JP6930892B2 - Naringin adsorbent - Google Patents

Description

The present invention relates to an adsorbent used for adsorbing naringin contained in citrus fruits such as grapefruit and orange.

Naringin is a flavanone glycoside and is represented by the following formula.

This naringin is contained in citrus fruits such as grapefruit and orange, and is known to be a bitter component of these citrus fruits. Therefore, the juice containing a large amount of naringin has a problem in terms of flavor, and it may be necessary to remove naringin from the juice in order to improve the flavor.
It is also known that naringin inhibits the activity of certain drugs, and the effect on the human body when the fruit juice containing naringin and the drug are taken at the same time has become a problem. It may be necessary to remove naringin from the juice.
Furthermore, naringin has a function of decomposing blood fatty acids and a function of alleviating the symptoms of pollinosis, and as a drug having such an effect, synthesis of naringin, extraction from fruit juice, purification, etc. are required. In particular, the extraction method from fruit juice to obtain naringin at low cost is attracting attention.

Patent Documents 1 to 3 propose ion exchange resins, resins having a porous structure, silica gel, and the like as adsorbents used for extracting naringin from fruit juice.

However, there is a problem that an ion exchange resin or a resin having a porous structure is very expensive. Further, silica gel such as silica gel is inexpensive, but has a fatal problem that it does not have high adsorption performance for naringin.

Japanese Unexamined Patent Publication No. 58-56663 Japanese Unexamined Patent Publication No. 9-182575 Japanese Unexamined Patent Publication No. 2005-21118

Therefore, an object of the present invention is to provide a naringin adsorbent capable of effectively adsorbing naringin contained in fruit juice and removing naringin from fruit juice.

As a result of conducting many experiments and examining the adsorption performance for naringin, the present inventors have found that a certain composition containing a magnesium component is excellent in its adsorption performance, and have completed the present invention. ..

According to the present invention, there is provided a naringin adsorbent consisting of at least one magnesium-containing composition selected from stebunsite, silica-magnesia complex and magnesium silicate.

In the naringin adsorbent of the present invention, among the magnesium-containing compositions, the stebunsite and silica-magnesia composites are suitable.
The silica-magnesia composite is a silica-magnesia composite particle in which silica particles and magnesia particles are integrally composited. In particular, the silica component and the magnesia component are expressed by the following formula (1):
R = Sm / Mm (1)
In the formula, Sm is the content (mass%) of the silica component in terms of _{SiO 2.}
Mm is the content (mass%) of the magnesia component in terms of MgO.
It is preferable that the mass ratio (R) represented by is 0.1 ≦ R ≦ 3.5.

The mineral adsorbent composed of the specific magnesium-containing composition of the present invention is remarkably inexpensive as compared with the ion exchange resin and the porous resin described above, and as shown in Examples described later, silica and silica. Compared with various clay minerals containing magnesium, it has extremely high adsorptivity to naringin.
Therefore, according to the present invention, naringin contained in fruit juice can be effectively adsorbed and removed, and further, naringin can be obtained by releasing naringin from an adsorbent that adsorbs and holds naringin. , Naringin can be effectively utilized by utilizing the pharmacological effect of naringin.

An X-ray diffraction chart derived from the plane index (06) of stibunsite (Example 1) used as a naringin adsorbent and montmorillonite (acidic white clay, Comparative Example 1) for comparison.

The naringin adsorbent of the present invention comprises at least one magnesium-containing composition selected from stibunsite, silica-magnesia complex and magnesium silicate, and excellent adsorption performance for naringin is present in these compositions. It seems that it is due to magnesium, but what is interesting is that even if it is a magnesium compound containing a magnesium component, magnesium hydroxide, magnesium oxide, etc. do not show any adsorption performance for naringin, and further, it contains magnesium. Clay minerals such as white clay, whose content is lower than that of stibunsite, for example, also have significantly lower naringin adsorptivity. That is, since only the above-mentioned specific magnesium-containing composition exhibits excellent naringin adsorptivity, the presence of a certain amount of magnesium in a specific form causes the phenolic hydroxyl group present in the molecule of naringin. The present inventors believe that the affinity with the above is increased, and as a result, excellent naringin adsorption is exhibited.
Hereinafter, various magnesium-containing compositions used for adsorbing naringin of the present invention will be described.

