KR101545694B1 - Adsorbent using mcn-1 for reducing indoor air pollutants and method for manufacturing the same - Google Patents

Abstract

The present invention relates to an adsorbent for reducing indoor air pollutants using mesoporous carbon nitride (MCN-1) and a method for producing the same. The adsorbent according to the present invention has significant formaldehyde abatement efficiency.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent for reducing indoor air pollutants using MCN-1,

The present invention relates to an adsorbent for reducing indoor air pollutants using mesoporous carbon nitride (MCN-1) and a method for producing the same. According to the present invention, the indoor air pollutant reduction efficiency can be remarkably improved.

The interest in the indoor environment began to rise in earnest as the environmental pollution increased due to the rapid increase of energy consumption through the rapid industrial structure development since the 1990s. The problem of indoor air quality (indoor air quality) in the indoor environment has been changed since the 1970s as part of efforts to improve energy efficiency and efficiency in various industrial fields. The indoor air quality of these buildings deteriorated.

Recently, various synthetic materials have been used in new building material and interior space due to the development of industrial technology and new symptoms of Sick house syndrome have been reported to residents due to indoor air pollution caused by dissemination of various chemicals . According to the definition of World Health Organization (WTO), sick house syndrome is a kind of chemical sensitization, which means abnormalities caused by formaldehyde and volatile organic compounds (VOCs).

Formaldehyde is one of the biggest factors of sick house syndrome, and has attracted attention both domestically and externally. It is very likely to be exposed because it is used in building materials, textiles, furniture, etc. in building a new house and it is prescribed as a carcinogenic substance under the Industrial Safety and Health Act. Formaldehyde is highly toxic to the human body in the event of inhalation to the occupational safety and health hazards and may result in respiratory tract burns, skin burns, mucous membrane burns, skin irritation, eye irritation, central nervous system depression, allergic reactions, . Formaldehyde is also defined as a carcinogen in the United States Occupational Safety and Health Administration (OSHA), the United States Independent Toxicology Program (NTP) and the International Carcinogenicity Research Institute (IARC).

In order to remove such formaldehyde, studies have been generally carried out to remove it from the gas phase, including adsorption, catalyst and photocatalytic oxidation. Among them, an adsorption method using activated carbon is most commonly used, and in addition to activated carbon, adsorbents such as silica gel, alumina, and zeolite are used. However, these adsorbents have low adsorption efficiency of formaldehyde and are known to have problems with their persistence. Therefore, development of an adsorbent having a high adsorption efficiency is required.

The present inventors intend to provide an adsorbent for reducing indoor air pollutants using MCN-1 and a method for producing the same, in order to remove formaldehyde, which is an indoor air pollutant causing sick house syndrome.

According to one aspect, an adsorbent for reducing indoor air pollutants using mesoporous carbon nitride (MCN-1) is disclosed.

The MCN-1 may be treated with ammonia.

According to another aspect, a method for producing an adsorbent for reducing indoor air pollutants using MCN-1 is disclosed. The method may include providing the MCN-1 by mixing the mesoporous material and the carbonitride. The method may further comprise ammonia treatment of the further produced MCN-I.

The adsorbent for reducing indoor air pollutants using MCN-1 according to the present invention can have remarkably excellent formaldehyde removal efficiency. In particular, the adsorbent for reducing indoor air pollutants using ammonia-treated MCN-1 according to the present invention may have a formaldehyde removal efficiency of 95% or more.

1 shows a schematic diagram of an apparatus for treating ammonia of MCN-1 according to Example 2. Fig.
Fig. 2 shows a formaldehyde adsorption method according to Experimental Example 2. Fig.
3 is a graph showing the measurement results of the concentration of formaldehyde according to Experimental Example 2. FIG.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, , Steps, operations, elements, components, or combinations thereof, as a matter of principle.

Unless otherwise defined herein, all terms used, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related art and should not be construed as an ideal or overly formal sense.

According to one embodiment, there is provided an adsorbent for reducing indoor air pollutants using mesoporous carbon nitride (MCN-1).

The term "indoor air pollutant " as used herein means pollutants such as dust, heavy metals, combustion gases, formaldehyde, and volatile organic compounds. In one embodiment, formaldehyde was used as the indoor air pollutant.

The formaldehyde (HCHO) has a molecular weight of 30 and a melting point of -92 캜, which means a material having a structural formula represented by the following formula (1). Since formaldehyde is in a gaseous state at room temperature and anhydrides are liable to polymerize, three molecules are polymerized with trioxane such as the following formula (2). In the case of commercial use, it is used in the form of a 37% aqueous solution called polyimide. When it is used for synthesis, it is made into a solid polymeric material of paraformaldehyde such as the following chemical formula (3)

As in the chemical structure of formaldehyde, the double bond of carbon and oxygen is an important functional group in the chemical reaction. Because carbon is more positively positively than oxygen, it easily reacts with a substance in which electronegative elements are present. can do. Adsorbents can be prepared using these properties of formaldehyde.

