DESCRIPTION
ADSORBENT FOR ADSORBING VIRUS AND/OR BACTERIUM,
CARBON/POLYMER COMPOSITE AND ADSORBENT SHEET
Technical Field
[OOOl] The present invention relates to an adsorbent
for adsorbing a virus and/or a bacterium and an
adsorbent sheet.
Background Art
[0002] Activated carbon made from traditional
coconut husks and petroleum pitches is used as a
material for a number of filters, and draws an
attention as an adsorbent for adsorbing a virus (see,
for example, Japanese Patent Application Laid-open No.
2008-273914).
[0003] Patent Document 1: Japanese Patent
Application Laid-open No. 2008-273914
Summary of Invention
Problem to be solved by the Invention
[0004] Since the virus adsorbent using the
traditional activated carbon includes activated carbon
mainly having micro pores with a size of 2 nm or less,
virus adsorption capability and bacterial adsorption
capability are insufficient. Through studies by the
present inventors, it has been revealed that the
adsorption capability should be further improved.
[0005] Accordingly, an object of the present
disclosure is to provide an adsorbent, a carbon/polymer
composite using the adsorbent, and an adsorbent sheet
for adsorbing a virus and/or a bacterium (in other
words, adsorbing a virus, or adsorbing a bacterium, or
adsorbing a virus and a bacterium) having further
improved virus adsorption capability and/or bacterial
adsorption capability.
Means for solving the Problem
[0006] An adsorbent for adsorbing a virus and/or a
bacterium according to a first aspect of the present
disclosure in order to achieve the above-described
object comprises a porous carbonaceous material having
a specific surface area value as measured by the
nitrogen BET method of 10 m2/g or more and a pore volume
as measured by the BJH method of 0.1 cm3/g or more.
[0007] An adsorbent for adsorbing a virus and/or a
bacterium according to a second aspect of the present
disclosure in order to achieve the above-described
object comprises a porous carbonaceous material having
a specific surface area value as measured by the
nitrogen BET method of 10 m2/g or more, and a total pore
volume determined by the Non Localized Density
Functional Theory of 0.1 cm3/g or more, of which the
pores have diameters in the range from 1 x 10-'m to 5 x
m.
[0008] An adsorbent for adsorbing a virus and/or a
bacterium according to a third aspect of the present
disclosure in order to achieve the above-described
object comprises a porous carbonaceous material having
a specific surface area value as measured by the
nitrogen BET method of 10 m2/g or more, at least one
peak in a pore diameter distribution determined by the
Non Localized Density Functional Theory in the range
from 3 nm to 20 nm, and a ratio of the total volume of
the pores with diameters in the range from 3 nm to 20
nm, being 0.2 or more of the total pore volume.
[0009] A carbon/polymer composite for adsorbing a
virus and/or a bacterium according to the first aspect
of the present disclosure in order to achieve the
above-described object comprises the porous
carbonaceous material according to the first aspect of
the present invention and a binder.
[OOlO] A carbon/polymer composite for adsorbing a
virus and/or a bacterium according to the second aspect
of the present disclosure in order to achieve the
above-described object comprises the porous
carbonaceous material according to the second aspect of
the present invention and a binder.
[OOll] A carbon/polymer composite for adsorbing a
virus and/or a bacterium according to the third aspect
of the present disclosure in order to achieve the
above-described object comprises the porous
carbonaceous material according to the third aspect of
the present invention and a binder.
[0012] An adsorbent sheet for adsorbing a virus
and/or a bacterium for adsorbing a virus and/or a
bacterium according to the first aspect of the present
disclosure in order to achieve the above-described
object comprises the porous carbonaceous material
according to the first aspect of the present invention
and a support member.
[0013] An adsorbent sheet for adsorbing a virus
and/or a bacterium for adsorbing a virus and/or a
bacterium according to the second aspect of the present
disclosure in order to achieve the above-described
object comprises the porous carbonaceous material
according to the second aspect of the present invention
and a support member.
[0014] An adsorbent sheet for adsorbing a virus
and/or a bacterium for adsorbing a virus and/or a
bacterium according to the third aspect of the present
disclosure in order to achieve the above-described
object comprises the porous carbonaceous material
according to the third aspect of the present invention
and a support member.
Effect of the Invention
[0015] In the adsorbent, the adsorbent, the
carbon/polymer composite, and the adsorbent sheet for
adsorbing a virus and/or a bacterium according to the
first to third aspects of the present disclosure, the
specific surface area value of the porous carbon
5 material used, the value of the pore volume, and the
pore diameter distribution are defined, thereby
adsorbing a virus and/or a bacterium with high
efficiency.
Brief Description of Drawings
10 [0016]
[Fig. 11 A graph showing accumulated measurement
results of the pore volumes about the adsorbents
according to Example 1-A, Example 1-B and Comparative
Example 1.
15 [Fig. 21 A graph showing accumulated measurement
results of the pore volumes about the adsorbents
according to Example 1-A, Example 1-B and Comparative
Example 1.
[Fig. 31 A graph showing measurement results of pore
20 diameter distributions according to Example 1-A,
Example 1-B and Comparative Example 1 determined by Non
Localized Density Functional Theory.
[Fig. 41 A graph showing a change in virus infectivity
titers to duration of activity of the adsorbents
25 according to Example 1-A, Example 1-B and Comparative
Example 1.
[Fig, 51 A graph showing a change in virus infectivity
titers to duration of activity of the adsorbents
according to Example 1-A, Example 1-B and comparative
Example 1, and masks according to Comparative Examples
5 2 to 4.
[Fig. 61 A diagram showing a schematic section
structure of the adsorbent sheet according to Example 1.
[Fig. 71 A graph showing various remaining bacteria
counts per minute (logarithmic expression) by
10 comparison.
Modes for Carrying Out the Invention
[0017] Hereinafter, embodiments of the present
disclosure will be described with reference to the
drawings. The present disclosure is not limited to the
15 embodiments, and various numerical values and materials
mentioned in the description of the embodiments are
merely examples. The embodiments will be described in
the following order.
