WO2009113445A1

WO2009113445A1 - Adsorbent desulfurizer for liquid phases

Info

Publication number: WO2009113445A1
Application number: PCT/JP2009/054189
Authority: WO
Inventors: 宏昭櫻井; 木内　正人
Original assignee: 独立行政法人産業技術総合研究所
Priority date: 2008-03-10
Filing date: 2009-03-05
Publication date: 2009-09-17
Also published as: JPWO2009113445A1; JP5170591B2; RU2448771C1

Abstract

Provided are an adsorbent desulfurizer for liquid phases made by loading gold nanoparticles with a mean particle diameter of 50 nm or less on a metal oxide, a desulfurizing method characterized by the fact that said desulfurizer is brought into contact with a liquid that includes sulfur-containing organic compounds, and a desulfurizer regeneration method characterized by the fact that the desulfurizer is heat-treated to remove the sulfur-containing organic compounds adsorbed onto said desulfurizer. This invention can remove even thiophene sulfur compounds, for which satisfactory removal was difficult with prior methods, to sulfur concentrations of 10 ppm and below. Also provided is a novel desulfurizer that can be regenerated with a simple treatment method after the desulfurizing treatment.

Description

Adsorption desulfurization agent for liquid phase

The present invention relates to a liquid phase adsorption desulfurization agent and a desulfurization method using the desulfurization agent.

From the standpoints of pollution prevention, improvement of engine fuel consumption, and response to future automotive fuel cell systems, it is required to further reduce the concentration of sulfur contained in liquid fuels such as gasoline, kerosene and light oil. For this reason, establishment of desulfurization technology from liquid fuel has become an important issue.

The so-called sulfur-free fuel with a sulfur concentration of about 10 ppm has already started to be supplied as a commercial product, but at present, there is a need for technology to further reduce the sulfur concentration. In particular, it is said that a fuel for fuel cells needs to have a sulfur concentration of 0.1 ppm or less. In the present specification, the sulfur concentration is expressed in ppm by weight, and 1 ppm when 1 μg of sulfur is contained as an element in 1 g of liquid fuel oil.

As a method for reducing the sulfur concentration in the liquid fuel, a hydrodesulfurization method using a cobalt-molybdenum-based catalyst is exclusively used in the production process of the liquid fuel. However, among the various sulfur compounds contained in the liquid fuel, dibenzothiophene has a relatively low hydrogenation reactivity, and therefore has a problem that it tends to remain in the liquid fuel after hydrodesulfurization treatment. In particular, 4,6-dimethyldibenzothiophene having an alkyl group substituted around the sulfur atom of dibenzothiophene has low reactivity on the catalyst surface due to steric hindrance, and is a difficult-to-removable compound. Therefore, improvement of hydrodesulfurization catalysts has been promoted, and other methods such as oxidative desulfurization and adsorptive desulfurization have been recently studied.

The liquid phase adsorptive desulfurization method is a method of adsorbing and removing sulfur compounds by bringing liquid fuel into contact with a desulfurizing agent, and has a feature that can be implemented with a simple apparatus. However, when the desulfurization agent reaches the adsorption saturation, no further desulfurization can be performed, and the adsorbent after replacement cannot be reused, resulting in a problem that a large amount of industrial waste is generated. For this reason, it is desirable to regenerate and reuse the desulfurization agent after use, but no thiophene adsorptive desulfurization agent satisfying such properties is known.

Currently, materials that are being studied as liquid phase adsorption desulfurization agents can be classified into four categories: activated carbon, metal oxide, zeolite, and metal (see Non-Patent Document 1 below). Among these, activated carbon is widely used as a general adsorbent, and its specific surface area is as large as 1000 m ² / g or more, and it has excellent adsorption ability for organic substances in general, but it is a choice that removes only sulfur-containing organic substances. It is not possible to expect a specific adsorption. In addition, the activated carbon is generally heated and regenerated, but there is a drawback that the activated carbon itself is partially decomposed during the regeneration. If activated carbon is not properly controlled, the activated carbon may ignite or carbon monoxide may be decomposed when the adsorbed material is decomposed. Can cause poisoning accidents.

As oxide-based desulfurization agents, materials such as iron oxide and zinc oxide have been put to practical use because they adsorb hydrogen sulfide, but those having sufficient performance as adsorbents for thiophene-based sulfur compounds have been reported so far. Absent.

Zeolite-based desulfurization agents have a large specific surface area of 500 m ² / g or more, have heat resistance, and have been studied as adsorptive desulfurization agents because their properties can be greatly changed by modification by ion exchange or the like. For example, it has been reported that Y-type zeolite (Cu-Y, Ce-Y) ion-exchanged with Cu or Ce is suitable as an adsorbent for thiophene compounds (see

Patent Documents

2 and 3 below). However, there has been no report on the regeneration method after desulfurization so far, and experiments by the inventors of the present application have confirmed that it is difficult to use the regeneration by a normal heating operation.

Regarding metal-based desulfurization agents, the types of sulfur compounds that can be effectively adsorbed and removed vary depending on the metal species, and it is known that Ni-based desulfurization agents exhibit excellent performance with respect to thiophene compounds. However, the Ni-based desulfurization agent needs to be adsorbed under heating at about 200 ° C. after undergoing hydrogen reduction at a high temperature and a special stabilization treatment, and the desulfurization operation is very complicated. Moreover, once Ni forms a stable sulfide, regeneration is very difficult (see Patent Document 1 below).

By the way, it is known that a material having a metal oxide as a carrier and supported as noble metal nanoparticles on the surface thereof has high activity for various chemical reactions, and is used as a catalyst for various chemical reactions. . In such noble metal catalysts, it is generally known that sulfur compounds are adsorbed on the active sites of noble metal catalysts and become catalyst poisons. For this reason, there are few reports examining noble metal catalysts such as Pt, Pd, etc. for the purpose of desulfurization compared to cobalt-molybdenum-based catalysts, but recently, for example, a system in which platinum is supported on zeolite shows activity in hydrodesulfurization. (See Non-Patent Document 4 below). In addition, although there has been a report of trying to control hydrodesulfurization performance by adding gold to a platinum catalyst, there is no report of a material containing only gold as a noble metal as a desulfurization catalyst.

