JP2020104090A - Oil adsorbent composed of inorganic porous body, and production method of the same - Google Patents

Abstract

To provide an oil adsorbent capable of easily removing contaminating chemical substances of petroleum, petroleum products, and the like such as a variety of solvents, crude oil, heavy oil, light oil, kerosene, lubricant, and gasoline, at low cost, safely, environment friendly even in a water-coexisting system without adsorbing water even if water coexists, and a production method of the same.SOLUTION: The oil adsorbent is produced by heating at 150°C or higher an inorganic porous body coated or impregnated with silicone oil after coating or impregnating the inorganic porous body with 0.1 mass% or more of the silicone oil.SELECTED DRAWING: None

Description

The present invention relates to a novel oil adsorbent that selectively adsorbs only an oil component from an oil/water mixed system such as various leaked oils, and a method for producing the same.

In recent years, various chemicals such as solvents, pesticides and antiseptics, and chemical substances such as crude oil, heavy oil, light oil, kerosene, lubricating oil and other petroleum and petroleum products have polluted rivers, sea, soil, groundwater, etc. Frequency is increasing, which is a big social problem. These substances generally have low solubility in water, and are present on water, in water, on the soil surface, in soil, in groundwater, etc. in a form separated from water or soil or dispersed in water. In order to remove these substances from the environment, various adsorption methods and adsorbents have been proposed.

Generally, in an oil/water mixed system, the oil component exists in a state of floating on the water surface due to the difference in specific gravity and the hydrophobicity of the oil component. Therefore, the adsorbent for this purpose is required to have a bulk specific gravity of less than 1. As such oil adsorbents, there are known polyolefin-based fibers, polyurethane fibers, organic-based adsorbents represented by natural cellulosics, lipophilic porous carbides, perlite, and inorganic-based adsorbents represented by diatomaceous earth. ..

Patent Document 1 discloses a charcoal-based material having a bulk specific gravity smaller than that of water obtained by firing a carbonized slag of a coffee bean to carbonize it. However, the water repellency is not sufficient and the oil content floating on the water surface gradually sinks from the water surface. There was a problem that could not be adsorbed efficiently.

Patent Document 2 discloses perlite for absorbing water-floating oil, in which perlite is sprayed with an aqueous methylsiloxane emulsion, but an aqueous methylsiloxane milk obtained by previously emulsifying about 50-200 cm ³ of methylsiloxane per 1 liter of water is disclosed. It was necessary to prepare a suspension. Furthermore, it is generally considered that a surfactant should be used in combination in the case of producing an emulsion of water and methyl siloxane, which may impair the function of selectively adsorbing only oil. It was

Patent Document 3 discloses an oil adsorbent in which obsidian pearlite is heated at about 1000° C. and volume-expanded, and hydrophobic silica powder is adhered thereto. However, it was considered that there is room for improvement in terms of production cost because it requires high temperature treatment, the substrate is limited to obsidian perlite, which is relatively expensive, and a binder is used.

Patent Document 4 is an oil adsorbent in which a phospholipid is attached to a mineral derived from diatomaceous earth. It can easily adsorb pollutant chemicals such as various solvents, chemicals such as pesticides and preservatives, petroleum and petroleum products such as crude oil, heavy oil, light oil, and lubricating oil, but it is not sufficiently water-repellent and at the same time water. However, there is a problem that oil that floats on the water surface cannot be efficiently adsorbed because it also adsorbs.

JP-A-10-99851 Japanese Patent Publication No. 43-13133 JP-A-2000-170145 Japanese Patent Laid-Open No. 2008-55319

The object of the present invention is to absorb polluted chemical substances such as petroleum and petroleum products such as various solvents, crude oil, heavy oil, light oil, kerosene, lubricating oil and gasoline without adsorbing water even if water coexists. (EN) An oil adsorbent that can be easily and inexpensively removed even in a system in which coexistent with each other and safely and environmentally friendly, and a method for producing the same.

