JP7847809B2 - Adsorbent material for viruses - Google Patents

Description

This invention relates to an adsorbent for viruses.

Viral infection occurs when an uninfected person inhales or ingests fine aerosols originating from an infected person (e.g., their breath, saliva, etc.). Infection can also occur when an uninfected person comes into contact with aerosols or mist containing the virus that have adhered to clothing, furniture, or tableware. Thus, viruses are widely dispersed in the environment, and preventing viral infection requires efficiently inactivating the viruses that are widely distributed in the environment.

A known method for inactivating viruses is the use of ozone (see, for example, Patent Document 1). High concentrations of ozone can inactivate not only viruses attached to objects but also viruses contained in aerosols floating in the air. However, since ozone is harmful to the human body, it cannot be used in environments where people are active.

A known method for inactivating viruses is the use of ultraviolet (UV) light (see, for example, Patent Document 2). UV light can inactivate viruses present in areas irradiated with UV light, but it cannot inactivate viruses present in areas not irradiated with UV light. Furthermore, since UV light is harmful to the human body, it cannot be used in environments where people are active.

A known method for inactivating viruses is the use of alcohol (see, for example, Patent Document 3). Alcohol (especially high-concentration alcohol) is primarily used to inactivate viruses adhering to the surface of hands and is utilized as a means of preventing contact transmission. However, since alcohol easily vaporizes and can affect the human body or the environment, it is difficult to use large amounts of alcohol in environments where people are active.

Japanese Patent Publication No. 2013-238392 Japanese Patent Publication No. 2000-107269 Japanese Patent Publication No. 2019-194164

As mentioned above, conventional methods have made it difficult to inactivate viruses present in environments with high infection risk (e.g., airborne viruses) without disrupting people's activities. Therefore, the development of novel adsorbents for viruses is needed.

This invention was made in view of the above-mentioned problems, and its purpose is to provide a novel adsorbent for viruses.

One embodiment of the present invention is as follows:

[1] A virus adsorbent comprising a hydrophilic porous inorganic material containing an additive material having an amino group.

[2] The above-mentioned virus is contained in the aerosol, and the adsorbent is as described in [1].

[3] The hydrophilic porous inorganic material is sepiolite, activated clay, silica gel, pargoskite, or a mixture thereof, as described in [1] or [2].

[4] The adsorbent according to any one of [1] to [3], wherein the adsorbent material having the above-mentioned amino group is aluminum hydrazine sulfate, magnesium hydrazine sulfate, hydrazine phosphate, an organic amino compound, or a mixture thereof.

[5] The hydrophilic porous inorganic material is an adsorbent according to any one of [1] to [4], comprising a lubricant or manganese dioxide.

[6] The hydrophilic porous inorganic material described above has a honeycomb structure, as described in any of [1] to [5].

[7] The adsorbent described above is a non-calcined and dried product, as described in any of [1] to [6].

According to one embodiment of the present invention, it has the effect of providing an adsorbent for viruses.

This is a schematic diagram of an ethanol adsorption performance evaluation test apparatus using the honeycomb-shaped adsorbent prepared in Example 1, according to one embodiment of the present invention.

One embodiment of the present invention is described below, but the present invention is not limited thereto. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included within the technical scope of the present invention. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents cited herein are incorporated as references. Unless otherwise specified herein, "A to B" representing a numerical range means "A or greater (including A and greater than A) and B or less (including B and less than B)."

[1. Technical Concept of the Invention]
For viruses and organisms, water is essential for sustaining life. Therefore, it is natural that viruses and organisms live in environments where water is abundant.

The surface of a virus contains many polar groups, such as hydroxyl groups (-OH), which have a high affinity for water. Therefore, these polar groups (e.g., hydroxyl groups) attract moisture from the atmosphere, forming a water film around the virus, as well as creating aerosols or mist.

Specifically, while the particle size of a virus is approximately 0.1 μm, aerosols with particle sizes of approximately 1 μm to 10 μm are formed. These virus-containing aerosols can remain suspended in the air for extended periods. As aerosols form, the viral components (e.g., proteins and lipids) are covered by a water film, preventing oxidation of these components by oxygen in the air. This allows the virus to maintain its activity and continue to infect people.