Among the sulfur compounds, alkanethiols (RSH), in particular, are known to regularly adsorb on the gold surface to form a self-assembled monolayer (SAM). As for thiophene, since the SAM formation of polyalkylthiophene by Gao et al. In 1995 (see Non-Patent Document 5 below), SAM formation has also been experimentally confirmed by several researchers. Since it can be applied to an electronic device as a conductive polymer, research in this field is becoming active. For such simple thiophene or alkylthiophene, the adsorption phenomenon on the Au surface and its application have been studied, but the single crystal of Au is exclusively used for the purpose of using a monomolecular film as SAM, and the adsorption amount Therefore, it is not used as an adsorptive desulfurization agent, and there has been no report on the adsorption of dibenzothiophenes that are important as an object of desulfurization from liquid fuel.
Japanese Patent Laid-Open No. 11-169601 Petroleum Industry Revitalization Center, Technical Planning Department, Petrotech, 11 (2005), 835-840 Chiyoda Osamu, Catalysis, 47 (2005) 568 M. Xue et al., J. Colloid Interf. Sci., 298 (2006) 535-542 M. Sugioka et al., J. Jpn. Petrol. Inst., 45 (2002) 342-354 Z. Gao et al., Synthetic Metals 75 (1995) 5-10

The present invention has been made in view of the above-mentioned problems of the prior art, and its main purpose is to provide a desulfurization agent by liquid phase adsorption effective for sulfur compounds contained in liquid fuel, in particular, It is possible to remove thiophene-based sulfur compounds that were difficult to remove sufficiently by this method until a sulfur concentration of less than 10 ppm is reached, and a new desulfurization that can be reused with a simple treatment method after desulfurization. Is to provide an agent.

The present inventor has intensively studied to achieve the above-mentioned purpose. As a result, metal oxides supporting gold nanoparticles known as various chemical reaction catalysts act as adsorbents with good selectivity for sulfur-containing organic compounds in liquid fuels. It was found that the thiophene sulfur compound, which was difficult to remove to a sufficiently low concentration by this method, could be adsorbed and removed to a sufficiently low concentration. Moreover, after the adsorption treatment, it has been found that the adsorbed sulfur compound can be efficiently removed by a simple heat treatment and can be reused as an adsorbent, and the present invention has been completed here.

That is, the present invention provides the following liquid phase adsorption desulfurization agent and a desulfurization method using the desulfurization agent.
1. A liquid phase adsorptive desulfurization agent obtained by supporting gold nanoparticles having an average particle size of 50 nm or less on a metal oxide.
2. Item 2. The desulfurizing agent according to Item 1, wherein the specific surface area is 1 m ² / g or more.
3. A liquid phase adsorptive desulfurization agent, wherein the gold nanoparticle-supported metal oxide according to Item 1 is immobilized on a support.
4). Item 2. The desulfurization agent according to Item 1, wherein the treatment target is a liquid fuel containing a sulfur-containing organic compound.
5). A desulfurization method comprising contacting the desulfurizing agent according to item 1 with a liquid containing a sulfur-containing organic compound.
6). The desulfurization method according to claim 5, wherein the treatment target is a liquid fuel containing a sulfur-containing organic compound.
7). Item 7. The desulfurization method according to Item 6, wherein the liquid fuel to be treated contains an organic compound having a thiophene ring.
8). Item 8. The desulfurization method according to Item 7, wherein the organic compound having a thiophene ring is at least one compound selected from the group consisting of dibenzothiophene and alkyldibenzothiophenes.
9. A method for regenerating a desulfurization agent, comprising performing a desulfurization treatment by the method of Item 5 above, and then heat-treating the desulfurization agent to remove the sulfur-containing organic compound adsorbed on the desulfurization agent.
10. A desulfurization method, wherein the desulfurization agent regenerated by the method of item 9 is contacted with a liquid containing a sulfur-containing organic compound by the method of claim 5.

Hereinafter, the desulfurization agent of the present invention, its production method and use method will be specifically described.

Desulfurizing agent The desulfurizing agent of the present invention has a structure in which gold nanoparticles having an average particle size of 50 nm or less are supported on a metal oxide.

Metal oxides carrying such gold nanoparticles are the oxidation removal of carbon monoxide and formaldehyde, the reduction of NOx in exhaust gas by hydrocarbons, the methanol synthesis reaction by hydrogenation of carbon monoxide and carbon dioxide, carbon monoxide It is known to exhibit high activity as a catalyst for various chemical reactions such as water gas shift reaction for producing carbon dioxide and hydrogen from water and water, and propylene oxide synthesis reaction by selective oxidation of propylene. However, until now, it has not been known at all to have a selective adsorption action for sulfur compounds in the liquid phase.

According to the present invention, the substance having a structure in which the above-described nanosized gold fine particles are supported on a metal oxide has a selective adsorption action on various organic compounds containing sulfur in the liquid phase, It was newly found to be effective as a desulfurization agent.

The desulfurizing agent of the present invention preferably has a structure in which nano-sized gold particles are uniformly supported on the surface of the metal oxide support. Since the gold fine particles supported on the metal oxide are in a very fine state of nano-size, the gold surface area necessary for adsorption is very large and can exhibit excellent adsorption performance. In addition, it is considered that the combustion active point necessary for regeneration of the adsorbent after desulfurization is formed at the bonding interface between gold and metal oxide, so that the particle size should be as small as possible in order to increase this bonding portion. preferable. Specifically, the average particle diameter of the gold particles may be not less than the size of the gold atom and not more than about 50 nm, preferably about 1 to 10 nm. In the present specification, the average particle diameter of the gold particles is the average value of the values measured by transmission electron microscopy, or the value of the crystallite diameter of gold calculated from the powder X-ray diffraction measurement data by the Sherrer equation. In the case of gold nanoparticle catalyst, it is confirmed that both values are almost the same.

Examples of metal oxides supporting gold particles include beryllium, magnesium, aluminum, silicon, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, strontium, yttrium. An oxide containing a metal element such as zirconium, cadmium, indium, tin, barium, or a lanthanoid element can be used. These metal oxides may be single metal oxides containing only one of the above metal elements, or complex oxides containing two or more metal elements. Among these metal oxides, metal oxides containing one or more metal elements such as titanium, manganese, iron, cobalt, nickel, zinc, zirconium, lanthanum, and cerium are particularly preferable. The above-mentioned single metal metal oxide and composite oxide can be mixed and used as necessary. In addition, beryllium, magnesium, calcium, strontium, and barium of the periodic group 2 elements may include hydroxides, basic carbonates, and the like in addition to the corresponding oxides depending on the manufacturing method. In the present invention, the “oxide” supporting gold in the form of nanoparticles may contain these hydroxides, basic carbonates and the like.

