KR100674255B1 - Catalytic nanoparticles for reducing harmful materials generated from incinerator, and functional additives and polymers containing the nanoparticles - Google Patents

Abstract

The present invention is coated with a porous inorganic layer of white color on the metal oxide nanoparticles having an activity to inhibit or remove carbon monoxide, VOC (volatile organic compounds) generated by dioxin or incomplete combustion, which are harmful substances caused by incineration of polymers Finally, the nanobilayer catalyst nanoparticles are prepared. These catalysts are excellent in oxidizing toxic substances at low temperature but have white or light color and have good dyeability and small particle size. In this way, the polymer containing additives is environmentally friendly since the generation of harmful substances is greatly reduced when incinerated in an incinerator.

Dioxins, volatile organic compounds, nano catalyst particles

Description

Catalytic Nanoparticles for Reducing Hazardous Substances in Incinerators, Functional Additives and Polymers Comprising the Same

1 is a view illustrating the measurement of harmful substances generated when incineration of polyethylene.

Figure 2 shows the measured harmful substances generated by incineration of polyethylene containing 10% by weight of the catalyst of Example 3.

The rapid development of industry has greatly improved the convenience and comfort of human life, but by-products such as industrial waste generated on the other hand have serious problems of environmental damage. Recently, due to the increased interest in environmental pollution, a lot of efforts have been made at the national level, but there are still no satisfactory solutions.

In particular, incineration of used plastic wastes results in carbon monoxide, VOCs (volatile organic compounds), particularly toxic dioxins, due to incomplete combustion. In particular, dioxins are produced by pyrolysis of organochlorine compounds (eg, vinyl chloride, vinylidene chloride, chlorinated paraffin, dichlorobenzene, etc.) contained in a large amount in the waste.

You may choose to adjust the incineration conditions in order to avoid the generation of hazardous substances in the incineration of waste, but it is difficult to adopt as such technologies are not yet developed or economical.

Therefore, it is now common to strengthen and install incinerator prevention facilities. Such prevention facilities include (1) independent operation of the electrostatic precipitator, (2) combined operation of the electrostatic precipitator and the wet cleaning equipment, and (3) the electrostatic precipitator + the wet cleaning equipment + the special selective catalytic reduction (SCR). Catalytic reduction) Combined operation of the catalyst tower, and (4) Semi-dry reaction equipment + bag filter + SCR catalyst tower combined operation.

In order to remove harmful substances, catalyst towers installed at the rear end of incinerators are now commonly installed in low pressure catalyst reactors using honeycomb type modules (Catalysis Review-Sci, and Eng., 36 (2), 179-270). , 1994). Although the post-treatment method using honeycomb can effectively remove the harmful substances, it is also necessary to provide a prevention facility for removing another harmful substance at the back of the incinerator, and also to carry out simple incinerators or open air. Incineration is still difficult to apply, so the generation of harmful substances still cannot be solved.

In an effort to fundamentally solve this problem, it has begun to consider a method of adding inorganic particles to a conventional polymer to simultaneously remove harmful substances generated from incineration of the polymer. According to the existing invention, dolomite (Japanese Laid-Open Patent Publication No. 2000-327400), iron oxide (Japanese Laid-Open Patent Publication No. 2000-309718), zeolite (Japanese Laid-Open Patent Publication No. 2001-31107) and the like are added to a polymer. Dioxins produced by incineration can be reduced. However, due to the low activity of removing harmful substances of the added materials and the inherent color of the catalyst, they are used only in extremely limited fields such as garbage bags.

Therefore, there is an urgent need to develop a white nanoscale catalyst that can significantly reduce the amount of toxic substances generated by incineration of waste and at the same time remove the catalyst's own color to make a positive contribution to the coloring of polymers. come.

The present invention provides catalyst nanoparticles from active metal oxides that can efficiently remove harmful substances such as CO, dioxins, and volatile organic compounds generated by incineration of waste at a relatively low temperature of 400 ° C. The purpose of the present invention is to prepare catalyst nanoparticles of a composite layer that can easily achieve product coloring such as polymers, while maintaining catalytic activity by coating a porous layer.

