KR100928910B1 - Magnetic substance-silica cluster, method for producing the same, and method for desulfurization of natural gas using the same - Google Patents

Abstract

The present invention is a magnetic body of silica clusters, a method of manufacturing the same, and relates to a desulfurization process of the gas using the same, and more particularly to ferrous ions (Fe ^{+ 2)} or the second aqueous solution containing ferrous ions (Fe ⁺³⁾ A first step of preparing a nano magnetic material surface-substituted with a hydrophilic substituent; A second step of adding the nanomagnetic material in an aqueous solution containing a catalyst and a surfactant; A third step of preparing a nano magnetic material-silica cluster by mixing the silicon precursor with the aqueous solution of the second step; And a method for preparing a magnetic-silica cluster comprising a fourth step of calcining the magnetic-silica cluster, and a method for removing a sulfur compound comprising adsorbing a sulfur compound to the magnetic-silica cluster thus prepared.

Magnetic agent-silica cluster, natural gas, sulfur compound, dimerization reaction

Description

Magnetic substance-silica cluster, its manufacturing method, and desulfurization method of natural gas using the same {Magnetite-Silica cluster, the method for preparing background and the method for desulfurization using the same}

The present invention has a sufficient adsorption performance for removing sulfur compounds present in various raw materials such as natural gas, adsorbents that can maintain the adsorption performance even when the adsorbed sulfur compounds are desorbed, a method for producing the same and sulfur compounds using the same It is about how to remove it.

Due to the rapid growth of the economy, air pollution is getting serious, and among them, the awareness of air pollution and acid rain caused by the increase of sulfur oxide emissions is increasing. In addition, fossil fuels such as petroleum and coal account for more than 80% of the current energy demand. However, current consumption is expected to deplete reserves within 50 years. Therefore, it is very necessary to develop clean and safe alternative energy, and in this context, hydrogen energy is attracting the most attention as the ideal alternative energy of the next generation. In order to obtain hydrogen energy, acid, metal chemical reaction, hydrogen thermal expansion compression, electrolysis, or pyrolysis can be used, but due to the amount of hydrogen and energy efficiency that can be obtained, electrolysis of water or pyrolysis of hydrocarbon series such as natural gas A method of obtaining hydrogen is considered. Natural gas mined from the basement contains water, polymers, hydrocarbons, nitrogen, helium, carbon dioxide and hydrogen sulfide in addition to methane, ethane, propane and butane. In particular, significant amounts (5 g / m 3) of sulfur compounds contained in natural gas can cause serious pollution problems when released into the air. In addition, when natural gas is used to obtain hydrogen energy, sulfur compounds come into contact with the catalyst of the fuel cell, thereby degrading the performance of the catalyst. Therefore, since the sulfur component of natural gas is fatal to the use of fuel cells, the desulfurization process of natural gas must be implemented. The concentration of sulfur compounds in the fuel should be reduced to below 1 ppmw for use in proton exchange membrane fuel cells (PEMFC) and below 10 ppmw for solid oxide fuel cells (SOFC).

As described above, related technologies for the adsorbent for separating the sulfur compound which is the main cause of air pollution contained in the fossil fuel are as follows.

Techniques for adsorbing sulfur compounds of dimethylsulfide (DMS) or t - butylmercaptan (TBM) for commercially available adsorbents Na-Y and H-β are known (Wakita, H. Tachibana, Y). Hosaka, M., Microporous Mesoporous Mater . 2001, 46, 237-247). As suggested in the literature, Na-Y had adsorption capacity of 1.10 mmol / g and 0.05 mmol / g for DMS and TBM, respectively. In addition, H-β showed 0.89 mmol / g and 0.5 mmol / g adsorption performance of DMS and TBM, respectively. Substituted with the amount of sulfur compounds adsorbed, Na-Y is 103.4 mg-sulfur / g-adsorbate and 7.05 mg-sulfur / g-adsorbate for DMS and TBM, respectively, and H-β is 83.66 mg for DMS and TBM, respectively. -sulfur / g-adsorbate, 70.5 mg-sulfur / g-adsorbate.

In addition, a technique for adsorbing sulfur compounds of DMS or TBM in natural gas using AgNa-Y prepared by ion exchange of silver nitrate used as a noble metal catalyst for Y zeolite is known (Shigeo Satokawa, Yuji Kobayashi). , Hiroshi Fujiki, Applied Catalysis B: Environmental 56 (2005) 51-56). In this document, adsorption performance was compared using activated carbon and adsorbents according to the concentration of silver. Ag (18) Na-Y adsorbent containing 18 wt.% Of silver showed the highest adsorption performance. Ag (18) Na-Y adsorbents had adsorption capacity of 1.9 mmol / g and 0.6 mmol / g for DMS and TBM, respectively. Compared with this, activated carbon showed adsorption performance of 0.2 mmol / g and 0.6 mmol / g for DMS and TBM, respectively. Substituted by the amount of sulfur compound adsorbed, Ag (18) Na-Y is 178.6mg-sulfur / g-adsorbate and 84.6mg-sulfur / g-adsorbate for DMS and TBM, respectively, and activated carbon for DMS and TBM. 18.8 mg-sulfur / g-adsorbate and 84.6 mg-sulfur / g-adsorbate, respectively.

However, in the case of the adsorbent disclosed in the above document, the adsorbent lacks its adsorption capacity and thus shows a higher adsorption capacity for the sulfur compound. In addition, it is necessary to develop an adsorbent capable of showing high adsorption capacity by replacing expensive metals such as silver.