The ability of viruses to collect moisture from the atmosphere is thought to vary depending on the type of virus. Atmospheric humidity fluctuates significantly from summer to winter (for example, from approximately 10% to 90%). For instance, with the novel coronavirus (SARS-CoV-2), no clear difference in infection trends is observed between summer and winter. This suggests that the novel coronavirus has a high ability to collect moisture from the atmosphere.

Based on the above, the inventors hypothesized that by removing the aqueous film covering the surface of the virus, the components of the virus would be oxidized by oxygen in the air, thereby causing the components to lose their activity.

Furthermore, the inventors hypothesized that simply removing the water film from the virus's surface would not be sufficient, as the polar groups (e.g., hydroxyl groups) on the virus's surface protect it, thus requiring time for oxygen in the air to oxidize and inactivate the virus's components. Therefore, to rapidly oxidize and inactivate the virus's components, it was considered necessary not only to remove the water film from around the virus, but also to damage the layer of polar groups (e.g., hydroxyl groups) on the virus's surface, thereby creating conditions that facilitate the oxidation of the virus's internal components by oxygen in the air.

In other words, the inventors considered that because the polar groups (e.g., hydroxyl groups) on the surface of viruses have a strong ability to retain water molecules, the first important step in removing the water film from around the virus is to attach the virus to an adsorbent with a water absorption capacity that exceeds the water molecule retention capacity of the polar groups (e.g., hydroxyl groups).

Furthermore, the inventors considered that a crucial second step involves destroying polar groups (e.g., hydroxyl groups) by utilizing chemical reactions.

The adsorbent according to one embodiment of the present invention inactivates viruses through the first and second steps described above. More specifically, the adsorbent according to one embodiment of the present invention performs the first step mainly with a hydrophilic porous inorganic material, and then performs the second step mainly with an impregnation material.

[2. Adsorbent]
In this specification, "adsorbent according to one embodiment of the present invention" may also be referred to as "the adsorbent." In this specification, "method for manufacturing the adsorbent according to one embodiment of the present invention" may also be referred to as "the manufacturing method."

An adsorbent according to one embodiment of the present invention is a virus adsorbent comprising a hydrophilic porous inorganic material containing an impregnating material having amino groups. Alternatively, an adsorbent according to one embodiment of the present invention may comprise a hydrophilic porous inorganic material to which an impregnating material having amino groups is attached. With this configuration, the adsorbent can capture viruses and inactivate them.

Furthermore, the adsorbent according to one embodiment of the present invention also possesses adsorption performance for aldehydes that are generally difficult to adsorb (e.g., acetaldehyde, formaldehyde). That is, even when processed into a honeycomb shape, this adsorbent containing an additive material having amino groups retains its effectiveness and can remove aldehydes. In this case, the adsorbent according to one embodiment of the present invention may contain manganese dioxide in the hydrophilic porous inorganic material.

The above-mentioned virus is preferably a virus contained in an aerosol. Since this adsorbent can more easily remove the water film forming the aerosol, it can capture the virus and more easily inactivate it.

In one embodiment of the present invention, the virus may be, for example, various coronaviruses such as the novel coronavirus (COVID-19), various influenza viruses, rubella virus, mumps virus, human rhinovirus, or adenovirus.

In one embodiment of the present invention, an aerosol refers to a mixture of solid or liquid fine particles dispersed and suspended in a gas. More specifically, an aerosol refers to a mixture of a substance and a water film that is suspended in the air, with the substance surrounded by a water film.

The above-mentioned hydrophilic porous inorganic material has the ability to adsorb and capture viruses, and the functional groups (amino groups) present on the surface of the adsorbent have the effect of inactivating viruses. These functional groups originate from the impregnating material contained in (or attached to) the hydrophilic porous inorganic material.

The virus inactivation effect of adsorbents occurs after the virus has been adsorbed onto the surface of the adsorbent. Therefore, a key factor is the functional structure of the adsorbent, which allows it to efficiently adsorb and capture the virus to be inactivated.

