JP2005007392A - Method for increasing cavitation bubble by introducing solid material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for increasing cavitation bubbles by introducing solid materials and a means therefor, and the like. <P>SOLUTION: The method for increasing cavitation bubbles involves adding solid materials into a solution under ultrasonic irradiation. Furthermore, the above method is a method for promoting the generation of OH radicals and hydrogen peroxide by the above increased cavitation. A method for lowering a cavitation threshold is for lowering the cavitation threshold by increasing cavitation in a solution by the above method. An ultrasonic cleaning apparatus uses the above method. Accordingly, there can be provided the method for increasing cavitation by adding an optional solid material and a high-performance ultrasonic cleaning apparatus utilizing the method for increasing cavitation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for increasing cavitation bubbles in a liquid at the time of ultrasonic irradiation, and particularly relates to a method for increasing cavitation by adding a solid substance such as particles into the liquid.
In the technical field of the formation of cavitation bubbles in a liquid by ultrasonic irradiation and its application, the present invention has hitherto been related to the relationship between the addition (introduction) of solid substances and the formation of cavitation bubbles and the increase in cavitation and chemistry caused by the addition of solid substances Based on the fact that there is no scientific verification of the correlation of reaction volume increase, we will elucidate the relationship and develop and provide new applied technology based on it. For example, cavitation in chemical reaction systems The method of increasing the chemical reaction site by arbitrarily controlling the increase, and increasing the chemical reaction rate by generating OH (hydroxy) radicals and hydrogen peroxide in the reaction solution, and the above cavitation increasing method were used. This is useful for providing an ultrasonic cleaning apparatus.

  It is known that cavitation bubbles are generated at a certain strength (cavitation threshold) or more when ultrasonic waves are irradiated into a liquid. This cavitation repeats expansion and contraction according to the period of the ultrasonic wave, but when the sound pressure amplitude exceeds 1 atm, it causes a sudden contraction called compression fracture (crush), and it is several thousand degrees and several hundreds of atmosphere due to semi-adiabatic compression. While the extreme environment of high temperature and high pressure is generated in the region near the limited bubble for a short time, the macro maintains normal temperature and normal pressure. At the time of the collapse, the cavitation bubbles react with water to generate OH (hydroxy) radicals and hydrogen peroxide. As a result, various chemical reactions can be performed efficiently and in a short time.

  Therefore, this cavitation bubble can be expected to be applied to an environmental purification process for decomposing or detoxifying pollutants. In addition, since the shock wave propagates to the periphery of the bubbles, it is attracting attention as a new material creation method that promotes dissolution and precipitation by material transport and is energy-saving and has a low environmental load compared to conventional methods. Thus, cavitation can be expected to efficiently and quickly decompose or detoxify harmful substances, remove pollutants, detoxify malignant cells, and create materials. In addition to purification technology, cleaning technology, medical technology such as cancer treatment, and powder industry are envisaged.

  Until now, the following basic studies have been made on the effect of adding particles to the liquid under ultrasonic irradiation. Keck et al. Examined the effect of adding quartz particles, and showed that particles having a size of 3-5 μm are effective in producing hydrogen peroxide when irradiated with ultrasonic waves of 206 kHz (Non-patent Document 1). . Moreover, Sekiguchi and Saita have shown that the effect of improving the decomposition of chlorobenzene can be expected when alumina is added and the surface area is increased as the particle size increases (Non-patent Document 2). However, these are phenomenological studies of the effects of the generation or decomposition of specific components. The group of the present inventors verified the chemical reaction promoting effect using alumina, silica, titanium dioxide, iron oxide titanium dioxide, iron oxide silica-containing titanium dioxide as the additive particles to the liquid during ultrasonic irradiation. In particular, we examined the effect of adding alumina when the particle size was changed, and found that particles with a size of 20 μm are effective against chemical reactions when irradiated with ultrasonic waves at 42 kHz. It has gained.