As a result of intensive studies on the solution of this problem, the present inventors have found a method of applying silicone oil to an inorganic porous material and then firing it, and arrived at the present invention.

That is, the present invention is as follows.
<1>
After coating or impregnating 0.1% by mass or more of silicone oil with respect to the inorganic porous material,
An oil adsorbent produced by heating the inorganic porous material coated or impregnated with the silicone oil to 150° C. or higher.
<2>
The oil adsorbent according to <1>, wherein the inorganic porous body is at least one selected from the group consisting of perlite, diatomaceous earth, and calcined diatomaceous earth.
<3>
The oil adsorbent according to any one of <1> and <2>, wherein the inorganic porous body is diatomaceous earth or calcined diatomaceous earth.
<4>
The silicone - kinematic viscosity at 25 ° C. of N'oiru ^is a ^{10mm 2 / s~5000mm 2 / s,} <1> ~ oil sorbent according to any one of <3>.
<5>
The oil adsorbent according to any one of <1> to <4>, wherein the silicone oil contains dimethyl silicone oil or methylphenyl silicone oil.
<6>
The oil adsorbent according to any one of <1> to <5>, which is used as a fire extinguishing agent.
<7>
A method for producing an oil adsorbent according to any one of <1> to <6>, comprising:
After coating or impregnating 0.1% by mass or more of the silicone oil with respect to the inorganic porous body,
A method for producing an oil adsorbent, comprising heating the inorganic porous material coated or impregnated with the silicone oil to 150° C. or higher.
<8>
After coating or impregnating the silicone oil with the inorganic porous body in an amount of 0.3% by mass or more and 10% by mass or less,
The production method according to <7>, wherein the inorganic porous body coated or impregnated with the silicone oil is heated to 190° C. or higher and 450° C. or lower.

With the oil adsorbent described in the present application, polluting chemical substances such as various solvents, crude oil, heavy oil, light oil, kerosene, lubricating oil, gasoline, etc. can be easily and inexpensively and safely placed in the environment even in a system where water coexists. It can be removed easily. That is, the oil adsorbent of the present application can easily adsorb the pollutant chemicals described above, and can selectively adsorb only oil completely even in the presence of water.

The oil adsorbent described in the present application is obtained by applying or impregnating 0.1% by mass or more of silicone oil to an inorganic porous material, and then applying an impregnation of the inorganic porous material with the silicone oil to 150° C. or higher. It is an oil adsorbent produced by heating to.

The bulk density of the inorganic porous material is preferably less than 1, and more preferably 0.3 or more and 0.9 or less, for the purpose of adsorbing and removing the oil component floating on the water surface. As such an inorganic porous material, specifically, magnesium silicate, aluminum silicate, clay such as silicic acid, amorphous silica, zeolite, kaolin, pumice, volcanic ash Shirasu (white sand, white sand), pearlite, Examples include montmorillonite, diatomaceous earth, and calcined diatomaceous earth obtained by calcining diatomaceous earth at high temperature to obtain crystalline silica. Among them, at least one selected from the group consisting of perlite, diatomaceous earth and calcined diatomaceous earth is more preferable, and diatomaceous earth or calcined diatomaceous earth is particularly preferable. The inorganic porous material of the present application does not include such hollow ceramic particles, unlike hollow ceramic particles having a structure in which the inside is empty and the outside is a shell.
The shape of the inorganic porous body may be any shape such as a plate shape, a block shape, a sheet shape, and a granular shape, but the handling becomes easy, and the oil component floating on the water surface can be easily adsorbed and removed. From the viewpoint, it is more preferable that the particles are granular, and it is further preferable that the particles are columnar. When the shape of the particles of the inorganic porous material is columnar, the columnar shape preferably has a diameter of 0.1 mm or more and a height of 3 mm or more, and the diameter is 1 mm or more and 5 mm or less and the height is 5 mm or more and 10 mm. The following cylindrical shape is more preferable. Here, the diameter and height of the cylinder are values measured by a caliper or a ruler.