Meanwhile, Korean Laid-Open Patent Publication No. 2003-016730 discloses a step of reacting a surfactant and a silica precursor with water and an alcohol as a solvent, and mixing magnetite (Fe ₃ O ₄ ) to attach medium-sized porous silica around magnetite. And it discloses a method for producing a medium-porous silica comprising the step of drying at 60 ~ 100 ℃ and calcining at 400 ~ 500 ℃.

In addition, Korean Patent Publication No. 2007-068871 discloses dispersing magnetic nanoparticles such as magnetite (Fe ₃ O ₄ ) in an aqueous solution in which surfactant such as CTAB is dissolved, and a catalyst such as NH ₄ OH and TEOS in an aqueous dispersion. Disclosed is a method for preparing mesoporous silica nanoparticles containing magnetic nanoparticles, comprising the step of adding a silica precursor to form an outer layer of mesoporous silica on the magnetic nanoparticles.

However, the magnetic body-silica composite prepared by the above method is a core / cell type composite body in which a magnetic body is present in the core and silica is formed in a cell form on the outside thereof, and the magnetic body and silica of the present invention are agglomerated with the magnetic body and silica. The clusters differ in form. In addition, the patent publication does not specifically disclose the adsorption of sulfur compounds.

The present invention is to overcome the problems of the background art as described above, an object of the present invention is to show a high adsorption capacity for the sulfur compound has excellent ability to remove the sulfur compound, the disulfide having a commercial use value by the dimerization reaction It is to provide an adsorbent having excellent reactivity as a catalyst capable of forming a disulfide and a method for producing the same.

Another object of the present invention is to provide a method for removing sulfur compounds present in various raw materials, especially natural gas, using such adsorbents.

The present invention provides a first step of preparing a nano magnetic material surface-substituted with a hydrophilic substituent in an aqueous solution containing ferrous ions (Fe ^{2 +} ) or ferric ions (Fe ^{+ 3} ); A second step of adding the nanomagnetic material in an aqueous solution containing a catalyst and a surfactant; A third step of preparing a nano magnetic material-silica cluster by mixing the silicon precursor with the aqueous solution of the second step; And it relates to a method for producing a magnetic-silica cluster comprising a fourth step of firing the magnetic-silica cluster.

In the above production method, the first step comprises the steps of mixing FeSO ₄ H ₂ O, Fe ₂ (SO ₄ ) ₃ H ₂ 0 and (NH ₄ ) ₂ C ₂ O ₄ in an aqueous solution; And step (b) of adding sodium hydroxide to the aqueous solution.

In the above production method, the catalyst of the second step is preferably a basic catalyst, more specifically, ammonium hydroxide, and the surfactant is preferably a compound of the formula (1).

[Formula 1]

C _a H _{2a +1} N (C _b H _{2b +1} ) ₃ X

Where

a is an integer of 8-20, b is an integer of 1 or 2, and X is a halogen.

In the above production method, the step of recovering the magnetic material-silica cluster prepared in the third step from the aqueous solution (c); And (d) drying the recovered magnetic body-silica cluster by filtration.

The present invention also relates to a magnetic body-silica cluster characterized in that the magnetic particles produced by the above production method and the silica particles having an average particle diameter of 8 to 20 nm and the silica particles having an average particle diameter of 100 to 140 nm are mutually aggregated.

The magnetic-silica cluster is characterized by having a BET specific surface area of 500 to 800 m 2 / g, pore volume of 0.4 to 0.8 cm 3 / g, and an average pore diameter of 30 to 45 mm 3.

The magnetic-silica clusters are characterized by having an X-ray diffraction pattern showing one peak at 2θ of 2 ° to 3 °.

The present invention also relates to a method for removing sulfur compounds comprising adsorbing sulfur compounds present in a raw material, preferably natural gas, to a magnetic-silica cluster.

Magnetic substance-silica cluster according to the present invention is an air pollutant capable of direct adsorption of sulfur compounds that lower the catalytic activity of fuel cells, and desorption is effective, suggesting the possibility of reuse, methyl mercaptan is an adsorbent. ) Has a dimerization reactivity converting dimethyl mercaptane into dimethyl mercaptane, and thus it can be used as a catalyst and various applications as a catalyst. Particularly, the breakthrough time was greatly increased by chemisorption with reactivity, and the use of efficient magnetic body-silica cluster is possible in that the desorption proceeds effectively.

The present invention relates to a magnetic substance-silica cluster capable of efficiently adsorbing and removing sulfur compounds contained in natural gas, a method for producing the same, and a method for desulfurizing natural gas using the same.

More specifically, the present invention provides a method for preparing a nano magnetic material surface-substituted with a hydrophilic substituent in an aqueous solution containing ferrous ions (Fe ^{2 +} ) or ferric ions (Fe ^{+ 3} );

A second step of adding the nanomagnetic material in an aqueous solution containing a catalyst and a surfactant;

A third step of preparing a nano magnetic material-silica cluster by mixing the silicon precursor with the aqueous solution of the second step; And

It relates to a method for producing a magnetic-silica cluster comprising a fourth step of firing the magnetic-silica cluster.

The production method of the magnetic body-silica cluster according to the present invention as described above is specified by the following.

The first step of the method for producing a magnetic body-silica cluster according to the present invention is to prepare a nano-magnetic material surface-substituted with a hydrophilic substituent in an aqueous solution containing ferrous ions (Fe ^{2 +} ) or ferric ions (Fe ^{+ 3} ) It's a step.

