KR102445472B1 - A silver contained hydrophobic alumino-silicate aerogel and preparation method thereof - Google Patents

Abstract

The present invention relates to a hydrophobic airgel and a method for producing the same, and the method for producing a hydrophobic silver-containing alumino-silicate airgel of the present invention does not use a supercritical drying method, but a method for producing an airgel having excellent adsorption capacity for radioactive iodine provides

Description

A silver contained hydrophobic alumino-silicate aerogel and preparation method thereof

The present invention relates to a hydrophobic airgel and a method for preparing the same.

Specifically, the present invention relates to silver-containing, hydrophobic alumino-silicate airgels and methods for their preparation.

Among the various types of fissile materials generated during nuclear fuel combustion in a nuclear reactor, iodine (eg, ¹³¹ I, ¹²⁹ I), which has a relatively high fission yield, is a representative volatile radionuclide, and can be easily released into the air through exhaust in an accident or emergency. material that can be Iodine is a long-lived nuclide (for example, ¹²⁹ I half-life: 1.57 x 10 ⁷ years), can be exposed to the environment due to its high volatility, and can be inhaled into the human body and accumulated in the thyroid gland, so detection of them and removal techniques.

As a technology for removing radioactive iodine, iodine must be collected and solidified with an adsorbent and then stored in a disposal facility. The adsorbent for collecting iodine should be able to be solidified by pressure sintering at a low temperature so that there is no loss of iodine. To this end, an inorganic airgel or an organic-inorganic composite airgel material has been continuously researched and developed as an iodine adsorbent.

In addition, as part of the research on airgels for the development of iodine adsorbents, metal Ag or Ag ⁺ ions combine with various types of iodine or iodine ions. .

Accordingly, silver-functionalized silica aerogel and silver impregnated aluminosilicate aerogel have been recently developed to increase iodine capture efficiency and facilitate low-temperature pressure sintering.

However, adsorbents using silver-functionalized silica airgel or silver-impregnated aluminosilicate airgel developed so far are hydrophilic and do not exhibit adequate adsorption efficiency to adsorb hydrophobic radioiodine (I ₂ ), and their specific surface area and silver content are also low. It is reported that there are still unsuitable problems in terms of performance.

In addition, the silver-containing inorganic or organic-inorganic composite airgel production method known to date uses a supercritical drying method as a drying method of an alcogel for airgel production. In general, since drying is carried out at a high temperature of 240°C or higher and a high pressure of 7.93 MPa or higher, there is a high risk of safety.

Accordingly, research and development for an iodine adsorbent having high hydrophobicity, high specific surface area and excellent iodine adsorption efficiency is still ongoing.

An object of the present invention is to provide an adsorbent for radioactive iodine having excellent adsorption performance.

Specifically, an object of the present invention is to provide a silver-containing airgel that is hydrophobic, has an increased specific surface area, and has an excellent silver content.

Another object of the present invention is to provide a method for preparing a radioactive iodine adsorbent having excellent adsorption performance while increasing the cost and stability of the manufacturing process.

Specifically, an object of the present invention is to provide a method for producing a silver-containing airgel that is hydrophobic, has an increased specific surface area, and has an excellent silver content.

In order to achieve the above purpose,

In one aspect, the present invention provides a method for forming a sodium alumino-silicate alcohol gel; a cosolvent exchange step of replacing the cosolvent in the alcogel with a first substituted solvent by a solvent exchange method; an ion exchange step of replacing cations in the alcohol gel with silver ions (Ag ⁺ ) to form a silver-containing hydrogel; a solvent exchange step of the hydrogel to form a silver-containing alcogel by replacing the solvent in the silver-containing hydrogel with an inert organic solvent by a solvent exchange method; and a surface modification step of modifying the surface to be hydrophobic by adding a surface modifier to the silver-containing alcogel.

In another aspect, the present invention is an alumino-silicate airgel, wherein the airgel contains silver (Ag) in the pores, and contains hydrophobic silver containing units derived from a hydrophobic surface modifier on the surface. An alumino-silicate airgel is provided.

In another aspect, the present invention provides a radioactive iodine adsorbent comprising the hydrophobic silver-containing alumino-silicate airgel.

In another aspect, the present invention provides a method for removing radioactive iodine using the hydrophobic silver-containing alumino-silicate airgel.

Since the airgel of the present invention has a hydrophobic surface, there is an effect of improving the trapping performance of hydrophobic iodine.

In addition, the airgel of the present invention has a high silver content and a large specific surface area, so that it has an excellent iodine trapping performance.

In addition, since the airgel of the present invention is composed of alumino-silicate as a basic skeleton, it has a large specific surface area compared to other materials, and has advantages in that it can be sintered under low pressure when preparing a solidified iodine body after iodine capture.

In addition, the airgel of the present invention has an effect expected to be used as an adsorbent for removing organic compounds of sulfur contained as impurities in diesel oil and diesel oil applied in general industries.

The method for producing an airgel of the present invention not only can produce an airgel having the above characteristics, but also has the effect of excellently improving cost and stability as a method for producing an airgel having excellent performance.

The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the above-described contents of the present invention, so the present invention is limited to the matters described in such drawings It should not be construed as being limited.
1 is a sodium alumino-silicate for forming an alcohol cogel according to an embodiment of the present invention - a schematic diagram of the process of the gel method.
2 is a schematic diagram of a manufacturing process of an airgel according to an embodiment of the present invention.
3 is a schematic diagram of a manufacturing process of an airgel according to an embodiment of the present invention.
4 is a graph showing the Na/Si and Ag/Si molar ratios for each manufacturing process and manufacturing step of the airgel according to an embodiment of the present invention.
5 is a photograph showing the results of a floating test of airgel according to an embodiment of the present invention. (a) From the left Example 1-1, Example 1-2, Example 1-3, (b) From the left Example 2-1, Example 2-2, Example 2-3, (c) Left From Example 3-1, Example 3-2, Example 3-3 is shown.
6 is a graph showing the result of confirming the hydrophobic bond by ATR-IR according to each process in the manufacturing step of Example 2. According to (a), when washing with pure water, hydrophobic bonding is not confirmed, (b) is when the surface is dried at room temperature after surface modification with HMDZ, (c) when the surface is dried at atmospheric pressure after surface modification with TMS, (d) is the surface with TMMS In the case of drying at atmospheric pressure after modification, and (e) shows a graph for hydrophobic bonding in the case of drying at atmospheric pressure after surface modification with HMDZ.
7 is a graph showing a result of XRD analysis of the phase change of silver according to each process in the manufacturing step of Example 2;
8 shows the pore size distribution of AgASA according to an embodiment of the present invention.
9 shows photographs of AgASA according to (a) Examples 1-3 and (b) Examples 3-2.
10 is a photograph of Example 1-3 and Example 3-2 before (a) and after (b) adsorption of iodine.
11 is a photograph after iodine adsorption of AgASA according to Example 1-3 and commercially available AgX (Sigma Aldrich).