The material constituting the above structure is preferably a porous material with a large specific surface area that allows the viruses to be treated to adhere to the adsorbent. That is, the above structure refers not only to the macroscopic structure forming spaces of several millimeters in size, but also to the microscopic structure on the surface of the adsorbent, ranging in size from several micrometers to several angstroms. For practical use as a virus adsorbent, it is preferable that the adsorbent has a large surface area per unit volume, is formed as a structure with good permeability (e.g., a honeycomb structure), and is also formed as a highly durable structure.

(2-1. Hydrophilic porous inorganic material)
A hydrophilic porous inorganic material according to one embodiment of the present invention is an inorganic material that possesses both hydrophilicity and porousness, and includes an impregnating material having amino groups. A hydrophilic porous inorganic material according to one embodiment of the present invention may be an inorganic material that possesses both hydrophilicity and porousness, and is formed by impregnating an impregnating material having amino groups.

In one embodiment of this application, hydrophilicity refers to a property that has a high degree of interaction and affinity with water. More specifically, in one embodiment of this application, hydrophilicity refers to a material that has the ability to absorb water molecules surrounding a virus having a polar group (e.g., a hydroxyl group). For example, in one embodiment of this application, a hydrophilic inorganic material may be an inorganic material in a size of 50 mm x 50 mm x 50 mm through which a gas containing 100 ppm or less, 50 ppm or less, or 10 ppm or less of water (or ethanol) is passed, after which the water content in the gas becomes 0 ppm.

In one embodiment of this application, the shape and number of pores in the porous inorganic material are not limited. Furthermore, these pores may penetrate the inorganic material or may not penetrate it.

The hydrophilic porous inorganic material according to one embodiment of this application is not particularly limited and includes, for example, sepiolite, activated clay, silica gel, pargoskite, or mixtures thereof.

Among the hydrophilic porous inorganic materials described above, those having chain-like magnesium silicate as the main component are preferred, and sepiolite is particularly preferred. Because sepiolite has drying and solidifying properties, using sepiolite offers the advantage of being able to form a honeycomb structure while maintaining the functionality of the impregnating material well. Furthermore, this configuration results in an adsorbent exhibiting excellent moldability and high adsorption to viruses, and maintaining the activity of the functional groups on the surface of the adsorbent over a long period. Sepiolite is also flame-retardant and can be reused repeatedly through regeneration, offering the advantage of lower running costs compared to disposable activated carbon. Moreover, since adsorption by the impregnating material is chemical adsorption, it has the advantage of preventing the target substance (virus) from easily detaching compared to activated carbon using physical adsorption, allowing for the capture of small molecules of 40 Å or less, and enabling the chemical decomposition and adsorption of larger molecules.

As described above, the hydrophilic porous inorganic material according to one embodiment of the present application may be a mixture of various materials, for example, a mixture of hydrophilic porous inorganic material A (e.g., sepiolite) containing chain-like magnesium silicate as the main component and hydrophilic porous inorganic material B (e.g., activated clay, silica gel) that does not contain chain-like magnesium silicate as the main component.

The content of the hydrophilic porous inorganic material A in one embodiment of this application is preferably high. For example, it is preferable to contain 10% to 100% by weight of the hydrophilic porous inorganic material A per 100% by weight of the hydrophilic porous inorganic material, more preferably 20% to 100% by weight, and even more preferably 30% to 100% by weight.

Furthermore, the content of the hydrophilic porous inorganic material B according to one embodiment of this application is preferably 10% to 70% by weight, more preferably 20% to 65% by weight, and even more preferably 30% to 60% by weight, per 100% by weight of the hydrophilic porous inorganic material. This configuration offers the following advantages: (i) the characteristic of sepiolite, which is a large shrinkage rate when used alone, is suppressed, allowing for reduced shrinkage even during drying; (ii) friction between the mold and the hydrophilic porous inorganic material is reduced, facilitating extrusion molding; and (iii) sufficient gaps between the particles of the hydrophilic porous inorganic material are ensured, making it easier for virus-containing gases to diffuse into the interior of the hydrophilic porous inorganic material.

(2-2. Adhesive material)
An adsorbent according to one embodiment of the present invention comprises a hydrophilic porous inorganic material, the hydrophilic porous inorganic material containing an impregnating material having amino groups. An adsorbent according to one embodiment of the present invention comprises a hydrophilic porous inorganic material, the hydrophilic porous inorganic material may contain a solution-like impregnating material having amino groups, and then the solvent of the impregnating material (e.g., water, alcohol, etc.) may be dried off (in other words, it may contain the solid components of the impregnating material).