Precursors providing ferrous ions or ferric ions usable in the first step are not particularly limited, but iron and -CO, -NO, -C ₅ H ₅ , alkoxide or other known ligands May be used, and specifically, iron pentacarbonyl (Fe (CO) ₅ ), ferrocene (ferrocene. Fe (C ₅ H ₅ ) ₂ ), or iron acetylacetonate (Fe (acac) ₃ ) various organometallic compounds such as; Or metals and Cl ^-, or NO ₃ ^- and combined with a known anion, such as iron to use a metal salt containing one, chloro three specifically hwacheol (FeCl _3), hwacheol in a cycle (FeCl _2), FeCl ₂ · Various types such as 4H ₂ O, FeCl ₃ · 6H ₂ O, FeSO ₄ · 7H ₂ O, dehydrated Fe ₂ (SO ₄ ) ₃ , or iron nitrate (Fe (NO ₃ ) ₃ ) can be used without limitation. FeSO ₄ · H ₂ O and Fe ₂ (SO _{4) 3} · it is preferred to use a mixture of H ₂ 0.

In addition, the first step may be used without particular limitation of acidic and basic aqueous solution, but in order to obtain stable and uniform particles, basic materials such as potassium hydroxide (KOH), ammonium hydroxide (NH ₄ OH), or sodium hydroxide (NaOH) It is preferable to use a basic aqueous solution added with water, and most preferably an aqueous sodium hydroxide solution.

On the other hand, the nano-magnetic material prepared in the first step is characterized in that the surface substituted with a hydrophilic substituent. The hydrophilic substituents are not particularly limited, C ^₂ O _{4 2} ^-, or R-COO ^- a compound containing an oxalate group, or a carboxylate such as; Or one or more carboxylates, organic amines or aminocarboxylates such as R'-NH ₂ , R'-NH-R '', RN (R ')-R'', citrates, tartaric salts, EDTA, etc. It may be derived from one or more compounds selected from the group consisting of. Where R, R ', R''means a hydrocarbon group.

Does not also limit how surface substituted with the hydrophilic substituent group, the method comprising adding at least one compound selected from the precursor in an aqueous solution containing ferrous ions (Fe ^{+ 2)} or ferric ions (Fe ⁺³⁾ Can be used.

When the nanomagnetic material is surface-substituted with a hydrophilic substituent, it is not uniformly dispersed in an aqueous solution in the second step to be described later, but dispersed in an aggregated cluster form. That is, since the surface of the nanomagnetic material substituted with a hydrophilic substituent is hydrophilic and a surfactant having a hydrophilic part is present in the aqueous solution of the second step, the nanomagnetic material is not uniformly dispersed in the aqueous solution of the second step but aggregated in cluster form. Will be. Thus, the structure of the magnetic body-silica composite according to the present invention may have a cluster structure in which magnetic clusters and mesoporous silica are aggregated with each other, not core / cell structures.

It is preferable that the size of the nano magnetic material prepared in the first step is 8 to 20 nm, and the size of the nano magnetic material aggregate in which such nano magnetic material is aggregated and dispersed is preferably 100 to 300 nm.

The mixing order of the raw material of the first step is not limited significantly, for example, FeSO ₄ · H ₂ O, Fe ₂ (SO ₄ ) ₃ · H ₂ 0 and (NH ₄ ) ₂ C ₂ used as a substituent in an aqueous solution Mixing O ₄ (a); And

It is preferable to include the step (b) of adding sodium hydroxide to the aqueous solution.

The composition of the aqueous solution of the first step is preferably 10 to 20 parts by weight of ferrous ions or ferric ion precursors, 0.5 to 1 parts by weight of the precursor of the hydrophilic substituent and 80 to 100 parts by weight of water. At this time, the aqueous solution is preferably adjusted to the pH of the aqueous solution to 7.6 to 9 by adding the above-described basic substance.

Nanomagnetic material thus prepared may further comprise the step of filtering and drying.

The second step of the method for producing a magnetic body-silica cluster according to the present invention is a step of adding the nano-magnetic material prepared in the first step in an aqueous solution containing a catalyst and a surfactant.

The second step of the catalyst can be used without limitation, basic compounds such as NH ₄ OH or NaOH, and acidic compounds such as nitric acid, hydrochloric acid, or sulfuric acid, but it is preferable to use NH ₄ OH which is a weak basic catalyst.

In addition, the surfactant of the second step may be used without limitation, alkyl ammonium salts, alkylamines consisting of 6 to 20 carbons or poly (alkylene oxide) terpolymers of polyethylene oxide-polypropylene oxide-polyethylene oxide. However, it is preferable to use an alkylammonium salt-based surfactant of the compound of formula (1).

[Formula 1]

C _a H _{2a +1} N (C _b H _{2b +1} ) ₃ X

Where

a is an integer of 8-20, b is an integer of 1 or 2, and X is a halogen.

The surfactant of Formula 1 is octadecyltrimethylammonium halide, hexadecyltrimethylammonium halide, tetradecyltrimethylammonium halide, dodecyltrimethylammonium halide, octadecyltriethylammonium halide, hexadecyltriethylammonium halide, tetradecyltriethyl halide Preference is given to using one selected from ammonium, dodecyltriethylammonium halide and mixtures thereof, more preferably hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide: CTMAB).

The molar composition of the second step is preferably 5 to 20M of catalyst and 500 to 1000M of water with respect to 1M of surfactant. In addition, the amount of the nano magnetic material to be added may be added without limitation between 20 to 60 parts by weight of the total cluster.