1. An adsorbent, a carbon/polymer composite, an
20 adsorbent sheet for adsorbing a virus and/or a
bacterium according to the first to third aspects of
the present disclosure, general description
2. Example 1 (the adsorbent, the carbon/polymer
composite, the adsorbent sheet for adsorbing a virus
25 and/or a bacterium according to the first to third
aspects of the present disclosure)
3. Example 2 (other application example of Example
1)
4. Example 3 (still other application example of
Example 1)
5 5. Example 4 (still other application example of
Example I), others
[0018] In the following description, the adsorbent
for adsorbing a virus and/or a bacterium according to
the first to third aspects of the present disclosure
10 may be simply called "the adsorbent of the present
disclosure". The carbon/polymer composite according to
the first to third aspects of the present disclosure
may be simply called "the carbon/polymer composite of
the present disclosure". The adsorbent sheet according
15 to the first to third aspects of the present disclosure
may be simply called "the adsorbent sheet of the
present disclosure". The adsorbent of the present
disclosure, the carbon/polymer composite of the present
disclosure, and the adsorbent sheet of the present
20 disclosure may be simply called "the present
disclosure". The porous carbon material constituting
the adsorbent of the present disclosure, the ,
carbon/polymer composite of the present disclosure, and
the adsorbent sheet of the present disclosure may be
25 called "the porous carbon material in the present
disclosureN.
[0019]
[An adsorbent, a carbon/polymer composite, an adsorbent
sheet for adsorbing a virus and/or a bacterium
according to the first to third aspects of the present
5 disclosure, general description]
In the present disclosure, the porous carbon
material is made from the plant-based material. Nonlimiting
examples of the plant-based material are chaff
and straws of rice (paddy), barley, wheat, rye,
10 Japanese millet and foxtail millet; coffee beans, tea
leaves (for example, leaves of green tea, bTack tea and
the like) ; sugar canes (in particular, bagasse) ; corns
(in particular, core of corn) ; fruit peels (for
example, citrus peels such as mandarin orange peel,
15 banana peel and the like); reeds; Wakame seaweed stems
(Undaria pinnatifida); terrestrial vascular plants;
ferns; bryophytes; algae; and marine algae. These
materials may be used alone, and plural types of such
materials may alternatively be used in combination. The
20 shape and the form of the plant-based material are not
especially limited. For example, the plant-based
material may be chaff or straw itself, or the dried
product. In addition, in terms of food processing of
beer, liqueur or the like, a residue of various
25 processing including fermentation, roasting, or
extracting, can be applied. In particular, from the
standpoint of recycling the industrial wastes, it is
desirable that chaff and straws after processing, e.g.,
after threshing, are used. These chaff and straws after
processing are easily available in large amounts from,
5 for example, agricultural cooperatives, alcoholic
beverage makers, food companies and food processing
companies.
[00201 In the adsorbent sheet of the present
disclosure including the above-described preferred
10 embodiments, a woven fabric and a non-woven fabric can
be used as the support member. Cellulose, polypropylene
and polyester can be used as the material of the
support member. Further, the adsorbent sheet can have
the embodiments that the porous carbon material in the
15 present disclosure is sandwiched between the support
members, and that the porous carbon material is kneaded
with the support member. As the binder included in the
carbon/polymer composite of the present disclosure,
carboxyl nitrocellulose can be used, for example.
20 [0021]
The present disclosure can be used for purifying
water or air, generally fluid. The adsorbent of the
present disclosure can be used as a sheet form, can be
used by filling it into a column or a cartridge, can be
25 used by shaping into a desired shape using a binder (a
binding agent), or can be used as powder. When a
purifier or the adsorbent is used by dispersing it in a
solution, the surface can be hydrophobically or
hydrophilically treated and can be then used. The
adsorbent sheet of the present disclosure or the
5 carbon/polymer composite of the present disclosure can
be made into a filter for an air purifier, a mask, a
pair of protective gloves, or protective shoes.
[0022] When the porous carbon material in the
present disclosure is made from a plant-based material
10 containing silicon (Si), it is not especially limited,
but the porous carbon material is made from the plantbased
material containing 5% by mass or more of silicon
(Si), containing 5% by mass or less of silicon (Si),
desirably 3% by mass or of less silicon (Si), and more
15 desirably 1% by mass or less of silicon (Si).
LO0231 The porous carbon material in the present
disclosure can be produced, for example, by carbonizing
the plant-based material at 400°C to 1400°c, and then
treating the material with acid or alkali. In the
20 method of producing the porous carbon material
according to the present disclosure (hereinafter simply
referred to as "the method of producing the porous
carbon material"), the material obtained by carbonizing
the plant-based material at 400°C to 1400°C, which is
25 not yet treated with acid or alkali is referred to as
"the porous carbon material precursor" or "the
carbonaceous substance".
[0024] In the method of producing the porous carbon
material, after the acid or alkali treatment,
activation treatment can be performed. Or, after the
5 activation treatment, the acid or alkali treatment may
be performed. In the method of producing the porous
carbon material including the above-described desirable
form, although it depends on the plant-based material
being used, the plant-based material may be heated
10 (pre-carbonized) at a temperature lower than the
carbonizing temperature (for example, at 400'~ to
700°C) in an oxygen-free state before the plant-based
material is carbonized. As a result of extracting a tar
component that would be produced during the
15 carbonization, the tar component that would be produced
during the carbonization can be reduced or removed. The
oxygen-free state can be achieved by, for example,
providing an inert gas atmosphere including a nitrogen
gas or an argon gas, providing a vacuum atmosphere, or
20 almost steaming and baking the plant-based material. In
the method of producing the porous carbon material,
although it depends on the plant-based material being
used, the plant-based material may be immersed into
alcohols (for example, methyl alcohol, ethyl alcohol
25 and isopropyl alcohol) in order to decrease mineral
components and a water content or to prevent odor
generation during the carbonization. Also, in the
method of producing the porous carbon material, precarbonization
may be performed thereafter. The plantbased
material that produces a large amount of
5 pyroligneous acid (tar and light crude oil) is an
example that is desirably heated under the inert gas
atmosphere. Seaweeds, which is the plant-based material
containing a large amount of iodine and various
minerals, is an example that is desirably pretreated
10 with alcohol.
[0025] In the method of producing the porous carbon
material, the plant-based material is carbonized at
400°C to 1400°C. The "carbonization" herein means that
organic substances (the plant-based material in the
15 porous carbon material according to the present
disclosure) are typically heated to convert them into
carbonaceous substance (for example, see JIS M0104-
1984). An example of the atmosphere for carbonization
is an oxygen-free atmosphere. Specifi'cally, there are a
20 vacuum atmosphere, an inert gas atmosphere including a
nitrogen gas or an argon gas, and an atmosphere where
the plant-based material is almost steamed and baked.
The rate of temperature increase to the carbonization
temperature is not limited, but can be 1°c/min or more,
25 desirably 3"C/min or more, more desirably 5"C/min or
more under such atmosphere. The upper limit of the
carbonization time may be 10 hours, desirably 7 hours
and more desirably 5 hours, but not limited thereto.