In addition, it is another object to reduce the generation of harmful substances from the waste, including the polymer comprising the catalyst nanoparticles prepared as described above and the polymer containing such additives, which are incinerated after use.

The present invention is intended to effectively remove the harmful substances generated by incineration of waste,

Catalytic nanoparticles essentially comprising two components of FeOx and TiO ₂ ;

Catalytic nanoparticles having FeO _x components supported on nanoscale TiO ₂ ; And

The present invention relates to a catalyst nanoparticle in which FeO _x and TiO ₂ are supported and dispersed together on a catalyst support selected from the group consisting of nano-sized Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO, and combinations thereof. .

In one embodiment of the present invention, the present invention is a porous coating of a white inorganic material including TiO ₂ , Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO and combinations thereof in addition to the catalyst nanoparticles It relates to a catalyst nanoparticle of a composite layer formed by.

In still another embodiment of the present invention, the present invention provides a porous white inorganic material comprising TiO ₂ , Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO and combinations thereof in addition to the catalyst nanoparticles. It relates to an additive comprising a catalytic nanoparticle formed by coating.

In another embodiment of the present invention, the present invention provides a porous coating of a white inorganic material comprising TiO ₂ , Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO and combinations thereof in addition to the catalytic nanoparticles. It relates to a polymer containing the catalyst nanoparticles formed by. When the polymer contains catalyst nanoparticles, it is preferably contained at 50 wt% or less, more preferably 10 wt% or less.

In a further embodiment of the present invention, the present invention includes catalytic nanoparticles formed by coating a porous TiO ₂ layer on a nano-sized FeO _x particle surface.

In addition, as another embodiment of the present invention, the present invention includes an additive comprising catalytic nanoparticles formed by coating a porous TiO ₂ layer on a nano-sized FeO _x particle surface.

In another embodiment of the present invention, the present invention includes a polymer containing catalytic nanoparticles formed by coating a porous TiO ₂ layer on a nano-sized FeO _x particle surface. In the case where the polymer comprises catalyst nanoparticles, the catalyst nanoparticles are preferably contained at 50 wt% or less, more preferably 10 wt% or less.

Polymers used in the production of the functional polymer including the catalytic nanoparticles include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polyether, polyester, polysulfone, polyamide, polyimide, polyurethane, or Although it may be selected from the group consisting of a combination thereof, it is not limited thereto.

In more detail with respect to the present invention, in the present invention, catalyst nanoparticles are prepared from active metal oxides that remove harmful gases such as dioxins.

In preparing catalyst nanoparticles of the present invention from an active metal oxide, iron oxide (FeOx) and TiO ₂ must coexist in the prepared catalyst.

The metal oxide of the present invention, which is active in removing harmful gases generated by incineration of waste, must coexist as a complex component of iron oxide and TiO ₂ . To this end, iron oxide nanoparticles such as Fe ₂ O ₃ , Fe ₃ O ₄ , FeO and FeOOH may be supported on TiO ₂ nanoparticles, or iron oxide and TiO ₂ may be supported on the surface of nanoparticles for other catalyst supports. have.

First, in the case of supporting the iron oxide on TiO ₂ nano-size, the particle size of the TiO ₂ is but one limitation for the nano-grade, preferably 10-5,000 nm, and more preferably 10-500 nm . In this case, the supported iron oxide is preferably 2-40% by weight, more preferably 5-10% by weight, respectively.

Nanoparticles for the catalyst support include Al ₂ O ₃ , SiO ₂ , ZrO ₂ and the like, but are not limited thereto. The catalyst support (eg TiO _2, Al ₂ O ₃ nanoparticles, etc.) is not limited in size as long as it corresponds to nanoscale, but is preferably 10-5,000 nm, even more preferably 10-500 nm.

In the case of supporting the active metal oxide, in particular the iron oxide and Ti of the present invention, the weight of the supported Fe is preferably 2-40% by weight, more preferably 5-10% by weight. good. When Ti is supported with Fe, the weight percentage of the Ti component is 5-60 wt%, preferably 5-30 wt%.

