C, 6D, and 6E show NO reduction characteristics according to the reaction time when the reaction temperature was adjusted to 150, 200, 300, 350, and 400 ° C.

The present invention relates to an electroless copper-coated pitch-based activated carbon fiber manufacturing method excellent in nitrogen monoxide reduction characteristics and an electroless copper-coated pitch-based activated carbon fiber.

Activated carbon fiber (ACF) has a larger specific surface area and total pore volume than conventional activated carbon, and most of the pores formed are micropores, which have almost no diffusion resistance to adsorbates. This is very high.

In recent years, attention has been focused on the invention of increasing the adsorption efficiency and adding catalytic properties by imparting functional groups to the ACF surface or by adhering transition metals.

The coating method of the metal catalyst using the activated carbon as a carrier mostly uses a liquid impregnation method, which requires a step of post-treatment in an inert gas or air after the liquid impregnation process, and thus requires a long manufacturing time. The secondary side after coating has a disadvantage of low stability.

An object of the present invention is to solve the problems of the prior art and to provide a method for producing an electroless copper coated pitch-based activated carbon fiber excellent in nitrogen monoxide reduction characteristics and an electroless copper coated pitch-based activated carbon fiber.

1. Manufacturing process

In the present invention, a single-step catalyzing-based electroless coating method was used to coat copper on the pitch-based activated carbon fiber surface, and a study of reducing NO in anoxic conditions together with its surface characteristics was carried out at a temperature range of 150-400 ° C. It was.

Electroless coating of copper on the surface of activated carbon fiber is largely divided into four processes. The first process is to remove oil from the surface of activated carbon fiber by the degreasing process, and the second fixation is to carry palladium, an active material for growing copper, the final coating material, on the surface of activated carbon fiber by catalyzation process. The third process is the Acceleration process, which removes the tin layer used together to support the palladium in the second process. The final process is to perform electroless copper coating on the activated carbon fibers processed up to the third process.

Electroless copper coated activated carbon fibers are referred to as ACF / Cu. Catalyzation process in the present invention used a one-stage process using Pd-Sn at the same time instead of a two-stage process to sensitize the surface of activated carbon fibers with tin and activate with palladium. The ACF / Cu samples applied in the NO abatement test also included ACF / Cu-05, ACF / Cu-10, ACF / Cu-15, including ACF / Pristine without copper, based on electroless copper coating time (minutes). And ACF / Cu-20's were applied.

Electroless copper-coated pitch-based activated carbon fiber manufacturing method excellent in nitrogen monoxide reduction characteristics according to the present invention for achieving the object of the present invention is a method for producing a pitch-based activated carbon fiber, (a) pitch-based activated carbon fiber Providing step (110), (b) Degreasing process 120 for the removal of oil of pitch-based activated carbon fibers, (c) Etching process 130 for improving the hook effect and wettability, (d) Catering process 140 for supporting palladium, an active material for growing copper on the pitch-based activated carbon fiber surface, (e) washing step 150 using water, and (f) in the catering process Acceleration process 160 to remove the tin (Sn) layer used to support palladium (Pd), and (e) electroless copper coating on the pitch-based activated carbon fibers subjected to the acceleration process Including the copper coating process 170 All.

Hereinafter, a method for producing an electroless copper-coated pitch-based activated carbon fiber having excellent nitrogen monoxide reduction characteristics according to the present invention will be described in detail according to an embodiment shown in the accompanying drawings.

1 is a flowchart illustrating a method for producing an electroless copper coated pitch-based activated carbon fiber having excellent nitrogen monoxide reduction characteristics according to an embodiment of the present invention.

The degreasing process 120 is a process for removing oil from the pitch-based activated carbon fibers.

The etching step 130 is a step for imparting hydrophilicity to the base surface and for strengthening adhesion by the hook effect with the plating layer. The etching process 130 is preferably a sodium hydroxide (NaoH) solution having a concentration of 13 to 17 g / ℓ for 9 to 11 minutes at a temperature of 40 ~ 60 ℃. If the concentration is less than 13 g / ℓ did not occur because the reaction does not occur at a low concentration, when the concentration is more than 17 g / ℓ caused a problem of the loss of activated carbon fiber material due to overreaction. If the temperature is 40 ℃ or less, there is a problem that the etching effect is lowered unreacted, and the reaction is over reaction when the temperature is 60 ℃ or more. When 9 to 11 minutes were carried out, the adhesion was enhanced by the hook effect with the plated layer.

