KR100791138B1 - Silica Compounds for Adsorbing Heavy Metals and Method for Synthesizing the compounds - Google Patents

Abstract

The present invention provides a silica compound for adsorption of spherical heavy metal having a mercapto group (-RSH) on a surface (wherein R is a C ₁ to C ₁₂ alkyl group). In addition, the present invention is a first reaction step of reacting tetraalkoxysilane (TAOS) with an acidic solution or a basic solution, and alcohol to produce a spherical first silica compound having a hydroxyl group on the surface, and acidic the first silica compound Or a second reaction step of reacting with 3- (mercaptopropyl) trimethoxysilane (MPTMS) in a basic solution and a mixed solution of alcohol to produce a spherical second silica compound having a mercapto group on the surface thereof. A method for synthesizing a silica compound for heavy metal adsorption is provided.

Description

Silica Compounds for Adsorbing Heavy Metals and Method for Synthesizing the compounds}

1 is a graph showing the size change of the silica compound according to the volume ratio of ammonium hydroxide to 2-propanol.

2 is electron micrographs of each of the second silica compounds synthesized in Example 2. FIG.

3 is a graph showing the concentration change of the lead ion solution according to the amount of the second silica compound added.

Figure 4 is a graph showing the concentration change of the lead ion solution according to the addition amount of each of the silica compounds according to Example 4.

FIG. 5 is a graph showing a change in concentration of lead ion solution according to a weight ratio of MPTMS to a first silica compound used in a production reaction of a second silica compound.

The present invention relates to a compound for adsorption of heavy metals, and more particularly, a heavy metal adsorption silica compound having excellent heavy metal removal efficiency, a heavy metal adsorbent comprising the same, a method for synthesizing the silica compound for heavy metal adsorption, and the silica compound for heavy metal adsorption. It relates to a method of separation.

In addition to strengthening international environmental regulations, Korea's hazardous chemical emission reporting system (Toxic Release Inventory, TRI) has been developed since 1999 regarding heavy metals that may adversely affect human and natural ecosystems such as mercury, lead, cadmium, copper and cobalt. Emissions regulations are being strengthened through such measures. Wastewater treatment up to the early 1990s mainly relied on aftertreatment technology. Since the mid-1990s, the development of clean technologies, such as the prevention and reuse of contaminants, has shifted to minimizing pollutant emissions. The importance of recovery of heavy metals is increasing in terms of saving resources, energy and efficient use.

Conventionally, functional groups are attached to inorganic materials such as activated carbon, synthetic zeolites, and clays, and used for adsorption of heavy metals. However, they have a large surface area, but are generally amorphous in pore structure and narrow inlet openings. As a result, the penetration of heavy metal ions into the pores in the liquid phase is suppressed to prevent contact with the functional group of a large area in the pores, and the heavy metal adsorption efficiency is drastically reduced.

As such, the conventional heavy metal adsorbents are not only poor in adsorption efficiency but also do not have enough sensitivity to detect a trace amount of heavy metals, so there is a limit to completely remove toxic heavy metals. Therefore, there is an urgent need for a better heavy metal adsorbent.

Accordingly, an object of the present invention is to solve the above-mentioned problems of the prior art and to take into account the needs of the times, and to provide a silica compound for heavy metal adsorption which is remarkably excellent in heavy metal adsorption efficiency.

It is another object of the present invention to provide a heavy metal adsorbent containing a compound for adsorption of heavy metals such as the silica compound.

The present invention also aims to provide a method for synthesizing the silica compound for heavy metal adsorption.

Another object of the present invention is to provide a separation method capable of efficiently separating heavy metal adsorbed on the silica compound for heavy metal adsorption from the silica compound for heavy metal adsorption.

The silica compound for heavy metal adsorption according to an aspect of the present invention for achieving the object of the present invention as described above has a mercapto group (-RSH) on the surface and has a spherical shape (wherein R is C ₁ To C ₁₂ alkyl group).

The size of the silica compound may be 250 nm to 1000 nm, depending on the application may be at least 1000 nm or more.

It is preferable that the said silica compound contains 5-30 weight part of mercapto groups with respect to 100 weight part of spherical silica compounds except the said mercapto group.

The mercapto group is bonded to at least one silicon (Si) atom of the silica.

The spherical silica consists of covalent crystals of silicon dioxide (SiO ₂ ).