<Steven site>
In the present invention, the stebunsite used as an adsorbent is ideally described by the following formula (1):
_{(X 0.03 Mg 2.97) Si 4} O 10 (OH) 2 · nH 2 O (1)
During the ceremony
X is a divalent metal element such as Fe and Mn, and is
n is a positive integer,
It is a 3-octahedral smectite clay having a chemical composition represented by, and has a Si-Mg-based main skeleton and does not contain Al. It is different from montmorillonite. That is, montmorillonite is a 28-octahedral smectite clay mineral, and its main skeleton is Si-Al. Furthermore, montmorillonite has a diffraction peak derived from the plane index (06) near 2θ = 62 degrees (d = 1.49 to 1.50 Å) in the X-ray diffraction measurement, but the stubby site has this region. Does not have a diffraction peak, but has a diffraction peak derived from the plane index (06) in the region of 2θ = 60 to 61 degrees (d = 1.52 to 1.54 Å).
That is, from the structural difference from montmorillonite, it is considered that the naringin adsorption property is largely due to the existence form of magnesium.

Further, as can be understood from the above chemical composition and the like, Al is not contained as a constituent element, and even if Al is contained, a trace amount of Al is mixed as an impurity. Therefore, when Stevensite is added to fruit juice as a naringin adsorbent, there is an advantage that the problem of elution of Al, which is disliked in food applications, does not occur.

In addition, Stevensite has the advantage of high filterability.
Since montmorillonite such as acidic white clay has a large layer containing cations such as Na between the basic layers, it exhibits high swelling property with respect to water, and it is considered that the filterability with respect to water is low due to volume expansion due to swelling. .. However, Stevensite does not have such a large interlayer and does not exhibit swelling properties like montmorillonite with respect to water, and as a result, exhibits high filterability with respect to water. That is, when this stibunsite is added to fruit juice and used, the used adsorbent (stibunsite) that adsorbs and holds naringin can be easily separated by filtration.

The feldspar used as the feldspar adsorbent in the present invention ideally has a chemical composition represented by the above-mentioned formula, but of course, it is not limited to such a chemical composition. As long as its unique structure is maintained (for example, as long as it shows the above-mentioned X-ray diffraction peak), some composition fluctuation may occur, and further, metal elements such as Na and impurities such as kerolite and feldspar may occur. A natural or synthetic feldspar can be used within this range, and for example, a synthetic feldspar disclosed in Japanese Patent Application Laid-Open No. 63-190705 can also be used. As commercially available products, for example, Ionite manufactured by Mizusawa Industrial Chemicals Co., Ltd., SEPIGEL NATURAL 200RF manufactured by Sepiorsa, SEPIGEL SUPREME 200RF manufactured by Sepiorsa, SEPIGEL ACTIVE 220RF manufactured by Sepiorsa, and the like can be used.
However, a compound having a high Na content, such as synthetic stivensite obtained by using a sodium-containing compound such as sodium silicate as a reactant, has increased swelling property with respect to water and impairs filterability, so that it is converted into an oxide (Na _2). Stevensite in which the Na content in O) is suppressed to 5% by mass or less is preferably used.

As described above, the Steven site whose Na content is suppressed to a low range is described in the following formula (2):
I = D × 1000 / NA (2)
During the ceremony
D indicates the Darcy coefficient measured with water,
NA indicates naringin adsorption capacity (mg) per 1 g of sample powder (anhydrous).
The filtration / adsorption balance value I represented by is in the range of 0.01 to 1.15. That is, both the filterability and the adsorptivity to naringin are excellent.

<Silica-Magnesia Complex>
The silica-magnesia composite used as a naringin adsorbent is a silica-magnesia composite particle in which silica particles and magnesia particles are integrally composited, and the silica particles and magnesia particles are at a very fine level (for example, nano level). The particles are in close contact with each other and have a structure in which they are integrated without being separated.
That is, unlike magnesium silicate, which will be described later, it is not a reaction product of silica and magnesia, and the reaction does not cause atomic recombination or the like. This can be confirmed by, for example, XRD measurement not expressing a peak peculiar to magnesium silicate and the amount of adsorption to the anionic dye (Orange II).

In the present invention, the silica-magnesia composite particles used as the adsorbent have an orange II adsorption amount in the range of 18 to 74 mmol / 100 g, which is measured by the method shown in Examples described later. Such an orange II adsorption amount is derived from the anion adsorption property peculiar to magnesia, and silica does not exhibit such an anion adsorption property. Therefore, the orange II adsorption amount is in the above range. , This composite particle means that the silica particle and the magnesia particle are composited without reacting.