In order to disperse the nano magnetic material in the form of a cluster by adding the nano magnetic material to the aqueous solution containing the catalyst and the surfactant, it is preferable to add the nano magnetic material to the aqueous solution and mix for about 10 to 40 minutes.

The third step of the method for producing a magnetic-silica cluster according to the present invention is a step of preparing a nano-magnetic-silica cluster by mixing a silicon precursor with the aqueous solution of the second step.

As described above, the method of manufacturing the magnetic-silica cluster of the present invention is characterized in that the nano-magnetic material is dispersed in the form of a cluster in the presence of a surfactant in the second step, and then a silica precursor is introduced. When the nanomagnetic material is introduced after the silica precursor is contacted with the surfactant, the magnetic-silica cluster according to the present invention is difficult to prepare.

The silica precursor is at least one selected from the group consisting of tetraethyl orthosilicate, tetramethyl orthosilicate, methyl triethoxysilane, phenyl triethoxysilane, dimethyl dimethoxy silane, ethyl triethoxysilane and mixtures thereof It is preferable to use tetraethyl orthosilicate (TEOS).

The silica precursor added in the third step is preferably added to 3 ~ 10M relative to the surfactant 1M of the second step.

In addition, the method of producing a magnetic-silica cluster according to the present invention comprises the steps of recovering the magnetic-silica cluster prepared in the third step from the aqueous solution (c); And

Preferably, the method further comprises the step (d) of filtering and drying the recovered magnetic body-silica cluster.

The method of recovering the magnetic substance-silica from the aqueous solution is not particularly limited, but may be a method of firstly recovering the particles having magnetic force by using a magnet and washing 3 to 4 times with water and ethanol. In addition, the step of filtering and drying the recovered magnetic substance-silica cluster is not particularly limited, but the solution of step (c) is filtered at room temperature through a filter connected to a vacuum pump, and the filtered particles are put in a beaker to about 100 ° C Drying in a heated oven for 4 to 8 hours can be used.

A fourth step of the method for producing a magnetic body-silica cluster according to the present invention is a step of firing the magnetic body-silica cluster synthesized in the third step.

The firing step of the particles dried in this step is also not particularly limited, but is fired for about 12 hours to 48 hours, for example, in a firing machine. In addition, the firing step is preferably raised at a rate of 0.5 to 2 ℃ / min to a firing temperature of about 500 to 600 ℃. Hold for about 3 to 8 hours at elevated temperature, stop heating and cool.

The present invention also relates to a magnetic body-silica cluster characterized in that the magnetic particles having an average particle diameter of 8 to 20 nm and the silica particles having an average particle diameter of 100 to 140 nm are aggregated with each other.

The magnetic body-silica cluster according to the present invention is characterized in that the magnetic particles themselves agglomerate to form agglomerates, and such magnetic agglomerates are also agglomerated with silica particles.

The magnetic silica-cluster preferably has a BET specific surface area of 500-800 m 2 / g, pore volume of 0.4-0.8 cm 3 / g, and an average pore diameter of 30-45 mm 3. More preferably, it has BET specific surface area of 550-650 m <2> / g, pore volume of 0.5-0.7 cm <3> / g, and average pore diameter of 35-40 mm <3>.

The total average particle diameter of the magnetic body-silica cluster is preferably 0.5 to 5 µm, more preferably 1 to 3 µm.

Since the magnetic body-silica cluster is composed of silica and a cluster using the magnetic material as seeds, it is preferable that the magnetic material contains 20 to 60 wt.% Of the magnetic material with respect to the total cluster.

In particular, the magnetic material Fe ₃ O ₄ constituting the complex has a reactivity to the sulfur compound. Therefore, it is preferable as a component of the composite because it increases the adsorption capacity through the chemical bonds and shows dimerization reactivity.

In addition, the magnetic-silica cluster is characterized in that it has an X-ray diffraction pattern showing one peak at 2θ of 2 ° to 3 °.

The present invention also relates to a method for removing sulfur compounds comprising adsorbing sulfur compounds present in various raw materials to the magnetic-silica cluster according to the present invention.

The raw material is not particularly limited as long as it is a raw material containing a sulfur compound, but is preferably a gaseous substance containing a sulfur compound, particularly hydrogen, ethane, ethylene, propane, propylene, butane, butylene, city gas or natural gas. . In addition, the sulfur compound is not particularly limited either, alkyl mercaptan such as methyl mercaptan or t-butyl mercaptan, H ₂ S, or tetrahydrothiophene is preferable.

Adsorption of the magnetic body-silica cluster according to the present invention to remove the sulfur compound in the raw material may be carried out under 550 ℃ and 15 atm or less, more preferably at room temperature ~ 550 ℃ and 1 to 15 atmosphere conditions. If the temperature condition exceeds 550 ° C., the structure of the mesoporous silica particles can be modified, and if the pressure is 15 atm or higher, the adsorption rate can be reduced.

The method for removing the sulfur compound in the raw material according to the present invention may include regenerating the magnetic body-silica cluster to which the sulfur compound is adsorbed. The regeneration step is calcined for about 12 to 48 hours in a calciner using hydrogen gas. In particular, the use of hydrogen gas serves to increase the activity of the adsorbent to promote reactivity. In the firing step, it is preferable to raise the temperature to about 200 to 600 ° C. by about 1 ° C. per minute from room temperature. Next, after maintaining about 3 to 8 hours at the elevated temperature, the heating is stopped and cooled.