The impregnating material having the above-mentioned amino group is preferably aluminum hydrazine sulfate, magnesium hydrazine sulfate, hydrazine phosphate, an organic amino compound, or a mixture thereof. These compounds have the advantage of resonating well with the hydroxyl groups on the surface of the virus, while maintaining activity over a long period due to the weak activity of the amino group.

Even functional groups that react with polar groups (e.g., hydroxyl groups) on the surface of viruses are impractical if they readily react with molecules and substances present in the air, resulting in a short usable lifespan. Functional groups that can maintain sufficient activity to chemically react with the polar groups (e.g., hydroxyl groups) on the surface of viruses for six months to several years, even when left exposed to air, are necessary. The aforementioned impregnation materials possess functional groups that suitably meet these properties.

In the adsorbent according to one embodiment of the present invention, the weight ratio of the hydrophilic porous inorganic material to the solid content of the impregnating material is not particularly limited. However, the solid content of the impregnating material may be 0.1 to 50 parts by weight, 0.1 to 40 parts by weight, 0.1 to 30 parts by weight, 0.1 to 20 parts by weight, 0.1 to 10 parts by weight, 0.1 to 5 parts by weight, or 0.1 to 1 part by weight per 100 parts by weight of the hydrophilic porous inorganic material. With this configuration, the adsorbent can better capture viruses and better inactivate them.

(2-3. Other ingredients)
The hydrophilic porous inorganic material according to one embodiment of the present invention preferably contains a lubricant (for example, an inorganic lubricant). It may also contain manganese dioxide. Examples of such lubricants include kaolin (kaolinite), smectite, and imogolite. By including such a lubricant, the moldability when the adsorbent is extruded can be improved.

Furthermore, by adding manganese dioxide to a hydrophilic porous inorganic material, the reactive oxygen species generated from the manganese dioxide can inactivate viruses, which is an advantage. Since these reactive oxygen species remain within the adsorbent (in other words, the filter) according to one embodiment of this invention and are not released, viruses can be efficiently inactivated, while the unwanted impact of the reactive oxygen species on the environment can be minimized.

Furthermore, while there is no particular lower limit to the temperature when manufacturing the adsorbent containing manganese dioxide, a higher temperature is preferable, and 100°C or higher is particularly preferable. This configuration has the advantage of being able to elicit a high level of reactivity (in other words, virus inactivation ability) from the reactive oxygen species derived from manganese dioxide.

(2-4. Form of adsorbent material)
The shape of the adsorbent according to one embodiment of the present invention is not particularly limited, but may be honeycomb-shaped, noodle-shaped, granular, or foil-shaped, and is preferably honeycomb-shaped. With this configuration, the adsorbent can better capture viruses and better inactivate them.

A honeycomb structure refers to a structure resembling a beehive, with numerous through-holes surrounded by thin partitions. More specifically, a honeycomb structure refers to a shape in which numerous cells are uniformly distributed in a honeycomb-like pattern. In one embodiment of this application, by coating and/or supporting an adsorbent material on the surface inside the cells, a three-dimensional adsorption function can be achieved, and the contact efficiency between the virus and the adsorbent can be increased. Furthermore, this configuration has the advantages of reducing equipment costs due to low pressure loss, eliminating the need for a binder in molding, and producing a flame-retardant adsorbent. In addition, the honeycomb structure has the advantage of a large surface area per unit volume (specific surface area) and low gas permeability resistance when passing through the honeycomb structure. That is, by using a honeycomb structure, the energy required for gas to pass through the structure can be suppressed, and the surface area in contact between the adsorbent material and the gas can be increased.