Catering process 140 is a process for evenly supporting the active material Pd in order to grow copper on the base. Catering process 140 is palladium chloride (PdCl ₂ ) concentration 0.35 ~ 0.45 g / L, tin chloride (SnCl ₂ · 2H ₂ O) concentration 18 ~ 22 g / L, hydrochloric acid ( HCl ) concentration 150 ~ 170ml 3 to 6 minutes at 35-55 ° C. using a catering solution of / l .

Palladium chloride (PdCl ₂ ), tin chloride (SnCl ₂ · 2H ₂ O), and hydrochloric acid (HCl) must be proportional to the catalysis solution for catalysis. The palladium chloride (PdCl ₂ ) concentration is 0.35 g / l or less, tin chloride (SnCl ₂ · 2H ₂ O) concentration value of 18 g / l or less, hydrochloric acid ( HCl ) concentration value of 150 ml / l or less , no catalyzing reaction or evenly supported Pd It was not possible to achieve the desired purpose of catering process 140.

When the palladium chloride (PdCl ₂ ) concentration value is 0.45 g / l or more, the tin chloride (SnCl ₂ · 2H ₂ O) concentration value is 22 g / l or more, and the hydrochloric acid ( HCl ) concentration value is 170 ml / l or more More than necessary palladium (Pd) is supported, an excessive tin (Sn) layer is generated, expensive palladium chloride (PdCl ₂ ) is consumed more than necessary, there was a problem that the production cost rapidly increased.

If the temperature is less than 35 ℃ unreacted catering effect is lowered, if the temperature is more than 55 ℃ there was a problem of overreacting. After 3 to 6 minutes, Pd, an active substance for growing copper, was evenly supported as needed.

Acceleration process 160 is a process of removing the tin layer used together to support palladium. Acceleration process 160 is performed for 6 to 8 minutes in a sulfuric acid (H ₂ SO ₄ ) solution of 9 to 11% (volume). When the concentration of sulfuric acid (H ₂ SO ₄ ) solution is below 9% When tin ions (Sn ⁺⁴ ) adhere to the surface of activated carbon fiber, the removal effect is reduced, and the concentration of sulfuric acid (H ₂ SO ₄ ) solution is above 11% Not only tin ions (Sn ⁺⁴ ) but also nuclei of palladium (Pd) were removed to interfere with surface nucleation during plating. It was performed for 6-8 minutes.

The electroless copper coating process 170 is performed using a copper coating liquid comprising CuSO ₄ .5H ₂ O, KNaC ₄ H ₄ O ₆ .4H ₂ O, and HCHO. The electroless copper coating process 170 has a CuSO ₄ · 5H ₂ O concentration of 0.22 to 0.33M, KNaC ₄ H ₄ O ₆ · 4H ₂ O concentration of 0.5 to 0.7M, HCHO concentration of 130 to 170 ml / l, and a PH of 12.5. It is preferably carried out using a copper coating liquid of ˜14.

For electroless copper coating, CuSO ₄ · 5H ₂ O, KNaC ₄ H ₄ O ₆ · 4H ₂ O, and HCHO should make a certain proportion relative to each other in the coating solution, CuSO ₄ · 5H ₂ O concentration 0.22 or less, KNaC ₄ When H ₄ O ₆ · 4H ₂ O concentration 0.5 or less, HCHO concentration 130mL / ℓ or less there was a problem that the plating is not made by unreacted, CuSO ₄ · 5H ₂ O concentration 0.33 or more, KNaC ₄ H ₄ O ₆ · 4H ₂ O concentration of 0.7 or more, HCHO concentration of 170ml / ℓ or more there is a problem that the autolysis reaction is not stable in the plating bath. The electroless copper coating process 170 was performed for 5 to 30 minutes. In order to obtain an appropriate amount of plating, the electroless copper coating time was 5 minutes or more. An experiment was performed on the pitch-based activated carbon fibers prepared by the method of manufacturing the electroless copper-coated pitch-based activated carbon fibers described above.