In a further embodiment of the present invention, a white-colored material is porously coated on the surface of the catalyst nanoparticles prepared as described above to prepare a nano-sized catalyst finally colored white.

In the case of forming a coating layer by coating a material having a white system on the catalyst nanoparticles as described above, the coating layer should be porous so that gas can diffuse into the surface of the active catalyst particles, and the final particles after coating should be nano-sized. The white-based material may include, for example, but not limited to TiO ₂ , Al ₂ O ₃ , SiO ₂ , ZrO ₂ , zeolite, and the like. The thickness of the final coating layer is a minimum thickness that can cover the color of the active catalyst particles in white color, and if the thickness is longer, it is disadvantageous because harmful gas takes time to diffuse and penetrate the surface of the active catalyst. Depending on the coating material, usually a thickness of about 10-1,000 nm, more preferably 10-100 nm thick is appropriate.

As another simple catalyst preparation method according to the present invention, there is a method of directly coating the TiO ₂ on the nano-sized iron oxide particles with a porous. In this case, the size of iron oxide is preferably 10-100 nm, the content of the TiO ₂ coating layer depends on the iron oxide particles and coating method, but about 20-90% of the total catalyst weight is appropriate.

In addition, according to the present invention, an additive including the catalyst nanoparticles prepared according to the present invention, and a functional polymer material for reducing harmful gases including the catalyst may be provided. The additive may be any additive that can be used in the manufacture of industrial or household polymer molded articles, as long as it can impart functionality according to the present invention.

More specifically, according to the present invention, polymer nanoparticles formed by coating a white-based material with a porous coating are mixed with a suitable amount, preferably 50% by weight or less, and more preferably 10% by weight or less, in the polymer material. It can be used for its original purpose without seriously damaging it. In the case of the polymer including the catalytic nanoparticle of the present invention, the amount of harmful gas generated by incineration of the polymer waste disposed of after use can be significantly reduced.

As a method of coating a white-based material porously to prepare the catalyst nanoparticles according to the present invention, any of wet or dry methods known to those skilled in the art may be used.

Particle coating during wet coating utilizes the difference in zeta potential between the active catalyst nanoparticles and the white nanoparticles to be coated to generate attraction to coat the white nanoparticles.

Another wet coating example is to apply the Grafting method to coat the catalyst nanoparticles surface by dispersing the catalyst nanoparticles in a suitable solvent and then dropping the precursor material, which can develop a white system, into a solvent and slowly dropping it in the prepared solution. Reacts at to form a white coating layer.

In another example, when the zeolite is coated, the active catalyst nanoparticles are dispersed in the precursor solution for zeolite synthesis, and the zeolite is synthesized to finally prepare the zeolite-coated nanoparticles.

Dry coating vapor-deposits a white coating layer on the prepared active catalyst nanoparticles. As a deposition agent, metal chlorides, organometallic compounds (eg, metal alkoxides) and the like are evaporated in air or an inert gas to decompose and oxidize the surface of the catalyst nanoparticles at a high temperature to form nanoscale coating layers. At this time, in order to make the coating layer porous, Si or Al components are deposited together, and then Si or Al components are extracted and removed with an acid or an alkali to finally prepare catalyst nanoparticles further coated with a white nanoporous porous nanolayer.

When the catalyst nanoparticles prepared above are mixed and processed in an appropriate amount in a polymer molding process, a functional polymer that can reduce harmful gases generated by incineration is produced.

Polymers that can be used herein are polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinyl acetate, polyether, polyester, polysulfone, polyamide, polyimide, polyurethane, etc., regardless of the type of composite catalyst nanoparticles. It can be applied to industrial and household polymers in general.

Hereinafter, the present invention will be described with reference to specific examples of the present invention. However, the present invention is not limited by the following examples, and does not exclude the extent of modification that is obvious to those skilled in the art to which the present invention belongs.