In the honeycomb structure described above, the number of cells refers to the number of cells per square inch, expressed as cpsi (= cells/ ^inch² ). The number of cells according to one embodiment of this application is not particularly limited, but is preferably 10 cpsi or more, more preferably 50 cpsi or more, more preferably 100 cpsi or more, more preferably 150 cpsi or more, and even more preferably 200 cpsi or more. The upper limit of the number of cells according to one embodiment of this application is not particularly limited, but may be 1000 cpsi or less, 500 cpsi or less, or 300 cpsi or less. When the thickness of the walls constituting the cells (hereinafter referred to as "wall thickness") is the same, the above configuration allows for a larger specific surface area of the adsorbent, thereby enabling the adsorbent to better capture viruses and better inactivate them.

The wall thickness of the honeycomb structure described above is not particularly limited, but is preferably 1.0 mm or less, more preferably 0.7 mm or less, and even more preferably 0.5 mm or less. The lower limit of the wall thickness of the honeycomb structure described above is not particularly limited, but may be 0.01 mm or more, 0.05 mm or more, or 0.1 mm or more. This configuration provides the effect of ensuring sufficient strength of the adsorbent material while reducing its weight.

While a high cell count and thin wall thickness are desirable, the adsorption capacity is proportional to the weight of the material. Therefore, if the wall thickness becomes too thin, the lifespan of the honeycomb structure will be shortened.

Here, the smaller the size of the unit cell in the opening, the larger the specific surface area of the honeycomb structure can be. On the other hand, even if the size of the unit cell in the opening is small, the thicker the wall thickness, the smaller the opening area of the cell through which a unit amount of gas passes. Therefore, if a unit amount of gas is to pass through the cell in a certain amount of time, the airflow velocity of the gas passing through the cell increases, resulting in increased airflow resistance. For this reason, it is necessary to create a honeycomb structure with small unit cells in the opening and thin walls. From the viewpoint of creating a honeycomb structure with thin walls, it is preferable to add a lubricant.

The adsorbent according to one embodiment of the present invention is preferably a non-fired and dried material (a low-temperature dried material). With this configuration, an adsorbent with sufficient strength can be easily manufactured without going through a firing process.

[3. Method for manufacturing adsorbent]
A method for manufacturing an adsorbent according to one embodiment of the present invention is:
A process of forming an impregnated material by impregnating a hydrophilic porous inorganic material (optionally, a hydrophilic porous inorganic material containing a lubricant) with a solution containing an impregnating material,
The process involves molding the impregnated material (for example, by extrusion molding) to form a molded body (for example, a honeycomb-shaped, noodle-shaped, granular, or foil-shaped molded body),
The manufacturing method may include a step of drying the molded article (for example, drying at a low temperature).

A method for manufacturing an adsorbent according to one embodiment of the present invention is:
A step of forming a molded body (for example, a honeycomb-shaped, noodle-shaped, granular, or foil-shaped molded body) by molding (for example, extrusion molding) a hydrophilic porous inorganic material (optionally, a hydrophilic porous inorganic material containing a lubricant),
The process involves impregnating the above-mentioned molded body with a solution containing an additive to form an impregnated object,
The manufacturing method may include a step of drying the impregnated material (for example, drying at a low temperature).

Regarding the configuration of the method for manufacturing the adsorbent according to one embodiment of the present invention, the configuration already described in [2. Adsorbent] above will be omitted here.

When forming materials, extrusion molding is preferable. Specific examples of extrusion molding include the honeycomb molding method and the noodle molding method.

In the honeycomb molding method, the outer shape of the holes constituting the honeycomb structure can be arbitrarily selected, such as circular, square, or triangular, using the die of the extrusion molding machine. The thickness of the adsorbent material is determined by where the extruded material is cut.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

The raw materials and equipment used in the examples and comparative examples are as follows:
<Porous inorganic material>
• Silica gel, sepiolite, activated clay <amino group-containing compounds>
• Aluminum hydrazine sulfate <lubricant>
Kaolin (manganese dioxide)
Activated manganese dioxide <inorganic binder sol>
• Alumina sol <virus>
• Influenza virus <device>
• Particle counter <Manufacturing of honeycomb structures containing amino groups>
(Example 1)
A porous inorganic material consisting of silica gel powder, sepiolite, and a lubricant, kaolin, was mixed in a weight ratio of 50:40:10. This porous inorganic material was then impregnated with an aqueous solution of aluminum hydrazine sulfate and kneaded.