Example

Plating equipment

The plating apparatus to be used for electroless plating is a type in which a plating vessel is placed in a thermostatic bath equipped with a stirrer and a heater. The plating bath uses pyrex glass material to prevent free metal ions from being deposited on the wall of the plating bath, and the plating bath has a capacity of 1000 ml. The tester was made of aluminum, and a protective film was formed on Teflon tape having excellent corrosion resistance and heat resistance, and was placed in the center of the plating bath.

In addition, the tester was used for the pretreatment process and the copper plating process to prevent metal ions from reducing precipitation during electroless copper plating due to the catalyst Pd ⁰ remaining on the surface during the pretreatment process.

The temperature change of the plating liquid has a great effect on the plating speed and the plating structure, so it was plated in a thermostat. The thermostat is an oil thermostat consisting of a heater, a stirrer and a thermoregulator. The fabricated oil thermostat has a relatively large capacity, and it is possible to control the thermostat temperature range within ± 1 ° C through stirring.

Specimen Preparation and Pretreatment Conditions

a. The activated carbon fiber used in this experiment has different characteristics from those of the existing metal or non-metallic material, so the pretreatment of the specimen was considered in consideration of the physical properties of the carbon fiber. In order to determine the pretreatment conditions of the specimens, the specimens were treated at various pretreatment conditions, and then electroless plating was performed at a given bath property. First, we tried to give the anchoring effect to the surface of the metal body and to improve the wettability of the specimen. At this time, pretreatment conditions were performed for 10 minutes at a constant concentration and temperature in NaOH solution. For the surface activation process of the body, a single step process of sensitization and catalyzing was used. 10% H ₂ SO ₄ was used in the accelerating process, which removes Sn components remaining in the catalyzing process. Each process was washed three times at room temperature using tap water.

b. Pretreatment Condition

Substrate is activated carbon fiber to obtain a uniform plating layer while minimizing the effects on acids and bases in the pretreatment process. In this experiment, the etching process is closely related to the physical properties of the body, and it was confirmed that it is essential for improving the wetting property of the body in the aqueous solution and the anchoring effest. In general, the etching process is not only to impart hydrophilicity to the base surface, but also to enhance adhesion by the effect of hooking with the plating layer. Too much or too little etching may degrade the adhesion between the plated layer and the substrate.

In the etching process, the concentration of NaOH was fixed at 15 g / l, and the temperature of the liquid was fixed at 50 ° C. The etching time was fixed at 10 minutes for electroless copper plating.

In the catalyzing process, a catalyzing solution of electroless copper plating was used. The composition of the catalyzing solution used here was 0.4 g / l for PdCl ₂ , 20 g / l for SnCl ₂ · 2H ₂ O, and 160 ml / l for HCl. Was catalyzed. The specimen thus treated was accelerated with 10% H ₂ SO ₄ (volume standard) solution at room temperature for 7 minutes through water washing, and then electroless copper plating was performed.

As a result of electroless copper plating, there was no local nonuniformity of plating, and a uniform plating layer was obtained.

Electroless Copper plating

a. Preliminary experiments were conducted to check whether copper plating could be performed by electroless plating in addition to activated carbon fibers with various copper plating solutions. Based on the preliminary test results, the best electroless copper plating bath was selected in consideration of the uniformity and adhesion of the plating.

The main components of the electroless copper plating bath used in this experiment were CuSO ₄ · 5H ₂ O, KNaC ₄ H ₄ O ₆ · 4H ₂ O, HCHO, and pH was used as NaOH. The copper plated body was washed three times with tap water, dried at 105 ° C. for 3hr, and stored in a desiccator.

b. In order to uniformly obtain copper plating on activated carbon fibers, various types of electroless copper plating baths were selected and tested. Specimens treated by the pretreatment methods described above were performed for 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, and 30 minutes at the given temperatures, respectively. The composition and plating conditions of the representative electroless copper plating bath used in the experiment were CuSO ₄ · 5H ₂ O 0.28M, KNaC ₄ H ₄ O ₆ · 4H ₂ O 0.62M, HCHO 150ml / ℓ, pH was 13.25 The copper plating solution was carried out at room temperature.