The general silicone oil, from which a kinematic viscosity at 25 ° C. below 1 mm 2 / ^s, when it until those of about 1,000,000 mm 2 ^{/ s} are known, consider the handling or the like in the coating operation, the present silico - kinematic viscosity at 25 ° C. of N'oiru is ^preferably 10mm ² / s~5000mm 2 / ^s, more preferably silicone oil ^{20mm 2 / s~1000mm 2 / s,} 100mm 2 / More preferably, it is s to 1000 mm ² /s of silicone oil. As such silicone oil, a linear polymer having a siloxane bond is preferable. Specific examples thereof include dimethyl silicone oil, methylphenyl silicone oil, methyl hydrogen silicone oil, and modified silicone oil in which various organic groups are introduced into a part of the methyl group of dimethylpolysiloxane. Among them, dimethyl silicone oil, methylphenyl silicone oil, and methyl hydrogen silicone oil are more preferable, and dimethyl silicone oil and methylphenyl silicone oil are particularly preferable from the viewpoint of easy procurement.

As described above, the oil adsorbent of the present application coats or impregnates the silicone oil with 0.1% by mass or more of the inorganic porous material. That is, the amount of silicone oil applied or impregnated into the inorganic porous material is 0.1 part by mass or more of the inorganic porous material with respect to 100 parts by mass of the silicone oil. Preferably, silicone oil is applied to or impregnated with the inorganic porous material in an amount of 0.3% by mass or more. When less than 0.1% by mass of silicone oil is applied or impregnated to the inorganic porous material, the amount of silicone oil applied or impregnated is not sufficient, and when left in water for a long time, the water repellency is weak, It absorbs water and sinks without adsorbing and removing oil. Further, it is preferable that 10% by mass or less of silicone oil is applied to or impregnated with the inorganic porous material. When silicone oil is applied to or impregnated with 0.1% by mass or more and 10% by mass or less of the inorganic porous material, sufficient water repellency is ensured and surplus silicone oil is not generated, which is advantageous in terms of cost. It is also environmentally friendly.

Examples of the method of applying or impregnating the silicone oil to the inorganic porous body include a method of immersing the inorganic porous body in the silicone oil for a certain period of time and a method of coating the inorganic porous body with the silicone oil. Any method may be used as long as it can be applied to or impregnated into the surface and the inside of the inorganic porous body. For example, a method of applying using a brush or the like, a method of applying with a spray gun and the like can be mentioned. In order to efficiently coat or impregnate the inorganic porous material with the silicone oil, a method may be mentioned in which a predetermined amount of the inorganic porous material is put in a mixer and sprayed with the silicone oil while stirring. As the mixer, a rotary kiln, a ribbon mixer, a conical mixer, a Henschel mixer, a concrete mixer, a mortar mixer, etc. can be used to minimize the impact load on the inorganic porous material and uniformly apply the silicone oil to the inorganic porous material. I wish I had it. As such a mixer, for example, a concrete mixer is preferable because it is inexpensive and easily available.