  Further, examples of the prior art include the following. That is, a method for generating hydroxy radicals by irradiating ultrasonic waves in water in the presence of an oxide semiconductor catalyst (Patent Document 1), and a decomposition method using high-temperature and high-pressure generated by cavitation bubbles during ultrasonic irradiation. In addition, a catalyst in which a metal of Group VIII of the Periodic Table or an oxide thereof is supported on a support made of at least one of zeolite, porous titanium oxide, alumina, and silica is used as an additive catalyst, and an organic chlorine compound and / or ionic sulfur is used. There are a method of decomposing a compound (Patent Document 2) and a method of dispersing and dispersing titanium dioxide catalyst particles by ultrasonic waves (Patent Document 3). As described above, several methods for improving the reaction efficiency by irradiating a chemical reaction system to which a catalyst is added with ultrasonic waves have been proposed. However, these are also phenomena that capture the effects of improving the reaction efficiency by improving the dispersibility of the catalyst particles, and so far, for example, addition (introduction) of solid substances and formation of cavitation bubbles There has been no study on the relationship between the increase in cavitation due to the addition of solid substances and the correlation between the increase in the amount of chemical reaction, etc., and their relationship was completely unknown.

JP 2003-26406 A Japanese Patent Laid-Open No. 2000-300982 JP 2000-237771 A Keck A, Gilbert E, Koster R, "Influence of particles on sonochemical reactions in aqueous solutions", ULTRASONICS 40 (1-8): 661-665 MAY 2002 Sekiguchi H, Saita Y, "Effect of alumina particles on sonolysis degradation of chlorobenzene in aqueous solution", JOURNAL OF CHEMICAL ENGINEERING OF JAPAN 34 (8): 1045-1048 AUG 2001

Under such circumstances, the present inventors examined the correlation between an increase in cavitation due to the addition (introduction) of a solid substance (hereinafter referred to as a solid) and an increase in the amount of chemical reaction in view of the above-described conventional technology. As a result of overlapping, it was found that the presence of solids in the liquid under ultrasonic irradiation increased cavitation bubbles, and the present invention was completed.
The present invention relates to a method of increasing cavitation by adding (introducing) solids such as particles into the liquid during ultrasonic irradiation, causing the solid to exist in the liquid under ultrasonic irradiation, and increasing cavitation bubbles. It is intended to provide.

The present invention for solving the above-described problems comprises the following technical means.
(1) A cavitation increasing method characterized by increasing cavitation bubbles by causing a solid substance to be present in a liquid under ultrasonic irradiation.
(2) The method according to (1), wherein the generation of OH radicals and hydrogen peroxide is promoted by increasing the cavitation.
(3) The method according to (2), wherein the reaction sites in the chemical reaction are increased by promoting the generation of the OH radicals and hydrogen peroxide.
(4) The method according to (1), wherein metal ions are present in the liquid.
(5) The method according to (2), wherein the reaction rate of a chemical reaction is improved by increasing the number of reaction sites.
(6) A method for reducing a cavitation threshold, wherein the cavitation threshold is lowered by an increase in cavitation in the liquid according to the method described in (1).
(7) The method according to (1), wherein the cavitation increase rate is improved by increasing the surface area of the solid substance or by providing irregularities on the surface thereof.
(8) The method according to (1), wherein particles are added as a solid substance into the reaction solution as an external component of the predetermined reaction system.
(9) A method for increasing a shock wave and a microjet in a liquid, wherein the shock wave and the microjet associated with bubble contraction are increased by an increase in cavitation in the liquid according to the method described in (1) above.
(10) A method for increasing microstreaming in a liquid, comprising increasing microstreaming around bubbles by increasing cavitation in the liquid according to the method described in (1) above.
(11) A method for promoting dispersion or emulsification of a liquid, wherein the dispersion or emulsification of the liquid is promoted by increasing cavitation in the liquid by the method according to (1).
(12) A method for promoting dispersion of fine particles, comprising dispersing fine particles in a liquid by increasing cavitation in the liquid according to the method described in (1).
(13) The object to be cleaned is ultrasonicated using the method for increasing cavitation described in (1) above, which is to increase cavitation bubbles by causing a solid substance to exist in the liquid under ultrasonic irradiation. Cavitation bubbles for separating the ultrasonic cleaning bath having ultrasonic transducers capable of ultrasonic vibration, the first tank containing the treatment liquid and the additive particles, and the second tank containing the treatment liquid. An ultrasonic cleaning apparatus comprising: an inner tank provided with a permeable membrane as a constituent element; and an object to be cleaned is placed in a second tank containing the treatment liquid for ultrasonic cleaning.