On the other hand, the magnetic body-silica cluster according to the present invention showed the adsorption performance of removing the sulfur compound in the natural gas and at the same time, the dimerization reaction of the adsorbate as a sulfur compound was changed to a commercially available material.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the following Examples are provided to assist the understanding of the present invention, and the scope of the present invention is not limited by the following Examples in any case.

Reference Example  One: MCM -41 synthetic

2.4 g CTMAB (Cetyltrimethylammonium bromide) and 8 ml ammonium hydroxide were added and mixed with 120 g of water. 10 ml of TEOS (Tetraethyl- orthosilicate) was added to the beaker, mixed for 5 minutes, and stirred for 12 hours. The obtained product was washed with 100 ml of deionised water and filtered. Drying was carried out at 50 ° C. for 24 hours using an oven, and the dried particles were calcined at 550 ° C. for 5 hours using a calcination machine to obtain MCM-41.

Reference Example  2: SBA -15 Synthesis

Triblock copolymer P123 was placed in a polypropylene container and dissolved in 80 ml of 0.1 M HCl solution. 4.461 ml of TEOS was added to this solution and mixed at 40 ° C. for 24 hours. Cured at 120 ° C. for 24 hours in an enclosed space. After filtration, it was dried for 6 hours and calcined at 550 ° C. for 12 hours to obtain SBA-15.

Reference Example  3: T-99 ( Zr ) Synthesis

93 ml of hydrochloric acid was added to 126 ml of water, followed by mixing for 10 minutes using a magnetic stirrer to prepare an aqueous acid solution. 2.26 g of TBAB (Tetrabutyl ammonium bromide), 2.551 g of CTMAB (Cetyltrimethylammonium bromide) and 0.162 g of ZrO (NO ₃ ) ₂ .xH ₂ O were added to the acid aqueous solution, followed by further mixing for 10 minutes. 12 ml of petroleum benzine was added to the obtained solution and mixed for 8 minutes, and the beaker containing the prepared aqueous solution was aged in a refrigerator (maintained at 5 ° C.) for 1 hour. The beaker removed from the refrigerator was placed on a magnetic stirrer, and 8 ml of TEOS (Tetraethylortho silicate) was added and mixed for 5 minutes to prepare a silicon precursor solution. The beaker containing the prepared silicon precursor solution was aged for 12 hours in a refrigerator (-16.5 ° C.). And the beaker was taken out of the refrigerator and the produced particle was filtered. The particles obtained through filtration were placed in a mantle heater (180 ° C.) and dried for 24 hours. The dried particles were calcined at 550 ° C. for 5 hours to obtain silica particles T-99 (Zr).

Production Example  1 Preparation of magnetic material

(1) A vessel was placed in a hotplate, 100 ml of distilled water was added, and a 4-neck flask was heated. To each neck of the four neck flask was connected an impeller, an N ₂ input line, a screw tube cooler, and a rubber stopper of an overhead stirrer. At this time, the temperature of the heater was set to 83 ° C.

(2) Into the 4-neck flask, hot distilled water prepared in advance was added and N ₂ was flowed for 4 to 5 minutes to remove oxygen. At this time, the actual temperature of the solution was 78 ℃.

(3) 6.0036 g of FeSO ₄ · 7H ₂ O, 8.6334 g of Fe ₂ (SO ₄ ) ₃ · nH ₂ O, and 0.7506 g of (NH ₄ ) C ₂ O ₄ were added thereto, and the mixture was stirred at 200 rpm for 10 minutes.

(4) 6M NaOH was added thereto to adjust the pH to 9 and stirred at 300 rpm for 1 hour.

(5) After the device was separated, it was washed with hot distilled water (hot) and ethanol using a magnet, and then filtered and dried using ethanol.

The average particle diameter of the magnetic particles produced in Preparation Example 1 was 10 nm as measured by High resolution Transmission Electron Microscope (HR-TEM).

Example  1: Preparation of Magnetic Body-Silica Cluster

(1) Place a four-necked flask on a heating mantle and connect an overhead stirrer impeller, N ₂ input line, screw cooler, and rubber stopper to each neck. It was.

(2) 76 mL of distilled water and 2.7 mL of NH ₄ OH were added to the 4-neck flask, followed by mixing at 200 rpm for 5 minutes.

(3) 1.8223 g of CTMAB (Cetyltrimethylammonium bromide) was added to the aqueous solution of the above base and mixed again for 5 minutes. (200rpm, 25 ℃)

(4) Here, 1.6 g of the magnetic substance dried in Preparation Example 1 was added and mixed at 360 rpm for 20 minutes.

(5) 7 mL of TEOS (Tetraethylorthosilicate) was injected into the solution in which the magnetic material was dispersed.

(6) The temperature was raised to 100 ° C. and mixed at 250 rpm for 24 hours.

(7) After the device was separated, it was washed with hot distilled water (hot) and ethanol, and magnets were used to obtain magnetic particles.

(8) Filtered with distilled water and ethanol and dried at 80 ℃ for 5 hours.

(9) The dried particles were fired by using a firing apparatus and a pump. At this time, the steps for firing were as follows.

Temperature rising process: The temperature is raised from room temperature to 550 ° C at a rate of 1 ° C / min.

Maintenance process: Maintain temperature for 5 hours at 550 ℃

Cooling process: cooling from 550 ℃ to room temperature

Example  2: Preparation of Magnetic Body-Silica Cluster

Magnetic body-silica clusters were prepared in the same manner as in Example 1, except that 0.8 g of the magnetic body was added in the step (4) of Example 1.