The method for producing a hydrophobic silver-containing alumino-silicate airgel of the present invention comprises the steps of: forming a sodium alumino-silicate alcogel; a cosolvent exchange step of replacing the cosolvent in the alcogel with a first substituted solvent by a solvent exchange method; an ion exchange step of replacing cations in the alcohol gel with silver ions (Ag ⁺ ) to form a silver-containing hydrogel; a solvent exchange step of the hydrogel to form a silver-containing alcogel by replacing the solvent in the silver-containing hydrogel with an inert organic solvent by a solvent exchange method; and a surface modification step of modifying the surface to be hydrophobic by adding a surface modifier to the silver-containing alcohol gel.

Forming a sodium alumino-silicate alcogel

The method for preparing the hydrophobic silver-containing alumino-silicate airgel includes forming a sodium alumino-silicate alcogel.

In one embodiment, the step of forming the alcogel may be by a sol-gel method, but is not limited thereto.

In one embodiment, although a flow chart of the manufacturing process of the sol-gel method is shown in FIG. 1, the process of the sol-gel method is not limited thereto.

A precursor material for forming the sodium alumino-silicate alcohol gel includes a Na source, an Al source and a Si source. The Na, Al and Si sources may include an alkoxide compound containing Na, Al and/or Si metal, respectively.

The sodium-containing alkoxide compound may include, for example, sodium methoxide (NaOCH _{3 ,} NaOMe), sodium ethoxide (NaOC ₂ H ₅ ), sodium isoprooxide [NaOCH(CH ₃ ) ₂ ] or mixtures thereof. However, the present invention is not limited thereto. The alkoxide compound containing aluminum is, for example, aluminum tri-sec-butoxide {Al[OCH(CH ₃ )C ₂ H ₅ ] ₃ , Al(OBu ^s ) ₃ }, aluminum trimethoxide [Al(OCH ₃ ) ) ₃ ], aluminum triethoxide [Al(OC ₂ H ₅ ) ₃ ], aluminum triisoprooxide {Al[OCH(CH ₃ ) ₂ ] ₃ } or mixtures thereof, but is not limited thereto it is not The silicon-containing alkoxide compound is tetramethyl orthosilicate [Si(OCH ₃ ) ₄ ], tetraethyl silicate [Si(OC ₂ H ₅ ) ₄ ], tetraisopropyl orthosilicate {Si[OCH(CH ₃ ) ₂ ] ₄ } or a mixture thereof, but is not limited thereto.

In one embodiment, for the formation of the sodium alumino-silicate alcogel, a silanol group as a monomer [HO-Si(OC ₂ H ₅ ) ₃ ] by partial hydrolysis under an acid catalyst with a molar ratio of silicon alkoxide and water to 1 can form. Here, aluminum alkoxide is added to form -O-Si-O-Al-O- by alcohol condensation reaction, Na is added to induce Na[AlO ₄ ] bonding, and then water is added for condensation and polymerization. It may include inducing crosslinking by

Since Na ions in the sodium alumino-silicate alcogel are then substituted with silver ions (Ag ⁺ ) through an 'ion exchange step', to increase the content of silver in the airgel to improve the content of Na contained in the alcogel something may be needed Accordingly, in the precursor material for manufacturing the airgel, the Na, Al and Si alkoxides may be included in an amount such that the molar ratio of their metal elements is 1 to 2:1 to 1.5:1, respectively. Specifically, the molar ratio of these metal elements may be included in an amount of 1.05:1:1 to 1.3:1.1:1. In this case, the Na/Al molar ratio is preferably set to 1.05 - 1.2 so that Na alkoxide acting as a base and Al alkoxide acting as an acid are neutralized. Excess Na alkoxide within the above range may shorten the gelation time, for example, the time required for gelation may be shortened to 2 to 3 hours. If excessive Na alkoxide is added, for example, when the Na/Al molar ratio is 1.25 or more, gelation proceeds during the hydration reaction and injection into the mold cannot be performed, so that various types of gels cannot be obtained. As above, the three-component precursor material must be dissolved by the alcohol solvent added before the cross-linking by the condensation and polymerization reaction following the addition of water.

When the sodium alumino-silicate alcogel (Na ⁺ AlSi-OH alcogel) is gelled at room temperature, it may take about 6 days to ripen, but after gelation at room temperature, the aging temperature of the Na ⁺ AlSi-OH alcogel is adjusted to 50° C. to In the case of a range of 55 ° C., aging is completed within 1 day, thereby shortening the manufacturing time, which may have the effect of strengthening the network structure of the alcohol gel.

Cosolvent Exchange Steps

The method for preparing the hydrophobic silver-containing alumino-silicate airgel includes replacing a cosolvent in the sodium alumino-silicate alcogel with a first substituted solvent by a solvent exchange method.

The co-solvent exchange step may be performed by repeated dilution exchange at room temperature and atmospheric pressure.

The co-solvent exchange step is a problem due to supercritical drying in performing the silver impregnation process after removing the solvent by supercritical drying after the formation of the alcohol in the production of the conventional silver-containing airgel, for example, the high cost of the process; It can exhibit the effect of solving problems such as a decrease in the stability of the process and a decrease in the physical properties of the airgel.

In the cosolvent exchange step, the cosolvent in the alcogel to be substituted includes a solvent for forming the alcogel. The co-solvent exchange step removes 2-butanol in the co-solvent in the alcohol gel, which has very low solubility (affinity) in water, so that AgNO ₃ as an ion exchange agent can easily access the pore surface, NaOH and / or exchange with a solvent having a low affinity for AgNO ₃ , in order to improve the silver content in the airgel in a later step.

The cosolvent to be substituted may be an alcohol produced by a hydration reaction with an alcohol added for the preparation of the sodium alumino-silicate alcohol gel. For example, the cosolvent may include ethanol, isopropanol, 2-butanol, methanol, and the like.