The heavy metal adsorbent according to an aspect of the present invention comprises a spherical core compound and a plurality of heavy metal adsorbers bonded to the surface of the core compound.

The core compound consists of a silica compound or a polystyrene-based high molecular compound, and the silica compound consists of spherical silicon dioxide co-crystals.

The heavy metal adsorber may be a mercapto compound or a chelate compound. EDTA etc. are mentioned as said chelate compound.

The compounds for the adsorption of heavy metals are dispersed in the heavy metal adsorbent to have a size variation of less than 10%.

The heavy metal adsorbent may be present in a solid phase or a liquid phase.

A method for synthesizing a silica compound for heavy metal adsorption according to an aspect of the present invention comprises reacting tetra-alkoxysilane (TAOS) with an acidic solution or a basic solution and an alcohol to form a spherical first silica compound having a hydroxyl group on the surface thereof. The resulting first reaction step and the first silica compound is reacted with 3- (mercaptopropyl) trimethoxysilane (MPTMS) in a mixed solution of an acidic or basic solution and an alcohol to have a spherical mercapto group on the surface. A second reaction step of producing a phosphorus second silica compound.

As the tetraalkoxysilane, tetramethoxysilane, tetraethoxysilane, tetra propoxysilane, tetrabutoxysilane, etc. may be used.

The first reaction step and the second reaction step are performed at room temperature.

It is preferable that 2-propanol is used as said alcohol.

The first reaction step and the second reaction step are carried out under a 2-propanol and ammonium hydroxide solution.

The MPTMS is preferably used 5 to 30 parts by weight based on 100 parts by weight of the first silica compound.

According to one aspect of the present invention, in order to separate the heavy metal adsorbed compound for heavy metal adsorption from the heavy metal, an acidic compound may be added to the heavy metal adsorbed compound.

Hereinafter, the present invention will be described in detail.

Silica Compound for Heavy Metal Adsorption

The silica compound for heavy metal adsorption according to the present invention is spherical and contains a plurality of mercapto groups (-RSH) on its surface. That is, the mercapto groups are exposed to the outside of the silica compound for heavy metal adsorption.

The silica compound consists of covalent crystals of silicon dioxide (SiO ₂ ). 'R' of the mercapto group is an alkyl group having 1 to 12 carbon atoms.

External heavy metal ions may be adsorbed by the silica compound for heavy metal adsorption by forming a bond with a sulfur (S) atom of the mercapto group. The heavy metal ions may be bonded to any one sulfur atom alone, or may be simultaneously bonded to two adjacent sulfur atoms.

Formula (1) conceptually shows the appearance of the silica compound for heavy metal adsorption.

In the formula (1), wherein R represents an alkyl group of C ₁ to C _12. In the formula (1), the spherical compound is shown in plan, but in fact, the silica compound has a three-dimensional sphere shape, and mercapto groups are bonded to the surface of the sphere.

The size of the silica compound for the heavy metal adsorption is preferably having a 250 to 1000 nm. When the size of the silica compound for heavy metal adsorption is 250 nm or less, it is difficult to separate the heavy metal adsorbed silica compounds on which the heavy metal is adsorbed using a centrifugal separation or a filtration device. On the other hand, when the size of the silica compound for heavy metal adsorption exceeds 1000 nm, there is a problem in that the size uniformity of the compound for heavy metal adsorption is reduced and the surface area is reduced to reduce the heavy metal adsorption efficiency.

On the other hand, if the size of the silica compound for heavy metal adsorption is 250 nm to 600 nm, the liquid phase is advantageous, whereas if the size of the silica compound is 600 nm to 1000 nm, the silica compound to which the heavy metal is adsorbed can be easily precipitated. The separation of the silica compound using the precipitation from the aqueous solution is easy.

On the other hand, in some cases, the silica compound for heavy metal adsorption may advantageously have a size of 1000 nm or more. When the size of the silica compound for heavy metal adsorption is 1000 nm or more, the cost reduction can be expected when the silica compound for heavy metal adsorption is applied to various products, and the silica compound for heavy metal adsorption may be used more widely. Even when the size of the compound for adsorption of heavy metals exceeds 1000 nm, heavy metal adsorption efficiency is not significantly reduced, and the heavy metal ions can be almost completely removed by increasing the amount of use thereof.

The total weight of the mercapto group in the silica compound for heavy metal adsorption is preferably 5 to 30 parts by weight based on 100 parts by weight of the silica compound excluding the mercapto group, that is, spherical core portion (SiO ₂ covalent crystal).