The lower limit of the carbonization time may be such
that the plant-based material is surely carbonized. The
5 plant-based material may be pulverized to the desired
particle size, or classified, as necessary. The plantbased
material may be pre-cleaned. Also, the resultant
porous carbon material precursor or the porous carbon
materials may be pulverized to the desired particle
10 size, or classified, as necessary. In addition, the
processed porous carbon material by the activation
treatment may be pulverized to the desired particle
size, or classified, as necessary. Furthermore, the
finally resultant porous carbon material may be
15 sterilized. The furnace used for carbonization is not
limited in terms of a shape, a configuration and a
structure, and may be a continuous furnace or a batch
furnace.
[0026] In the method of producing the porous carbon
20 material, as described above, the activation treatment
can increase the numbers of micro pores each having a
pore diameter of not greater than 2 nrn (which will be
described later). Examples of the activation treatment
are gas activation and chemical activation. In the gas
25 activation, oxygen, water vapor, carbon dioxide gas,
air or the like can be used as an activator. Under the
gas atmosphere, the porous carbon material is heated at
700°C to 1400°C, desirably 700°C to 1 0 0 0 " ~mo~r e
desirably 800°C to 1000°C for several tens of minutes
to several hours, so that the microstructure is grown
5 by the volatile components and carbon molecules in the
porous carbon material. More specifically, the heating
temperature may be selected based on the types of the
plant-based material, the kinds and concentration of
the gas and the like, as necessary. In the chemical
10 activation, the porous carbon material is activated by
using zinc chloride, iron chloride, calcium phosphate,
calcium hydroxide, magnesium carbonate, potassium
carbonate, sulfate or the like is used for activation
instead of oxygen and water vapor used in the gas
15 activation, and is cleaned with hydrochloric acid. The
pH of the porous carbon material is adjusted by using
an alkaline solution. Then, the porous carbon material
is dried.
[0027] The surface of the porous carbon material in
20 the present disclosure may be chemical treated or
molecular modified. For example, as one of the chemical
treatments, a nitric acid treatment is performed to
produce carboxyl groups on the surface. By the similar
treatment as the activation treatment with water vapor,
25 oxygen, alkali or the like, various functional groups
such as a hydroxyl group, a carboxyl group, a ketone
group or an ester group can be produced on the surface
of the porous carbon material. In addition, when the
porous carbon material is chemically reacted with
chemical species or protein containing a hydroxyl group,
5 a carboxyl group, an amino group or the like, the
molecular modification may be possible.
[0028] In the method of producing the porous carbon
material, silicon components are removed by the acid or
alkali treatment from the carbonized plant-based
10 material. The silicon components may be silicon oxides
such as silicon dioxide, silicon oxide and a salt of
silicon oxide. By removing the silicon components in
the carbonized plant-based material, there can be
provided the porous carbon material having high
15 specific surface area. In some cases, the silicon
components in the carbonized plant-based material may
be removed by a dry etching method.
[0029] The porous carbon material in the present
disclosure may contain magnesium (Mg) , potassium (K),,
20 calcium (Ca), non-metal elements such as phosphorous
(P) and sulfur (S), and metal elements such as
transition elements. The amount of magnesium (Mg) may
be from 0.01% by mass to 3% by mass, the amount of
potassium (K) may be from 0.01% by mass to 3% by mass,
25 the amount of calcium (Ca) may be from 0.05% by mass to
3% by mass, the amount of phosphorous (P) may be from
0.01% by mass to 3% by mass, and the amount of sulfur
(S) may be from 0.01% by mass to 3% by mass, as
examples. In terms of an increase in the specific
surface area value, the amounts of these elements are
5 desirably small. It should be appreciated that the
porous carbon material may contain elements other than
those described above, and the amounts of various
elements as described above may be changed.
[0030] In the porous carbon material in the present
10 disclosure, various elements can be analyzed by energy
dispersive spectrometry (EDS) using an energy
dispersive X-ray spectrometer (for example, JED-2200F
manufactured by JEOL Ltd.). The measurement conditions
may include, for example, a scanning voltage of 15kV
15 and an illumination current of 10 PA.
[0031] The porous carbon material in the present
disclosure has many pores. The pores include
"mesopores" having a pore diameter in the range from 2
nm to 50 nm, "micropores" having a pore diameter less
20 than 2 nm and "macropores" having a pore diameter
exceeding 50 nm. Specifically, the mesopores have many
pores having a size of 20 nm or less, especially 10 nm
or less, for example. The porous carbon material
according to the present disclosure desicably has a
25 pore volume by the BJH method of 0 . 1 cm3/g or more,
desirably 0.2 cm3/g or more, more desirably 0 . 3 cm3/g or
more, and even more desirably 0.5 cm3/g or more.
[0032] It is desirable that the porous carbon
material in the present disclosure desirably has the
specific surface area value by the nitrogen BET method
5 (hereinafter may be simply referred to as "the specific
surface area value") of 50 m2/g or more, more desirably
100 m2/g or more, most and even more desirably 400 m2/g
or more in order to provide higher functionality.
[0033] The nitrogen BET method is to measure the
10 adsorption isotherm by adsorbing and desorbing
admolecules, i.e. nitrogen, to/from an adsorbent
(herein, the porous carbon material), and analyze the
measured data by the BET equation represented by the
equation (1). Based on the method, the specific surface
15 area, the pore volume and the like can be calculated.
Specifically, when the specific surface area value is
calculated on the basis of the nitrogen BET method, the
adsorption isotherm is first measured by adsorbing and
desorbing the adrnolecules, i.e., nitrogen, to/from the
20 porous carbon material. Then, [p/{ V, (po-p)) 1 is
calculated from the measured adsorption isotherm based
on the equation (1) or the deformed equation (1' ) and
is plotted to the relative pressure in equilibrium
(p/po). The plot is considered as a straight line, and
25 the slope s (=[ (C-1) / (C-V,) 1 ) and the intercept i ,
(= [1/ (C-V,) I ) are calculated based on least squares
method. The Vm and C are calculated from the calculated
slope s and the intercept i based on the equations (2-
1) and (2-2) . The specific surface area ~SBET is
calculated from V, based on the equation (3) (see
5 BELSORP-mini and BELSORP analysis software manual, pp.
62-66, made by BELL Japan Inc.). The nitrogen BET
method is the measuring method in accordance with JIS R
1626-1996 "Measuring methods for the specific surface
area of fine ceramic powders by gas adsorption using
10 the BET method".
va= (Vrn-C-p/) [ (p-PO){ I+ (C-1)( p/po)1 I (1)
[~/{V~(PO-}PI)= [ (C-1)/(C*Vm)l( p/po)+[l/(co Vm ) I
(1')
Vm=l/ (s+i) (2-1)
C= (s/i) +l (2-2)
asBET=( Vm0Loo/)2 2414 (3)
[0035]
where,
Va: Adsorbed amount
Vm: Adsorbed amount of monolayer
p: Nitrogen pressure in equilibrium
po: Saturated vapor pressure of nitrogen
L: The Avogadro number
o: Adsorbed section area of nitrogen
[0036] When the pore volume V, is calculated by the
nitrogen BET method, the adsorption data of the
measured adsorption isotherm is, for example, linearly
interpolated to determine the ads.orbed amount V at
relative pressure set for calculating the pore volume.