The substituted solvent of the co-solvent exchange step, that is, the first substituted solvent is a solvent different from the cosolvent to be substituted, for example, from the group consisting of purified water (PW), isopropanol (IPA) and methanol (MeOH). It may include at least one selected, but is not limited thereto. Specifically, it may be preferable to use isopropanol, methanol, or a mixed solvent thereof in consideration of the silver content of the airgel to be prepared as the first substitution solvent.

In one embodiment, it may include exchanging butanol having low solubility with water in the alcohol gel with isopropanol.

The volume of the solvent substituted in the co-solvent exchange step may be 10 to 15 times the volume of the alcohol gel, for example 12 to 13 times. Specifically, the volume of the cosolvent remaining in the pores of the alcogel after the cosolvent exchange step may be 1% or less of the pore volume, but is not limited thereto.

In one embodiment, the sodium alumino-silicate cosolvent in the Na ⁺ AlSi-OH alcogel prepared by adding the molar ratio of Na:Al:Si to 1.05:1:1 for forming the silicate alcogel is mixed with purified water (Purified Water, PW), the Na/Si molar ratio was 0.69, whereas when it was replaced with isopropanol, it was confirmed that the Na/Si molar ratio increased to 1.07. This may be because unreacted NaOH remaining in the pores of the alcohol gel has very low solubility in isopropanol and is not released to the outside but remains in the pores of the alcohol gel, but the mechanism of the present invention is not limited thereto.

Ion exchange step

The method for preparing the hydrophobic silver-containing alumino-silicate airgel includes an ion exchange step of replacing cations in the alcohol gel with silver ions (Ag ⁺ ) to form a silver-containing hydrogel.

The ion exchange step is a process for containing silver in the airgel to be manufactured, and may be performed by any known means.

For example, cations in the alcogel may be substituted with silver by immersing the alcogel in an aqueous solution containing the silver ion. The cations in the alcohol gel substituted by the ion exchange step may include sodium ions (Na ⁺ ). In addition, the aqueous solution may include, for example, AgNO ₃ having high solubility in water as a silver ion source.

In one embodiment, the ion exchange step may include contacting the alcogel with AgNO ₃ .

In one embodiment, the ion exchange step may include immersing the alcogel in an AgNO ₃ aqueous solution. The AgNO ₃ aqueous solution may include AgNO ₃ at a concentration of 0.1M to 1M, such as 0.2M to 0.8M, specifically 0.5M, but is not limited thereto.

In one embodiment, when the alcogel is immersed in an AgNO ₃ aqueous solution, the Ag/Na molar ratio may be 5 to 7, specifically, 6.5, but is not limited thereto.

In one embodiment, the ion exchange may be performed by stirring at room temperature.

The ion exchange step may include reacting the silver ion source, such as AgNO ₃ with NaOH, etc. at room temperature in order to increase the silver content in the prepared airgel. Ag ₂ O generated through this can be captured in the airgel pores to be produced, thereby exhibiting the effect of improving the silver content in the airgel.

Thereafter, by repeatedly washing the prepared airgel with water, the Ag ₂ O phase is exposed to the air and may exist as an Ag ₂ CO ₃ phase, but the form of the present invention is not limited thereto.

In one embodiment, as a result of X-ray diffraction analysis, it was confirmed that the Ag ₂ CO ₃ phase was present in the airgel according to the present invention.

Solvent exchange step of hydrogel

In the method for producing the hydrophobic silver-containing alumino-silicate airgel, the silver-containing hydrogel (Ag ⁺ AlSi-OH) is replaced with an inert organic solvent by a solvent exchange method to form a silver-containing hydrogel. solvent exchange step.

This may be a preparation step for inducing a graft reaction by replacing the water in the pores of the silver-containing hydrogel with an inert organic solvent so that the hydrophobic surface modifier can easily access the surface of the gel pores in a later step.

In one embodiment, in the step of exchanging the solvent of the hydrogel, water in the silver-containing hydrogel is first substituted with an alcohol having water affinity (primary solvent exchange), and then the substituted alcohol is substituted with the inert organic solvent (secondary solvent exchange). Here, the alcohol substituting for the water may include at least one selected from the group consisting of methanol, ethanol, and isopropanol.

The inert organic solvent is a solvent having low solubility in Ag, and may include, for example, at least one selected from the group consisting of hexane, heptane toluene, and xylene, but is not limited thereto.

The volume of the alcohol solvent to be first substituted in the solvent exchange step of the hydrogel may be 10 to 15 times, for example, 12 to 13 times, of the volume of the hydrogel, and the volume of water remaining in the pores of the gel after the exchange is It may be less than or equal to 1% by volume, but is not limited thereto.

The volume of the inert organic solvent to be secondarily substituted in the solvent exchange step of the hydrogel may be 10 to 15 times, for example 12 to 13 times, the volume of the alcohol gel formed by the first solvent exchange, and the pores of the gel after the exchange The volume of water remaining therein may be 0.1% or less of the pore volume, but is not limited thereto.

The exchanging step of the hydrogel, for example, the first solvent exchange and the second solvent exchange, respectively, may be carried out in the range of 45° C. to 60° C., such as 50° C. to 55° C., so that the solvent to be substituted can easily diffuse in the pores. However, the present invention is not limited thereto.

The solvent exchange step of the hydrogel may include reducing silver ions (Ag ⁺ ) in the silver-containing hydrogel.

Specifically, when exchanging the water of the hydrogel with alcohol in the above temperature range (primary solvent exchange), the Ag ₂ O or Ag ₂ CO ₃ phase may be reduced and converted to the Ag phase, which is bound to the network structure of the gel. Ag ⁺ [AlO ₄ ] ^- in the form of a complex with Al, may include the separation of Ag and conversion into metallic Ag.

surface modification step

The method for preparing the hydrophobic silver-containing alumino-silicate airgel includes a surface modification step of modifying the surface to be hydrophobic by adding a surface modifier to the silver-containing alcohol gel (AgAlSi-OH).

The silver-containing alcohol gel may exhibit hydrophilicity because a large number of hydroxyl functional groups (eg, -Si-OH, -Al-OH) exist on the surface, specifically, the pore surface. In this case, there is no reaction with Ag, and the surface of the alcohol gel can be hydrophobically modified by a surface modifier having a small molecular diameter and easy access to the gel pores.

The surface modifier may include a compound represented by any one of Chemical Formulas 1 to 3, but is not limited thereto.

[Formula 1]

R ₃ SiOH

[Formula 2]

R ₃ SiOR

[Formula 3]

R ₃ SiNHSiR ₃

In Formulas 1 to 3, each R is independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, provided that at least two functional groups in one molecule of the compound are an alkyl group.