In the desulfurization agent of the present invention comprising a metal oxide supporting gold nanoparticles, the gold content is not particularly limited as long as it can be prepared so that gold can be maintained in a nanoparticle state. For example, by appropriately selecting the metal oxide used as the carrier and the preparation method, a desulfurization agent having a gold content of about 0.1 to 60% by weight can be prepared based on the total amount of gold nanoparticles and metal oxide.

The form of the desulfurization agent of the present invention, that is, the metal oxide supporting the gold nanoparticles can be appropriately selected depending on the purpose of use. For example, it can be used in a powder form, or can be used after being formed into a granular form, a pellet form, or the like. Further, a metal oxide supporting gold nanoparticles on a support can be fixed and used as a shape of the support. With respect to the support, the shape of the support is not particularly limited as long as the metal oxide carrying gold nanoparticles on the surface can be fixed, and is flat, block, fiber, net, bead, honeycomb, etc. anything is fine. For example, when used as a honeycomb, a desulfurization agent prepared in a powder form can be used by adhering to the surface of the honeycomb, or an oxide is supported on the surface of the honeycomb in advance, and a precipitation method described later is applied. Gold nanoparticles can be directly supported on the surface of the lever. The material of the support is not particularly limited as long as it is stable under conditions for supporting gold nanoparticles or under desulfurization conditions. For example, various ceramics can be used.

The specific surface area of the metal oxide in a state where gold nanoparticles are supported is preferably about 1 to 2000 m ² / g, more preferably about 5 to 1000 m ² / g as measured by the BET method. . In order to obtain such a gold nanoparticle-supporting oxide, for example, a metal oxide supporting gold nanoparticles having a specific surface area in the above range may be used.

Production method of desulfurization agent The method for supporting gold as nano-sized particles on the metal oxide is not particularly limited, and for example, the following known preparation methods can be employed.
(a) Coprecipitation method (JP-A-60-238148, etc.)
(b) Precipitation / precipitation method (JP-A-3-97623, etc.)
(c) Colloid mixing method (Tsubota S. et al., Catal. Lett., 56 (1998) 131)
(d) Gas phase grafting method (JP-A-9-122478)
(e) Liquid phase grafting method (Okumura M. et al., Chem. Lett., (2000) 396)

In these methods, as a gold precursor for precipitating gold fine particles, depending on the method employed, for example, heating of a water-soluble gold compound (for example, chloroauric acid), gold acetylacetonate complex, etc. A compound that vaporizes due to the above can be used.

Also for the metal oxide raw material, various metal nitrates, sulfates, acetates, chlorides, and the like can be used depending on the loading method employed. Specifically, nitrates such as cerium nitrate and zirconium nitrate, sulfates such as titanium sulfate, chlorides such as cerium chloride, titanium trichloride, and titanium tetrachloride can be used.

In the coprecipitation method (a), first, a precursor of these oxides and a gold precursor are simultaneously precipitated under alkaline conditions. Subsequently, the precipitate of the mixture of the obtained gold hydroxide and the oxide precursor hydroxide is filtered, washed with water, and dried, and then heat treatment described later is performed to obtain an oxide carrying gold nanoparticles.

In the preparation methods (b) to (e), it is necessary that the oxide precursor is preliminarily formed into an oxide or hydroxide before carrying gold. It is also possible to use what is marketed as an oxide or hydroxide from the beginning. These may be in any form, and may be in the form of powder, beads, pellets, honeycombs, etc. Even if they are not of a single composition, for example, a ceramic honeycomb coated with titanium oxide is also used. it can. A gold precursor is supported on the surface of the oxide or hydroxide as described above by the methods (b) to (e), and if necessary, filtered, washed with water, dried, and then subjected to a heat treatment to be described later. An oxide carrying particles can be obtained.

Among the above preparation methods, in the case of the coprecipitation method and the precipitation method, for example, as shown in Japanese Patent Publication No. 5-325 and Japanese Patent Publication No. 6-29137, it is possible to add magnesium citrate during the preparation. This method is effective for reducing the particle size, and this method is particularly effective when the amount of gold supported is large.

In the above-described known preparation method, in order to finally bring the gold into a metal state, for example, heat treatment may be performed in various atmospheres such as an oxygen-containing atmosphere, a reducing gas atmosphere, and an inert gas atmosphere. . As the oxygen-containing atmosphere, an air atmosphere or a mixed gas atmosphere in which oxygen is diluted with nitrogen, helium, argon, or the like can be used. As the reducing gas, for example, about 1 to 10 vol% hydrogen gas or carbon monoxide gas diluted with nitrogen gas can be used. For example, nitrogen, helium, argon, or the like can be used as the inert gas.

The heat treatment temperature may be appropriately selected from the range of known metal gold production conditions, and is usually preferably about room temperature to 600 ° C. In order to obtain stable and fine gold particles, about 200 to 400 ° C. is more preferable. The heat treatment time may be about 1 to 12 hours, for example.

Object of Desulfurization Treatment The desulfurization agent of the present invention can be applied to a method of adsorbing and removing various organic compounds containing sulfur in the liquid phase. Examples of such sulfur-containing organic compounds include thiol (R-SH), sulfide (RSR), disulfide (RSSR), tetrahydrothiophene, and thiophene compounds. Here, the thiophene compound means a compound group having a thiophene ring, and examples thereof include thiophene, alkylthiophene, benzothiophene, alkylbenzothiophene, dibenzothiophene, alkyldibenzothiophene, and dialkyldibenzothiophene. .

The desulfurizing agent of the present invention is effectively used for adsorptive desulfurization of sulfur-containing organic compounds remaining in liquid fuel, particularly thiophene compounds. By using the desulfurizing agent of the present invention, it has been difficult to reduce the sulfur concentration below 10 ppm by a conventional method until a sulfur concentration below 10 ppm is reached for a thiophene compound such as 4,6-dimethylbenzothiophene. It can be removed by adsorption.

The type of liquid fuel to be treated is not particularly limited, and any of gasoline, kerosene, kerosene, light oil, heavy oil, etc. may be used. The sulfur concentration contained in the liquid fuel before treatment is not particularly limited, but hydrodesulfurization and other methods are taken into consideration that the amount of desulfurization agent required is increased when directly treating high-sulfur fuel oil. The sulfur concentration is preferably 50 ppm or less in advance, and more preferably 10 ppm or less.

Desulfurization method In the desulfurization method using the desulfurization agent of the present invention, a sulfur-containing organic compound in the liquid can be adsorbed and desulfurized by bringing the liquid to be desulfurized, for example, liquid fuel into contact with the desulfurization agent. As a general method, there are two methods, a batch method and a flow method.