In magnesium silicate obtained by reacting silica and magnesia, the adsorption amount of Orange II is equal to or less than the above range, and exhibits the same excellent naringin adsorption as the silica-magnesia composite particles. Its behavior during adsorption is different from that of silica-magnesia composite particles. This behavior will be described later.

Further, when the silica particles and the magnesia particles are not compositely integrated and exist as a mere mixture, the amount of Orange II adsorbed shows a value higher than the above range or varies greatly. This is because the silica particles that do not exhibit anion adsorption and the magnesia particles that exhibit anion adsorption exist independently. Moreover, as can be understood from the fact that neither the silica particles nor the magnesia particles exhibit naringin adsorptivity, such a mixture also exhibits almost no naringin adsorptivity.
That is, in the composite particle in which the silica particle and the magnesia particle are compositely integrated, the composite integration of the silica particle and the magnesia particle causes the magnesia particle to be physically adsorbed by the silica particle and at the same time to the phenolic hydroxyl group of naringin. It seems that the chemical adsorptivity shown in the above acts synergistically to develop excellent adsorptivity for particles.

Further, in the above composite particles, the silica component and the magnesia component are represented by the following formula (1):
R = Sm / Mm (1)
In the formula, Sm is the content (mass%) of the silica component in terms of _{SiO 2.}
Mm is the content (mass%) of the magnesia component in terms of MgO.
It is preferable that the mass ratio (R) represented by is contained in a ratio of 0.1 ≦ R ≦ 3.5.
That is, since silica and magnesia are present in the above-mentioned quantitative ratio, the composite integrated state is stably maintained. For example, when the mass ratio (R) is more than 3.5 or less than 0.1, silica or magnesia is likely to fall off, so that the adsorptivity to naringin becomes unstable and variation is likely to occur. Because.

Further, in such silica-magnesia composite particles, since the silica component and the magnesia component are not liberated from each other and are closely compounded, the pH (25 ° C.) of the suspension having a concentration of 5% by mass is usually set. It is in the range of 6.0 to 10.0.

In the present invention, the silica-magnesia composite particles used as a naringin adsorbent are obtained by uniformly mixing silica (A) and magnesia or its hydrate (B) in the presence of water to obtain an aqueous slurry. It can be produced by (homogeneous mixing), then aging, and further removing water.
The amount ratio of silica (A) to magnesia or its hydrate (B) is set so that the mass ratio (R) represented by the above formula (1) is 0.1 to 3.5. do it.

As the raw material silica (A), an amorphous water-containing type is preferable, and it may be produced by either a gel method or a precipitation method, but one having small primary particles is preferable. A BET specific surface area of 40 m ² / g or more, particularly 140 m ² / g or more is preferable.
Further, as the magnesia or its hydrate (B), those having small crystals and not being carbonated with time are preferable. For example, magnesia powder having a BET specific surface area of 2 m ² / g or more, preferably 20 m ² / g or more, particularly preferably 50 m ² / g or more is used.

In the presence of water between the above silica (A) and magnesia or its hydrate (B), for example, in homogeneous mixing in water, silica (silicon dioxide), which is one of the raw materials, is colloidal particles or finely aggregated particles ( Primary to secondary particles) can be solved. The other magnesia (magnesium oxide) also hardly dissolves when it is put into water and stirred or crushed, but its crystals (or newly formed hydrate) are formed by partial hydration of the surface of magnesia particles. Part or all of the crystals) are disintegrated or exfoliated to form fine particles composed of magnesia (magnesium oxide) and / or magnesium oxide hydrate and dispersed in water.

In the preparation of the aqueous slurry in the presence of water as described above, there are no restrictions on the order of adding the raw materials (A) and (B) and water, but when aggregation or gelation phenomenon (thickening) occurs, the above-mentioned There is a risk that the progress of fine particle formation (nanoparticle formation) and integral compounding will be hindered. Therefore, it is preferable that the solid content concentration of the aqueous slurry is low. On the other hand, from the viewpoint of productivity and economy, the higher the solid content concentration is, the better. Therefore, the solid content concentration is preferably 3 to 15% by mass, particularly preferably 8 to 13% by mass.

