JPH0615164A - Oil absorbent and absorbing method of oil - Google Patents

Abstract

PURPOSE:To avoid such problems concerning to an oil absorbent that the absorbent causes sedimentation after absorption of oil to make recovery of the absorbent difficult, that, if the absorbent is made of an inorg. material, it is not economical because of low oil absorption per unit weight, or that the absorbent costs large because it does not smoothly burn for processing after oil absorption. CONSTITUTION:This oil absorbent consists of hollow ceramic particles having 0.02-0.20 bulk density which is subjected to water-repellent treatment. Water containing oil is brought into contact with this oil absorbent consisting of the water-repellent hollow ceramic particles to adsorb the oil content while mechanical energy is given to the oil-contg. water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-absorbing material mainly composed of hollow ceramic particles subjected to water-repellent treatment and an oil-absorbing method using the oil-absorbing material, which collects and collects oil spilled into industrial waste oil, rivers, seas, etc. The purpose is to provide an oil-absorbing material useful for collecting and an efficient oil-absorbing method by using the oil-absorbing material.

[0002]

2. Description of the Related Art With the modernization of industry and lifestyle, the frequency of collecting waste oil and spilled oil has become extremely high. For example, the collection of oils that are normally needed in the industry or during an emergency, such as oil released from oil processing plants such as machine factories and refineries, traffic troubles on roads, or fires. Oil collection as an environmental measure such as the collection of wastewater, domestic drainage flowing out to rivers, seas, etc.

Conventionally, as the oil absorbing material for collecting oil, when the purpose is to treat oil alone, natural fiber cloth, synthetic fiber cloth, wood powder, sand, porous inorganic material, and oil is water. In the case of coexisting with, a synthetic or natural fiber woven fabric, a non-woven fabric or a material obtained by subjecting a porous inorganic material to a water repellent treatment is used. As a method of using these, in the case of oil alone, a method of absorbing powder by covering powder or fabric on the oil in a sheet shape, or when the oil and water coexist, such as when the oil floats on the water surface A general method is to cover the surface with a powder or sheet-like material that has been subjected to a water-repellent treatment and adsorb only oil.

The mechanism of oil absorption in these oil absorbing materials is usually explained as follows. The oil permeates three-dimensionally through the gaps of the structure due to the capillary phenomenon. The speed of movement and adsorption and the amount of adsorption are determined by the size of the gap, the amount of space, and the viscosity of oil. If the surface of the structure is made water-repellent to reduce the surface tension, in a system in which oil and water coexist, water is not permeated and adsorbed in the structure, but only oil is retained.

[0005]

However, among the conventional oil-absorbing materials, those having a high bulk specific gravity such as wood powder and pearlite are oil and water systems, and even if the oil is adsorbed by the above-mentioned mechanism, sedimentation occurs and recovery is not possible. It has the drawback of being extremely difficult. In addition, sand and inorganic materials having a high true specific gravity have a low oil absorption rate per unit weight and are not economical.

[0006] As a disposal after oil absorption, the oil and the oil absorbent are usually incinerated together. Oil burns easily,
There is a problem when the oil absorbing material is a synthetic compound, especially a resin type.
That is, since the synthetic compound has a high calorific value during combustion, it causes damage to the incinerator, and because the melting temperature is low, it adheres to the bottom surface and side surfaces of the incinerator, which hinders smooth combustion, resulting in a large economical burden. There is a drawback. In addition, when there is a component in the synthetic compound that burns to generate a harmful gas, the environment is deteriorated. The present invention aims to solve these problems.

[0007]

Means for Solving the Problems The present inventor uses hollow ceramic particles to maintain a high oil absorbing ability and to select an appropriate bulk specific gravity so that the oil absorbing material can absorb oil in a system where water and oil coexist. The present invention relates to a method of preventing sedimentation in water after adsorption and adsorbing and removing even fine oil particles of oil finely dispersed in water by using such an oil absorbing material.

That is, the oil absorbing material is an oil absorbing material composed of hollow ceramic particles that have been subjected to water repellent treatment, and the bulk specific gravity of the hollow ceramic particles is 0.02 to 0.20.

Further, the method is characterized in that the oil content is brought into contact with the oil-absorbing material composed of the hollow ceramic particles subjected to the water-repellent treatment while applying mechanical energy to the oil-containing water.