The oil adsorbent of the present application is produced by heating the inorganic porous material coated or impregnated with the above-mentioned silicone oil to 150° C. or higher, that is, by performing a baking treatment (firing treatment). The heating temperature is preferably 190°C or higher and 450°C or lower, more preferably 190°C or higher and 350°C or lower, further preferably 200°C or higher and 300°C or lower, particularly preferably 200°C or higher and 280°C or lower, and most preferably 230°C or higher. It is 280°C or lower. By heating the inorganic porous material coated or impregnated with silicone oil to 150° C. or higher, water repellency for a long time can be imparted to the oil adsorbent. Specifically, the inorganic porous material coated or impregnated with silicone oil is placed in a conical dryer, a dryer, an electric furnace, a rotary kiln, a paddle dryer, a shelf dryer, etc., and heated at 150° C. or higher.
It is considered that this baking treatment causes the hydrophobic groups of the silicone oil to be oriented and imparts hydrophobicity to the oil adsorbent. When heated in air, the siloxane bond is broken, formalin and its oxides are generated together with the low molecular weight siloxane due to the oxidation reaction, and intermolecular cross-linking occurs, the viscosity of the silicone oil increases, and the fluidity is easily suppressed. Further, the silicone oil is easily immobilized by these reactions. The oxidation reaction in the air proceeds considerably actively at a temperature of 200° C. or higher, and at 250° C. or higher, the mass loss during heating tends to be significantly large even for a short time. Further, if the temperature is 450° C. or higher, combustion is likely to occur, the organic component is lost, only silica remains, and water repellency cannot be imparted. Taking these into consideration, the minimum required heating time is determined by the heating temperature, but since the loss of water repellent component due to the oxidation reaction during heating of silicone oil can be suppressed and the water repellency can be imparted with a smaller amount of silicone oil applied, for example, 190 When the heating is performed at a temperature of not lower than 450°C and not higher than 450°C, the preferable heating time is not shorter than 1 hour and not longer than 10 hours, more preferably not shorter than 1 hour and not longer than 5 hours.

The preferred method for producing the above-mentioned oil adsorbent is such that after applying or impregnating 0.1% by mass or more of the silicone oil with respect to the inorganic porous body, the inorganic porous body coated or impregnated with the silicone oil is used. It is a manufacturing method of heating to 150° C. or higher. A more preferred manufacturing method is to apply or impregnate the silicone oil to the inorganic porous body in an amount of 0.3% by mass or more and 10% by mass or less, and then coat or impregnate the inorganic porous body with the silicone oil. It is a manufacturing method of heating to 190° C. or higher and 450° C. or lower.

The features of the oil adsorbent of the present invention described above will be described below.
The first feature is that the oil in the water/oil system can be completely adsorbed and removed in a short time without leaving an oil film. This oil adsorbent has water repellency, and when the bulk specific gravity is less than 1, it easily stays on the water surface and adsorbs only the oil present on the water surface. There is no problem of remaining.

The second feature is that even if the oil in the water/oil system is completely adsorbed and removed, the oil is not re-released for a long time even if it is left in water as it is. Therefore, it can also be used in a method in which this agent is mixed with oil-contaminated soil, oil is adsorbed, and left as it is for a long period of time to be decomposed by microorganisms.

The third characteristic is that since the adsorbent itself is an inorganic substance, there is no danger of burning the adsorbent itself, and it is possible to adsorb oil safely compared to commonly used organic oil adsorbents. Is. It can be suitably used for oil adsorption removal at a site where a fire is expected or where a fire is actually occurring. In addition, when oil is adsorbed, it sinks in water and does not release oil even in water, so it can be expected to be used as a new fire extinguisher on the ocean and rivers.

The fourth feature is that an inexpensive inorganic porous material and a small amount of silicone oil can be used, and a preferable firing temperature is 190°C or higher and 450°C or lower. With such a firing temperature, no special equipment is required, and since it can be produced by general equipment, it can be produced at low cost.

Next, the method of the present invention will be described more specifically by way of examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition,% is mass %.

<Method of measuring levitation rate (%)>
After putting 80 ml of water in a 200 ml vial and 5 g of the oil adsorbent, cover it, shake it up and down at 120 rpm for 4 hours using a shaker, and then collect the oil adsorbent floating in water. It was dried and weighed. The ratio of the mass of the oil adsorbent floating in water to 5 g of the oil adsorbent used was defined as the floatation rate (%).