In the aging step, water is removed from the slurry in which these fine particles are uniformly dispersed, and as the solid content concentration increases, the silica particles (A) and the magnesia particles (B) gradually or rapidly change. The silica-magnesia composite particles of interest can be obtained by approaching each other and reaching an integrally composited form (completion of integrally composited) without involving chemical bonds that involve atom exchange or recombination.

The above-mentioned homogeneous mixing and aging are preferably carried out at 100 ° C. or lower, preferably at 50 to 97 ° C., and at 50 to 79 ° C., gelation is effectively prevented and composite integration is performed in a short time. It is suitable for doing.

The homogeneous mixing and aging are generally carried out under stirring in a stirring tank equipped with a stirring blade, but can also be carried out under pulverization or dispersion using a wet ball mill or a colloid mill.
Further, although it depends on the temperature, the charging capacity of the slurry, and the like, it is necessary to carry out homogeneous mixing and aging for at least 0.5 hours. Further, the higher the temperature, the higher the fluidity of the nanoparticles and the more efficiently the nanoparticles are homogenized, so that the process can be performed in a shorter time. Generally, mixing and aging are carried out over 1 to 24 hours, particularly about 3 to 10 hours.

After aging, water is removed by evaporative drying using a spray dryer, slurry dryer, etc., but after some dehydration by means such as filtration or centrifugation, a box dryer, band dryer, etc. Drying may be performed using a fluidized layer dryer or the like. At this time, at least a part or all of the hydration of the raw material (B) is eliminated.

As described above, for example, the silica-magnesia composite particles having a water content of 10% by mass or less and in which silicon dioxide (silica) particles, which are raw material particles, and magnesia particles are closely composited by dehydration, are granular. Obtained in the form of powder, cake or baby boom. If necessary, these are pulverized, classified, or molded, and are used as particle shapes suitable for adsorption.
Such silica-magnesia composite particles are commercially available from Mizusawa Industrial Chemicals, Inc. under the trade names of "Mizuka Life F-1G" and "Mizuka Life F-2G".

<Magnesium silicate>
In the present invention, magnesium silicate used as a naringin adsorbent is obtained by reacting silicon dioxide (silica) with magnesia (or magnesium hydroxide) according to a method known per se, and has magnesium atoms. It is incorporated in the form of salt.
Such magnesium silicate exhibits excellent adsorptivity to naringin due to the high abundance ratio of magnesium atoms, but it adsorbs naringin with a completely different behavior from the above-mentioned stivuncite and silica-magnesia composite particles. The present inventors presume that the substance shows the property.

That is, as shown in Examples described later, when stibunsite, silica-magnesia composite particles, or magnesium silicate are added to an aqueous solution of naringin, naringin can be effectively adsorbed. Only when magnesium silicate is added, the phenomenon that the aqueous solution is colored yellow is observed. For example, the aqueous solution of naringin is a transparent aqueous solution, and its absorbance with respect to visible light is practically zero. However, when magnesium silicate is added, the aqueous solution immediately turns yellow and is visible regardless of the adsorption of naringin. The absorbance with respect to light increases, and this colored state is maintained as it is.
As can be understood from such experimental results, in magnesium silicate, a peculiar phenomenon that a coloring substance is generated at the time of adsorption of naringin is observed. This chromogenic substance has not been identified at this stage due to its extremely small amount, but it is presumed that naringin is decomposed to produce flavanone.

<Use as an adsorbent>
The various magnesium-containing compositions described above are adjusted in particle size suitable for adsorption and are used as a naringin adsorbent.
In this case, the stibunsite, silica-magnesia composite particles, and magnesium silicate may be used alone or in combination of two or more.
Further, the magnesium-containing composition of the present invention is hydrophobic, for example, by subjecting it to instantaneous heating in a microwave oven or heat treatment at 100 ° C to 1000 ° C in advance to remove water contained in the adsorbent such as adhering water before use. It is preferable to use it after enhancing the properties.

Further, the above-mentioned adsorbent is usually added to citrus juice such as grapefruit and orange, that is, fruit juice containing naringin, and is used for adsorbing and removing naringin from the juice by stirring and mixing. It can also be applied to capture of naringin by adding it to an aqueous solution of naringin or an organic solvent solution produced in the synthesis process and stirring and mixing.
The amount used is not particularly limited, and an appropriate amount may be added according to the concentration of naringin contained in the liquid. For example, when used for adsorption and removal of naringin from fruit juice, it depends on the concentration of the fruit juice. Then, an adsorbent may be added.