When the weight relationship is satisfied, the heavy metal adsorption performance may be close to 100% (99.999985%), and when the weight relationship is out of range, a sudden decrease in the adsorption performance may be caused.

Although not described in detail in the present invention, the heavy metal adsorption compound may be composed of a polystyrene-based polymer compound as a core portion, and a chelate compound such as EDTA as a functional group for heavy metal adsorption.

Heavy metal adsorbent

The heavy metal adsorbent according to the present invention includes a spherical core compound and compounds for adsorption of heavy metal consisting of a plurality of heavy metal adsorbers bonded to the surface of the core compound. In addition, although not specifically illustrated, it may include conventional additives for improving general physical properties such as storage stability required for improvement and commercialization of heavy metal adsorption efficiency.

As the core compound, the above-described silica compound or polystyrene polymer compound may be applied. The core compound may have a spherical surface area can be maximized to increase the heavy metal adsorption efficiency.

The silica compound consists of covalent crystals of silicon dioxide.

As the heavy metal adsorber, a chelate compound such as EDTA can be applied in addition to the mercapto group described above.

That is, as the core compound, a silica compound or a polystyrene polymer compound may be selectively applied, and as the heavy metal adsorber, a mercapto group or a chelate compound may be selectively applied, and various combinations may be possible.

The heavy metal adsorption compounds preferably have a size variation within 10%. In order to make the size variation of the heavy metal adsorption compounds included in the heavy metal adsorbent within 10%, various synthetic conditions and quantitative conditions of the reagents used for synthesizing the compound for heavy metal adsorption must be specifically controlled. This will be described later.

Synthesis of Silica Compound for Heavy Metal Adsorption

The method for synthesizing a silica compound for heavy metal adsorption according to the present invention comprises the steps of: i) producing a first silica compound having a hydroxyl group (-OH) on the surface and spherical; and ii) having a spherical mercapto group on the surface Producing a phosphorus second silica compound. In order to synthesize the first silica compound, tetra-alkoxysilane (TAOS) is prepared as a starting material. The TAOS reacts with an acidic or basic solution and an alcohol to produce a spherical first silica compound having hydroxyl groups on its surface. Examples of the alcohol that can be used include methanol, propanol, butanol and the like, and in particular, 2-propanol is preferably used. The production reaction of the spherical silica compound is carried out under acidic or basic solution. In order to produce spherical silica compounds having a uniform size, it is preferable to carry out the reaction under basic solution.

As said TAOS, tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, etc. can be used. The compounds may be used alone or in combination of two or more.

As the acid solution, nitric acid (HNO ₃ ) solution, hydrochloric acid (HCl) solution, acetic acid (CH ₃ COOH) solution may be used, and as basic solution, ammonium hydroxide (NH ₄ OH) may be used.

In particular, as the basic solution, the size deviation of the spherical silica compounds produced when using ammonium hydroxide is less than 10%, more preferably within 5% can be produced silica compounds having a very uniform size.

If the size of the spherical silica compounds produced is uniform, the surface area that can be combined with the heavy metal can be maximized, the heavy metal adsorption efficiency can be maximized, has a great advantage in the material handling or separation process. Therefore, it is preferable that the size of the spherical silica compounds is adjusted so that the size deviation of the spherical silica compounds is within 10%.

When ammonium hydroxide is used as the basic solution and 2-propanol is used as the alcohol, the ammonium hydroxide is preferably used to be 100 to 25 vol% with respect to the 2-propanol.

When the amount of the ammonium hydroxide is increased relative to the 2-propanol, and when the amount of the tetraalkoxysilane used is increased, the size of the spherical silica compound is increased.

By the production reaction, a spherical first silica compound having a hydroxyl group (-OH) on its surface is produced.

The first silica compound, the intermediate product, is reacted with 3- (mercaptopropyl) trimethoxysilane (MPTMS) to produce a second silica compound whose spherical surface is modified with a mercapto group.

Prior to the production reaction of the second silica compound, the first silica compound obtained is separated from the reaction solution using a centrifugal separator and washed several times with methanol or the like.

The production reaction of the second silica compound is carried out under a basic or acidic solution. In addition, the alcohol must be included in the reaction solution in the same manner as the reaction for producing the first silica compound. It is preferable that 2-propanol is used as said alcohol. As a basic solution which can be used, ammonium hydroxide is mentioned and an acidic solution is nitric acid.