<A heavy oil adsorption amount (g)>
30 ml of water, 3 g of oil adsorbent, and 2.25 ml (1.91 g) of A heavy oil were put in a 50 ml polypropylene centrifuge settling tube, which was then capped and stirred for 15 minutes to adsorb A heavy oil. Subsequently, the centrifugal separation settling tube was centrifuged at 3000 rpm for 5 minutes with a centrifugal separator (table top cooling centrifuge 5420 manufactured by Kubota Manufacturing Co., Ltd., rotor radius 160 mm). 11 ml of the water containing the unadsorbed A heavy oil in the supernatant was collected in a 15 ml polypropylene centrifuge settling tube and separated from the A heavy oil adsorbed and removed by the oil adsorbent. Further, 1 ml of 10% saline was added to the above-mentioned water, the lid was covered, and the mixture was centrifuged at 3500 rpm for 15 minutes. Unadsorbed A heavy oil containing A heavy oil emulsified by shaking and water are separated and frozen at −20° C., and the upper layer oil is used as a fluorocarbon solvent (3,3-dichloro-1,1,1,2, It was dissolved in a mixed solvent of 2-pentafluoropropane and 1,3-dichloro-1,1,2,3,3-pentafluoropropane) and transferred to a vial. Sodium sulfate was added thereto, and after dehydration, the amount of oil was measured with an infrared oil concentration measuring device (oil concentration meter OCMA-355 manufactured by Horiba Ltd.) to determine the mass. The amount of A heavy oil adsorbed was calculated by obtaining the difference from the amount of A heavy oil added at the beginning of 2.25 ml (1.91 g).

(Example 1)
In a 50 ml eggplant-shaped flask, 580 mg of Shin-Etsu Chemical Co., Ltd. silicone oil shown in Table 1 was taken, and 30 g of calcined diatomaceous earth Isolite CG-1 (bulk specific gravity 0.59) manufactured by Isolite Industrial Co., Ltd. was added as an inorganic porous body. This was heated at 230° C. for 2 hours in an oil bath under atmospheric pressure and air while rotating and stirring with a rotary evaporator to obtain an oil adsorbent. Table 1 shows the results of the floating ratio and the amount of adsorbed heavy oil A of the obtained oil adsorbent. When left as it was without shaking, sedimentation of the oil adsorbent was not observed for 3 months or longer.

(Examples 2 to 6)
An oil adsorbent was obtained in the same manner as in Example 1 except that the silicone oil described in Table 1 was used and the heating temperature shown in Table 1 was used. Table 1 shows the results of the floating ratio and the amount of the heavy oil A adsorbed on the obtained oil adsorbent.

(Comparative Examples 1 to 3)
An oil adsorbent was obtained in the same manner as in Example 1 except that the silicone oil described in Table 1 was used and the heating temperature shown in Table 1 was used. Table 1 shows the results of the floating ratio and the amount of the heavy oil A adsorbed on the obtained oil adsorbent.

(Comparative Examples 4 and 5)
An oil adsorbent was obtained in the same manner as in Example 1 except that the heating temperature shown in Table 1 was used without using silicone oil. Table 1 shows the results of the floating ratio and the amount of the heavy oil A adsorbed on the obtained oil adsorbent.

(Comparative example 6)
The same procedure as in Example 1 was performed except that an adsorbent for pollutant chemicals (Utras K-2, manufactured by Dia Aqua Solutions Co., Ltd.) in which phospholipid was attached to a mineral derived from diatomaceous earth was used as the inorganic porous body. .. As a result, the floatation rate was 18%, and the heavy oil A adsorption amount was 0.47 g.

(Example 7)
A small concrete mixer for 10 kg was charged with 300 g of calcined diatomaceous earth Isolite CG-1 manufactured by Isolite Industrial Co., Ltd., and a lid having a minimum opening only in the central portion was attached. While rotating and stirring at 24 rpm, 5.43 g (1.81% based on the mass of Isolite CG-1) of silicone oil KF-96-100CS manufactured by Shin-Etsu Chemical Co., Ltd. was sprayed and applied from a hole in the center of the mixer with a spray gun. .. This was transferred to an aluminum dish and fired at 190° C. for 5 minutes in an electric furnace. Table 2 shows the results of the floating rate and the amount of adsorbed heavy oil A of the obtained oil adsorbent.

(Examples 8 to 18, Comparative Examples 7 to 10)
The same procedure as in Example 7 was carried out except that the conditions shown in Table 2 were used. Table 2 shows the results of the floating rate and the amount of adsorbed heavy oil A of the obtained oil adsorbent.