In one embodiment, the surface modifier is trimethylsilanol [(CH ₃ ) ₃ Si-OH, TMS], trimethylmethoxysilane [(CH ₃ ) ₃ Si-OCH ₃ , TMMS], hexamethyldisilazane [( CH ₃ ) ₃ Si-NH-Si(CH ₃ ) ₃ , HMDZ] or a mixture thereof may be used.

By the surface modification step, the hydroxyl group (-Si-OH) in the silver-containing alcohol gel reacts with -OH, -OCH ₃ , -NH present in the surface modifier to have a -Si-R bond hydrophobization-modified gel (AgAlSi -R) can be converted to

In one embodiment, the silver-containing alcogel may be converted into an AgAlSi-CH ₃ gel having a -Si-CH ₃ bond.

The amount of the surface modifier used, the reaction temperature and time for the surface modification step is to allow sufficient surface modification of the airgel, and is not particularly limited.

In one embodiment, the surface modifier may be used in an amount of 10 to 40%, such as 15 to 30%, specifically 20%, based on the total volume of the gel. In addition, the volume ratio of the surface modifier to the total volume of the inert organic solvent in the gel may be used in an amount of 0.1 to 0.5, for example 0.2.

In one embodiment, when TMS, TMMS or HMDZ is used as the surface modifier, respectively, the volume ratio of the surface modifier to the total volume of the inert organic solvent is maintained at a constant ratio, for example, when the amount is 0.2, TMS/oxide ( Based on NaAlSiO _2+x ), a molar ratio of 8 to 10, a TMMS/oxide molar ratio of 8 to 10, and a HMDZS/oxide molar ratio of 6 to 10 may be used.

In one embodiment, the reaction temperature for the surface modification reaction may be 55 ℃, the reaction time may be 2 to 3 days, but is not limited thereto.

atmospheric drying step

The method for preparing the hydrophobic silver-containing alumino-silicate airgel may further include a drying step at atmospheric pressure to dry the solvent contained in the hydrophobic-modified gel after the surface modification step.

The atmospheric drying step may be, for example, drying by a heat treatment program of maintaining at 55° C. for 3 hours at a temperature increase rate of 1.5° C./min, maintaining at 150° C. for 12 hours and maintaining at 200° C. for 3 hours, but is limited thereto. it's not going to be

The heat treatment atmosphere was carried out in a hydrogen atmosphere in the conventional case, but according to the present invention, since silver ions are reduced to Ag particles having excellent reactivity with iodine in the solvent substitution step, the drying reaction is performed even under an inert gas argon or nitrogen atmosphere and/or air atmosphere. has the effect of being able to

The hydrophobic silver-containing alumino-silicate airgel of the present invention is an alumino-silicate airgel (Alumino-silicate aerogel), wherein the airgel contains silver (Ag) in the pores, and contains a unit derived from a hydrophobic surface modifier on the surface. include

In one embodiment, the hydrophobic silver-containing alumino-silicate airgel may be prepared according to the above-described manufacturing method.

The pores of the hydrophobic silver-containing alumino-silicate airgel may be characterized in that their size is distributed in the medium-large pore region.

In general, the pore size of the airgel can be classified into a micropore region with a pore diameter of less than 2 nm, a meso pore region with a range of 2 to 100 nm, and a macropore region with a pore diameter greater than 100 nm. According to the invention, the pore size may be in a medium-large pore region (a region having a pore diameter of about 2 to about 200 nm).

The hydrophobic silver-containing alumino-silicate airgel may have a specific surface area of 160 to 300 m ² /g, 160 to 250 m ² /g, 165 to 200 m ² /g, or 165 to 180 m ² /g. , but is not limited thereto.

The hydrophobic silver-containing alumino-silicate airgel may have a pore volume of 0.8 to 2 cm ³ /g, 0.8 to 1.5 cm ³ /g, or 1.0 to 1.3 cm ³ /g, but is not limited thereto.

The hydrophobic silver-containing alumino-silicate airgel may have a silver content of 40 to 60% by weight or 43 to 55% by weight based on the total weight, but is not limited thereto.

The silver particles contained in the hydrophobic silver-containing alumino-silicate airgel may have an average particle diameter of 5.4 to 6.6 nm, but is not limited thereto. As the silver content in the airgel increases, the average particle diameter of the silver particles may also increase.

In one embodiment, the average particle diameter of the silver particles may be confirmed through TEM.

The surface modifier is as described above, and the unit derived from the surface modifier may represent a bond with an alkyl group present in the surface modifier, but is not limited thereto.

The hydrophobic silver-containing alumino-silicate airgel may have a pore size of 10 to 30 nm, 10 to 25 nm, 11.9 to 15.1, 19.0 to 21.5, or 20.7 to 23.3 nm, but is not limited thereto.

Since the hydrophobic silver-containing alumino-silicate airgel has a large specific surface area, there is an advantage in that iodine can be collected and then sintered under low pressure when preparing a solid body.

The radioactive iodine adsorbent of the present invention comprises the hydrophobic silver-containing alumino-silicate airgel. The radioactive iodine adsorbent may be composed of only the hydrophobic silver-containing alumino-silicate airgel, but may be used in the form of a blanket prepared by including the airgel in a substrate, and the form of use thereof is particularly limited. not.

In addition, the radioactive iodine adsorbent has the advantage that it can be used as an adsorbent for removing sulfur-containing organic compounds contained as impurities in light oil, diesel oil, etc. as well as adsorbing radioactive iodine.

The method of removing radioactive iodine of the present invention includes using the hydrophobic silver-containing alumino-silicate airgel.

The method of removing the radioactive iodine has an advantage in that the hydrophobic silver-containing alumino-silicate airgel minimizes the problem of performance degradation due to water vapor and has excellent collection efficiency because it can capture the radioactive I ₂ gas which is hydrophobic.

In one embodiment, it was confirmed that the iodine adsorption capacity representing the weight of iodine adsorbed relative to the weight of the adsorbent may be 0.4 to 0.7, specifically 0.468 to 0.56, but the adsorption performance of the present invention is not limited thereto.

Hereinafter, examples and the like will be described in detail to help the understanding of the present invention. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the following examples. The embodiments of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art to which the present invention pertains.

[Preparation of a silver-contained hydrophobic alumino-silicate aerogel, hereinafter referred to as hydrophobic AgASA]

The hydrophobic AgASA was prepared by sol-gel synthesis, cosolvent exchange, Ag/Na ion exchange, impurity cleaning, solvent exchange, pore surface modification, unreacted silylating agent cleaning, and atmospheric drying steps.