In the case of using the acidic solution, it is preferable to use a basic solution, because aggregation can be performed relatively better than that of the basic solution, thereby maximizing the surface area of the second silica compound.

The production reaction of the first silica compound and the second silica compound is performed at room temperature.

Scheme (1) conceptually represents a continuous production reaction of the first silica compound and the second silica compound. In addition, the following reaction formula (1) shows the state that the lead (Pb) is adsorbed by the second silica compound.

In said Scheme (1), said R represents an alkyl group having 1 to 12 carbon atoms. In addition, although the first silica compound and the second silica compound are shown planarly in the reaction formula (1), this is conceptual and actually has a three-dimensional sphere shape. .

As shown in the reaction formula (1), lead ions (Pb ^{+ 2)} is replaced by the hydrogen of the mercapto group, it is combined with sulfur (S) atom. In addition, the lead ions may be bonded to two adjacent sulfur atoms.

Hereinafter, the present invention will be described in detail with reference to specific embodiments. However, the technical spirit of the present invention is not limited by the following embodiments, and those skilled in the art may configure various modified embodiments with reference to the following embodiments.

In the following examples, the following reagents were used.

1.TEOS (99.9%, manufactured by Aldrich)

2.MPTMS (95%, manufactured by Aldrich)

3. Ammonium hydroxide (28.3%, made by Mallinckrodt)

4. Nitric acid (15.8 N, manufactured by Fisher)

5. 2-propanol (98%, manufactured by Aldrich)

Example 1

2- Propanol  Analysis of Size Changes of Spherical Silica Compounds Depending on Volume and Volume Ratio of Ammonium Hydroxide

Ammonium hydroxide was mixed with 12.5 ml of 2-propanol in volume volumes of 1: 1, 1: 2, 1: 4 and 1: 6 with respect to the 2-propanol, and then 250 mg of TEOS was added to each mixed solution. The reaction was performed at room temperature. Each of the first silica compounds obtained was spherical and its size was measured using an electron microscope. The size refers to the diameter of the spherical silica compound. The results are shown in FIG.

1 is a graph showing the size change of the silica compound according to the volume ratio of ammonium hydroxide to 2-propanol.

Referring to FIG. 1, it can be seen that the size (sphere size) of the silica compound decreases as the volume ratio of ammonium hydroxide to 2-propanol increases. In addition, it can be seen that the size of the silica compound changes almost primarily with the amount of ammonium hydroxide used. That is, the amount of the silica compound may be adjusted by adjusting the amount of the ammonium hydroxide. However, the determinant of sphere size depends primarily on the amount of TAOS used.

Example 2

Observation of silica compounds for heavy metal adsorption

250 mg of TEOS was added to a mixed solution of 12.5 ml of 2-propanol and 12.5 ml of ammonium hydroxide, followed by reaction at room temperature to obtain a first silica compound. The obtained first silica compound was added to a mixed solution of 10 ml of ammonium hydroxide and 10 ml of 2-propanol, and 7 wt% of MPTMS was added to the first silica compound and reacted to produce a second silica compound. (Example 2-1).

In addition, instead of 10 ml of ammonium hydroxide and 10 ml of 2-propanol, 2 ml of nitric acid and 20 ml of 2-propanol were added respectively to obtain a second silica compound in the same manner as in Example 2-1 (Example 2- 2).

Electron micrographs (SEM) of the second silica compounds obtained in Examples 2-1 and 2-2 are shown in FIG. 2.

2 is electron micrographs of each of the second silica compounds synthesized in Example 2. FIG.

2-a is an electron micrograph of second silica compounds obtained by reacting a first silica compound with MPTMS under a basic solution (NH ₄ OH) (base catalyzed method), and FIG. 2-b shows an acid solution of the first silica compound. Electron micrographs of second silica compounds obtained by reaction with MPTMS under (HNO ₃ ) (acid catalyzed method).

 Referring to FIG. 2, it can be seen that the second silica compound obtained under the basic solution is dispersed in a uniform distribution without aggregation (a), while the second silica compound obtained under the acidic solution is obtained. Aggregation occurred and it was found that the irregular distribution (b).

Therefore, it was found that reacting the first silica compound with MPTMS under basic solution rather than under acidic solution is advantageous in obtaining higher quality silica compounds (second silica compound) for heavy metal adsorption.