Next, the present invention will be described in more detail.
The present invention relates to a cavitation increasing method characterized by increasing cavitation in a liquid by adding a solid to the liquid under ultrasonic irradiation. Conventionally, for example, it is known to irradiate a reaction solution containing catalyst particles or the like with ultrasonic waves. However, it is not known at all whether or not cavitation in the liquid is increased by adding a solid to the liquid. The present invention has been completed based on the novel finding that cavitation in a liquid is increased by adding a solid to the liquid under ultrasonic irradiation, as specifically shown in the examples described later. . In the present invention, for example, ceramic particles, metal particles, metal compound particles such as metal oxides, and the like are preferably used as the solid to be added. (Substance) can be used similarly. In the present invention, the method of adding a solid into a liquid under ultrasonic irradiation is, for example, a method of applying ultrasonic waves into a liquid to which a solid has been added in advance, or a method of adding solids into a liquid while performing ultrasonic irradiation. It can be carried out by the method, and the addition timing of the solid is not particularly limited. In the present invention, for example, a method in which a solid is separately added as an external component of a predetermined reaction system, that is, as a component other than the predetermined component constituting the reaction system is exemplified. It is not limited. Specifically, for example, in a predetermined chemical reaction system, a method of introducing a solid for the purpose of increasing cavitation in addition to predetermined components that essentially constitute the system is exemplified.

  The liquid to be irradiated with ultrasonic waves may be liquid other than gas and solid, and examples thereof include various chemical reaction systems, but are not limited thereto. That is, the method for increasing cavitation in a liquid of the present invention is applied to a method for increasing cavitation bubbles by ultrasonic irradiation in all types of liquids that are the targets of ultrasonic irradiation, regardless of the type and composition of the liquid. To get. In the method of the present invention, the size and form of the solid added to the liquid are not particularly limited as long as the solid itself can be a cavitation nucleus. Examples thereof include those having irregularities on the surface, those having protrusions or gaps on the particle surface, and particles having a large surface area.

  When ultrasonic waves are radiated into the liquid, cavitation bubbles are generated at a cavitation threshold value or more. However, when solids are added to the liquid, cavitation bubbles increase. The increase in cavitation promotes the generation of OH radicals and hydrogen peroxide, thereby increasing the reaction sites in the chemical reaction system and improving the chemical reaction rate. In this case, the presence of metal ions such as iron ions in the liquid further promotes them. Furthermore, in the present invention, the cavitation threshold can be lowered by increasing the cavitation, thereby making it possible to relax the irradiation conditions of the ultrasonic irradiation required to generate the predetermined cavitation. Can be an energy saving process.

  A sound wave received by an underwater microphone in the presence of ultrasonic waves is distorted by cavitation-derived noise when cavitation occurs in the liquid. This occurs because of a shift between the period of sound waves and the period of expansion and contraction of cavitation. In order to clarify this distortion, it is general that the received waveform is decomposed into Fourier components and shown as frequency characteristics of acoustic intensity. In this frequency characteristic, it is known that the existence of cavitation can be proved if a component (subharmonic component) at a frequency 1/2, 3/2, 5/2,... N / 2 times the fundamental wave exists. (N: odd number). As cavitation increases, each of these components increases. In addition, due to the presence of the shock wave radiated into the liquid around the bubbles when the cavitation collapses, the sound intensity increases not only at a specific frequency, but when the cavitation increases, an overall increase occurs.

  In the present invention, the chemical reaction rate can be increased by increasing the number of cavitation bubbles. As a method for increasing cavitation bubbles, in the present invention, for example, particles are added. When the added particles are about 0.1 μm, even if the presence of the particles becomes cavitation nuclei or has a size larger than that, If there are protrusions or gaps on the particle surface, it becomes a cavitation nucleus. That is, cavitation nuclei increase due to the addition of particles, so that the cavitation threshold can be lowered compared to the case without particles.

  In the present invention, as shown in the examples described later, with respect to the increase in cavitation due to the addition of solids in the solution under ultrasonic irradiation, measurement of cavitation noise and absorbance related to iodine ion precipitation reaction from aqueous potassium iodide solution The study was conducted by measuring. As a result of noise measurement, the effect of increasing cavitation was also detected in particles containing photocatalyst and alumina alone, silica alone, Teflon (registered trademark), molecular sieve, Muskmelon D-50 (ceramics-coated titanium dioxide), etc. not containing photocatalyst It can be said that the same effect can be expected by adding any solid substance. Similarly, an increase in absorbance can be detected in a chemical reaction, confirming an increase in reaction sites due to an increase in cavitation due to solid addition. Therefore, solid addition during ultrasonic irradiation brings about chemical reaction promotion, which is considered to contribute to technological development such as environmental purification, cleaning, and material creation. In the present invention, by increasing the number of cavitation bubbles in the liquid, the shock wave and the microjet in the liquid accompanying the bubble contraction are increased, the microstreaming around the bubbles is increased, for example, the dispersion of the heterogeneous liquid or the liquid Can be emulsified, and dispersion of fine particles in the liquid can be promoted.