In the batch method, for example, a method of introducing a desulfurizing agent into a container containing liquid fuel and stirring can be employed. The appropriate amount of the desulfurizing agent varies depending on the type of desulfurizing agent actually used. For example, it is preferably used in the range of 1 to 500 g of desulfurizing agent for 1 liter of liquid fuel, and 10 to 10 desulfurizing agent for 1 liter of liquid fuel. More preferably, it is used in the range of 100 g. The processing temperature is not particularly limited as long as the fuel to be processed can maintain a liquid state, and may be performed at room temperature, for example. The pressure is not particularly limited, and it may be in a pressurized state. Usually, the treatment may be performed under atmospheric pressure.

A desulfurizing agent is added, and a liquid and a desulfurizing agent with a reduced amount of sulfur-containing organic compound can be obtained by separating the liquid and the desulfurizing agent after a predetermined time has elapsed. The treatment time varies depending on the concentration of the sulfur compound and the amount of the desulfurization agent used, so it cannot be specified unconditionally. For example, the treatment is performed within the range of 1 hour to several days until the desired desulfurization effect is obtained. Just do it.

The separated desulfurizing agent can be regenerated and reused by, for example, a method described later, which is dried and then heated in air.

In the case of the flow method, a desulfurizing agent is filled in a layered manner in a tubular container, and the liquid to be treated is circulated at a constant flow rate. In this case, the liquid hourly space velocity (LHSV) can be set, for example, within a range of about 0.01 to 100 h ⁻¹ , preferably about 0.01 to 1 h ⁻¹ . The temperature conditions, pressure conditions, and the like at the time of desulfurization are not particularly limited as long as the fuel is in a liquid range as in the case of the batch method. If there is no external heating source, it may be performed at room temperature. When the liquid fuel is supplied in a preheated state, adsorptive desulfurization can be performed at the same temperature.

Regeneration method After the sulfur-containing organic compound in the liquid is adsorbed and desulfurized by the method described above, the sulfur-containing organic compound adsorbed on the desulfurizing agent is removed by heating the desulfurizing agent, and the desulfurizing agent is regenerated and reused. Can do. In the heat treatment of the desulfurizing agent, it is desirable to heat the desulfurizing agent after washing with a solvent or the like, if necessary.

The heat treatment can be performed in various atmospheres such as inert gas, diluted oxygen, air, water vapor, diluted hydrogen and the like.

The metal oxide supporting the gold nanoparticles constituting the desulfurizing agent of the present invention is a reaction of hydrocarbons such as methane and propane with O ₂ (combustion reaction), a reaction of carbon compounds such as CO and H ₂ O (shift reaction). It is known that it has catalytic activity for any of the reaction (hydrogenation reaction) of carbon compounds such as CO, CO _{2 and} aldehyde with H ₂ (hydrogenation reaction). For this reason, by performing a heat treatment in an atmosphere containing any of O ₂ , H ₂ O, and H ₂ , a catalytic reaction between these molecules and the sulfur-containing organic compound adsorbed on the surface of the desulfurizing agent or a sulfur-containing organic compound Thus, the adsorbed sulfur-containing organic compound can be efficiently removed.

The concentration range of O ₂ , H ₂ O, H _2, etc. in the atmosphere is not particularly limited, but especially when H ₂ is included, it is necessary to avoid the explosion composition. Regarding the pressure condition, normal pressure may be used in the case of a combustion reaction, but in the case of performing a hydrogenation reaction or the like, the reaction may be accelerated by pressurizing at about 10 MPa or less. The heating temperature can be selected in the range of about 50 to 500 ° C, preferably about 100 to 400 ° C, more preferably about 150 to 400 ° C. An excessively high heating temperature is not preferable because gold nanoparticles tend to aggregate and the adsorption performance after regeneration deteriorates.

The desulfurizing agent of the present invention has a selective adsorption action for sulfur-containing organic compounds in the liquid phase. In particular, the sulfur compound concentration in the liquid fuel can be lowered to a level that is difficult with the prior art.

The desulfurizing agent of the present invention can be used for various applications by utilizing such excellent adsorption removal performance for sulfur-containing organic compounds. For example, after reducing the concentration of the sulfur-containing organic compound by a conventional hydrodesulfurization process, the sulfur-containing organic compound is adsorbed and removed using an adsorption tower filled with the desulfurizing agent of the present invention, thereby allowing sulfur in the liquid fuel. The concentration can be made 10 ppm or less, and in particular, the sulfur concentration desired for fuel for fuel cells can be lowered to 0.1 ppm or less.

In addition, as described in Non-Patent Document 1 above, a column filled with the desulfurization agent of the present invention is installed between a tank of a gas station and a fueling machine, and desulfurization is performed when fueling an automobile. It can also be used.

3 is a graph showing a change over time in a dibenzothiophene concentration in a solution in Test Example 1. FIG. 4 is a graph showing the sulfur concentration remaining in the solution after conversion to equilibrium (converted from the analysis value of dibenzothiophene concentration) and the amount of dibenzothiophene adsorbed on the desulfurizing agent when the amount of desulfurizing agent used is changed in Test Example 2. Saturated adsorption amounts of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), and naphthalene (NA) in the first (before regeneration) and second (after regeneration) adsorption operations of each sample in Test Example 3 It is a graph which shows. 6 is a graph showing the amount of saturated adsorption of dibenzothiophene (DBT) in each adsorption operation when adsorption-regeneration is repeated in Test Example 4. 6 is a graph showing the relationship between the heating temperature of regeneration treatment in Test Example 5 and the saturated adsorption amount of dibenzothiophene (DBT) of a sample after regeneration. 6 is a graph in which the amount of CO ₂ generated during temperature rise is plotted against temperature when heat regeneration treatment at 350 ° C. is performed in Test Example 5. In Test Example 6, a graph showing the saturated adsorption amount of 4,6-dimethyldibenzothiophene (DMDBT) in test solution E obtained for each sample in comparison with the adsorption amounts of DBT, DMDBT, and NA in test solutions A and C It is.

Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1
(1) Preparation of desulfurization agent Desulfurization agent 1: gold / cerium oxide (Au / CeO ₂ )
1000 mL of an aqueous solution of chloroauric acid [HAuCl ₄ · 4H ₂ O] (5 mmol / L) was heated to 70 ° C., and KOH was added dropwise to adjust the pH to 7. 7.7 g of cerium oxide powder was added, and then 370 mL of a 10 mmol / L solution of magnesium citrate was added. After stirring for 1 hour, filtration, washing and drying, the resulting powder is calcined in air at 400 ° C. for 4 hours to desulfurize the structure in which gold nanoparticles with an average particle size of 5.5 nm are supported on the surface of cerium oxide Agent 1 (Au / CeO ₂ ) (Au supported amount 11.3 wt%) was prepared. In addition, the average particle diameter of the gold nanoparticles in the examples is the value of the crystallite diameter of gold calculated from the powder X-ray diffraction measurement data according to the Sherrer equation.