The pore volume V, can be calculated from the adsorbed
5 amount V based on the equation (4) (see BELSORP-mini
and BELSORP analysis software manual, pp. 62-66, made
by BELL Japan Inc.). The pore volume determined by the
nitrogen BET method may be referred to simply as ",the
pore volume".
10 [0037]
V,= (V/22414) x (M,/p,) (4)
[0038]
where,
V: Adsorbed amount at relative pressure
15 M,: Molecular weight of nitrogen
p,: Density of nitrogen
[0039] The pore diameter of the mesopores can be
calculated as, for example, the pore distribution from
the change rate of the pore volume to the pore diameter
20 based on the BJH method. The BJH method is widely used
as a method for pore diameter distribution analysis.
When the pore diameter distribution is analyzed by the
BJH method, the adsorption isotherm is first measured
by adsorbing and desorbing the admolecules, i-e.,
25 nitrogen, to/from the porous carbon material. Then,
based on the measured adsorption isotherm, the
thickness of the adsorbed layer is determined when the
adsorbed molecules (for example, nitrogen) that fill
the pores are gradually adsorbed/desorbed, and the
inner diameter (twice a core diameter) of the pores is
5 determined. Based on the equation (5), the pore radius
r, is calculated. Based on the equation (6), the pore
volume is calculated. Then, the pore distribution curve
is obtained by plotting the change rate of the pore
volume (dVp/drp) to the pore diameter (2rp) based on the
10 pore radius and the pore volume (see BELSORP-mini and
BELSORP analysis software manual, pp. 85-88, made by
BELL Japan Inc. ) .
[0040]
rp=t+rk (5)
Vpn=Rn*dV,-Rn*dtn*XcAgpj ( 6)
where,
~,=r,:/ (rkn-l+dtn) (7 )
[0041]
where,
20 r,: Pore radius
rk: Core radius (inner diameter/2) when the adsorbed
layer having a thickness of t is adsorbed on the inner
wall of the pore having the pore radius r, at the
pressure
25 V,,: Pore volume at the time of n-th
adsorption/desorption of nitrogen
dV,: Amount of change at the time of n-th
adsorption/desorption of nitrogen
dt,: Amount of change in the thickness t, at the time of
n-th adsorption/desorption of nitrogen
5 rk,: Core radius at the time of n-th
adsorption/desorption of nitrogen
c: Fixed value
r,,: Pore radius at the time of n-th
adsorption/desorption of nitrogen
10 In addition, CApj represents the integration value of
the areas of the pore walls from j=l to j=n-1.
[0042] The pore diameter of the micropores can be
calculated as, for example, the pore distribution from
the change rate of the pore volume to the pore diameter
15 based on the MP method. When the pore distribution is
analyzed by the MP method, the adsorption isotherm is
first measured by adsorbing nitrogen to the porous
carbon material. Then, the adsorption isotherm is
converted (t plotted) into the pore volume to the
20 thickness t of the adsorbed layer. The pore
distribution curve is obtained based on curvature
(amount of change in the pore volume to amount of
change in the thickness t of the adsorbed layer) of the
plot (see BELSORP-mini and BELSORP analysis software
25 manual, pp. 72-73, 82, made by BELL Japan Inc.).
[0043] The Non Localized Density Functional Theory
(NLDFT) method specified in JIS 28831-2:2010 "Pore Size
Distribution and Porosity of Powders (Solid Materials)
- Part 2: Method of Measuring Mesopores and Macropores
using Gas Absorption" and JIS 28831-3:2010 "Pore Size
5 Distribution and Porosity of Powders (Solid Materials)
- Part 3: Method of Measuring Micropores using Gas
Absorption" employs a program accompanying the
automatic specific surface area/pore distribution
measuring apparatus "BELSORP-MAX" manufactured by BELL
10 JAPAN, INC. as an analyzing program. An analysis is
carried out using a model having a cylindrical shape
and assuming carbon black (CB), as prerequisites for
the analysis. Then, a distribution function for pore
distribution parameters is set as "no-assumption", and
15 smoothing will be performed ten times on distribution
data thus obtained.
[0044] The porous carbon material precursor is
treated with an acid or alkali. For example, the porous
carbon material precursor may be immersed into a water
20 solution of an acid or alkali. Or, the porous carbon
material precursor may be reacted with an acid or
alkali in the vapor phase. More specifically, the acid
treatment may be carried out using an acidic fluorine
compound as an acid such as a hydrogen fluoride,
25 hydrofluoric acid, ammonium fluoride, calcium fluoride,
or sodium fluoride. When a fluorine compound is used,
the amount of fluorine is desirably four times the
amount of element silicon in silicon components
included in the porous carbon material precursor, and a
water solution of the fluorine compound desirably has a
5 concentration of 10 wt % or more. When silicon
components (e-g., silicon dioxide) included in the
porous carbon material precursor are removed by the use
of a hydrofluoric acid, silicon dioxide reacts with the
hydrofluoric acid as indicated by chemical formula (A)
10 or (B), and silicon can be eliminated as hydrogen
hexafluorosilicate (H2SiF6) or silicon tetrafluoride
(SiF4). Thus, a porous carbon material is obtained.
The material may thereafter be washed and dried.
[0045]
15 Si02 + 6HF + H2SiF6 + 2H20 (A)
Si02 + 4HF + SiF4 + 2H20 (B)
[0046] When the precursor is treated with alkali
(base), the alkali may be sodium hydroxide. When a
water solution of alkali is used, the pH of the water
20 solution may be 11 or more. When silicon components
(e.g., silicon dioxide) included in the' porous carbon
material precursor are removed by the use of a water
solution of sodium hydroxide, silicon dioxide is made
to react as indicated by chemical formula (C) by the
25 heating of the water solution of sodium hydroxide. The
silicon can be eliminated as sodium silicate (Na2Si03).
Thus, a porous carbon material is obtained. When the
precursor is treated by the reaction caused by sodium
hydroxide in the vapor phase, sodium hydroxide in a
solid state is heated to cause it to react as indicated
5 by the chemical formula (C). The silicon can be
eliminated as sodium silicate (Na2Si03). Thus, a porous
carbon material is obtained. The material may
thereafter be washed and dried.