  Furthermore, in the present invention, the object to be cleaned is ultrasonically cleaned using the cavitation increasing method comprising increasing the cavitation bubbles by the presence of a solid substance in the liquid under ultrasonic irradiation according to the present invention. A cavitation bubble permeable membrane for separating an ultrasonic cleaning bath having an ultrasonic transducer capable of ultrasonic vibration, a first tank containing a treatment liquid and additive particles and a second tank containing a treatment liquid. The ultrasonic cleaning apparatus is characterized in that an object to be cleaned is placed in a second tank containing the treatment liquid and ultrasonic cleaning is performed. In this case, the cavitation bubble permeable membrane has a function of permeating the cavitation bubbles and not allowing the additive particles to permeate, and can transfer the cavitation bubbles into the second tank containing the treatment liquid, thereby preventing the additive particles from moving. Any type can be used, and the type is not particularly limited. Also, the method and means for forming the cavitation bubble permeable membrane in the inner tank are not particularly limited. Further, examples of the objects to be cleaned include glasses, jewelry, and the like, but are not limited to these, and any object can be used as long as ultrasonic cleaning is possible. Furthermore, in the present invention, the type, shape and structure of the ultrasonic vibrator, ultrasonic cleaning bath, cavitation bubble permeable membrane, inner tank are not particularly limited, depending on the purpose of use, Can be designed arbitrarily.

  According to the present invention, 1) cavitation bubbles in the liquid under ultrasonic irradiation can be increased, 2) generation of OH radicals and hydrogen peroxide can be improved by increase of cavitation bubbles, and 3) increase of cavitation bubbles. The reaction sites in chemical reactions increase, 4) The addition of titanium dioxide-containing particles, or the presence of iron ions in the liquid can be expected to significantly increase the reaction sites. 5) The increase in cavitation bubbles Shock waves and micro jets associated with bubble contraction can be increased, and improvement of mass transport and solid surface cleaning using these can be achieved. 6) Increased cavitation bubbles increase micro-streaming, shock waves and OH radicals around bubbles. And pathogen cells produced by the production of oxidants such as hydrogen peroxide. It can be expected to improve various biological actions such as disinfection and sterilization, 7) can improve the dispersion and emulsification action of heterogeneous media, and can improve the dispersion action of fine particles, 8) high performance using the above cavitation increasing method The effect that an ultrasonic cleaning apparatus can be provided is produced.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

  In this example, in order to verify the effect of increasing cavitation due to the addition of various solids to the liquid under ultrasonic irradiation, cavitation noise was measured to estimate the rate of increase in cavitation, and iodine from an aqueous potassium iodide solution was measured. Absorbance measurements on ion precipitation were performed. FIG. 1 shows a scheme of the apparatus used in this example. As an ultrasonic irradiation device, an ultrasonic cleaning bath 2 (Branson, 1510J-MT, 42 kHz, 70 W) was used. 1 ml of pure water was put into the test tube 3 (IWAKI GLASS, 13 × 100 mm), and the height of the surface of the sample liquid was adjusted to the level of the bath water surface, and fixed to the center of the bath. In the figure, ultrasonic waves were radiated from the ultrasonic transducer 1 into the ultrasonic cleaning bath 2 and transmitted to the inside of the test tube 3 immersed in the bathtub 2 to generate cavitation in the liquid containing solids. The irradiation time was 1 minute, and the bath water temperature was adjusted to 20 ° C.

As additive solid particles, alumina Al ₂ O ₃ polishing (20 μm), alumina Al ₂ O ₃ spherical admafine (10 μm), Teflon (registered trademark), molecular sieve, mask melon D-50 (2 μm), mask melon D- 50 (5 μm), muskmelon D-50 (40 μm), titanium dioxide p-25 (10 μm), iron oxide-containing titanium dioxide KMA042 (10 μm), iron oxide silica-containing titanium dioxide Fe ₂ O ₃ —SiO ₂ —TiO ₂ was used. The amount of each particle added was 40 mg.