Desulfurization agent 2: Gold / cerium oxide (Au / CeO ₂ )
The gold nanoparticles with an average particle size of 4.9 nm are supported on the cerium oxide surface in the same manner as the preparation of the desulfurizing agent 1 except that the amount of chloroauric acid used is reduced and magnesium citrate is not added. A desulfurizing agent 2 (Au / CeO ₂ ) having a structure as described above (Au loading 1.0 wt%) was prepared.

Desulfurization agent 3: Gold / Zinc oxide (Au / ZnO)
An aqueous solution in which 8 g of sodium carbonate Na ₂ CO ₃ was dissolved in 200 mL of water was heated to 70 ° C. An aqueous solution prepared by dissolving 14.2 g of zinc nitrate and 1.1 g of chloroauric acid in 200 mL of water was added thereto at 70 ° C. to form a precipitate. After stirring for 1 hour, filtration, washing and drying, the resulting powder is calcined in air at 400 ° C. for 4 hours to desulfurize the structure in which gold nanoparticles with an average particle size of 5.8 nm are supported on the surface of zinc oxide Agent 3 (Au / ZnO) (Au supported amount 10.0 wt%) was prepared.

Desulfurization agent 4: Gold / titanium oxide (Au / TiO ₂ )
1000 mL of an aqueous solution of chloroauric acid (5 mmol / L) was heated to 70 ° C., and KOH was added dropwise to adjust the pH to 7. 3.6 g of titanium oxide powder was added, and then 400 mL of a 10 mmol / L solution of magnesium citrate was added. After stirring for 1 hour, filtration, washing with water and drying, the resulting powder is baked in air at 400 ° C. for 4 hours to desulfurize the structure in which gold nanoparticles with an average particle size of 4.0 nm are supported on the surface of titanium oxide. Agent 4 (Au / TiO ₂ ) (Au gold supported amount 21.5 wt%) was prepared.

Comparative desulfurization agent 1: Cerium oxide (CeO ₂ )
The cerium oxide powder used for the preparation of the

desulfurizing agents

1 and 2 was used as it was.

Comparative desulfurization agent 2: Platinum / Cerium oxide (Pt / CeO ₂ )
500 mL of an aqueous solution of chloroplatinic acid [H ₂ PtC ₆ · 6H ₂ O] (2 mmol / L) was heated, and KOH was added dropwise to adjust the pH to 7. 6.5 g of cerium oxide powder was added. After stirring for 1 hour, filtration, washing with water and drying, the powder obtained was calcined in air at 400 ° C for 4 hours, and further raised to 350 ° C under the flow of H ₂ (3%) + He (balance) mixed gas. Pt was reduced by heating to prepare a comparative desulfurization agent 2 (Pt / CeO ₂ ) (Pt loading 3.0 wt%) in which platinum having an average particle size of 2.0 nm or less was supported on the surface of cerium oxide.

Comparative desulfurization agent 3: Cerium ion exchange Y-type zeolite (Ce-Y)
0.75 g of Y-type zeolite powder was added to 30 mL of an aqueous solution of cerium nitrate [Ce (NO ₃ ) ₃ · 6H ₂ O] (0.2 mol / L), and the mixture was shaken and stirred for 3 days. The comparative desulfurization agent 3 made of cerium ion-exchanged Y-type zeolite (Ce-Y) was prepared by filtering, washing and drying, and calcining the obtained powder at 400 ° C. in air for 2 hours.

Comparative desulfurization agent 4: Copper / Zinc oxide (Cu / ZnO)
An aqueous solution in which 7.6 g of sodium carbonate Na ₂ CO ₃ was dissolved in 200 mL of water was heated to 70 ° C. An aqueous solution in which 12.5 g of zinc nitrate and 4.3 g of copper nitrate were dissolved in 300 mL of water was added thereto at 70 ° C. to form a precipitate. After stirring for 1 hour, it was filtered, washed with water and dried. The obtained powder was calcined in air at 400 ° C. for 4 hours, and further heated to 400 ° C. under the flow of a mixed gas of H ₂ (3%) + He (balance) to reduce Cu to obtain an average particle size of 3.3 Comparative desulfurizing agent 4 (Cu / ZnO) (Cu supported amount 25.1 wt%) in which copper of nm was supported on the surface of zinc oxide was prepared.

(2) Desulfurization test The following test solutions A, B, C, D and E were prepared.

Test solution A
n-decane (manufactured by Kishida Chemical, special grade) as a solvent, dibenzothiophene (manufactured by Kanto Chemical Co., special grade) as an organic sulfur compound, 39.9 mg / L, n-tetradecane (manufactured by Kishida Chemical, special grade) as an internal standard for solution analysis ) Was prepared to contain 39.5 mg / L. The sulfur concentration of this solution corresponds to 9.5 ppm.

Test solution B
Similarly to test solution A, a solution containing 51.2 mg / L of dibenzothiophene as an organic sulfur compound was prepared using n-decane as a solvent. The sulfur concentration of this solution corresponds to 12.2 ppm.

Test solution C
n-decane (manufactured by Kishida Chemical, special grade) as a solvent, dibenzothiophene (manufactured by Kanto Chemical Co., special grade) as an organic sulfur compound, 22.7 mg / L, 4,6-dimethyldibenzothiophene (manufactured by Wako Pure Chemical, special grade), 23.1 mg / L, 22.1 mg / L of naphthalene (made by Wako Pure Chemicals, special grade) as an aromatic organic compound not containing sulfur, and 26.5 mg / L of n-tetradecane (made by Kishida Chemical, special grade) as an internal standard for solution analysis A solution containing L was prepared. The sulfur concentration of this solution is 5.4 ppm as dibenzothiophene and 4.8 ppm as 4,6-dimethyldibenzothiophene, for a total of 10.2 ppm.

Test solution D
Similarly to the test solution A, a solution containing n-decane as a solvent, 43.2 mg / L of dibenzothiophene as an organic sulfur compound, and 69.3 mg / L of n-tetradecane as an internal standard for solution analysis was prepared. The sulfur concentration of this solution corresponds to 10.3 ppm.