In addition, in this embodiment, the silica compound for heavy metal adsorption was found to have a size of about 370 nm.

Example 3

Evaluation of Heavy Metal Adsorption Performance with Addition of Silica Compound for Heavy Metal Adsorption

The second silica compound obtained in Example 2-1 (acid catalized method) and Example 2-2 (base catalized method) was respectively prepared with 10 ml of lead ion (Pb ²⁺ ) solution (initial lead ion concentration: 1000 ppm). ) In varying amounts, and then analyzed the change in concentration of the lead ion solution.

3 is a graph showing the concentration change of the lead ion solution according to the amount of the second silica compound added.

Referring to FIG. 3, the lead ion solution, which had a concentration of the first 1000 ppm, gradually decreased as the silica compound was added. That is, it can be seen that lead ions are gradually removed while adsorbed onto the silica compound.

In particular, as shown in FIG. 3, the adsorption performance of the heavy metals of the second silica compound formed under the basic solution was better, and almost 100% (99.999985) when more than 40 mg was added to the second silica compound produced under the basic solution. Lead ion removal performance was close to%).

Example 4

250 mg of TEOS was added to a mixed solution of 12.5 ml of 2-propanol and 12.5 ml of ammonium hydroxide, followed by reaction at room temperature to produce a first silica compound. The obtained first silica compound was added to a mixed solution of 10 ml of ammonium hydroxide and 10 ml of 2-propanol, and then 8.26 wt% (Sphere-A) and 6.78 wt% (Sphere) with respect to the obtained first silica compound, respectively. -B) and 5.90 wt% (Sphere-C) MPTMS were added and reacted to produce a second silica compound, respectively. The concentration change of the lead ion solution was analyzed while changing the amount of the second silicide compound produced in the 10 ml of the lead ion solution. The concentration of the initial lead ion solution was 81.388 ppm.

Figure 4 is a graph showing the concentration change of the lead ion solution according to the addition amount of each of the silica compounds according to Example 4.

Referring to Figure 4, in the case of Sphere-A and Sphere-B it can be seen that the lead ions are removed almost 100% (99.999985%) is added more than 30 mg. On the other hand, in the case of Spher-C, even if 40 mg was added, it was found that lead ions remained in the solution. However, although not shown in the graph, even in the case of Sphere-C, the excessive amount of lead ion removal performance was nearly 100%. Therefore, it was found that Sphere-A and Sphere-B were superior to Sphere-C in terms of heavy metal removal efficiency.

The lead ion concentration was measured using inductively coupled plasma spectroscopy (ICP-MS).

Example 5

250 mg of TEOS was added to a mixed solution of 12.5 ml of 2-propanol and 12.5 ml of ammonium hydroxide, followed by reaction at room temperature to produce a first silica compound. The obtained first silica compound was added to a mixed solution of 10 ml of ammonium hydroxide and 10 ml of 2-propanol, and then MPTMS was added in various weight ratios to the weight of the obtained first silica compound to obtain a second silica compound, respectively. It was.

After the addition of each of the second silica compounds to 10 ml of the lead ion solution, the concentration change of the lead ion solution was measured after sufficient time.

FIG. 5 is a graph showing a change in concentration of lead ion solution according to a weight ratio of MPTMS to a first silica compound used in a production reaction of a second silica compound.

Referring to FIG. 5, when the weight ratio of the MPTMS added to the first silica compound is less than 5 wt% and 30 wt% or more, it was found that lead ion removal performance is rapidly lowered.

Therefore, it was found that the MPTMS is preferably used at 5 to 30 wt% based on the weight of the first silica compound. The MPTMS is a component constituting the mercapto group of the second silica compound after the reaction, and it may be considered that the weight ratio of the mercapto group in the silica compound for final heavy metal adsorption is also within the above range with respect to the spherical silica weight.

On the other hand, the MPTMS was found to react almost 100% (99.999985%).

Separation of Compounds for Heavy Metal Adsorption

The compound for adsorption of heavy metals according to the present invention can adsorb not only heavy metal ions in aqueous solution but also heavy metals in the atmosphere. The heavy metal adsorbed compound adsorbed as described above may be preferentially separated from an aqueous solution by centrifugation or precipitation, and the heavy metal adsorbed compound adsorbed the separated heavy metal may be added by adding an acidic compound. The compound for heavy metal adsorption and the heavy metal can be separated chemically.