<Example 1>

TiO ₂ nanoparticles having a size of 25 nm were placed in an aqueous solution of FeCl ₃ and stirred. The NH ₄ OH solution was slowly dropped into the solution, and finally Fe (OH) x was precipitated on the TiO ₂ particle surface. After filtration and dry firing, an active nanoparticle catalyst of Fe ₃ O ₄ / TiO ₂ component containing 5 wt% Fe was finally prepared.

<Example 2>

Al ₂ O ₃ particles having a size of 25 nm were added to an aqueous solution in which FeCl ₃ and Ti (SO ₄ ) ₂ were dissolved at a Fe / Ti weight ratio of 1/4 and stirred. The NH ₄ OH solution is slowly dropped into the solution, and finally Fe and Ti are co-precipitated in the form of hydroxide to support Al ₂ O ₃ particle surface. After filtration and dry firing, Fe-Ti / Al ₂ O ₃ component metal oxide nano catalyst particles having 5 wt% Fe and 20 wt% Ti were finally prepared.

<Example 3>

TiO ₂ particles of 25 nm size are dispersed in water to fix the pH to 6 (solution A). Fe ₃ O ₄ , 30 nm in size, is likewise dispersed in water and the final pH is adjusted to 6 (solution B). Stir vigorously while dropping Solution A into Solution B. At the same time, attraction is generated between Fe ₃ O ₄ and TiO ₂ so that the porous TiO ₂ particle layer is coated on the Fe ₃ O ₄ particles by 80% by weight. After the coating is finished, the membrane is filtered using a membrane having nano pores, and finally, a light gray catalyst nanoparticle is prepared through a dry firing process.

<Example 4>

5 wt% Fe ₃ O ₄ -TiO ₂ / Al ₂ O ₃ catalyst nanoparticles prepared in Example 2 were placed in a CVD (chemical vapor deposition) apparatus of a fluidized bed reactor to form a fluidized bed using dry air. Ti (OC ₄ H ₉ ) ₄ and SiCl ₄ were added at a concentration of 100ppm and 50ppm, respectively, to control the coating thickness by controlling the temperature and flow rate of the reactor. After coating to a thickness of 10nm and immersed in HF solution to elute Si. After filtration, washing and drying, the mixture was calcined at 400 ° C. to prepare white catalyst nanoparticles coated with TiO ₂ .

<Example 5>

The activity of the catalytic nanoparticles produced in Examples 1-4 was tested using 1,2-dichlorobenzene oxidation, which is similar in structure to dioxin. In a fixed bed reactor, the inlet concentration was 1,000 ppm and the flow rate was WHSV 6,000 L / kg cat h. The activity was observed while changing the reaction temperature to 200 ~ 800 ℃. As a comparative example, the activities of Fe ₃ O ₄ with a size of 30 nm and catalyst particles with a size of 25 nm were shown.

Table 1.Activity Comparison of Catalyst Nanoparticles with Temperature

    Catalytic reaction temperature Fe ₃ O ₄ (Comparative) TiO ₂ (Comparative) Example 1 Example 2 Example 3 Example 4 300 ℃ 40 25 45 47 42 44 400 ℃ 65 40 98 95 92 95 500 ℃ 90 75 98 97 95 97 700 ℃ 98 98 98 98 98 98

Can be seen from Table 1, as an exemplary iron oxide prepared according to Example 1-3 of the catalyst -TiO ₂ composite component is active at a low temperature (near 400 ℃) than the catalyst nanoparticles of the sole components, such as Fe ₃ O ₄ or TiO ₂ This is greatly improved. In addition, as shown in Example 4, even when the white porous layer is coated on the catalyst nanoparticles, the final catalytic activity is maintained without being reduced.

<Example 6>

10 wt% of the Fe ₃ O ₄ particles having a size of 30 nm and the TiO 2 coated white Fe-Ti composite catalyst particles prepared in Example 4 were added to the polyethylene, and then mixed several times with an extruder to finally prepare a functional polyethylene mixed with a catalyst. Prepared.

<Example 7>

The physical properties (tensile strength, permeability, etc.) of the functional polyethylene made in Example 6 were tested.