An underwater microphone (RESON, TC4038, 4 mmφ) is immersed in the liquid, and the received sound pressure waveform is converted into a Fourier spectrum by a spectrum analyzer (SONY Tektronix, 3026, 3 GHz), thereby generating noise (intensity) corresponding to the frequency of occurrence of cavitation. City). FIG. 2 shows a frequency characteristic of noise when the added solid particles are iron oxide silica-containing titanium dioxide Fe ₂ O ₃ —SiO ₂ —TiO ₂ as a measurement example. It can be seen that the subharmonic component is more prominent in the case with particles than in the case without particles.

Next, the noise increase rate due to the presence or absence of solid particles was estimated. Noise growth rate, defined below, were calculated by the formula I _N representing using a and b in the frequency with the measuring range. Here, the sum Σ was performed for the measured frequency range.
a = {(value of noise when no particles are included) − (minimum value of noise when particles are not included)}
b = {(value of noise when particles are included) − (minimum value of noise when particles are not included)}
I _N = Σb / Σa (1)

  Table 1 shows the cavitation noise increase rate calculated by Equation (1) using the measured noise value for each added solid particle. A value greater than 1 was shown in all cases of added solid particles. Since cavitation increased in all cases, it can be said that the addition of arbitrary solid particles has an effect of increasing cavitation regardless of the type of solid particles. Further, in the case of the mask melon particles shown in the second row of Table 1, noise tends to increase as the particle size increases, which is considered to be caused by an increase in surface area. When the titanium dioxide shown in the third stage of Table 1 was included, the increase rate was relatively large as compared with the case where the upper two stages of titanium dioxide were not included.

In this example, in order to examine the quantification of the amount of chemical reaction by ultrasonic irradiation at the time of adding solid particles, the absorbance measurement was performed using the precipitation reaction of iodine ion I ₃ ^{− in} the ultrasonically irradiated potassium iodide aqueous solution. It was. An absorbance meter (JASCO, V-530) was used for measuring the absorbance. I ₃ ⁻ shows a characteristic peak at 350 nm. The ultrasonic irradiation apparatus and the test tube were the same as those in Example 1. 1 ml of the sample solution was put in a test tube, and the height of the surface of the sample solution was adjusted to the level of the water surface of the bath, so that the center of the bath was fixed. The irradiation time was 1 minute, and the bath water temperature was adjusted to 20 ° C. As the added solid particles, silica SiO ₂ nanoparticles, alumina Al ₂ O ₃ polishing (20 μm), titanium dioxide p-25, iron oxide-containing titanium dioxide KMA042, iron oxide silica-containing titanium dioxide Fe ₂ O ₃ —SiO the ₂ -TiO ₂ was used.

  In this example, since a UV lamp was not used, there was almost no effect of the photocatalyst, and the investigation was mainly related to the effect derived from ultrasonic cavitation. Prior to the absorbance measurement, the reaction solution was subjected to solid-liquid separation using a centrifuge (AS ONE, CN-1050). Table 2 shows the rate of increase in the absorbance of the reaction solution in each particle. Here, the rate of increase in absorbance was defined as the ratio of the reaction solution irradiated with ultrasound in the absence of particles to the absorbance (control). As shown in Table 2, an increase rate of 1 or more was detected in all cases. This confirms the increase in reaction sites due to the increase in cavitation due to the addition of particles.

However, in this example, since the amount of added particles is relatively small, an increase in cavitation is obtained in all examples. However, when the added amount is large, sound waves are shielded by particles and cavitation becomes difficult, so the rate of increase Is considered to be less than 1. Those containing titanium dioxide showed relatively high values compared to the other cases, but this was not only a direct contribution due to an increase in OH radicals and an increase in hydrogen peroxide with an increase in cavitation, but also an excessive amount. It seems that titanium oxide is generated on the particle surface. In addition, a dramatic increase in iron oxide silica-containing titanium dioxide Fe ₂ O ₃ —SiO ₂ —TiO ₂ has been observed due to the presence of iron (ions) in the solution. It is thought that OH radicals by Fenton reaction between iron ions and hydrogen peroxide can contribute (Yim BB, Yoo YG, Maeda Y, "Sonolysis of alkylphenols in aqueous solution with Fe (II) and Fe (III)", CHEMOSPHERE 50 (8): 1015-1023 MAR 2003).