[Common Conditions for Implementation]

Sol-gel synthesis

The sol-gel was synthesized according to the manufacturing process of the sol-gel shown in FIG. 1 .

To synthesize the sol-gel, 25wt% sodium methoxide (hereinafter referred to as NaOMe), aluminum tri-sec-butoxide (Aluminum-tri-sec-) dissolved in methanol as precursors of sodium, aluminum, and silicon, respectively butoxide, hereinafter referred to as Al(OBu ^s ) ₃ ), and tetraethyl orthosilicate (hereinafter referred to as TEOS) were used.

The sol generation conditions were as shown in Table 1 below, and the cylindrical Na ⁺ AlSi-OH alcohol gel prepared using a cylindrical mold was cut and granulated to have particle sizes of 10 mm and 5 mm or less, respectively.

The weight of the sol-gel was prepared by 5 g to 15 g based on Na _y Al _y SiO _2+x . During the sol synthesis and hydration reaction of the sol, the stirring speed of the sol was set to 200 to 600 rpm.

division Na:Al:Si
addition molar ratio EtOH:TEOS
molar ratio PW: TEOS
molar ratio HOAc:TEOS
molar ratio Pr ⁱ OH:Al(OBu ^s ) ₃
volume ratio mold diameter (mm) gelation temperature (°C) Aging temperature (℃) Cutting granule size (mm) Example 1 1.05:1:1 One One 0.05 3 23 room temperature room temperature <10 Example 2 1.05:1:1 One One 0.05 3 23 room temperature 50 <10 Example 3 1.3:1.1:1 One One 0.05 3 14 room temperature 55 <5

common solvent exchange

The co-solvent of the aged gel was exchanged using purified water (PW) or isopropanol (Pr ⁱ OH), respectively.

Here, the cosolvent is an alcohol produced by hydration reaction with an alcohol added during sol-gel synthesis as shown in FIG. 1, and includes ethanol (EtOH), isopropanol (Pr ⁱ OH), 2-butanol, and methanol.

Cosolvent exchange was repeated three times for 1 day at room temperature to dilute/filter the Na ⁺ AlSi-OH prepared according to the sol-gel synthesis so that the volume of the cosolvent in the pores of the alcogel was 1% or less. Stirring was performed at 120 rpm using a plastic shaker.

Ag/Na ion exchange

Ag/Na ion exchange was performed using 0.5 M AgNO ₃ aqueous solution. Specifically, based on Na _y Al _y SiO _2+x oxide, the Na/Ag molar ratio was performed in an amount of 6.5, and the molar ratio was adjusted by the volume of AgNO ₃ aqueous solution.

Ion exchange was performed at room temperature for 1 day, and stirring was performed at 120 rpm using a plastic shaker.

Impurity cleaning

Impurities such as NaNO ₃ and excess AgNO ₃ generated by the ion exchange reaction were washed with pure water while wetted with a tissue in the filtered solution and dried at room temperature until discoloration did not occur.

Stirring was performed at 120 rpm using a plastic shaker.

Solvent exchange of hydrogels

(First solvent exchange) Before surface-modifying the hydrophilic Ag ⁺ AlSi-OH hydrogel to be hydrophobic, the water remaining in the pores was first exchanged with an alcohol having an affinity for water.

Table 2 shows the type of alcohol used for the substitution and the exchange temperature. The solvent exchange was repeated 3 times for 1 day so that the volume of water in the pores of the Ag ⁺ AlSi-OH hydrogel was 1% or less.

(Secondary solvent exchange) The alcohol remaining in the Ag ⁺ AlSi-OH hydrogel pores was exchanged with an inert organic solvent, and the type and exchange temperature of the inert organic solvent used for substitution are shown in [Table 2]. The solvent exchange was repeated 3 times for 1 day, diluted/filtered so that the volume of alcohol in the pores of the Ag ⁺ AlSi-OH alcohol gel was 1% or less.

Experiment
number Primary solvent exchange Second solvent exchange alcohol type exchange temperature Inert organic solvent type exchange temperature Example 1 EtOH 50 HEP 50 Example 2 Pr ⁱ OH 50 HEP 50 Example 3 Pr ⁱ OH 55 HEP 55

Hydrophobic surface modification of pores

Trimethylsilanol (TMS), (CH ₃ ) ₃ Si-OH], trimethylmethoxysilane, trimethylsilanol (TMS), (CH 3 ) 3 Si-OH], trimethylmethoxysilane, which are not reactive with Ag and have a small molecular diameter for surface modification (TMMS), (CH ₃ ) ₃ Si-OCH ₃ ], hexamethyldisilazane [Hexamethyldisilazane (HMDZ), (CH ₃ ) ₃ Si-NH-Si(CH ₃ ) ₃ ] was selected to perform surface modification. .

In the surface modification, the same HEP (heptane) was used as the solvent when exchanging the inert organic solvent, and the concentration and temperature of the silylating agent are shown in Table 3, and the surface modification was performed for 3 days.

Unreacted silylating agent cleaning

The unreacted silylating agent was washed/filtered by repeating dilution 3 times for 1 day using the same volume of HEP as the solvent exchange at the temperature shown in [Table 3] below.

Experiment
number surface modifier surface modification temperature
(℃) Surface modifier volume (%) Surface modifier/HEP
volume ratio Surface modifier/gel* molar ratio Example 1-1 TMS 55 20 0.2 10 Example 1-2 TMMS 55 20 0.2 8 Examples 1-3 HMDZ 55 20 0.2 6 Example 2-1 TMS 55 20 0.2 10 Example 2-2 TMMS 55 20 0.2 8 Example 2-3 HMDZ 55 20 0.2 06 Example 3-1 TMS 55 20 0.2 10 Example 3-2 TMMS 55 20 0.2 10 Example 3-3 HMDZ 55 20 0.2 10

* Number of moles of gel: based on oxide

atmospheric drying

The hydrophobized surface-modified gel was dried under a 4% H ₂ /Ar flow, a reducing gas mixture, for 3 h at 55° C., 12 h at 150° C., and 3 h at 200° C. at a temperature increase rate of 1.5° C./min at atmospheric pressure.

[Physical and Chemical Characterization]

The analysis of the relative content of Na, Ag, Al and Si elements for each step to be prepared below was analyzed using an energy dispersive X-ray spectrometer (EDS).