Hollow ceramic grains have a structure in which the inside is empty and the outside is a shell. The thickness of the shell and the specific gravity of the constituent minerals are related to the oil absorption capacity of the oil absorbent, the oil absorption speed, and the overall buoyancy. In order to artificially make hollow ceramic particles, an inorganic material having a shaping property and a sinterability may be used as the shell.
For example, a method of forming a coat layer having a certain thickness by sprinkling a solid material forming a hollow portion with a raw material having a water content and having a caking property can be adopted. For example, spherical polystyrene foam is coated with a clay-containing inorganic material such as silica or alumina, granulated, dried, and sintered. As a result, hollow particles are formed as a structure. Here, by adopting the hollow sphere, the oil component floating or dispersed on the water surface is adsorbed and the adsorbed portion advances. At the same time, the specific gravity of the mixture of oil and oil absorbing material becomes large, but the degree of sedimentation below the water surface can be reduced by the buoyancy of the hollow particles.

As a result of various experiments, the inventor has found that it is necessary to satisfy the following conditions as hollow ceramic particles which do not settle in the water layer and have a high oil absorbing ability. That is, the size of the hollow particles in the aggregate is practically 50 to 2000 microns, preferably 100 to 1000 microns approximately spherical, and the sphere diameter is related to the oil absorption capacity and oil absorption speed, The smaller the spherical diameter, the faster the oil absorption rate and the lower the oil absorption. If the diameter of the sphere becomes huge, both the size and volume of the space between the spheres become small, so both the oil absorption amount and the speed decrease. Since the bulk specific gravity of the aggregate is related to the volume of the hollow portion, it is proportional to the buoyancy and, as a result, to the degree of sedimentation in the water system. If the bulk specific gravity is 0.02 or less, the buoyancy will be unnecessarily large and the oil absorption capacity will decrease.On the contrary, if the bulk specific gravity is 0.20 or more, it will settle below the water surface as the oil absorption progresses, and in extreme cases, the water content in the oil absorption system Invasion will occur and the effectiveness as an oil absorbent will be reduced. The more preferable bulk specific gravity is 0.05 to 0.
Is 15.

Silicone oil or emulsion can be used as the water repellent agent. Above all, the emulsion system forms a uniform film, which is efficient and economical. A catalyst for controlling the curing rate of silicone is added to the silicone oil emulsion, and further water is added to adjust the concentration of silicone oil. The amount of silicone oil attached in a hollow shape is based on the weight of the hollow ceramic particles.
1 to 5%, preferably 1.5 to 3% is preferable. If it is 1% or less, uniform water repellency cannot be obtained, a part of low water repellency is recognized, and if it is 5% or more, the oil absorption capacity is saturated. It is uneconomical. The hollow ceramic particles having the water repellent emulsion attached to the surface are dried to remove water, and further heat treated at 100 to 170 ° C, preferably 120 to 150 ° C for the curing reaction of the water repellent. The heat treatment requires several minutes for each part.

The oil absorption method is characterized in that the oil content is adsorbed by contacting with an oil absorption material composed of hollow ceramic particles subjected to a water repellent treatment while applying mechanical energy to the water containing oil. The mechanical energy referred to here is the mechanical energy provided by any means that increases the chances of contact between the oil absorbent and the oil content in the oil-containing water, and means the energy provided by means such as stirring or convection. .

[0014]

The oil-absorbing material of the present invention is obtained by subjecting fine ceramic particles to a water-repellent treatment. As a function, it exhibits a high oil-absorption ability at a high speed in a system in which oil and water coexist, and further the oil absorption is increased. Also has a function of not floating below the surface of the water and floating on the surface of the water for a long period of time, and even if mechanical (dynamic) energy such as stirring is applied, it does not settle due to the presence of buoyancy.

Further, when the oil component after oil absorption is treated as waste by the incineration method, since the fire resistance of the ceramic is high and the morphology is stable, only the oil component is easily burned at the time of incineration. However, it can be recovered in a stable form even after incineration and can be reused.

Further, according to the method of adsorbing the oil content by bringing the oil-containing water into contact with the oil-absorbing material while applying mechanical energy to the oil-containing water, the chances of the oil content coming into contact with the oil-absorbing material are increased, and the adsorption treatment speed and time are improved. You can speed it up.