Test solution E
n-decane (manufactured by Kishida Chemical, special grade) is used as a solvent, 4,6-dimethyldibenzothiophene (manufactured by Wako Pure Chemical Industries, special grade) is 46.7 mg / L, and n-tetradecane (manufactured by Kishida Chemical Co., Ltd.) is used as an internal standard for solution analysis. , Special grade) 45.3 mg / L. The sulfur concentration of this solution corresponds to 9.7 ppm.

Adsorption and regeneration test method test example 1
Each sample powder of

desulfurizing agents

1 and 2 and comparative desulfurizing agent 1 prepared by the above method was heated in air at 300 ° C. for 30 minutes to remove adsorbed water, and then cooled to room temperature in a desiccator containing silica gel. . 100 mg of this sample was weighed into a screw tube bottle, 5 mL of test solution A was added, the cap was capped, and this time was taken as the adsorption start time. The solution was stirred using a shaker at room temperature. On the way, the temperature of the desulfurizing agent 1 is raised to 60 ° C for 8.5 to 24 hours, and the desulfurizing agent 2 and the comparative desulfurizing agent 1 are raised to 60 ° C for 27 to 47 hours. It has been confirmed in a separate experiment that there is almost no effect on adsorption. Every few hours after the start of adsorption, about 0.1 mL of the solution was extracted with a dropper and the solution composition was analyzed with FID-GC. The time change of the dibenzothiophene concentration in the solution is shown in FIG.

From FIG. 1, the

desulfurization agents

1 and 2 in which gold nanoparticles are supported on cerium oxide have a larger adsorption amount of dibenzothiophene than the comparative desulfurization agent 1 made only of cerium oxide. It can be seen that with a large amount (11.3 wt%) of the desulfurizing agent 1, the amount of adsorption of dibenzothiophene is very large. In addition, as for desulfurizing

agents

1 and 2, the adsorption amount was stabilized after 24 hours or more, whereas in comparative desulfurizing agent 1 consisting only of cerium oxide, it was confirmed that the adsorption amount decreased after 5 hours. .

From the above results, it is clear that dibenzothiophene having a sulfur concentration of 10 ppm in the decane solution can be effectively adsorbed and desulfurized by using

desulfurization agents

1 and 2 in which gold nanoparticles are supported on cerium oxide.

Test example 2
One sample powder of the desulfurizing agent prepared by the above method was heated in air at 300 ° C. for 30 minutes to remove adsorbed water, and then cooled to room temperature in a desiccator containing silica gel. Weighed 26, 51, 101, 200, and 300 mg of this sample in 5 screw tube bottles, added 5 mL of test solution B to each screw tube bottle, capped, and this time was taken as the adsorption start time. . The solution was stirred using a shaker at room temperature. The solution was extracted and analyzed with a dropper 74 hours after the start of adsorption (confirming that the adsorption equilibrium was reached). A known amount of 2,8-dimethyldibenzothiophene (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to each analysis solution as an internal standard substance, and composition analysis was performed by FPD-GC.

FIG. 2 is a graph showing the relationship between the weight of the desulfurizing agent used, the sulfur concentration remaining in the test example solution after adsorption, and the amount of dibenzothiophene (DBT) adsorbed by the desulfurizing agent. The sulfur concentration in the test solution in FIG. 2 is obtained by converting the DBT concentration into the sulfur concentration.

FIG. 2 clearly shows that the total amount of adsorbed dibenzothiophene (DBT) increases and the amount of DBT remaining in the solution decreases as the amount of the desulfurizing agent increases. In particular, when 300 mg of desulfurizing agent was used, 1.37 μmol DBT close to the initial DBT amount (1.38 μmol) of the 5 mL test solution was adsorbed, and the sulfur concentration, which was 12.2 ppm before adsorption, was reduced to 0.1 ppm. It was possible to decrease.

Test example 3
Using the

desulfurizing agents

1, 3, and 4 and comparative desulfurizing agents 2 to 4 prepared by the above method, adsorption and regeneration experiments were performed by the following procedures (1) to (3).

(1) First adsorption Each desulfurization agent was heated in air at 300 ° C for 30 minutes to remove adsorbed water, and then cooled to room temperature in a desiccator containing silica gel. 100 mg of each desulfurizing agent was weighed into a screw tube bottle, 5 mL of test solution C was added and the solution was capped, and this time was taken as the adsorption start time. The solution was stirred using a shaker at room temperature. When the adsorption equilibrium was reached after 24 hours or more had passed, about 0.1 mL of the solution was extracted with a dropper and the solution composition was analyzed with FID-GC.

(2) Regeneration After performing the adsorption experiment by the above method, the desulfurizing agent was filtered off, washed with hexane, and dried at room temperature. The desulfurizing agent powder after drying was filled in a quartz glass reaction tube, and quartz wool was packed in front and back and fixed. While flowing a gas of He (80%) + O ₂ (20%) through the reaction tube at 100 mL / min, the temperature was raised to 350 ° C. at 10 ° C./min, and then maintained at 350 ° C. for 10 min. By this operation, the component adsorbed on the surface of the desulfurizing agent was removed by thermal desorption or catalytic combustion, and the desulfurizing agent was regenerated. The progress of this process was grasped by monitoring the outlet gas of the reaction tube with a mass spectrometer.

(3) Second adsorption Each desulfurization agent was regenerated by the above-described method, and then the desulfurization agent powder returned to room temperature was weighed and placed in a screw tube bottle. At this time, since the amount of the desulfurizing agent recovered after the regeneration treatment decreased, the ratio of 5 mL with respect to 100 mg of the desulfurizing agent powder so that the ratio of the test solution to the desulfurizing agent is the same as the adsorption test of (1) above. Test solution C was added and the lid was closed. When the adsorption equilibrium was reached after 24 hours or more had passed, about 0.1 mL of the solution was extracted with a dropper and the solution composition was analyzed with FID-GC.

From the analysis results of the solution composition, the adsorption amounts of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), and naphthalene (NA) per 1 g of the desulfurizing agent powder were calculated. The results are shown in FIG.

From FIG. 3, when desulfurizing

agents

1, 3 and 4 in which gold nanoparticles are supported on a metal oxide are used, dibenzothiophenes (DBT + DMDBT) can be selectively adsorbed. It turns out to be expensive. Moreover, the comparative desulfurizing agent 2 made of cerium ion Y-type exchanged zeolite (Ce-Y) has a larger total adsorption amount than the

desulfurizing agents

1, 3, and 4, but DBT, DMDBT, NA are almost equimolar The selective adsorption to sulfur-containing organic compounds was not observed.