A manufacturing method according to Example 1 is schematically illustrated in FIG. 1, and the properties of the prepared magnetic body-silica cluster according to the present invention were measured as follows.

The BET analysis results of the magnetic body-silica cluster according to the present invention prepared in Example 1 are shown in Table 1 below, and are shown together to compare the properties with the general mesoporous silica particles prepared in Reference Example. The synthesis conditions are summarized in Table 2. In addition, the composition of the magnetic material and the silica was analyzed by inductively coupled plasma (ICP), which is shown in Table 3. Meanwhile, SEM and HR-TEM images of the magnetic body-silica clusters prepared in Examples 1 and 2 are shown in FIGS. 2 to 5, and the XRD analysis results of the clusters prepared in Example 1 are shown in FIG. 6.

Surface Area (BET) (m ² / g) Pore Volume (cm ³ / g) Pore Diameter (Å) Sphere Diameter (㎛) Example 1 616 0.57 37 1-3 MCM-41 1200 1.14 20-30 0.4-1 SBA-15 890 1.29 110 1-2 T-99 (Si) 1331 0.82 24 2-5

Surfactant Silica source Catalyst Pore structure Ferro-Silica Cluster CTMAB TEOS NH ₄ OH hexagonal MCM-41 CTMAB TEOS NH ₄ OH hexagonal SBA-15 P123 ^* TEOS HCl hexagonal T-99 (Zr) CTMAB, TBAB TEOS HCl hexagonal P123 ^* : PEO-PPO-PEO triblock copolymer

Fe [ppm] Example 1 236292 Example 2 338075

As shown in Table 2, the manufacturing method according to the present invention is synthesized with the same raw material as the synthesis method of MCM-41. In step (4) of Example 1, a magnetic material is added as a precursor to form a composite of the magnetic material and silica. It features. Compared to the conventional method, the surface area and the pore volume are reduced, and the pore size shows the value of the mesoporous region. In addition, as shown in Table 3, it was confirmed that the magnetic body-silica clusters according to Example 1 and Example 2 constituted about 24 wt.% And 34 wt.% Of magnetic bodies, respectively. In Example 2, a smaller amount of magnetic material was added than in Example 1, but the content of the magnetic material in the cluster was higher. This result is inferred because when the excess magnetic material is added, the magnetic material does not form a cluster, and some of the magnetic material is separated into the magnetic material itself. In other words, the addition of too much magnetic material compared to the silica source did not help to increase the amount of magnetic material in the cluster. However, the presence of too much magnetic material in the cluster is preferable as a catalyst, but not as an adsorbent in consideration of adsorption capacity.

Test Example

Adsorption breakthrough experiments were carried out to remove sulfur from natural gas using the following methods, and the adsorption breakthrough was examined using a calcination device and hydrogen gas and then resorbent breakthrough tests.

The device configuration of the breakthrough experiment is shown in detail in FIG. 8 and the breakthrough test result was obtained by gas chromatograph (GC). In addition, Table 4 shows the contents related to the adsorption tower. The flow rate of the adsorbate is controlled by a mass flow controller (MFC), and a mixing tank is installed for uniform mixing of the adsorbate. The inside of the mixing tank was filled with glass beads (glass beads, Dia. Size 1.5mm) to increase the effect.

In addition, a valve was installed behind the mixing tank to create a line to the tower and a line to the GC. This is to proceed with the experiment after confirming through GC whether the concentration of the mixed gas is correct before entering the tower. A check valve (CV) was installed to prevent backflow of the injected gas, and behind the tower, GC injection of impurities was prevented through a filter (2-5 microns).

The adsorption tower is made of 316 stainless steel to minimize corrosion due to adsorbates. A temperature controller (TC) and a resistance temperature detector (RTD) are used to conduct experiments with changing temperature conditions. Was used. From this, the temperature inside the tower was precisely controlled and the breakthrough experiment was performed according to the temperature change.

Adsorbent mass 0.3 g Column diameter 7 mm Gas flow rate 0.5 L / min Column length 50 mm

(1) In order to minimize the loss and end effect of the adsorbent in the adsorption tower, 0.1 g of glass wool was put at each end of the tower.

(2) 0.3g of the adsorbent obtained by firing was filled, and the feed flow rate was 50mL / min into the adsorption tower. In this case, in order to minimize the channeling (channel) of the adsorption tower and the tower voids were filled using a rubber hammer.

(3) The concentration of the adsorbate and the adhesion temperature of the experimental conditions were kept constant and the concentration of the gas exiting the adsorption column was repeatedly analyzed through GC.

(4) After the adsorption process, the adsorption agent was desorbed through the above-mentioned desorption process, and then the breakthrough experiment was performed by the same breakthrough test method.

The breakthrough test results of the magnetic body-silica cluster (methyl mercaptan: 300 ppm, 25 ° C.) are shown in FIG. 9. The magnetic body-silica cluster according to the present invention has a breakthrough time of 37 minutes. In addition, the dimerization reaction of the complex shows that it has a breakthrough curve of methyl mercaptan and dimethyl disulfide. At 37 minutes from each breakthrough curve, methyl mercaptan is detected first, followed by dimethyl disulfide at 56 minutes. In addition, the breakthrough curve of the total gas exiting the adsorption column was shown by substituting methyl mercaptan for dimethyl disulfide.