The size of Ag particles was confirmed by transmission electron microscope (TEM), and analysis of Ag phase change was confirmed by X-ray diffractometer (XRD), and BET of AgASA manufactured BET and BJH models were used for surface area and pore size distribution.

Ag content and iodine content in the iodine collection solution were analyzed with an inductively coupled plasma mass spectrometer (ICP-MS).

[Example 1. Preparation of low-content silver-containing hydrophobic AgASA]

Hydrophobized AgASA was prepared according to the sol-gel synthesis conditions shown in Table 1 and the process flow diagram of FIG. 2 . As shown in the process flow diagram of FIG. 2 , pure water (PW) was used as a substitution solvent in the cosolvent exchange step, and EtOH was used for the primary solvent exchange as shown in Table 2. The rest of the conditions were the same as the above common conditions.

The molar (atomic) ratio of Na and Ag to Si added at a constant molar ratio for each process step is shown as Test No. 1 in FIG. 4 . Referring to FIG. 4, when the cosolvent in Na ⁺ AlSi-OH alcohol gel pores is exchanged with pure water, Na ⁺ [AlO ₄ ] ^- unreacted NaOH that did not form a complex compound is dissolved and escaped to the outside of the gel during gelation. It was confirmed that the /Si molar ratio decreased from 1.05 (injection ratio during sol synthesis) to 0.69.

Since AgASA has hydrophobicity by the surface modification reaction, it was confirmed that the Ag/Si ratio was in the range of 0.51 to 0.52, almost regardless of the type of the surface modifier, due to the increase in the Si content.

Here, it was confirmed that the average size of Ag particles contained in AgASA surface-modified by TMMS (Example 1-2) was 5.4 nm.

In addition, in order to confirm the hydrophobicity of the prepared AgASA, the result of a floating test on water is shown in FIG. 5(a). As can be seen from the photograph of Figure 5 (a), the granules surface-modified with TMS (Example 1-1), TMMS (Example 1-2) and HMDZ (Example 1-3) were all on water. was wealthy.

Next, the BET surface area, cumulative pore volume, and average pore size of AgASA prepared according to Example 1 are shown in Table 4 below. According to Table 4, the BET surface areas of AgASA surface-modified with TMMS (Example 1-2) and HMDZ (Example 1-3) were 238 and 233 m ² /g, respectively, but with TMS (Example 1-1). It was confirmed that the BET surface area of the surface-modified AgASA was slightly lowered to 175 m ² /g.

In addition, the cumulative pore volume and average pore size of the AgASA of Examples 1-2 and 1-3 were 0.92-0.96 cm ³ /g and 11.9-12.6 nm, respectively, whereas the AgASA of Example 1-1 was 0.84, respectively. It was confirmed that, although the pores were large at cm ³ /g and 15.1 nm, the structure showed a rather low pore volume (porosity).

division BET surface area
(m ² /g) Cumulative pore volume, based on desorption
(cm ³ /g) Average pore size, based on desorption
(nm) Example 1-1 175 0.84 15.1 Example 1-2 238 0.92 11.9 Examples 1-3 233 0.96 12.6

According to (a) of FIG. 8 showing the pore size distribution, unlike the silver exchange zeolite having a meso-large pore size distribution, AgASA of Example 1 has the characteristic of having a meso-macropore size pore size distribution. Confirmed.

[Example 2. Preparation of hydrophobized AgASA containing high silver content]

Hydrophobized AgASA was prepared according to the sol-gel synthesis conditions shown in Table 1 and the process flow diagram of FIG. 3 . As shown in the process flow diagram of FIG. 3 , Pr ⁱ OH was used as a substitution solvent in the cosolvent exchange step, and Pr ⁱ OH shown in Table 2 was used for the primary solvent exchange. The rest of the conditions were the same as the above common conditions.

The molar (atomic) ratio of Na and Ag to Si added at a constant molar ratio for each process step is shown as Test No. 2 in FIG. 4 . In the case of exchanging the cosolvent in the pores of Na ⁺ AlSi-OH alcohol gel with Pr ⁱ OH, unreacted NaOH remaining in the pores during gelation has little solubility in Pr ⁱ OH, so it continues to remain in the pores during Ag/Na ion exchange. It reacts with AgNO ₃ and is deposited as insoluble Ag ₂ O in the pores [2NaOH + 2AgNO ₃ → Ag ₂ O + NaNO ₃ + 1/2H ₂ O]. Therefore, referring to FIG. 4, when exchanging the cosolvent with Pr ⁱ OH, the Na/Si molar ratio does not differ from 1.05 (injection ratio during sol synthesis), and even after Ag/Na ion exchange, the Ag/Si molar ratio is almost the same. Confirmed.

7 shows the results of XRD analysis to confirm the generation of the Ag ₂ O phase for each step. As a result of the analysis, a peak of the Ag ₂ CO ₃ phase as shown in (a) of FIG. 7 appeared. It was inferred that Ag ₂ O was converted into Ag ₂ CO ₃ by contact with CO ₂ during repeated washing/filtration of impurities with pure water and powdering during XRD sample preparation.

It was confirmed that Ag was separated from Ag ⁺ [AlO ₄ ] ^- in the form of a complex compound by bonding with Al bound to the network in the solvent exchange step with the primary Pr ⁱ OH, and the metal Ag phase and Ag ₂ CO ₃ were reduced to the Ag phase ( 6(b)). All Ag phases were maintained after this step (Fig. 7(c): after secondary solvent exchange, Fig. 7(d): TMS surface-modified airgel, Fig. 7(e): TMMS surface-modified airgel, Fig. 7(f)) : HMDZ surface-modified airgel).

In addition, the average size of Ag particles contained in AgASA according to Example 2-2 surface-modified with TMMS was 5.9 nm.

In addition, in order to confirm the hydrophobic properties of the prepared AgASA, the result of a floating test on water is shown in FIG. 5(b). As can be seen from the photograph (b) of FIG. 5 , the granules surface-modified with TMS (Example 2-1) and TMMS (Example 2-2) were slightly immersed in water, which resulted in an increase in Ag content. was inferred by

As a result of confirming the hydrophobic bonding of AgASA according to Example 2 using ATR-IR (FIG. 6), no hydrophobic bonding was detected when washing with pure water (FIG. 6(a)), and drying at room temperature after surface modification with HMDZ (Fig. 6(b)), TMS (Fig. 6(c)), TMMS (Fig. 6(d)) and HMDZ (Fig. 6(e)) in the airgel dried at atmospheric pressure after surface modification, CH (2961cm ^-1 ), Si -C (547 and 1258 cm ⁻¹ ) binding was detected.