(Comparative Examples 11 to 15)
The same procedure as in Example 7 was carried out except that no baking treatment was performed. Table 2 shows the results of the floating rate and the amount of adsorbed heavy oil A of the obtained oil adsorbent.

(Example 19)
A ribbon mixer was charged with 140 kg of calcined diatomaceous earth isolite CG-1 manufactured by Isolite Industrial Co., Ltd., and an air spray gun (W-200-251 manufactured by Anest Iwata) was used to make a silicone oil KF-96-100CS 1.8 kg manufactured by Shin-Etsu Chemical Co., Ltd. ( The coating amount of silicone oil was 1.3%) and was sprayed from above for 15 minutes while rotating the mixer. This was spread on a stainless vat to a depth of 1 cm, placed in a shelf dryer, and baked at 250° C. for 20 minutes. Then, the heating was stopped and the mixture was allowed to cool. The firing treatment required a total of 6 hours for the temperature increase from 25° C. to 250° C. and further for cooling to 100° C. The floating ratio of the obtained oil adsorbent was 70%, and the A heavy oil adsorption amount was 0.46 g.

(Example 20)
Using the oil adsorbent obtained in Example 19, a recovery test of the A heavy oil that floated was carried out. That is, 10 g of heavy oil A was added to a 1-liter water tank containing 600 g of water in advance, 20 g of the oil adsorbent obtained in Example 19 was poured, and the mixture was stirred with a spoon to bring the oil adsorbent into contact with heavy oil A. It was visually confirmed that the heavy oil A floating on the water surface was adsorbed and removed by the oil adsorbent, and the oil adsorbent was submerged in water. In addition, it was visually confirmed that excess oil adsorbent and oil adsorbent adsorbing a small amount of oil were floating on the water surface. No oil film was confirmed.

(Comparative Example 16)
Instead of the oil adsorbent used in Example 19, about 30 cm of a commercially available oil adsorption mat (PP-100 manufactured by Nippon Crecia Co., Ltd.) of about 2 cm×2 cm was used. A recovery test was conducted. It was visually confirmed that the oil-adsorbing mat that adsorbed the heavy oil A remained floating and that no mat was sinking. Further, an oil film was visually confirmed on the water surface, and the heavy oil A could not be completely removed.

(Example 21)
Using the oil adsorbent obtained in Example 19, a recovery test of gasoline floating on the water surface was conducted. That is, 3.8 ml of gasoline was added to a 50 ml vial container containing 47 ml of water in advance, and 5 g of the oil adsorbent obtained in Example 23 was gently poured. The gasoline floating on the water surface was adsorbed and removed by the oil adsorbent and submerged in water, and no oil film was visually confirmed. After that, an open flame was brought near the mouth of the vial, but no combustion was confirmed.

(Comparative Example 17)
It carried out like Example 19 except not spraying silicone oil. Although Isolite CG-1 was submerged in water, an oil film was visually confirmed on the surface of the water and burned violently by an open flame.

(Example 22)
Instead of the calcined diatomaceous earth isolite CG-1 manufactured by Isolite Industry Co., Ltd., perlite (bulk specific gravity 0.08) obtained by removing fine powder with a 12-mesh sieve was used, and the coating amount of silicone oil was 5.6%. The same procedure as in Example 19 was performed except that the baking treatment was performed at 280° C. for 30 minutes. The obtained oil adsorbent was gently poured into a vial filled with water in advance and left for 12 days, but it was visually confirmed that all the oil adsorbent had floated above the water surface. The oil absorption was similar to that of the oil adsorbent produced in Example 11.

(Comparative Example 18)
The procedure of Example 22 was repeated, except that the silicone oil was not sprayed. Most of the oil adsorbent floated below the surface of the water, and even when it was submerged in water, it was visually observed. Since the oil adsorbent floats below the water surface, it was not suitable as an oil adsorbent for adsorbing and removing oil floating on the water surface in the presence of water.