Catalyst Characterization

In general, the gravimetric method used to measure the plating rate is incorrect because the weight change occurs because the pores of the activated carbon fibers are developed. Therefore, the change in the deposition rate (deposition rate) was measured by the thickness plated per unit time. The thickness of the plated layer was measured by the optical analyzer and Scannong Electron Microscopy (SEM), and the cross-sectional photograph of the plated layer was measured 15 times for each specimen by an image analyzer program (Media Cybernetics) and displayed as the average value. XRD was used for the composition analysis of the plating layer, and the composition of the plating layer was analyzed using EDS and ICP (Inductively Coupled Plasma Spectrometer: PERKINELMER OPTIMA 3000). The uniformity and shape of the plating film according to the plating temperature, the pH of the plating solution, the pH regulator, and the composition of the plating layer were observed using a scanning electron microscope (SEM).

2. Experiment

NO of Reduction characteristics

In order to activate the reduction characteristics of NO, an electroless copper-coated ACF / Cu sample was dried in a dry oven, and then 3.0g of sample was charged into the reactor and nitrogen gas was injected for 20 minutes to remove residual oxygen and water. . The gases entering the reactor were NO and N ₂ , respectively, as the test gas and the carrier gas. The initial concentration of NO was adjusted to 160ppm to confirm the reduction characteristics of NO under anoxic conditions. The concentration of NO before and after the reaction of NO flowing into the reactor was measured in real time. The concentration of NO was measured by a chemiluminescent NOx analyzer (NO-NO _{2 -} NO _x Analyzer, 42C, Thermo Environmental).

 Figure 2 shows the experimental apparatus applied to the NO reduction test. The concentration at the outlet of the reactor was calculated by the following equation (1), compared with the concentration at the inlet.

Where NO _i and NO _f are the NO concentrations (ppm) at the reactor inlet and outlet, respectively.

3. Results

To activated carbon fiber Electroless  Copper coating

Figure 3 below shows the shape of the ACF / Cu sample. Overall, as the electroless copper coating time increases, the amount and size of copper particles coated on the ACF surface increases.

4 shows the results of X-ray diffractometry (XRD) analysis of FIG. 3. As the electroless copper coating time increases, the amount of carbon decreases while the amount of copper increases. In addition, it was confirmed that the material coated on the ACF is mostly copper metal.

Sample Cu content (%) Pd content (ppm) Cu-5 3.7 230 Cu-10 8.7 265 Cu-15 10.4 280 Cu-20 13.3 361

Table 1 summarizes the results of inductively coupled plasma (ICP) analysis of the absolute amount of copper coated on ACF. As the electroless copper coating time increased, the absolute amount of copper coated on the ACF also increased. Also shown is the amount of palladium that leads to the coating of copper.

Figure 5 shows the results of the 77K / N ₂ isotherm (adsorption isotherm) of ACF / Cu samples containing ACF / Pristine. All samples prepared according to the present invention through the ACF / Pristine and ACF / Cu samples reached Plateau, where the amount of adsorption rapidly increased at the initial low relative pressure and then the amount did not increase at the subsequent relative pressure increase. I could see that.

On the other hand, in the case of ACF / Cu samples, the adsorption amount was lower than that of ACF / Pristine sample, and the adsorption amount decreased with the increase of the electroless copper coating time. Guess as.

NO Reduction characteristics

6A, 6B, 6C, 6D, and 6E show NO reduction characteristics according to reaction time when the reaction temperature was adjusted to 150, 200, 300, 350, and 400 ° C. At 150 and 200 ° C, there was only a slight difference in properties between ACF / Pristine and ACF / Cu samples, indicating no catalytic conversion of NO in copper-coated ACF samples. On the other hand, when the reaction temperature was increased from 300 to 400 ℃, it was confirmed that the reduction characteristics of NO were significantly higher than that of ACF / Cu in the case of ACF / Pristine, which was in proportion to increasing the reaction temperature. However, in ACF / Cu samples, the NO reduction characteristics tended to decrease as the coating time of Cu increased, that is, as the amount of copper coated on ACF increased.

  As the amount of copper particles coated on the ACF increased, Park et al. In contrast to the results of the study, the reason for the decrease of the NO reduction property is due to the property of decreasing as the amount of copper particles coated with the adsorption pores of the ACF increases. According to the report reported by Illan-Gomez et al, this study was carried out under anoxic conditions, considering that the oxygen injection in the catalytic conversion of NO is a very important factor in increasing the catalytic conversion rate of NO. It can be explained that the result is generated.