In the present invention, the above-mentioned stibunsite, silica-magnesia composite particles and magnesium silicate all show the same excellent adsorption performance for naringin, but magnesium silicate produces a colored substance upon adsorption. Considering that, for the adsorption of naringin from fruit juice, stebunsite and silica-magnesia composite particles are preferably used.

After the adsorption of naringin, filtration can be performed by a known means to isolate the adsorbent on which naringin is adsorbed.
In addition, naringin can be released from the adsorbent on which naringin is adsorbed and retained by a solvent extraction method or the like. For example, an adsorbent in which naringin is adsorbed and held in pure water is put into the water, and the naringin is released by subjecting it to a stirring operation such as ultrasonic vibration, and the naringin can be recovered by concentrating or removing the solvent.

The excellent effect of the present invention will be described with reference to the following experimental examples.

(1) pH
The adsorbent powder was added to the ion-exchanged water so that the adsorbent concentration was 5% by mass, and the mixture was stirred for 30 minutes and then measured with a pH meter HM-30R manufactured by Toa DKK.

(2) X-ray diffraction Measurement was performed by RINT-Ultima IV (X-ray = CuKα-ray) manufactured by Rigaku Co., Ltd.

(3) Amount of Orange II Adsorbed The Orange II adsorption capacity in this example was calculated by measuring and calculating the number of mmol of Orange II capable of adsorbing 1 g of a sample from an aqueous solution of Orange II having a concentration of 10 mmol / L.
First, Orange II (special grade reagent, manufactured by Wako Pure Chemical Industries, Ltd.) is dissolved in water to obtain an orange II aqueous solution having a concentration of 10 mmol / L. Weigh 20 ml of this 10 mmol / L concentration orange II aqueous solution into a 50 ml centrifuge tube, add 0.20 g of test powder, and use a shaker (SA300 manufactured by Yamato Scientific Co., Ltd., shaking speed 5) to 7.5. Shake the time. After shaking, let stand for 12 hours or more. Next, 0.5 mL of the supernatant of the liquid treated with a centrifuge (5200 manufactured by Kubota Co., Ltd.) at a centrifugal acceleration of 3000 rpm for 15 minutes was collected, and this was diluted 200-fold with ion-exchanged water to obtain the absorbance of 484 nm wavelength light. Was measured with a spectrophotometer (V-630 manufactured by JASCO Corporation). Then, the residual amount of Orange II in the sample solution was calculated using a calibration curve showing the relationship between the Orange II content of the Orange II aqueous solution and the absorbance of the 484 nm wavelength light. The value obtained by subtracting this value from the amount of Orange II added to the sample was taken as the amount of Orange II adsorbed.

(4) Adsorption test The naringin adsorption capacity was set to the amount (mg) that 1 g of the adsorbent (anhydrous) could be adsorbed, measured by the following method, and the calculated values are shown in Table 1.
First, naringin was dissolved in water to obtain a naringin aqueous solution having a concentration of 0.16 g / L. 30 g of this aqueous solution is weighed in a centrifuge tube having a capacity of 50 ml, 0.1 g of an adsorbent (0.33% by mass with respect to the liquid) is added, and a horizontal shaking type shaker (SA300 manufactured by Yamato Scientific Co., Ltd., shaking speed). Shake for 2.5 hours according to 5).
Next, the supernatant liquid of the liquid treated with a centrifuge (5200 manufactured by Kubota Co., Ltd.) at a centrifugal acceleration of 3000 rpm for 20 minutes was diluted 10-fold with ion-exchanged water to obtain a sample liquid. The absorbance of the sample solution at a wavelength of 285 nm was measured with a spectrophotometer (V-630 manufactured by JASCO Corporation). The residual amount of the component of the sample solution was calculated using a calibration curve showing the relationship between the component concentration and the absorbance prepared in advance, and the value subtracted from the amount of the component before the addition of the adsorbent was taken as the component adsorption amount of the adsorbent.
Then, the absorbance of the sample solution at a wavelength of 460 nm was measured, and the degree of color development due to the influence of the adsorbent was compared.