The oil adsorbents obtained in Examples 1 to 22 described above can easily and inexpensively produce various solvents, crude oils, heavy oils, light oils, kerosene, lubricating oils, and polluting chemical substances such as gasoline even in a system in which water coexists. , Can be removed safely and environmentally in a short time. For example, if the oil adsorbent of the present invention is used as an oil adsorption treatment agent for oil recovery on the road in rainy weather, oil leakage accident in factories, oil leakage accidents in rivers and seas, the spread of pollution can be prevented. Can be done. Further, by preliminarily forming the oil adsorbent of the present invention in a granular shape into a sheet shape, a mat shape, a rope shape, and spreading the oil adsorbent at or near an oil leakage risk location, for example, oil from a petroleum tank caused by an earthquake or the like. Leakage damage can be minimized. Furthermore, since the oil adsorbent of the present invention is an inorganic substance, there is no risk of burning the oil adsorbent itself, and not only can oil be recovered more safely, but it can also be used as a fire extinguishing agent.

(Example 23)
2 g of the oil adsorbent obtained in Example 2 was placed in a porcelain crucible and heated at 300° C. for 60 minutes using an electric furnace (YAMATO, model FO310). After allowing to cool, changes in appearance were examined, and the weight loss rate (%) and the floating rate were measured.
(Examples 24 to 26)
The same procedure as in Example 23 was performed except that the conditions shown in Table 3 were used. Table 3 shows the change in appearance, the weight loss rate (%), and the floating rate (%) obtained.
(Comparative Examples 19 to 21)
Commercially available adsorption mat (PP-100) made of synthetic resin used in Comparative Example 16, commercially available oil adsorbent made of specially processed natural cellulose (Biofuture Cell Sorb Co., Ltd., cotton-like), commercially available natural material The following oil adsorbing and decomposing agent (Oil Gator manufactured by Biofuture Co., Ltd., powder) was selected and heated in the same manner as in Example 23. Table 3 shows the obtained changes in appearance and the weight loss rate (%).

In Examples 23 to 26, no change in appearance was observed even when heated at 300°C or higher. On the other hand, in Comparative Examples 19 to 21, when heated at 300° C. for 60 minutes, it burnt and discolored to black, and the appearance did not retain the original shape.

(Example 27)
An oil adsorbent was added to the place where the floating oil was burning, and a test was conducted to see if the oil was adsorbed and submerged to subside the combustion and accelerate the extinction. When 2.5 L of tap water (water temperature 23° C., specific gravity 1.00) was added to a stainless steel pan (height 18 cm, inner diameter 15 cm), water having a depth of 14 cm was collected. 200 mL of commercially available regular gasoline (liquid temperature 23° C., specific gravity 0.74) was added thereto. An ignition source was prepared, gasoline was burned, and 4 minutes after the ignition was stabilized, 100 g of the oil adsorbent obtained in Example 2 was added at once. After the addition, the oil adsorbent absorbed gasoline and slowly sank. 53 seconds later, the gasoline remaining on the surface of the liquid disappeared and the fire was extinguished. The combustion time from ignition to extinction was 4 minutes and 53 seconds.

(Examples 28 to 30)
The same procedure as in Example 27 was performed except that the conditions shown in Table 4 were used. Table 4 shows the results of the combustion time from ignition to extinction.

(Example 31)
The procedure of Example 27 was repeated, except that the amount of the oil adsorbent added was increased to 190 g. After the charging, part of the oil adsorbent remained floating on the liquid surface, but after 1 minute 19 seconds passed, the gasoline remaining on the liquid surface disappeared and the fire extinguished. The combustion time from ignition to extinction was 5 minutes and 19 seconds.