In order to understand the tendency of the breakthrough curve of the magnetic body-silica cluster according to the content of the magnetic body, the breakthrough test results of the magnetic body-silica cluster according to Example 2 (methyl mercaptan: 300 ppm, 25 ° C.) are shown in FIG. 10. As can be seen from the results of FIG. 10, it has a breakthrough time of 27 minutes and shows reactivity. At 27 minutes from each breakthrough curve, methyl mercaptan is detected first, followed by dimethyl disulfide at 85 minutes. In particular, comparing the portion of the maximum conversion of dimethyl disulfide was confirmed that the concentration of the converted gas is higher than the magnetic-silica cluster of Example 1. Therefore, as the magnetic content increased, the breakdown time tended to decrease slightly because the reaction conversion rate of dimethyl disulfide was higher and the content of Silica in the composite decreased due to the composition of the magnetic material.

The breakthrough experiments performed by varying the adsorbate concentration and adsorption temperature are shown in FIG. 11. In addition, Table 5 below summarizes the reactivity of each experimental result. As shown in Table 5, the higher the temperature and the lower the concentration of the adsorbate, the higher the conversion of the reaction. In addition, as shown in FIG. 11, the breakthrough time decreases as the temperature increases, and as the concentration decreases, the breakthrough time increases. However, all breakthrough curves were expressed by converting dimethyl disulfide to methyl mercaptan.

300ppm, 25 ℃ methyl mercaptan + dimethyl disulfide 300ppm, 50 ℃ dimethyl disulfide 300ppm, 100 ℃ dimethyl disulfide 100ppm, 25 ℃ dimethyl disulfide 100ppm, 100 ℃ dimethyl disulfide

Breakthrough curves for re-breakthrough experiment (methyl mercaptan: 300 ppm, 25 ° C.) are shown in FIG. 12. As can be seen from the result of FIG. 12, it has a breakthrough time of 37 minutes and shows reactivity. At 37 minutes from each breakthrough curve, dimethyl disulfide is detected first, followed by methyl mercaptan at 171 minutes. In particular, it can be seen that the resorption breakthrough experiment also has the same breakthrough time as compared to FIG. However, the resorption breakthrough increased the activity of the adsorbent during the desorption process, indicating that the gas component initially observed was dimethyl disulfide.

The breakthrough test result (adsorbent (methyl mercaptan): 300 ppm, 25 ° C) of MCM-41 of Reference Example 1 is shown in FIG. 13. This was done to observe the constitutive effects of the composites from the adsorption performance of MCM-41, which is the same as the method for producing silica constituting the magnetic body-silica cluster according to the present invention. In particular, MCM-41 breaks through the adsorption column with methyl mercaptan, which is adsorbent without reactivity. And it was confirmed that the breakthrough time was very short since the adsorbate was injected into the tower and exited the adsorption tower. Therefore, MCM-41 has a weak adsorption capacity for methyl-mercaptan, and it can be seen that the adsorption capacity for sulfur compound increases as it forms a complex with magnetic material.

The results of the breakthrough experiments performed under the conditions of T-99 (Zr) in Reference Example 3 are shown in FIG. 14. T-99 (Zr) has a high adsorption capacity of sulfur compounds in the liquid phase. Therefore, the magnetic body-silica cluster according to the present invention was performed to compare the adsorption performance. As can be seen from FIG. 14, the lower the temperature, the longer the breakthrough time, and the lower the adsorbate concentration, the longer the breakthrough time. In particular, it did not show the reactivity of the adsorbate and confirmed that the adsorbent methyl mercaptan exit the adsorption tower. Unlike magnetic-silica clusters, it has no reactivity with adsorbates and has a short breakthrough time of less than 5 minutes.

The amount of adsorption was reversely estimated from the amount of desorbed during the desorption of the adsorbents after the adsorption experiment. The results of the magnetic body-silica cluster, MCM-41, and T-99 (Zr) are shown in FIGS. 15A-15C, respectively. Comparing the desorption amount of the sulfur compound except for the initial desorption of water, it was confirmed that the desorption amount of the magnetic body-silica cluster was about 5.2 to 5.4 times larger than that of MCM-41 and T-99 (Zr). Therefore, the magnetic-silica clusters showed that the adsorption amount of methyl mercaptane was 5.2 ~ 5.4 times higher than that of MCM-41 and T-99 (Zr).

In addition, the desorption experiment after the re-breakthrough experiment shown in FIG. 16 confirms that the reuse of the adsorbent has a similar adsorption amount to the sulfur compound and the desorption force is also excellent. It can be seen that it is possible to use the adsorption of the adsorbent without degradation in performance.

mass (%) mg-adsorbate / g-adsorbent mmol-adsorbate / g-adsorbent Ferro-Silica Cluster 16.49 164.9 3.509 MCM-41 3.07 30.7 0.6533 T-99 (Zr) 3.15 31.5 0.670

FIG. 1A is a flowchart illustrating a method of manufacturing a nano-magnetic material according to an embodiment of the present invention. FIG. 1B is a flowchart illustrating a method of manufacturing a magnetic material-silica cluster according to an embodiment of the present invention.

2 is a scanning electron micrometer (SEM) photograph of the magnetic body-silica cluster according to Example 1 of the present invention.

3 is a High Resolution Transmission Electron Microscope (HR-TEM) photograph of the magnetic material-silica cluster according to Example 1 of the present invention.

4 is a scanning electron micrometer (SEM) photograph of the magnetic body-silica cluster according to Example 2 of the present invention.

5 is a High Resolution Transmission Electron Microscope (HR-TEM) photograph of the magnetic-silica cluster according to Example 2 of the present invention.

6 is an XRD pattern for a magnetic-silica cluster according to Example 1 of the present invention.