(5) Calculation of Filtration / Adsorption Balance Value (I Value) 200 ml of ion-exchanged water was placed in a beaker, 5 g of a sample dried at 110 ° C. for 1 hour was placed therein, and the mixture was stirred with a stirrer for 5 minutes. A filter paper (ADVANTEC No. 2) was set in a stainless steel Buchner funnel (filtration area 38.5 cm ^{2), and the vacuum pump was switched on.} The sample dispersion was poured into the funnel, the suction pressure was adjusted to 20 cmHg, and when the amount of the filtrate reached 100 ml, the stopwatch was started. The suction pressure was maintained at 20 cmHg during filtration. The stopwatch was stopped when the amount of the filtrate reached 150 ml, and this time was taken as the filtration time.
After measuring the filtration time, filtration was continued until the interval at which the filtrate fell from the filtration cake exceeded 30 seconds. When the drop interval exceeded 30 seconds, the thickness of the filtered cake was measured, and the Darcy coefficient was calculated by the following formula.
Darcy coefficient = (cake thickness cm x filtered liquid volume 50 ml x liquid viscosity 0.89 mPa · s)
÷ (Filtration time sec × Filtration area cm ² × (Suction pressure cmHg ÷ 76))
After that, the following formula (2):
I = D × 1000 / NA (2)
In the formula, D indicates the Darcy coefficient measured with ion-exchanged water.
NA indicates naringin adsorption capacity (mg) per 1 g of adsorbent (anhydrous).
The filtration / adsorption balance value I was calculated from the above.

Table 2 shows the results of the adsorption test for the adsorbent powders shown in the following Examples and Comparative Examples.

(Comparative Example 1)
Mizusawa Industrial Chemicals Co., Ltd.'s Acid Clay Mizuka Ace No., which contains montmorillonite as the main component. 20 (pH 4.9, I = 1.20).

(Comparative Example 2)
Active clay galleon earth V2 (pH 3.5, I = 11.00) made of an acid-treated montmorillonite manufactured by Mizusawa Industrial Chemicals Co., Ltd.

(Comparative Example 3)
Adeplus SP (pH 8.9), an adsorbent containing sepiolite as the main component, manufactured by Mizusawa Industrial Chemicals Co., Ltd.

(Comparative Example 3)
Silicon dioxide Mizuka Sorb C-6 (pH 6.5) manufactured by Mizusawa Industrial Chemicals Co., Ltd.

(Comparative Example 4)
Magnesium hydroxide (pH 10.1) manufactured by Ube Material Industries Ltd.

(Comparative Example 5)
Magnesium oxide star mug U (pH 10.9) manufactured by Konoshima Chemical Co., Ltd.

(Example 1)
Natural Spanish site (pH 8.5, I = 0.37).

(Example 2)
Ionite (pH 10.0, I = 0.17), an adsorbent made of synthetic stibuncite manufactured by Mizusawa Industrial Chemicals, Inc.

(Example 3)
SEPIGEL SUPREME 200RF (pH 7.2, I = 0.94), an adsorbent containing Stevensite as a main component, manufactured by Sepiorsa.

(Example 4)
Mizusawa Industrial Chemicals Co., Ltd.'s composite adsorbent Mizuka Life F-2G (pH 8.9, R = 1.9, anion adsorption capacity 55 mmol / 100 g) containing silicon dioxide and magnesium oxide as the main components is used as silica particles and magnesia particles. It was used as a silica-magnesia composite particle integrally composited with.

(Example 5)
Mizusawa Industrial Chemicals Co., Ltd.'s adsorbent Mizuka Life P1 (pH 8.7, anion adsorption capacity 33 mmol / 100 g) containing magnesium silicate as the main component.

Claims (3)

A naringin adsorbent comprising at least one magnesium-containing composition selected from stibunsite, silica-magnesia complex and magnesium silicate. The naringin adsorbent according to claim 1, wherein the magnesium-containing composition is stebunsite. The magnesium-containing composition is a silica-magnesia composite, and is composed of silica-magnesia composite particles in which silica particles and magnesia particles are integrally composited.
R = Sm / Mm (1)
In the formula, Sm is the content (mass%) of the silica component in terms of _{SiO 2.}
Mm is the content (mass%) of the magnesia component in terms of MgO.
The naringin adsorbent according to claim 1, wherein the mass ratio (R) represented by is contained in a ratio of 0.1 ≦ R ≦ 3.5.

Images