As used herein, the term "adsorbent " refers to a substance capable of concentrating certain components of the gas or liquid at the solid-liquid, gas-liquid or liquid-liquid interfaces. When a component is adsorbed on the adsorbent, the adsorbed component is referred to as an adsorbate. The adsorption takes place at any interface of the solid, the adsorbent is porous and the more capillary the more the interface of the solid required for adsorption is increased. The most important property that the adsorbent should have is the specific surface area and the affinity for the adsorbed material. The larger the specific surface area and affinity, the larger the adsorption effect.

In this embodiment, the adsorbent can increase the specific surface area by increasing the total pore volume and average pore size. In one embodiment, an adsorbent having a specific surface area of about 300 m ² / g to about 700 m ² / g, a total pore volume of about 0.5 cm ³ / g to about 0.8 cm ³ / g, and an average pore size of about 4.0 nm to about 7.0 nm .

In this embodiment, MCN-1 may be ammoniated. The adsorbent for reducing indoor air pollutants using ammonia-treated MCN-1 has a specific surface area of about 500 m ² / g to about 700 m ² / g, a total pore volume of about 0.7 cm ³ / g to about 0.8 cm ³ / g, And may have a size of about 4.0 nm to about 5.0 nm.

According to another embodiment, a method for producing an adsorbent for indoor air pollutant abatement using MCN-1 is provided. The method may include providing the MCN-1 by mixing the mesoporous material and the carbonitride. The method may further comprise treating the MCN-1 with ammonia.

MCN ≪ / RTI >

The step of providing the MCN-1 may be performed by mixing the mesoporous material with carbon nitride.

The mesoporous material means a material in which regular pores are regularly arranged. The mesoporous material may have pores having a size of 1 to 50 nm or 1 to 20 nm. Preferably, the mesoporous material may have a pore size of 5 to 10 nm.

The mesoporous material may be selected from the group consisting of silica, silicates, aluminosilicates, titanosilicates, aluminophosphates, silicoaluminophosphates, and borosilicates. Preferably, the mesoporous material may be silica.

In one embodiment, SBA-15 silica was used.

The carbon nitrides are the most promising candidates for complementing carbon in material applications, especially incorporation of nitrogen atoms in carbon nanostructures can increase mechanical, conductive, field-emission and energy-storage characteristics It is an attractive material attracting worldwide attention.

In one embodiment, ethylenediamine and carbon tetracholide were used.

MCN - 1  Ammonia treatment step

The step of treating the MCN-1 with ammonia means a method of activating the MCN-1 at high temperature using NH ₃ composed of hydrogen and nitrogen. Since the nitrogen functional group is increased by the ammonia treatment, the affinity with the indoor air pollutant can be further improved.

The ammonia treatment of MCN-1 can be carried out by introducing MCN-1 into the reactor and flowing NH ₃ at a temperature of about 600 ° C to about 800 ° C for about 2 hours. As the activation temperature increases, the specific surface area and porosity of MCN-1 may be increased, but above about 800 ° C the formation of nitrogen functional groups may be reduced.

In one embodiment, the ammonia treatment of MCN-1 was carried out at a temperature of about 700 DEG C for about 2 hours.

The adsorbent for reducing indoor air pollutants using ammonia-treated MCN-1 according to the above embodiment can exhibit formaldehyde removal efficiency of 95% or more.

In one embodiment, it exhibited a formaldehyde removal efficiency of at least 99%.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

Example  One: MCN -1 manufacture

0.5 g of mesoporous silica SBA-15 synthesized at 150 ° C was added to a mixture of 1.35 g of ethylenediamine and 3 g of carbon tetrachloride and dissolved at 90 ° C for 6 hours under stirring. The resulting dark brown solid mixture was dried in an oven for 12 hours and ground to produce a fine powder.

Example  2: MCN -1 ammonia treatment

The prepared MCN-1 was activated by ammonia treatment.

MCN-1 was placed in a U-shaped reactor and NH ₃ was flowed at 700 ° C for 2 hours at a flow rate of 50 ml / min using PID. Next, ammonia physically adsorbed on the surface of MCN-1 was removed by purging under a nitrogen atmosphere at a flow rate of 50 ml / min at room temperature. The adsorbent thus prepared was named MCN-1-NH ₃ . 1 shows a schematic diagram of an apparatus for treating ammonia of MCN-1 used above.