In addition, since AgASA has hydrophobicity by the surface modification reaction, it was confirmed that the Ag/Si ratio was in the range of 0.93 to 0.96 due to the increase in the Si content, almost regardless of the type of the surface modifier.

Next, the BET surface area, cumulative pore volume, and average pore size of AgASA prepared according to Example 2 are shown in Table 5 below. According to Table 5, the BET surface area of AgASA surface-modified with TMS (Example 2-1), TMMS (Example 2-2) and HMDZ (Example 2-3) was almost the same as 168-179 m ² /g. and it was confirmed to be somewhat decreased than in Example 1 by increasing the Ag content.

Meanwhile, it was confirmed that the cumulative pore volume and average pore size of AgASA according to Example 2 were 0.97-1.15 cm ³ /g and 19.0-21.5 nm, which were slightly increased compared to Example 1.

division BET surface area
(m ² /g) Cumulative pore volume, desorption criteria
(cm ³ /g) Average pore size, based on desorption
(nm) Example 2-1 168 0.97 19.0 Example 2-2 179 1.04 19.2 Example 2-3 174 1.05 21.5

According to (b) of FIG. 8 showing the pore size distribution, AgASA according to Example 2 has a pore size distribution in the medium-large pore region.

[Example 3. Preparation of hydrophobized AgASA containing high silver content]

Hydrophobized AgASA was prepared according to the sol-gel synthesis conditions shown in Table 1 and the process flow diagram of FIG. 3 . As shown in the process flow chart of FIG. 3 , Pr ⁱ OH was used as a substitution solvent in the cosolvent exchange step, and Pr ⁱ OH was used as shown in Table 2 of the primary solvent exchange. The rest of the conditions were the same as the above common conditions.

The molar (atomic) ratio of Na and Ag to Si added at a constant molar ratio for each process step is shown as Test No. 3 in FIG. 4 . Referring to FIG. 4 , as in Example 2, as the cosolvent is exchanged with Pr ⁱ OH, the Na/Si molar ratio does not differ from 1.30 (injection ratio during sol synthesis), and even after Ag/Na ion exchange, the Ag/Si molar ratio was found to be almost identical.

In addition, in order to confirm the hydrophobic properties of the prepared AgASA, the result of a floating test on water is shown in FIG. 5(c). As can be seen from the photograph of Figure 5 (c), the granules surface-modified with TMS (Example 3-1), TMMS (Example 3-2) and HMDZ (Example 3-3) were all submerged in water. It was confirmed that the Ag content was greatly increased.

In addition, since AgASA has hydrophobicity due to the surface modification reaction, it was confirmed that the Ag/Si ratio was in the range of 1.08-1.1 almost regardless of the type of the surface modifier due to the increase in the Si content.

Next, Table 6 shows the BET surface area, cumulative pore volume and average pore size of AgASA prepared according to Example 3. According to Table 6, the BET surface area of AgASA surface-modified with TMS (Example 3-1), TMMS (Example 3-2) and HMDZ (Example 3-3) was 169-172 m ² /g. 2 and similar levels were shown.

On the other hand, it was confirmed that the cumulative pore volume and average pore size of AgASA according to Example 3 were 1.12-1.24 cm ³ /g and 20.7-23.4 nm, respectively, which were slightly increased compared to AgASA according to Example 2.

division BET surface area
(m ² /g) Cumulative pore volume, desorption criteria
(cm ³ /g) Average pore size, based on desorption
(nm) Example 3-1 169 1.12 20.7 Example 3-2 172 1.24 22.6 Example 3-3 172 1.29 23.4

AgASA according to Example 3 was also confirmed to have a pore size distribution in the medium-large pore region as shown in FIG. 8(c), and Ag particles contained in AgASA surface-modified with TMMS according to Example 3-2 has an average size of 6.6 nm.

For comparison of the BET surface area, cumulative pore volume, and average pore size of AgASA according to Examples 1-1 to 3-3, the values of Tables 4 to 6 are shown in Table 7 below.

division BET surface area (m ² /g) Cumulative pore volume, based on desorption (cm) ³ /g) Average pore size, based on desorption (nm) Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 One
(TMS) 175 168 169 0.84 0.97 1.12 15.1 19.0 20.7 2 (TMMS) 238 179 172 0.92 1.04 1.24 11.9 19.2 22.6 3 (HMDZ) 233 174 172 0.96 1.05 1.29 12.6 21.5 23.4

[Silver content analysis]

Analysis of the silver content of AgASA prepared by surface modification with HMDZ according to Example 1-3 (FIG. 9(a)) and AgASA prepared by surface modification with TMMS according to Example 3-2 (FIG. 9(b)) As a result, they were 43 wt% and 55 wt%, respectively.

[Iodine adsorption capacity analysis]

An iodine adsorption experiment was performed using AgASA according to Example 1-3 and AgASA according to Example 3-2.

Iodine adsorption capacity was measured for iodine adsorption at 150° C. for 20 hours after loading iodine of the same weight as the weight of the adsorbent shown in Table 8 in a sealed cell, and desorption of physically adsorbed iodine for 2 hours under vacuum at 150° C. The results of the experiments are shown in Table 8 below. From Table 9, it was confirmed that the iodine adsorption capacity (iodine adsorption weight relative to the adsorbent weight) of AgASA of Examples 1-3 and 3-2 was 0.468 to 0.560.

Use AgASA Adsorbent weight, m _s (g) Iodine adsorption weight, m _I (g) Iodine adsorption capacity, m _I /m _s Examples 1-3 0.5068 0.237 0.468 Example 3-2 0.5089 0.285 0.560

In addition, the photos before and after the iodine adsorption experiment using Examples 1-3 and 3-2 are shown in FIG. 10, and according to FIG. 10, it was confirmed that there was an iodine adsorption effect through discoloration before and after iodine adsorption.

[Iodine Capture Experiment]

A comparative experiment for iodine capture was performed using AgX (silver exchanged zeolite) manufactured by Sigma Aldrich and AgASA, which was surface-modified to be hydrophobic using HMDZ according to Examples 1-3. The conditions of the capture experiment are shown in Table 9 below.

AgX was converted into reduced AgX by heat treatment at 400° C. for 12 h under a flow of 4% H ₂ /Ar gas. The HMDZ-modified AgASA according to Example 1-3 was crushed to fill the adsorbent column, and then sorted through a sieve of 1-2 mm. In the capture experiment, the flow rate of the carrier gas (4% H ₂ /Ar) was 47-57 mL/min based on the standard temperature and pressure, and the corresponding linear velocity was 1.0-1.2 cm/s.