As the acidic compound, a general acidic solution may be used.

Therefore, the heavy metal adsorption compound may be regenerated through such a separation process.

As described above, according to the present invention, the silica compound for heavy metal adsorption has a heavy metal adsorption performance close to 100% even with a small amount of use, so that the heavy metal in aqueous solution or gaseous state can be completely removed.

In addition, it can react sensitively with trace amounts of heavy metals having a concentration of less than several ppm, and thus has excellent sensitivity.

The silica compound for the heavy metal adsorption is expected to be used in various applications depending on the size. That is, not only may be included as one component of the heavy metal adsorbent, but may also be used as a raw material in various applications.

In addition, according to the method for synthesizing the compound for heavy metal adsorption of the present invention, the silica compound for heavy metal adsorption can be easily synthesized at room temperature by a simple process, so that mass production is possible, and process efficiency can be maximized. Furthermore, by specifically providing the properties of the compound as the final binder and the causal relationship of various synthetic conditions, it is possible to prepare a specific heavy metal adsorption compound suitable for various applications.

On the other hand, the present invention by providing a method for separating the heavy metal adsorbed compound and the heavy metal adsorbed heavy metal, it is possible to facilitate the removal of heavy metals as well as post-heavy heavy metal separation can double the risk of heavy metals. In addition, it is possible to enable the regeneration of the heavy metal compound through effective heavy metal separation.

As described above, although the present invention has been described with reference to limited embodiments and drawings, the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

Claims (20)

A silica compound for adsorption of a heavy metal having a mercapto group (-RSH) on a surface thereof and having a spherical shape, wherein the mercapto group is bonded to at least one silicon atom of the silica. Provided that R is an alkyl group having ₁ to ₁₂ carbon atoms. The silica compound for adsorption of heavy metals according to claim 1, wherein the silica compound has a size of 250 nm to 1000 nm. delete delete The silica compound for adsorption of heavy metals according to claim 1, wherein the silica compound contains spherical silicon dioxide (SiO ₂ ) covalent crystals. The silica compound for heavy metal adsorption according to claim 5, wherein the silica compound contains 5 to 30 parts by weight of mercapto group based on 100 parts by weight of the silicon dioxide co-crystal. Any one core compound selected from the group consisting of a spherical polystyrene-based high molecular compound and a silica compound consisting of a spherical silicon dioxide co-crystal; And A heavy metal adsorbent comprising compounds for adsorption of heavy metals comprising a plurality of heavy metal adsorbers bonded to a surface of the core compound. delete delete The heavy metal adsorbent according to claim 7, wherein the heavy metal adsorbent is any one compound group selected from the group consisting of a mercapto compound and a chelate compound. The heavy metal adsorbent of claim 10, wherein the chelate compound is EDTA. The heavy metal adsorbent according to claim 7, wherein the compounds for adsorption of heavy metals are dispersed in the heavy metal adsorbent so as to have a size deviation within 10%. 8. The heavy metal adsorbent according to claim 7, wherein the heavy metal adsorbent is solid or liquid. A first reaction step of reacting tetraalkoxysilane (TAOS) with an acidic solution or a basic solution and an alcohol to produce a spherical first silica compound having a hydroxyl group on the surface; And Reacting the first silica compound with 3- (mercaptopropyl) trimethoxysilane (MPTMS) in a mixed solution of an acidic or basic solution and an alcohol to produce a spherical second silica compound having a mercapto group on its surface Synthesis method of silica compound for heavy metal adsorption comprising a second reaction step. 15. The method of claim 14, wherein at least one compound selected from the group consisting of tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane and tetrabutoxysilane is used as the tetraalkoxysilane. Synthesis method of silica compound. 15. The method of claim 14, wherein the first reaction step and the second reaction step are carried out at room temperature. The method for synthesizing a silica compound for heavy metal adsorption according to claim 14, wherein 2-propane is used as the alcohol. 15. The method of claim 14, wherein the first reaction step and the second reaction step are performed under a 2-propanol and ammonium hydroxide solution. 15. The method of claim 14, wherein the MPTMS is used in the synthesis of silica compounds for heavy metal adsorption, characterized in that 5 to 30 parts by weight based on 100 parts by weight of the first silica compound. . A method for separating the heavy metal from the silica compound for heavy metal adsorption by adding the compound for adsorption of heavy metal of claim 1 in which heavy metal is adsorbed into an acidic solution.

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