7 is a diagram showing the reaction path of the adsorbate (Methyl-mercaptan) in one embodiment of the present invention.

8 is an apparatus diagram of a breakthrough test according to an embodiment of the present invention.

9 is a breakthrough test result of the magnetic body-silica cluster according to Example 1 of the present invention.

10 is a breakthrough test result of the magnetic material-silica cluster according to the second embodiment of the present invention.

11 is a breakthrough test result according to the adsorption temperature and the concentration of the adsorbate of the magnetic material-silica cluster according to Example 1 of the present invention.

12 is a result of re-breakthrough experiment of the magnetic body-silica cluster in Example 1 of the present invention.

13 is a breakthrough test result of the conventional adsorbent MCM-41.

14 is a breakthrough test result of T-99 (Zr) which is a conventional adsorbent.

15 is a diagram of a Tg curve after a breakthrough test of a magnetic body-silica cluster and a Tg curve after a breakthrough test of MCM-41 and T-99 (Zr), which are conventional adsorbents, according to an embodiment of the present invention. .

FIG. 16 is a Tg curve after re-breakthrough of a magnetic-silica cluster conducted in order to compare with a Tg curve after breaking through a magnetic-silica cluster according to an embodiment of the present invention.

Claims (20)

Selected from the group consisting of compounds, organic amines or aminocarboxylates comprising at least one oxalate group or carboxylate group in an aqueous solution containing ferrous ions (Fe ²⁺ ) or ferric ions (Fe ⁺³ ) A first step of producing a nano-magnetic surface substituted with a hydrophilic substituent derived from one or more compounds; A second step of adding the nanomagnetic material in an aqueous solution containing a catalyst and a surfactant; A third step of preparing a nano magnetic material-silica cluster by mixing the silicon precursor with the aqueous solution of the second step; And Method for producing a magnetic-silica cluster comprising a fourth step of firing the magnetic-silica cluster. The method of claim 1, The aqueous solution of the first step is a method of producing a magnetic-silica cluster, characterized in that the basic aqueous solution. delete The method of claim 1, The first step includes mixing FeSO ₄ H ₂ O, Fe ₂ (SO ₄ ) ₃ H ₂ 0 and (NH ₄ ) ₂ C ₂ O ₄ in an aqueous solution; And Method for producing a magnetic-silica cluster, characterized in that it comprises the step (b) of adding sodium hydroxide to the aqueous solution. The method of claim 1, The catalyst of the second step is a method for producing a magnetic-silica cluster, characterized in that the basic catalyst. The method of claim 1, The surfactant of the second step is a method of producing a magnetic-silica cluster, characterized in that the compound of formula (1). [Formula 1] C _a H _{2a +1} N (C _b H _{2b +1} ) ₃ X Where a is an integer of 8-20, b is an integer of 1 or 2, and X is a halogen. The method of claim 6, Surfactants of the formula (1) include octadecyltrimethylammonium halide, hexadecyltrimethylammonium halide, tetradecyltrimethylammonium halide, dodecyltrimethylammonium halide, octadecyltriethylammonium halide, hexadecyltriethylammonium halide, tetradecyltriethylammonium halide And at least one selected from dodecyl triethylammonium halide. The method of claim 1, The silicon precursor of the third stage is selected from the group consisting of tetraethyl orthosilicate, tetramethyl orthosilicate, methyl triethoxysilane, phenyl triethoxysilane, dimethyl dimethoxy silane, ethyl triethoxysilane and mixtures thereof Method for producing a magnetic-silica cluster, characterized in that above. The method of claim 1, Recovering the magnetic body-silica cluster prepared in the third step from the aqueous solution (c); And And (d) filtering the dried magnetic body-silica cluster and drying the recovered magnetic body-silica cluster. The method of claim 1, The firing temperature of the fourth step is a method for producing a magnetic-silica cluster, characterized in that 500 to 600 ℃. A magnetic-silica cluster in which magnetic particles having an average particle diameter of 8 to 20 nm and silica particles having an average particle diameter of 100 to 140 nm are aggregated with each other. The method of claim 11, And the cluster has a BET specific surface area of 500-800 m 2 / g, pore volume of 0.4-0.8 cm 3 / g, and an average pore diameter of 30-45 mm 3. The method of claim 11, Magnetic body-silica cluster, characterized in that the total average particle diameter of the magnetic body-silica cluster is in the form of a cluster of 0.5 to 5㎛. The method of claim 11, Magnetic-silica cluster, characterized in that the content of the nano-magnetic particles are 20 to 60 wt% with respect to the total magnetic silica cluster. The method of claim 11, The magnetic body-silica cluster having an X-ray diffraction pattern showing one peak in 2θ of 2 ° to 3 °. A method for removing a sulfur compound comprising adsorbing a sulfur compound present in the raw material to the magnetic-silica cluster according to claim 11. The method of claim 16, The raw material is hydrogen, ethane, ethylene, propane, propylene, butane, butylene, city gas or natural gas. The method of claim 16, A method for removing sulfur compounds, characterized in that the magnetic body-silica cluster is brought into contact with the raw materials under the conditions of 500 ° C. or lower and 15 atm or lower. The method of claim 16, And removing the sulfur compound adsorbed magnetic material-silica cluster in a hydrogen atmosphere at 200-600 ° C. to recover the sulfur compound. The method of claim 16, A method of removing a sulfur compound, characterized in that the magnetic body-silica cluster has a dimerization reactivity of the sulfur compound.

Images