After kneading, the kneaded material was molded into a honeycomb shape by extrusion molding and allowed to air dry for 24 hours. Subsequently, a honeycomb-shaped adsorbent (wall thickness 0.5 mm, cell count 160 cpsi (= cells/inch ² )) was obtained.

(Comparative Example 1)
The adsorbent was obtained using the same method as in Example 1, except that an aqueous solution of aluminum hydrazine sulfate was not added.

<Ethanol adsorption performance evaluation test>
To investigate the reactivity of the amino groups in the adsorbent prepared in Example 1, an ethanol adsorption performance evaluation test was conducted by passing air containing ethanol through the adsorbent. Figure 1 shows a schematic diagram of the ethanol adsorption performance evaluation test apparatus using the honeycomb-shaped adsorbent prepared in Example 1. Specifically, the honeycomb-shaped adsorbent 2 (50 mm x 50 mm, 50 mm thick) prepared in Example 1 was connected to a first container 1 containing air containing ethanol, and an air pump 3 (7 L/min.) was connected between the honeycomb-shaped adsorbent 2 and the second container 4 so that the gas that passed through the honeycomb-shaped adsorbent 2 would flow to the second container 4. The ethanol concentration before passing through the honeycomb-shaped adsorbent was set to 20 ppm. Table 1 shows the results of measuring the rate of decrease in ethanol concentration using the adsorbents prepared in Example 1 and Comparative Example 1.

The results in Table 1 clearly show that ethanol containing a hydroxyl group is effectively adsorbed and removed by a honeycomb-shaped adsorbent containing an amino group.

<Water Aerosol Capture Test>
In Example 1, aerosols consisting of water with a particle size of 0.3 μm or less were passed through a honeycomb-shaped adsorbent (100 mm x 100 mm, 10 mm or 50 mm thick) prepared in the honeycomb-shaped adsorbent from one side to the other. The number of aerosols before and after passing through the honeycomb-shaped adsorbent was measured using a laser-type particle counter. Table 2 shows the number of aerosols before and after passing through the adsorbent. The 10 mm thick honeycomb-shaped adsorbent captured 97.9% of the aerosols, and the 50 mm thick honeycomb-shaped adsorbent captured 100% of the aerosols.

<Influenza virus inactivation test>
Cells infected with influenza virus were cultured to prepare a culture medium containing influenza virus. Next, an aerosol generated from the influenza virus-containing culture medium was passed through a sample consisting of a 10 mm thick honeycomb adsorbent prepared in Example 1 to capture the influenza virus. After that, the honeycomb adsorbent was crushed to recover the influenza virus, and the recovered influenza virus was used to reinfect cultured cells. This allowed us to investigate the inactivation rate of influenza virus by the honeycomb adsorbent. The same test was performed three times. The evaluation results are shown in Table 3. The influenza virus recovered from the honeycomb adsorbent could not reinfect cultured cells, and as a result, the inactivation rate was calculated to be 100%.

This invention has developed a filter that captures 100% of virus-containing aerosols in a single pass and completely inactivates the captured viruses.

This invention can be used in antiviral air purification devices that are characterized by their ability to adsorb and simultaneously inactivate viruses that float in the air as aerosols and cause disease.

1. First container 2. Honeycomb-shaped adsorbent 3. Air pump 4. Second container

Claims (6)

It comprises a hydrophilic porous inorganic material containing an additive material having an amino group,
The above-mentioned additive material having an amino group is aluminum hydrazine sulfate, magnesium hydrazine sulfate, hydrazine phosphate , or a mixture thereof .
The above-mentioned hydrophilic porous inorganic material contains a lubricant, which is kaolin, smectite, or imogolite, and is an adsorbent for viruses. The adsorbent according to claim 1, wherein the above-mentioned virus is contained in an aerosol. The adsorbent according to claim 1 or 2, wherein the hydrophilic porous inorganic material is sepiolite, activated clay, silica gel, pargoskite, or a mixture thereof. The above-mentioned hydrophilic porous inorganic material is an adsorbent according to any one of claims 1 to 3, comprising manganese dioxide. The above-mentioned hydrophilic porous inorganic material has a honeycomb structure, as described in any one of claims 1 to 4. The adsorbent described above is a non-fired and dried product, as described in any one of claims 1 to 5.