(Example 32)
Similar to Example 27, 100 g of the oil adsorbent obtained in Example 2 was added at once after 4 minutes from ignition with stable combustion, and 4 minutes and 30 seconds after ignition, a stainless steel colander (outer diameter 15 cm, A depth of 7 cm and an opening of 0.5 mm) was added. The oil adsorbent floating on the liquid surface by the colander all settled together with the colander, and the fire was extinguished simultaneously with the submersion in water. The time from charging the colander to extinguishing the fire was 5 seconds. The combustion time from ignition to extinction was 4 minutes and 35 seconds.

(Comparative Example 22)
Example 27 was repeated except that the oil adsorbent was not added. The combustion time from ignition to extinction was 9 minutes 27 seconds.
(Comparative Examples 23 and 24)
The same procedure as in Example 27 was performed except that the conditions shown in Table 4 were used. Table 4 shows the results of the combustion time from ignition to extinction.

In Examples 27 to 30, all of the added oil adsorbents sufficiently adsorbed gasoline, so that the bulk specific gravity of the oil adsorbent became heavier than water and the water was submerged. I was able to remove some of the gasoline. Therefore, less gasoline remained on the liquid surface, and the combustion time was significantly shortened as compared with Comparative Example 22. It can be used as a fire extinguishing agent or a disaster extinguishing agent for floating oil fires by utilizing the property of adsorbing gasoline and not releasing it even in the presence of water.

In Example 31, since the input amount was increased, a part of the oil adsorbent that could not adsorb gasoline sufficiently and absorbed halfway had a bulk specific gravity lighter than water and remained floating on the liquid surface. However, as shown in Example 32, the fire was extinguished after 5 seconds when forced to submerge with a colander. In this way, if the property of adsorbing gasoline and not releasing it even in an environment with water is utilized, it can be used as a fire extinguisher or a mitigating agent for floating oil fires.

The oil adsorbents used in Comparative Examples 23 and 24 did not have a property of sufficiently adsorbing gasoline and not releasing it in the coexistence of water, so that the combustion time could not be significantly shortened.

(Examples 33 to 38, Comparative Examples 25 to 28)
The same test as in Example 27 was performed on 190 mL of commercially available kerosene (liquid temperature 23° C., specific gravity 0.79) or 190 mL of A heavy oil (liquid temperature 23° C., specific gravity 0.88). 10 mL of gasoline was added to increase the combustion effect. Table 5 shows the results of the burning time from ignition to extinction.

Even when kerosene or heavy oil A was used, the combustion time was significantly shortened as in Examples 33 to 38. By utilizing the property that kerosene or heavy oil A is not adsorbed and released even in the presence of water, it can be used as a fire extinguisher or a mitigating agent against floating oil fires.

Claims (8)

After coating or impregnating 0.1% by mass or more of silicone oil with respect to the inorganic porous material,
An oil adsorbent produced by heating the inorganic porous material coated or impregnated with the silicone oil to 150° C. or higher. The oil adsorbent according to claim 1, wherein the inorganic porous body is one or more selected from the group consisting of perlite, diatomaceous earth, and calcined diatomaceous earth. The oil adsorbent according to claim 1, wherein the inorganic porous body is diatomaceous earth or calcined diatomaceous earth. The silicone - kinematic viscosity at 25 ° C. of N'oiru ^is a 10mm ² / s~5000mm 2 / s, oil sorbent according to any one of claims 1-3. The oil adsorbent according to any one of claims 1 to 4, wherein the silicone oil contains dimethyl silicone oil or methylphenyl silicone oil. The oil adsorbent according to any one of 1 to 5 above, which is used as a fire extinguishing agent. A method for producing the oil adsorbent according to any one of claims 1 to 6, comprising:
After coating or impregnating 0.1% by mass or more of the silicone oil with respect to the inorganic porous body,
A method for producing an oil adsorbent, comprising heating the inorganic porous material coated or impregnated with the silicone oil to 150° C. or higher. After coating or impregnating the silicone oil with respect to the inorganic porous body in an amount of 0.3% by mass or more and 10% by mass or less,
The manufacturing method according to claim 7, wherein the inorganic porous material coated or impregnated with the silicone oil is heated to 190°C or higher and 450°C or lower.