100471
10 Si02 + 2NaOH -t Na2Si03 + H20 (C)
[0048] The porous carbon material according to the
present disclosure may be a porous carbon material
including holes having three-dimensional regularity,
for example, as disclosed in Japanese Unexamined Patent
15 Application Publication No. 2010-106007 (a porous
carbon material having what is called an inverse opal
structure). Specifically, the porous carbon material
has spherical holes in a three dimensional arrangement
having an average diameter in the range from 1 x lo-' m
to 1 x m and having a surface area of 3 x lo2 m2/g
or more. Desirably, the holes are arranged in a
disposition similar to a crystalline structure in a
macroscopic point of view. Alternatively, the porous
carbon material has holes arranged on a surface thereof
in a disposition similar to the alignment of a (111)
plane of a face-centered cubic structure in a
macroscopic point of view.
[Example 11
[0049] Example 1 relates to the adsorbent for
adsorbing a virus and/or a bacterium according to the
5 first to third aspects of the present disclosure, the
carbon/polymer composite according to the first to
third aspects of the present disclosure, and the
adsorbent sheet according to the first to third aspects
of the present disclosure.
10 [0050] The adsorbent for adsorbing a virus and/or a
bacterium of Example 1 (hereinafter referred simply to
as "the adsorbent") includes a porous carbonaceous
material having a specific surface area value as
measured by the nitrogen BET method of 10 m2/g or more
15 and a pore (mesopore to micropore) volume as measured
by the BJH method of 0.1 cm3/g or more in accordance
with the adsorbent for adsorbing a virus and/or a
bacterium according to the first aspect of the present
disclosure.
20 [0051] The adsorbent of Example 1 includes a porous
carbonaceous material having a specific surface area
value as measured by the nitrogen BET method of 10 m2/g
or more, and a total pore volume determined by the Non
Localized Density Functional Theory of 0.1 cm3/g or
25 more, of which the pores have diameters in the range
from 1 x 10-'m to 5 x 10-'m in accordance with the
adsorbent for adsorbing a virus and/or a bacterium
according to the second aspect of the present
disclosure.
[0052] Further, the adsorbent of Example 1 includes
5 a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more, at least one peak in a pore
diameter distribution determined by the Non Localized
Density Functional Theory in the range from 3 nm to 20
10 nm, and a ratio of the total volume of the pores with
diameters in the range from 3 nm to 20 nm, being 0.2 or
more of the total pore volume in accordance with the
adsorbent for adsorbing a virus and/or a bacterium
according to the third aspect of the present disclosure.
15 [ 0 0 5 3 ] In Example 1, the porous carbonaceous
material is made from chaff of rice (paddy) used as the
plant-based material. The porous carbonaceous material
of Example 1 is obtained by carbonizing the chaff as
the plant-based material, converting it into a
20 carbonaceous substance (a porous carbon material
precursor), and then performing an acid treatment.
Hereinafter, a method of producing the adsorbent of
Example 1 will be explained.
[0054] The porous carbon material of Example 1 was
25 obtained by carbonizing the plant-based material at
400°C to 1400°C, and then treating the material with
acid or alkali. In other words, the chaff is heated
(pre-carbonized) in an inert gas. Specifically, the
chaff is carbonized by heating at 500°C for 3 hours in
a flow of nitrogen gas, and a carbide is obtained. Such
5 a process makes it possible to reduce or eliminate tar
components that would be produced at a subsequent
carbonizing step. Thereafter, 10 grams of the carbide
was put in a crucible made of alumina, and the
temperature of the carbide was raised to 800°c at a
10 rate of 5"c/min in a flow of nitrogen gas (5
liters/min). The carbide was carbonized at 800°c for
one hour and converted into a carbonaceous substance (a
porous carbon material precursor), and the substance
was cooled down to room temperature. The nitrogen gas
15 was kept flowing during the carbonization and cooling.
Next, the porous carbon material precursor was acidtreated
by immersion in a water solution of
hydrofluoric acid of 46 vol % overnight, and the
precursor was washed with water and ethyl alcohol until
20 it reached a pH of 7. Next, the precursor was dried at
120°C and the temperature of the precursor was raised
to 900°c in a flow of nitrogen gas. Then, the precursor
was activated by heating at 900°c for 3 hours in a flow
of water vapor. Thus, the adsorbent of Example 1 could
25 be obtained. Thus-obtained adsorbent is called as an
adsorbent of Example 1-A.
[0055] By changing firing conditions such as a
firing temperature, an adsorbent of Example 1-B was
obtained.
[0056] As Comparative Example 1, a commercially
5 available adsorbent including coconut husks activated
carbon (manufactured by Wako Pure Chemical Industries,
Ltd.)was used. As Comparative Example 2, a commercially
available polypropylene non-woven mask was used. As
Comparative Example 3, a commercially available
10 polypropylene non-woven mask was used. As Comparative
Example 4, a commercially available polyester non-woven
mask was used.
[0057] A nitrogen absorption/desorption test was
carried out to find the specific surface areas and the
15 pore volumes, using a measuring apparatus BELSORP-mini
(manufactured by BELL JAPAN, INC.). The measurement was
carried out at a measurement relative pressure in
equilibrium (p/po) of 0.01 to 0.99. Pore diameter
distributions of mesopores and micropores were
20 calculated by conducting a nitrogen
absorption/desorption test using the above-mentioned
measuring apparatus using the BELSORP analysis program
based on the BJH method and the MP method. The pore of
the porous carbon material was measured by mercury
25 intrusion method. Specifically, a mercury porosimeter
(PASCAL440 manufactured by Thermo Fisher Scientific
Inc.) was used to conduct the mercury intrusion method.
Further, the measurement based on the Non Localized
Density Functional Theory (NLDFT) was carried out using
a software attached to an automatic specific surface
5 area/pore distribution measuring apparatus "BELSORPMAX"
manufactured by BELL JAPAN, INC. Prior to the
measurement, the samples were subjected to drying at
200°C for 3 hours as a pre-process.
[0058] The specific surface area and the pore volume
10 of each of the adsorbents of Example 1-A, Example 1-B
and Comparative Example 1 and each of the masks of
Comparative Example 2 to Comparative Example 4 were
measured. Table 1 shows the results. In Table 1, the
"specific surface area" and the "total pore volume"
15 refer to a specific surface area and a total pore
volume obtained according to the nitrogen BET method.