An electroless copper-coated pitch-based activated carbon fiber manufacturing method having excellent nitrogen monoxide reduction characteristics according to the present invention having such a configuration and an operation of the electroless copper-coated pitch-based activated carbon fiber will be described.

The electroless copper coating on the pitch-based activated carbon fiber was performed based on single-step catalyzation to confirm that the uniform copper particles were dispersed to the ACF surface. The XRD and ICP analysis confirmed that the particles were metallic copper. It was.

When ACF / Cu samples were applied to NO reduction, it was found that the catalytic conversion performance was remarkable at the reaction temperature of 300 ° C or higher, whereas the reduction characteristics of NO decreased as the amount of copper coated on ACF increased. This may be due to the reduction of adsorption pores of ACF by anoxic reaction conditions and copper coating.

Although the present invention has been described in connection with the above-mentioned preferred embodiment, the scope of the present invention is not limited to the embodiment, various modifications and variations will be possible.

According to the present invention solves the problems of the prior art, there is provided a method for producing an electroless copper coated pitch-based activated carbon fiber excellent in nitrogen monoxide reduction characteristics and an electroless copper coated pitch-based activated carbon fiber.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, the scope of the present invention is not limited to these embodiments, and the scope of the present invention is defined by the following claims, and equivalent scope of the present invention. It will include various modifications and variations belonging to.

Claims (6)

In the manufacturing method of pitch-based activated carbon fiber, (a) providing a pitch-based activated carbon fiber (110); (b) a degreasing process 120 for removing oil from the pitch-based activated carbon fibers; (c) an etching process 130 for improving hook effect and wettability; (d) a catering process 140 for supporting palladium, which is an active material for growing copper, on the pitch-based activated carbon fiber surface; (e) washing with water (150); (f) an acceleration process (160) for removing the tin (Sn) layer used to support palladium (Pd) in the catering process; (e) an electroless copper coating process 170 for performing electroless copper coating on the pitch-based activated carbon fibers subjected to the acceleration process; excellent electroless copper having excellent nitrogen monoxide reduction characteristics, characterized in that it comprises a Coated pitch-based activated carbon fiber manufacturing method. The method of claim 1, The etching step 130 is performed for 9 to 11 minutes at a temperature of 40 to 60 ° C. with a sodium hydroxide (NaoH) solution having a concentration of 13 to 17 g / l; The catering process 140 is palladium chloride (PdCl ₂ ) concentration 0.35 ~ 0.45 g / L, tin chloride (SnCl ₂ · 2H ₂ O) concentration 18 ~ 22 g / L, hydrochloric acid ( HCl ) concentration 150 ~ 170 Method for producing an electroless copper-coated pitch-based activated carbon fiber excellent in nitrogen monoxide reduction characteristics, characterized in that carried out for 3 to 6 minutes at 35 ~ 55 ℃ using a catering solution of ㎖ / ℓ . The method of claim 3, The acceleration process 160 is carried out in a 9-11% (volume) sulfuric acid (H ₂ SO ₄ ) solution; The electroless copper coating process 170 is characterized in that the nitrogen monoxide reduction characteristics characterized in that it is performed using a copper coating liquid comprising CuSO ₄ · 5H ₂ O, KNaC ₄ H ₄ O ₆ · 4H ₂ O, and HCHO. This excellent electroless copper coated pitch-based activated carbon fiber manufacturing method. The method of claim 3, The electroless copper coating process 170 is CuSO ₄ · 5H ₂ O concentration 0.22 ~ 0.33M, KNaC ₄ H ₄ O ₆ · 4H ₂ O concentration 0.5 ~ 0.7M, HCHO concentration 130 ~ 170 mL / L , PH is A method for producing an electroless copper-coated pitch-based activated carbon fiber having excellent nitrogen monoxide reduction characteristics, which is performed using a copper coating solution of 12.5 to 14. The method of claim 4, wherein The electroless copper coating process 170 is an electroless copper coated pitch-based activated carbon fiber manufacturing method having excellent nitrogen monoxide reduction characteristics, characterized in that performed for 5 to 30 minutes. An electroless copper-coated pitch-based activated carbon fiber prepared by the method for producing an electroless copper-coated pitch-based activated carbon fiber according to claim 1.

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