1st collection experiment 2nd collection experiment Adsorbent type reduced AgX Examples 1-3 reduced AgX Examples 1-3 Weight of adsorbent used (g) 1.003 0.802 0.703 0.697 Iodine weight used (g) 0.079 0.082 0.085 0.083 Weight of iodine used/weight of adsorbent used 0.079 0.103 0.121 0.119 Column diameter (mm) 10 carrier gas 4% H ₂ /Ar Flow (mL/min) 57 57 47 47 Linear velocity (cm/s) 1.2 1.2 1.0 1.0 Temperature (℃) generator-dryer 100 100 100 100 collection column 150 dryer-collector 100 Collection solution volume (mL) 200

The results of analysis by ICP-MS with a detection limit of 50 ppb by diluting the iodine collection solution 100 times for each collection experiment are shown in Table 10 below. Collection efficiency [(1-w _c /w _g ) based on the weight of iodine (w _c ) obtained by multiplying the concentration of iodine analyzed by ICP-MS and the volume of the collection solution and the weight of iodine added to the iodine generator (w _g ) ) × 100%] was calculated and shown in Table 11 below.

According to the results of Tables 10 and 11 below, in the first experiment, the weight ratio of the input iodine to the input adsorbent was 0.103 in Examples 1-3, which was higher than 0.079 of the reduced AgX, but the collection efficiency was 99.98%. In the second experiment, the weight ratio of the input iodine to the input adsorbent was almost the same, and the linear velocity of the carrier gas was lowered from 1.2 cm/s (first experiment) to 1.0 cm/s (second experiment). As a result, the collection solution The concentration of iodine was all less than 50 ppb, so it was impossible to detect.

The iodine capture efficiency of the two adsorbents, calculated based on the ICP-MS detection limit, was over 99.98%.

Experiment number Iodine Concentration (ppb) AgX Examples 1-3 One 300 68 2 < 50 < 50

Experiment number Iodine capture efficiency (%) AgX Examples 1-3 One 99.92 99.98 2 > 99.98 > 99.98

As a result of randomly collecting the adsorbent whose surface was completely discolored by reaction with iodine, crushing it and visually observing it, in the case of reduced AgX, most of the inner layer did not react, whereas Example 1-3 was almost completely discolored to the inside, so that the iodine adsorption utilization rate was decreased. It was confirmed that it was very high (FIG. 11).

As a result of the experiment, it was confirmed that AgASA according to Examples 1-3 had higher iodine capture efficiency and iodine adsorption utilization rate than silver exchange zeolite (AgX).

Claims (19)

forming a sodium alumino-silicate alcogel;
a cosolvent exchange step of replacing the cosolvent in the alcogel with a first substituted solvent by a solvent exchange method;
an ion exchange step of replacing cations in the alcohol gel with silver ions (Ag ⁺ ) to form a silver-containing hydrogel;
a solvent exchange step of the hydrogel to form a silver-containing alcogel by replacing the solvent in the silver-containing hydrogel with an inert organic solvent by a solvent exchange method; and
A method for producing a hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine, comprising a; surface modification step of modifying the surface to be hydrophobic by adding a surface modifier to the silver-containing alcohol gel,
The solvent exchange step of the hydrogel comprises reducing silver ions (Ag+) in the silver-containing hydrogel,
The surface modifier is used in an amount of 15 to 30% based on the total volume of the silver-containing alcohol gel, and 0.1 to 0.5 percent based on the total volume of the inert organic solvent in the silver-containing alcohol gel. A method for producing a silver-containing alumino-silicate airgel. The method according to claim 1,
A method for producing a hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine, wherein the cations in the alcohol gel replaced by the ion exchange step include sodium ions (Na ⁺ ). The method according to claim 1,
The first substitution solvent comprises at least one selected from the group consisting of isopropanol and methanol. The method according to claim 1,
The ion exchange step comprises contacting the alcogel with AgNO ₃ A method for producing a hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine. The method according to claim 1,
The solvent exchange step of the hydrogel comprises replacing water in the silver-containing hydrogel with alcohol and then replacing the substituted alcohol with the inert organic solvent. Method for manufacturing airgel. 6. The method of claim 5,
The method for producing a hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine, wherein the water-substituted alcohol comprises at least one selected from the group consisting of methanol, ethanol and isopropanol. The method according to claim 1,
The inert organic solvent comprises at least one selected from the group consisting of hexane, heptane, toluene and xylene. The method according to claim 1,
The surface modifier contains at least one selected from the group consisting of trimethylsilanol (TMS), trimethylmethoxysilane (TMMS) and hexamethyldisilazane (HMDZ). Hydrophobic silver-containing for adsorption of radioactive iodine A method for preparing an alumino-silicate airgel. delete The method according to claim 1,
A method for producing a hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine comprising a drying step at atmospheric pressure after the surface modification step. The method according to claim 1,
The precursor material for the production of the sodium alumino-silicate alcogel includes a Na source, an Al source and a Si source. manufacturing method. An alumino-silicate airgel comprising:
The airgel contains silver (Ag) in the pores,
A hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine comprising units derived from a hydrophobic surface modifier on the surface and having a silver content of 40 to 60% by weight relative to the total weight. 13. The method of claim 12,
A hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine, wherein the pore size is distributed in the medium-large pore region. 13. The method of claim 12,
A hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine, which has a specific surface area of 160 to 300 m ² /g. 13. The method of claim 12,
A hydrophobic silver-containing alumino-silicate airgel for adsorption of radioactive iodine having a pore volume of 0.8 to 2 cm ³ /g. delete 13. The method of claim 12,
The surface modifier comprises at least one selected from the group consisting of (CH ₃ ) ₃ Si-OH, (CH ₃ ) ₃ Si-OCH ₃ and (CH ₃ ) ₃ Si-NH-Si(CH ₃ ) ₃ Hydrophobic silver-containing alumino-silicate airgel for adsorption of phosphorus radioactive iodine. 12. A radioactive iodine adsorbent comprising a hydrophobic silver-containing alumino-silicate airgel prepared according to any one of claims 1 to 8, 10 and 11. A method for removing radioactive iodine using a hydrophobic silver-containing alumino-silicate airgel prepared according to any one of claims 1 to 8, 10 and 11.

Images