The units are in m2/g and cm3/g. The "MP method", "BJH
method" and "mercury intrusion method" refer to a pore
(micropore) volume result measured by the MP method, a
20 pore (mesopore to macropore) volume result measured by
the BJH method, and a pore volume result measured by
the mercury intrusion method, respectively. The units
are in cm3/g. Figs. 1 and 2 show the results of the
measurement of the total pore volume in each of Example
25 1-A, Example 1-B and Comparative Example 1. Furthermore,
Fig. 3 shows the results of the measurement of the pore
diameter distribution determined by the Non Localized
Density Functional Theory. A ratio of the total volume
of the pores each having a pore diameter in the range
from 3 nm to 20 nm to the total pore volume is as
5 follows :
Example 1-A: 0.407 (total pore volume: 2.16 ~m'/~)
Example 1-8: 0.479 (total pore volume: 1.33 cm3/g)
Comparative Example 1: 0.134 (total pore volume: 0.756
cm3/g)
[0059]
[Table 11
[0060] It shows that the adsorbents of Example 1-A
and Example 1-B have greater values in mesopores to
MP
method
0.651
0.515
0.570
<0.01
<0.01
<0.01
Total
pore
volume
1.54
1.08
0.57
<0.01
<0.01
c0.01
Example 1-A
Example 1-B
Comparative
Example 1
Comparative
Example 2
Comparative
Example 3
Comparative
Example 4
Specific
surface
area
1700
1360
1270
<10
<10
12
BJH
method
1.08
0.641
0.070
<0.01
<0.01
<0.01
Mercury
intrusion
method
4.12
---
1.50
---
---
---
macropores volume and in pore volume obtained by the
mercury intrusion method as compared with the adsorbent
of Comparative Example 1.
5 [0061] An antivirus property against influenza A is
evaluated for each of the adsorbents of Example 1-A,
Example 1-B and Comparative Example 1 and each of the
masks of Comparative Example 2 to Comparative Example 4.
A size of the influenza A is from 80 nm to 120 nm.
10 [0062] Specifically, a virus infectivity titer of
the influenza A was measured based on a TCID5O method.
Table 2 and 3 show the results. A unit of the virus
infectivity titer is in TCID50/ml. An infectivity titer
log reduction value is determined by loglo (initial
15 infectivity titer/infectivity titer during duration of
activity). An adsorbent concentration is represented by
an amount (unit: mg) of the adsorbent added per 5 ml of
a buffer solution. In Reference, no adsorbent is added.
Figs. 4 and 5 each show a change in virus infectivity
20 titers to duration of activity.
[0063]
[Table 21

32 '
~ 0 C ' ) O O b b L O C L U ) .
Q>
-7
9
0
.c-
E
. - r \ i * d b & d
5 .M*-
..>-- +
rQc) .c5to
0
c
0
Cd
= .m- .-c- . .c- u
.I-=
f
0
-0
am
k
a, -- "la
fig
1
w ~ = ~ & . , o % b b I C O ,
~ c 9 X X X ' X X X X
~ X X X X X X X X
r C ) q o o P -
c \ i k m 4 4 4 4 4
\ T - r r r F F
$ C V C C D Q ) b b C \ I r r ,
i = + l c : c d r : c r j
I
I
b
0
r
X -
m
ui
- Z = = = r l ) U ) L D r l ) ~ L O
~ ~ ~ ) 0 r ~ 0 0 0 0
-a
Zq: m y
' E E E E
' 4 . - 4 \ - . .
o r o > c n o , m U ) I
E E E E E E E ,
o n i u 5 n i i r j d d d I
-a
m:* y a
.>- N
39
E
EOwg
a a a , .zm
39
GQ mE
EOLgU
0 0 0
.ld-
59
ZQ ClE
EOwg
a0, s ca
g ? ~
a,m
3tY G
[0065] The adsorbent of Example 1-A showed the
infectivity titer log reduction value of "2.2" and
'3.9" during duration of activity for 60 min when 5 mg
of the adsorbent was added to the 5 ml of the buffer
5 solution. The adsorbent of Example 1-B showed the
infectivity titer log reduction value of "3.7" during
duration of activity for 60 min when 5 mg of the
adsorbent was added to the 5 ml of the buffer solution.
In addition, it has been found that the antivirus
10 property is dependent on the adsorbent concentration.
It is confirmed that Example 1-A and Example 1-B each
has a higher antivirus property than comparative
Example 1, which may be attributed to a difference
between the pore diameter distribution in a mesopore
15 area and that in a macropore area. In other words, the
adsorbents of Example 1-A and Example 1-B where the
mesopore area and macropore area are grown adsorb
effectively a single virus having a size of about 80 nm
to 120 nm and/or a spike protein found on a surface of
20 the virus. As a result, it is estimated that a high
antivirus effect could be provided. On the other hand,
since the adsorbent of Comparative Example 1 has
extremely small mesopore area and macropore area,
mainly has the micropore area, and cannot adsorb
25 effectively a single virus having a size of about 80 nm
to 120 nm and/or a spike protein found on a surface of
the virus. It is estimated that only a low antivirus
effect could be provided.
[0066] Neuraminidase that is the spike protein
present on the surface of the influenza viruses was
5 dissolved into a phosphate buffer so that the
concentration of neuraminidase was 20 mg/ml. To 5 ml of
a neuraminidase solution, 3 mg of the adsorbents of
Example 1-A and Comparative Example 1 were added,
respectively. After one hour and three hours, a rate of
10 neuraminidase removal was measured. Table 4 shows the
results. The adsorbent of Example 1-A had a
significantly higher rate of neuraminidase removal than
that of Comparative Example 1.
[0067]
15 [Table 41
[0068] Fig. 6 shows a schematic section structure of
the adsorbent sheet according to Example 1. The
adsorbent sheet according to Example 1 includes the
porous carbon material of Example 1 and the support
20 members. Specifically, the adsorbent of Example 1 has a
structure that a porous carbon material in a sheet form,
i-e., a carbon/polymer composite 1, is sandwiched
Example 1-A
Comparative Example 1
Rate of neuraminidase removal (%)
1 hour
48.9
4.28
3 hours
51.8
5.03
between a cellulosic support member (non-woven fabric
2) and a support member (non-woven fabric 2). The
carbon/polymer composite 1 includes the porous carbon
material of Example 1 and the binder. The binder is,
5 for example, carboxyl nitrocellulose. Further, the
adsorbent sheet can have the embodiments that the
porous carbon material of Example 1 can be applied to
the support members, or the porous carbon material of
Example 1 may be kneaded with the support member.