In addition,

desulfurizing agents

1, 3 and 4 can adsorb 70% or more of dibenzothiophenes (DBT + DMDBT) in the first adsorption test, and the adsorption rate after regeneration is comparative desulfurizing agent 2 It is clear that it is much higher than 3 and 3.

Cu / ZnO (Comparative desulfurization agent 4), which is effective as an adsorbent for hydrogen sulfide, has a small amount of dibenzothiophenes adsorbed despite the fact that Cu, which is the same group IB element as Au, is supported in large quantities. It can be seen that the performance as an adsorbent for sulfur-containing organic compounds is poor.

Test example 4
Repeated tests of adsorption of dibenzothiophene (DBT) and regeneration of desulfurization agent were performed by the following methods (1) to (3). This test was conducted by devising a treatment method during regeneration in order to prevent a decrease in the recovered amount of the desulfurizing agent after regeneration.

(1) First adsorption 100 mg of desulfurizing agent 1 is weighed and placed in a pear-shaped flask (made of heat-resistant glass) with a capacity of 20 mL. The whole flask is placed in an electric furnace and heated in air at 350 ° C. for 30 minutes to remove adsorbed water. Then, it was cooled to room temperature in a desiccator containing silica gel. The flask was taken out from the desiccator, immediately sealed with a Teflon (registered trademark) stopper, and weighed to determine the weight of the desulfurization agent after heat dehydration. 5 mL of test solution D was added and a Teflon (registered trademark) stopper was added, and this time was taken as the adsorption start time. The solution was stirred using a shaker at room temperature. When the adsorption equilibrium was reached after 24 hours or more, the shaking was stopped and the flask was allowed to stand to allow the desulfurizing agent powder to settle. The supernatant was extracted with a dropper and the solution composition was analyzed with FID-GC.

(2) Regeneration After performing the adsorption experiment by the above method, the flask was allowed to stand and the desulfurizing agent powder was allowed to settle. The flask was gently tilted, and the remaining supernatant solution was discarded to such an extent that the desulfurizing agent powder was not washed away, and about 5 mL of hexane was added. The operation of adding hexane and discarding the supernatant solution was repeated a total of 3 times, and then nitrogen gas was blown into the flask to volatilize the hexane. The flask was placed in an electric furnace and heated in air at 350 ° C. for 30 minutes to regenerate the desulfurizing agent by heating. After heating, the mixture was cooled to room temperature in a desiccator containing silica gel, the flask was taken out of the desiccator, immediately plugged with Teflon (registered trademark), and weighed to determine the weight of the desulfurizing agent after regeneration. Thus, by performing regeneration without taking out the adsorbent powder from the flask, it was possible to maintain a weight of 99% or more of the adsorbent used initially even after performing regeneration four times.

(3) Adsorption and regeneration after the second time After regenerating the desulfurizing agent by the method described above, the test solution D was added at a rate of 5 mL to 100 mg of the desulfurizing agent powder in the flask, and the Teflon (registered trademark) stopper was attached. (Second adsorption start). The solution was stirred using a shaker at room temperature. When the adsorption equilibrium was reached after 24 hours or more, the shaking was stopped and the flask was allowed to stand to allow the desulfurizing agent powder to settle. The supernatant was extracted with a dropper and the solution composition was analyzed with GC. Thereafter, the regeneration and adsorption operations were repeated in the same manner. During repeated regeneration, the adsorbent powder stuck to the vessel wall at the top of the flask and contact with the solution worsened. Therefore, in the fourth and subsequent adsorptions, the adsorbent solution was added at the start of adsorption, and the Teflon (registered trademark) plug was inserted. Then, the flask was immersed in the water of an ultrasonic cleaner and operated for 10 seconds to several minutes to improve the dispersion of the adsorbent powder and to recover the contact with the solution.

The amount of dibenzothiophene (DBT) adsorbed per gram of desulfurizing agent powder was calculated from the analysis result of the solution composition at the end of each adsorption. The results are shown in FIG.

FIG. 4 clearly shows that there is no significant decrease in the amount of adsorption even if adsorption-regeneration is repeated. The adsorption amount is slightly reduced in the second and third times, but in the first to third adsorptions, the operation of improving the dispersibility of the adsorbent is not performed at the start of adsorption using an ultrasonic cleaner. This is probably due to the fact that the state of contact with the sample was slightly worse. The adsorption amount was stable in the fourth and fifth adsorption, and the adsorption amount of 95% or more during the first adsorption could be maintained.

From the above results, the desulfurization agent of the present invention in which gold nanoparticles are supported on a metal oxide is excellent in selective adsorption performance for sulfur-containing organic compounds, particularly dibenzothiophenes, and is also regenerated by heating. After the treatment, it is clear that sufficient adsorption performance can be exhibited and reused as a desulfurization agent.

Test Example 5
The desulfurization agent 1 prepared by the above method was used for adsorption and regeneration in the following procedures (1) to (3), and the influence of the heating temperature during regeneration was examined.

(1) First adsorption 100 mg of desulfurizing agent 1 was weighed in 7 screw tube bottles. Heat at 350 ° C in air for 30 minutes to remove adsorbed water, cool to room temperature in a desiccator containing silica gel, and leave overnight in a desiccator with relative humidity adjusted to 85% with saturated potassium chloride solution. To absorb moisture. In addition, since Test Example 5 aims to investigate the influence of the heating temperature during regeneration on the amount of adsorption of dibenzothiophene (DBT), in order to eliminate the influence on the adsorption of DBT due to the difference in the amount of residual water, The conditions are unified so that the sample absorbs moisture under certain conditions before the start of DBT adsorption.

5 mL of the test solution A was added to each screw tube bottle and the lid was covered, and this time was taken as the adsorption start time. The solution was stirred using a shaker at room temperature. When the adsorption equilibrium was reached after 24 hours or more had passed, about 0.1 mL of the solution was extracted with a dropper and the solution composition was analyzed with FID-GC.

(2) Regeneration After performing the adsorption experiment by the above method, the remaining solution in the screw tube bottle was discarded by the same operation as in Test Example 4, washed with hexane and dried. One screw tube bottle was left overnight in a desiccator containing silica gel at room temperature (25 ° C.). About five screw tube bottles, it put into the electric furnace one by one, set temperature was 100, 150, 200, 250, or 300 degreeC, and heated in the air for 30 minutes. For the remaining one screw tube bottle, take out the desulfurizing agent powder and fill it into a quartz glass reaction tube, and fill it with quartz wool before and after fixing it. He (80%) + O ₂ (20% ) Was circulated at 100 mL / min, the temperature was raised to 350 ° C. at 10 ° C./min, and then maintained at 350 ° C. for 30 min. The concentration of CO2 generated during the temperature increase was measured with a mass spectrometer and a photoacoustic multigas monitor (manufactured by INNOVA).