Tensile test

PE polymer type Pure LDPE LDPE + Fe ₃ O ₄ LDPE + Example 4 Catalyst Yield Tensile Strength (MPa) 20 13 18

Transmittance test by light wavelength

PE polymer type Relative transmittance (400 nm) Relative transmittance (800 nm) Pure LDPE 100 100 LDPE + Fe ₃ O ₄ 35 47 LDPE Example 4 Catalyst 78 92

As shown in the experimental results, Fe and Ti particles are used in combination with the Fe ₃ O ₄ nanocatalyst particles alone, but dispersed in smaller particles are better in terms of polymer properties.

 Example 8

Incineration experiments were performed using polyethylene without a catalyst and a polyethylene polymer containing 10% by weight of the catalyst prepared in Example 3. After pretreatment at 100 ° C. for 1 hour, the temperature was measured while raising the temperature from 100 ° C. to 800 ° C. As shown in the attached Figures 1 and 2, the functional polymer containing the catalytic nanoparticles was found to be reduced by more than 80% of the amount of generation of the organic compound compared to the other case.

Existing inorganic catalyst particles (Dolomite, Zeolite, Iron Oxide) catalyst particles added to reduce the harmful compounds generated by incineration of waste plastics are limited in their use at low temperatures or due to their inherent dark color. In addition, the size of the prepared catalyst is relatively large, when the polymer fiber yarn, such as thin, shows a break phenomenon.

The two-component catalyst nanoparticles composed of iron oxide / TiO ₂ developed in the present invention are superior to the activity of the single component due to the synergistic effect of iron and TiO ₂ to oxidize harmful gases, especially at low temperatures of about 400 ^o C. Excellent oxidation activity of noxious gas. In addition, by coating a porous white inorganic layer here, the final color disappears, so that coloring becomes easy, and thus the range of application to a polymer can be widened. The much smaller size also allows the molding of relatively thin and thin polymer products. Therefore, it provides a method for manufacturing environmentally friendly functional polymer that can remove or reduce various harmful substances generated by incineration of polymer waste.

Claims (13)

In the catalyst nanoparticles containing FeO _x and TiO ₂ 2 component, the FeO _x and Al ₂ O _3, SiO _2, zeolites, ZrO _2, MgO, CaO and combinations of 10 ~ 5000nm particle size with components of the TiO ₂ Catalyst nanoparticles characterized in that the support and dispersed in one or two or more catalyst supports selected from the group consisting of. The catalyst nanoparticle of claim 1, wherein the FeO _x is supported on the TiO ₂ having a particle size of 10 to 5000 nm. delete According to claim 1 or 2, in addition to the catalyst nanoparticles, one or two selected from the group consisting of TiO ₂ , Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO and combinations thereof. Catalyst nanoparticles formed by coating a white inorganic material containing the above material with porous. One or two or more materials selected from the group consisting of TiO ₂ , Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO and combinations thereof in addition to the catalyst nanoparticles according to claim 1. An additive comprising a catalyst nanoparticle formed by coating a porous white inorganic material comprising a. One or two or more materials selected from the group consisting of TiO ₂ , Al ₂ O ₃ , SiO ₂ , zeolite, ZrO ₂ , MgO, CaO and combinations thereof in addition to the catalyst nanoparticles according to claim 1. A polymer containing catalyst nanoparticles formed by coating a porous white inorganic material comprising a. The polymer according to claim 6, which contains 50 wt% or less of catalyst nanoparticles. 8. The polymer of claim 7, wherein the polymer contains 10 wt% or less of catalyst nanoparticles. The catalyst nanoparticle of claim 1, formed by coating a porous TiO ₂ layer on a surface of a FeO _x particle having a particle size of 10-5000 nm. An additive comprising catalytic nanoparticles formed by coating a porous TiO ₂ layer on a FeO _x particle surface having a particle size of 10-5000 nm. A polymer containing catalytic nanoparticles formed by coating a porous TiO ₂ layer on a FeO _x particle surface having a particle size of 10-5000 nm. 12. The polymer of claim 11, wherein the polymer contains up to 50% by weight of catalytic nanoparticles. 13. The polymer of claim 12, wherein the polymer contains 10 wt% or less of catalyst nanoparticles.

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