Experimental Example  1: Analysis of adsorbent

(1) XPS analysis

The MCN-1 and MCN-1-NH ₃ prepared in Examples 1 and 2 and the substance contained in the surface of CMK-3 as a control group were measured by X-ray photoelectron spectroscopy (XPS). The results are shown in Table 1 below.

Sample The atomic surface concentration (%) measured in XPS C O N CMK-3 96.67 2.11 - MCN-1 75.83 2.61 20.94 MCN-1-NH ₃ 83.45 1.22 15.33

As can be seen from the above Table 1, CMK-3 mostly contained C at its surface and had 2.11% of O. MCN showed a higher C content than CMK-3 and a very high nitrogen content of 20.94%. That is, MCN contained a large amount of nitrogen functional groups due to contained nitrogen.

On the other hand, the content of nitrogen in MCN-NH ₃ was slightly decreased compared with that of MCN. It is predicted that the nitrogen component present on the MCN surface is lost due to the high temperature ammonia treatment.

(2) Specific surface area analysis

To determine the specific surface area, the total pore volume and the average pore size of the adsorbent prepared by the methods of Examples 1 and 2, the amount of nitrogen adsorption and desorption was measured for adsorbent pretreated at 200 ° C under vacuum (BELSORP-MINI , BEL Japan Inc.). The specific surface area, total pore volume, and average pore diameter were calculated by the BET (Brunaure-Emmett-Teller) method using isothermal adsorption desorption curves. The specific surface area, total pore volume, and average pore size of CMK-1 (mesoporous carbon) containing no nitrogen component as a control group were calculated in the same manner as above. The results are shown in Table 2.

Sample Specific surface area (m ² / g) Total pore volume (cm ³ / g) Average pore size (nm) CMK-3 1178 1.28 3.8 MCN-1 375 0.57 6.4 MCN-1-NH ₃ 628 0.78 5.0

As shown in Table 2, the specific surface area of CMK-3 was the largest at 1178 m ² / g and the MCN was the smallest at 375 m ² / g. On the other hand, the specific surface area of MCN-1-NH _{3 with} MCN activated with ammonia increased to 628 m ² / g. Therefore, when ammonia is activated, it is considered that the surface area increases as the micropore and pore size are decreased.

Experimental Example  2: Formaldehyde adsorption experiment

This experiment was carried out using 100 ppm formaldehyde gas. Prior to the experiment, the 10L aluminum bag was cleaned with a pump and emptied in a vacuum to prevent contamination by outside air. The formaldehyde concentration was adjusted to 1 ppm by using nitrogen gas. 0.07 g of each of MCN-1, MCN-1-NH ₃ and CMK-3 prepared in Examples 1 and 2, respectively, was added. Also, the temperature was kept at 30 캜 using an incubator to remove the influence of the temperature during the adsorption, and the stirring was carried out in a shaking incubator to increase the mixing with the gas. The formaldehyde adsorption method is shown in Fig.

The concentration of adsorbed formaldehyde was measured using a formaldehyde analyzer (4000 Series, Woori System, Korea). The results are shown in Table 3 and FIG.

Sample 0 minutes 10 minutes 40 minutes 80 minutes CMK-3 1.10 0.75 0.65 0.58 MCN-1 1.00 0.23 0.21 0.20 MCN-1-NH ₃ 1.00 0.04 0.03 0.25

(Unit: ppm)

As can be seen from the above Table 3, the effect of reducing formaldehyde of MCN-1 prepared in Example 1 was superior to that of CMK-3. In particular, MCN-1-NH ₃ treated with ammonia according to Example 2 showed about 99% reduction in formaldehyde. It is considered that the reduction efficiency is increased by increasing the specific surface area by treating ammonia with MCN-1 and increasing the active sites on a large amount of nitrogen functional groups particularly on the surface.

It is to be understood that the specific structural or functional descriptions are illustrative only for the purpose of illustrating embodiments of the present invention and that the embodiments of the present invention may be embodied in various forms and that all changes, ≪ / RTI >

Claims (8)

The adsorbent has a specific surface area of 500 m ² / g to 700 m ² / g and a total pore volume of 0.7 cm ³ / g to 0.8 cm ³ / g , And an average pore size of 4.0 nm to 5.0 nm.
delete The method according to claim 1,
Wherein the indoor air pollutant is formaldehyde.
A method for producing an adsorbent for indoor air pollutant abatement, comprising the step of mixing MCN-1 with a mesoporous material and carbonitrile to treat MCN-1 with ammonia.
delete 5. The method of claim 4,
Wherein the ammonia treatment is carried out by reacting MCN-1 with NH ₃ at 600 ° C to 800 ° C and flowing N ₂ .
5. The method of claim 4,
Wherein the indoor air pollutant is formaldehyde.
delete

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