[0017]

EXAMPLES Next, specific examples will be shown, but various examples are conceivable within the scope of achieving the above-mentioned constitution and action, and therefore the present invention is not limited to these examples.

[0018]

[Example 1] A surface of a polystyrene foam having a diameter of 0.5 to 1.1 mm was mixed with a clayey mixture of 60% silica and 30% alumina mixed with an aqueous solution of sodium ligninsulfonate of 10% as a bonding agent. Was dusted to a thickness of 0.3 to 0.5 mm. Water was removed at 110 ° C, and sintering was performed in a furnace at 1280 ° C to obtain hollow particles. The shell thickness was 0.3-0.4 mm and the bulk specific gravity of the aggregate was 0.07.

A system was used in which organopolysiloxane had a chemical composition as a water repellent, and an organometallic salt was added as a catalyst thereto. For 100 parts of organopolysiloxane,
20 parts of catalyst and 1000 parts of water were added to 300 parts of silicone emulsion system to 100 parts of ceramic hollow particles and mixed so as to form a coating film uniformly on the surface. In the hot air dryer
It was dried at 110 ° C. to dryness and then heat treated in an air bath at 150 ° C. for 20 minutes with stirring. The rate of increase in weight indicating the amount of silicone oil deposited was 1.2%. The bulk specific gravity of the aggregate was 0.11. When this ceramic oil-absorbing material was put on the water liquid in which the heavy oil A was stored on the liquid surface, the heavy oil A rapidly adsorbed 11.5 times its own weight. When left in the room after oil absorption, the amount of oil absorption reached 13.8 times after 10 days, but it did not settle in water and floated on the liquid surface.

[0020]

[Example 2] Shirasu produced as volcanic debris in the southern Kyushu region was used as a raw material and was heated and expanded into a Shirasu foam having closed cells, and organopolyosiloxane 100
20 parts of the catalyst and 400 parts of the silicone emulsion of 1000 parts of water were added to 400 parts of 100 parts of the Shirasu foam, and mixed so as to form a film uniformly on the surface. The bulk specific gravity of the Shirasu foam was 0.09, and the particle size of 250-74 microns accounted for 85%. Drying and heat treatment were performed under the same conditions as in Example 1. The rate of increase in weight, which indicates the amount of silicone oil deposited, is 1.6%
Met. The bulk specific gravity of the aggregate was 0.10.

10 liters of water and 50 g of heavy oil A were placed in a tank equipped with a stirring blade, and 5 g of hollow ceramic particles were poured from the upper part to the liquid surface while stirring at 750 RPM. The hollow particles were drawn into the water by the energy of stirring, dispersed under the water surface and contacted with the droplets of the heavy oil A, which showed an adsorption phenomenon. When the stirring was stopped, the heavy oil A was adsorbed and concentrated on the liquid surface. The oil content of the oil-containing system before charging was 4870 mg / l, but the concentration of heavy oil A in the water portion below the bed of the adsorbent was 3.8 mg / l after 1 minute of stirring. The heavy fuel oil A floated in the tank and came into contact with hollow ceramic particles in the same water area to exhibit an adsorption phenomenon.

[0022]

The oil-absorbing material of the present invention has an extremely large oil-absorbing ability due to the above-mentioned constitution and action, and also absorbs moisture of the material generated over a long period of time on the water surface, shakes the liquid surface, and agitates. It is possible to stably position on the liquid surface without accompanying the sedimentation phenomenon from the liquid surface which occurs when receiving the energy of, and the oil absorbing ability is not lowered. In addition, since it has fire resistance, it can be reused after cooling by keeping its shape even when incinerating oil, and it can be reused. Although the collection and removal of waste oil and spilled oil have been described, the oil-absorbing material of the present invention can be widely used as an oil-absorbing material in general process such as separation of oil and water and other processes such as oil adsorption.

Claims (3)

[Claims] 1. An oil-absorbing material made of water-repellent hollow ceramic particles. 2. The bulk specific gravity of the hollow ceramic particles is 0.02 to 0.
The oil absorbing material according to claim 1, wherein the oil absorbing material is 20. 3. A method for absorbing oil, which comprises contacting an oil absorbing material composed of hollow ceramic particles subjected to a water repellent treatment to adsorb oil while applying mechanical energy to the oil containing water.