10 [Example 21
[0069] In Example 2, the bacterial adsorption
capability against various bacteria was evaluated. In
Example 2, the adsorbent of Example 1-A was used. To 5
ml of each test bacterial liquid, 5 mg of the adsorbent
15 of Example 2 was added to provide a test liquid. Then,
the test liquid was shaken (120 rpm) at 25'~ for a
predetermined time, and was immediately thereafter
centrifuged (2000 rpm, 10 seconds) to precipitate the
adsorbent. Then, 1 ml of a supernatant was taken, and
20 was added to 9 ml of a SCDLP bouillon culture media
(Eiken Chemical Co., Ltd.). Thus-obtained sample liquid
was measured and determined for bacteria numbers per ml
of the supernatant. A minimum determination limit is
100 CFU/ml. A similar operation was repeated to provide
25 a control except that no adsorbent is added. Table 5
shows the obtained test results. Fig. 7 shows various
remaining bacteria counts in the adsorbent of Example 2
per minute (logarithmic expression) by comparison. In
Fig. 7, five bar charts are shown in each time. There
are the test results about Staphylococcus aureus,
5 Enterohemorrhagic E. coli, lactic acid bacteria,
Citrobacter, and enterococci from left to right. As the
control, the value at 0 min was 4.0 x lo7, and the value
at 5 min was 2.8 x lo6.
[0070]
10 [Table 51
m-
0
.-
= I-
--
--
f = F --
I E
P
C F
0
w
C v
ni
w
F
(0
c v
b.
?
d
CD
0007 4
V)
3
a>
5 rn
V) s
0
0
0 31
-C
Q
P
P
F -
w
P
v
m
F
r a C 3 L g w
(D
\ E x x x x x - .- II
0
0
w'
.0-
=E
0'
S , E r r $
5
$ ICI " t j 5 a w
I
(D 0 0 0 0 0
E X x
b - r
o j + d : + c \ i
CD 0 0 0 0 0
E x x x x x
E O c f ? ( D r ( O
CD ~ 0 0 0 0 - E x G x x x
r n m m q W m
n i c i ~ c \ j
(0 ~ 0 0 0 0
v- E x x x x x
N y C V C V O F
c i c \ i c u '
(0 ~ 0 0 0 0
E x x x x x
- - c i c u ' r : c \ i
l'.
0 ~ 0 0 0
. y
Im
-'L o m
0 .I -c-. U -
P
CO
V)
? ? v
G r ' d
V-)
In
Y
CD
V ? ?
b.
7
+ r
U
0 ° " m am o
0 L
V)
F
rn
V)
(D
v
(0
F
-
(D
(D
F
co
(rj
.3 0
0
0
t5
-CC-r
[0071] The test results reveal that the adsorbent of
Example 2 adsorbs the bacteria and decreases the
remaining bacteria counts. In addition, the remaining
5 bacteria counts are decreased in a short time such as 1
to 5 minutes. Thus, when bacteria containing water is
treated with the adsorbent of Example 2, the bacteria
counts can be effectively decreased in a short time to
improve water quality. In particular, the adsorbent
10 well adsorbs Staphylococcus aureus that can be a
causative bacterium, Enterohemorrhagic E. coli that
produces toxins, Citrobacter that is contamination
bacterium, and less adsorbs lactic acid bacteria that
are intestinal good bacteria and enterococci that are
15 normal inhabitants. It was confirmed that the adsorbent
had selectivity.
[Example 31
[0072] In Example 3, the adsorbent of Example 1-A
was used to perform an adsorption test against E. coli.
20 Specifically, to 1 ml of sterile distilled water, 100 g
of the adsorbent of Example 3 was added, and 0.1 ml of
a test bacterial liquid was further added. A thusobtained
test liquid was shaken (100 rpm) at 2 5 ' ~ . 1 ml
of the test liquid was filtered with a membrane filter,
25 and was then washed with 2 ml of sterile distilled
water. Then, the SCDLP bouillon culture media was added
thereto as in Example 2 to a total volume of 10 ml to
provide a sample liquid. E. coli numbers were
determined per ml of the sample liquid. A minimum
determination limit is 100 CFU/ml. The adsorbent of
Comparative Example 1 was similarly tested. Table 6
shows the results. It reveals that the adsorbent of
Example 3 effectively adsorbs E. coli.
[0073]
[,Table 61
[Example 41
[0074] In Example 4, the adsorbent of Example 1-A
was used to evaluate the adsorption capability against
feline calicivisuses (size: about 30 nm to 40 nrn) as
alternatives for noroviruses (size: about 30 nm). The
norovirus is a virus having about 7500 bases and no
envelops that is categorized as a plus single-strand
RNA virus. Specifically, a virus infectivity titer was
measured based on a TCID50 method as in Example 1.
Table 7 shows the obtained test results. A unit of the
virus infectivity titer is in TCID50/ml. An infectivity
titer log reduction value is determined by loglo
5 min
1.0 x 10
1.5 lo3
7.4 lo4
Time
Example 3
Comparative
Example 1
Control
0 min
4.8 x lo4
4.8 x 10'
4.8 x lo4
(initial infectivity titer/infectivity titer during
duration of activity). An adsorbent concentration is
represented by an amount (unit: mg) of the adsorbent
added per 5 ml of a buffer solution. The adsorbent of
5 Comparative Example 1 was similarly tested.
Test
sample
~ x a m ~4l e
Comparative
Example 1
Control 1 .o
concentration
5.omg I m~
5.Omgl
---
Virus infectivity titer
0 rnin (initial)
1.1 X lo6
Infectivity titer log reduction value
after 30 min
r
3.0
r
2.1
I--
after 30 min
1 . 2 ~ 1 0 ~
8.4 X 1 o3
---
after 60 rnin
r
3.2
r
2.7
r
after 60 rnin
7.6 x lo2
2.0 x lo3
~ . olxo 5
[0076] Since the viruses are small, the infectivity
titer log reduction value after 60 min in Example 4 is
close to that in Comparative Example 1. However, the
5 infectivity titer log reduction value after 30 min in
Example 4 is about 1 smaller than that in Comparative
Example 1. It reveals that Example 4 shows higher
adsorption capability than Comparative Example 1. Also,
it reveals that Example 4 shows excellent adsorption
10 capability not only for the influenza viruses, but also
for smaller viruses.
[0077] The present disclosure has been described
based on the embodiment thereof, and the present
disclosure is not limited to the embodiments and may be
15 modified in various ways. While the chaff is used as
the raw material of the porous carbon material in
Examples, other plants may be used. For example, other
usable plants include straws, reeds, stems of Wakame
seaweed, terrestrial vascular plants, ferns, bryophytes,
algae, and marine algae. Those plants may be u.sed alone,
and plural types of such plants may alternatively be
used in combination. Specifically, chaff of paddy (e-g.,
Isehikari produced in Kagoshima prefecture in Japan)
may be the plant-based material which is the raw
25 material of the porous carbon material. The chaff may
be carbonized into a carbonaceous substance (a porous
carbon material precursor), and the carbonaceous
substance may be treated with an acid to obtain the
porous carbon material. Alternatively, gramineous reeds
may be the plant-based material is the raw material of
5 the porous carbon material. The gramineous reeds may be
carbonized into a carbonaceous substance (a porous
carbon material precursor), and the carbonaceous
substance may be treated with an acid to obtain the
porous carbon material. Advantages similar to those
10 described above were achieved by the porous carbon
material obtained by treating a material using alkali
(base) such as a water solution of sodium hydroxide
instead of a water solution of hydrofluoric acid.