After the heat treatment of the desulfurization agent at 25, 100, 150, 200, 250, 300 or 350 ° C in this way, it was cooled to room temperature in a desiccator containing silica gel and the relative humidity was adjusted to 85% with a saturated potassium chloride solution. It was left overnight to absorb moisture.

(3) Second adsorption With respect to the desulfurization agent absorbed after the heat regeneration treatment at each temperature by the method described above, the test solution A was added at a ratio of 5 mL with respect to 100 mg of the desulfurization agent powder, and the cap was capped. When the adsorption equilibrium was reached after 24 hours or more had passed, about 0.1 mL of the solution was extracted with a dropper and the solution composition was analyzed with FID-GC.

The amount of dibenzothiophene (DBT) adsorbed per gram of desulfurizing agent powder was calculated from the analysis results of the solution composition. As for the first adsorption, the DBT adsorption amount of 3.3 ± 0.1 μmol / g-catalyst for each of the seven screw tube bottles adsorbed under the same conditions. FIG. 5 shows the relationship between the heat treatment temperature and the DBT adsorption amount for the second DBT adsorption amount after the heat treatment regeneration at each temperature. From FIG. 5, it can be seen that for the desulfurization agent 1 (Au / CeO ₂ ), at the heat treatment temperature of 100 ° C. or less, the second adsorption amount is greatly reduced compared to the first treatment, and the heat treatment is not sufficient. Further, at a heat treatment temperature of 200 ° C. or higher, the amount of adsorption at the second time becomes almost the same as that at the first time, and it can be confirmed that the regeneration is completely completed.

FIG. 6 is a graph in which the amount of CO ₂ generated during heating is plotted against temperature when heated to 350 ° C. CO ₂ peaks were observed at two temperatures, 115 ° C and 225 ° C. Of these, the peak on the low temperature side was also observed in the Au / CeO ₂ sample that did not adsorb DBT, which is thought to have adsorbed CO ₂ in the air. The peak on the high temperature side was observed only after DBT adsorption, and it is considered that the adsorbed DBT burned on the catalyst surface and became CO ₂ . The amount of CO ₂ corresponding to the shaded portion in FIG. 6 is 37.2 μmol / g-catalyst, and all of the DBT (3.3 μmol / g-catalyst) adsorbed by the first adsorption burns to CO _2. This agrees well with the amount of CO ₂ (39.6 μmol / g-catalyst).

Test Example 6
The

desulfurization agents

1, 3 and 4 prepared by the above method were subjected to adsorption experiments according to the following procedure using the test solution E (a solution containing only 4,6-dimethyldibenzothiophene as dibenzothiophenes).

Each desulfurization agent was heated in air at 350 ° C. for 30 minutes to remove adsorbed water, and then cooled to room temperature in a desiccator containing silica gel. 100 mg of each desulfurizing agent was weighed into a screw tube bottle, 5 mL of the test solution E was added and the lid was covered, and this time was taken as the adsorption start time. The solution was stirred using a shaker at room temperature. When the adsorption equilibrium was reached after 24 hours or more had passed, about 0.1 mL of the solution was extracted with a dropper and the solution composition was analyzed with FID-GC.

From the analysis result of the solution composition, the adsorption amount of 4,6-dimethyldibenzothiophene (DMDBT) per 1 g of the desulfurizing agent powder was calculated. The results are shown in FIG. FIG. 7 further shows the results of an adsorption test using test solution A (a solution containing only DBT) and test solution C (a mixed solution of DBT, DMDBT, and NA) calculated from the results of Test Example 1 and Test Example 3. Also shown. The compositions of the test solutions A, C, and E are as shown in Table 1 below.

In the results shown in FIG. 7, as a result of the adsorption test using the test solution C containing DBT, DMDBT, and NA, the amount of DBT adsorbed in all of the

desulfurization agents

1, 3 and 4 was compared with the amount adsorbed in DMDBT. Increased. This seems to be because DBT and DMDBT are adsorbed competitively at the same adsorption site, and DBT with no methyl group and less steric hindrance is adsorbed with better selectivity.

On the other hand, in the adsorption test using test solution E, which is a solution of DMDBT alone, the DMDBT adsorption amount was much larger than the DMDBT adsorption amount from test solution C, which is a mixed solution. For desulfurization agent 1 (Au / CeO ₂ ), the amount of DMDBT adsorbed from a solution of DMDBT alone (test solution E) compared to the amount of DBT adsorbed from a solution of DBT alone (test solution A) is approximately 97%. It can be confirmed that the adsorbent of the present invention has excellent adsorption performance for DMDBT.

In the currently available sulfur-free fuels, among the remaining dibenzothiophenes, 4,6-dimethyldibenzothiophene, which is the most difficult to remove with the current technology, occupies a relatively large part. The results shown in FIG. 7 indicate that the desulfurization agent of the present invention has characteristics suitable for removing a trace amount of 4,6-dimethyldibenzothiophene.

Claims

A liquid phase adsorptive desulfurization agent obtained by supporting gold nanoparticles having an average particle size of 50 nm or less on a metal oxide.
The desulfurizing agent according to claim 1, wherein the specific surface area is 1 m 2 / g or more.
A liquid phase adsorptive desulfurization agent, wherein the gold nanoparticle-supported metal oxide according to claim 1 is immobilized on a support.
The desulfurizing agent according to claim 1, wherein the treatment target is a liquid fuel containing a sulfur-containing organic compound.
A desulfurization method comprising contacting the desulfurizing agent according to claim 1 with a liquid containing a sulfur-containing organic compound.
The desulfurization method according to claim 5, wherein the treatment target is a liquid fuel containing a sulfur-containing organic compound.
The desulfurization method according to claim 6, wherein the liquid fuel to be treated contains an organic compound having a thiophene ring.
The desulfurization method according to claim 7, wherein the organic compound having a thiophene ring is at least one compound selected from the group consisting of dibenzothiophene and alkyldibenzothiophenes.
6. A method for regenerating a desulfurizing agent, comprising performing a desulfurization treatment by the method of claim 5 and then heat-treating the desulfurizing agent to remove a sulfur-containing organic compound adsorbed on the desulfurizing agent.
A desulfurization method wherein the desulfurization agent regenerated by the method of claim 9 is brought into contact with a liquid containing a sulfur-containing organic compound by the method of claim 5.