[0078] Alternatively, stems of Wakame seaweed
15 (cropped in Sanriku, Iwate prefecture in Japan) may be
the plant-based material which is the raw material of
the porous carbon material. The stems of Wakame seaweed
may be carbonized into a carbonaceous substance (porous
carbon material precursor), and the carbonaceous
20 substance may be treated with an acid to obtain the
porous carbon material. Specifically, the stems of
Wakame seaweed are heated at a temperature of, for
example, 500°C and carbonized. The stems of Wakame
seaweed may be treated with alcohol before the heating.
Specifically, the raw material may be immersed in ethyl
alcohol or the like. As a result, moisture included in
the raw material is reduced, and the process also
allows elution of elements other than carbon and
mineral components which will otherwise be included in
the porous carbon material finally obtained. The
5 treatment with alcohol suppresses the generation of
gasses during the carbonizing process. More
specifically, stems of Wakame seaweed are immersed in
ethyl alcohol for 48 hours. It is desirable to perform
an ultrasonic process on the material in ethyl alcohol.
10 The stems of Wakame seaweed are then carbonized by
being heated at 500'~ for 5 hours in a flow of nitrogen
gas to obtain a carbide. Such a process (preliminary
carbonizing process) can reduce or eliminate tar
components that would be produced at the subsequent
15 carbonizing step. Thereafter, 10 grams of the carbide
is put in a crucible made of alumina, and the
temperature of the carbide is raised to 1000'~ at a
rate of 5"c/min. in a flow of nitrogen gas (10
liters/min). The carbide is carbonized at 1000'~ for 5
20 hours and converted into a carbonaceous substance
(porous carbon material precursor), and the substance
is cooled down to room temperature. The nitrogen gas is
kept flowing during the carbonization and cooling.
Next, the porous carbon material precursor is acid-
25 treated by immersion in a water solution of
hydrofluoric acid of 46 vol % overnight, and the
precursor is washed with water and ethyl alcohol until
it reaches a pH of 7. Finally, the precursor is dried
so that a porous carbon material will be obtained.
Description of Reference Numerals
5 1 carbon/polyrner composite
2 non-woven fabric

Claims
[I] An adsorbent for adsorbing a virus and/or a
bacterium, comprising:
a porous carbonaceous material having a specific
5 surface area value as measured by the nitrogen BET
method of 10 m2/g or more and a pore volume as measured
by the BJH method of 0.1 cm3/g or more.
[2] An adsorbent for adsorbing a virus and/or a
bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more, and a total pore volume
determined by the Non Localized Density Functional
Theory of 0.1 cm3/g or more, of which the pores have
15 diameters in the range from 1 x lo-' m to 5 x m.
[3] An adsorbent for adsorbing a virus and/or a
bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
20 method of 10 m2/g or more, at least one peak in a pore
diameter distribution determined by the Non Localized
Density Functional Theory in the range from 3 nm to 20
nm, and a ratio of the total volume of the pores with
diameters in the range from 3 nm to 20 nm, being 0.2 or
25 more of the total pore volume.
[4] The adsorbent for adsorbing a virus and/or a
bacterium according to any one of claims 1 to 3,
wherein
the porous carbonaceous material is made from a
plant-based material; and
the plant-based material is at least one of
materials selected from the group consisting of chaff,
straws, coffee beans, tea leaves, sugar canes, corns,
fruit peels, reeds and Wakame seaweed stems.
[5] A carbon/polymer composite for adsorbing a virus
and/or a bactexium, comprising:
'a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more and a pore volume as measured
by the BJH method of 0.1 cm3/g or more; and
a binder.
[6] A carbon/polymer composite for adsorbing a virus
and/or a bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more, and a total pore volume
determined by the Non Localized Density Functional
Theory of 0.1 cm3/g or more, of which the pores have
diameters in the range from 1 x lo-'m to 5 x 10-~m;a nd
a binder.
[ 7 ] A carbon/polymer composite for adsorbing a virus
and/or a bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more, at least one peak in a pore
diameter distribution determined by the Non Localized
5 Density Functional Theory in the range from 3 nm to 20
nm, and a ratio of the total volume of the pores with
diameters in the range from 3 nm to 20 nm, being 0.2 or
more of the total pore volume; and
a binder.
10 [ 8 ] The adsorbent for adsorbing a virus and/or a
bacterium according to any one of claims 5 to 7,
wherein
the porous carbonaceous material is made from a
plant-based material; and
15 the plant-based material is at least one of
materials selected from the group consisting of chaff,
straws, coffee beans, tea leaves, sugar canes, corns,
fruit peels, reeds and Wakame seaweed stems.
[ 9 ] An adsorbent sheet for adsorbing a virus and/or a
20 bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more and a pore volume as measured
by the BJH method of 0.1 cm3/g or more; and
a support member.
[lo] An adsorbent sheet for adsorbing a virus and/or a
bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more, and a total pore volume
5 determined by the Non Localized Density Functional
Theory of 0.1 cm3/g or more, of which the pores have
diameters in the range from 1 x 10-'m to 5 x 10-~m;an d
a support member.
[ll] An adsorbent sheet for adsorbing a virus and/or a
10 bacterium, comprising:
a porous carbonaceous material having a specific
surface area value as measured by the nitrogen BET
method of 10 m2/g or more, at least one peak in a pore
diameter distribution determined by the Non Localized
15 Density Functional Theory in the range from 3 nm to 20
nm, and a ratio of the total volume of the pores with
diameters in the range from 3 nm to 20 nm, being 0.2 or
more of the total pore volume; and
a support member.
20 [I21 The adsorbent sheet for adsorbing a virus and/or a
bacterium according to any one of claims 9 to 11,
wherein
the porous carbonaceous material is made from a
plant-based material; and
25 the plant-based material is at least one of
materials selected from the group consisting of chaff,
straws, coffee beans, tea leaves, sugar canes, corns,
fruit peels, reeds and Wakame seaweed stems.
[13] The adsorbent sheet for adsorbing a virus and/or a
bacterium according to any one of claims 9 to 12,
wherein
the support member is composed of a non-woven
fabric.
[RANJNA MEHTA-DUTT]
OF REMFRY & SAGAR
ATTORNEY FOR THE APPLICANT [S]