In this example, in order to examine the quantification of the amount of chemical reaction by ultrasonic irradiation at the time of particle addition, absorbance measurement was performed using the precipitation reaction of iodine ions I ₃ ^{− in} an aqueous solution of potassium iodide irradiated with ultrasonic waves. went. The additive particles are abrasive alumina particles. 1) When the particle diameter is fixed at 10 μm and the addition amount is changed (FIG. 3), 2) When the addition amount is fixed at 20 mg and the particle diameter is changed About (FIG. 4), the increase rate of the reaction by the presence or absence of particle | grains was measured, respectively. The results are shown in FIG. 3: dependence of the chemical reaction increase rate due to the addition of particles on the amount of added particles, and FIG. 4: dependency of the chemical reaction increase rate due to the addition of particles on the particle diameter. From FIG. 3, it was found that if the amount added was too large, the rate of increase would decrease. This is presumably because the amplitude of the ultrasonic wave is lowered due to the presence of excessive particles. From FIG. 4, it seems that if the particle diameter is too small, the effect is not seen, but this is considered to be because I ₃ ⁻ ions to be detected are adsorbed on the particles. It was found that under an appropriate addition amount, the effect of increasing the increase rate can be expected almost independent of the particle size.

  In this example, an ultrasonic cleaning apparatus for cleaning an object to be cleaned was constructed using the cavitation increasing method of the present invention. FIG. 5 shows an example of the cleaning apparatus constructed in this example. This cleaning apparatus includes an ultrasonic cleaning bath 2 in which an ultrasonic vibrator 1 is installed at the bottom so as to be capable of ultrasonic vibration, a first tank 4 containing a processing liquid and additive particles, a second tank 5 containing a processing liquid, It is comprised from the inner tank 6 provided with the cavitation bubble permeable membrane for dividing a 1st tank and a 2nd tank, and the peripheral device (not shown) for operating the said ultrasonic transducer | vibrator. As the additive particles, alumina particles having a particle diameter of 10 μm were used. Further, the cavitation bubble permeable membrane used had a specific network structure through which cavitation bubbles permeated and the alumina particles did not permeate. The ultrasonic vibrator of this apparatus is vibrated to generate cavitation bubbles, the cavitation bubbles are increased in the first tank 4 containing the treatment liquid and the added particles, and this is introduced into the inner tank 6 through the cavitation bubble permeable membrane. I migrated. In this state, the glasses were inserted into the inner tub 6 and the eyeglass cleaning test was attempted. As a result, the cleaning time was reduced to about half or less compared to the case where the same test was performed using a conventional ultrasonic cleaning device. It was found that it can be greatly shortened.

  As described above in detail, the present invention relates to a method for increasing cavitation bubbles by introducing solids, and the present invention can increase cavitation bubbles in a liquid under ultrasonic irradiation. The increase of cavitation bubbles can improve the generation of OH radicals and hydrogen peroxide. The increase of cavitation bubbles increases the reaction site in the chemical reaction. The addition of titanium dioxide-containing particles or the presence of iron ions in the liquid can be expected to significantly increase the reaction site. By increasing the number of cavitation bubbles, it is possible to increase shock waves and micro jets associated with the bubble contraction, and to improve the material transport and the solid surface cleaning action using these. The increase in cavitation bubbles can be expected to improve biological effects such as killing and sterilization of pathogen cells due to microstreaming around the bubbles, shock waves, OH radicals, and generation of oxidizing agents such as hydrogen peroxide. The dispersion and emulsifying action of the heterogeneous medium can be improved, and the dispersing action of the fine particles can be improved. It is possible to provide a high-performance ultrasonic cleaning apparatus that greatly improves the cleaning effect as compared with conventional ultrasonic cleaning apparatuses.

FIG. 1 shows a scheme of an ultrasonic irradiation apparatus. FIG. 2 shows the increase in cavitation noise (intensity) due to the addition of particles. The dependence of the chemical reaction increase rate due to the addition of particles on the amount of added particles is shown. The particle diameter dependence of the chemical reaction increase rate by particle addition is shown. An example of an ultrasonic cleaning apparatus is shown.

Explanation of symbols

1: Ultrasonic vibrator 2: Ultrasonic cleaning bath 3: Test tube containing treatment liquid and additive particles 4: First tank containing treatment liquid and additive particles 5: Second tank containing treatment liquid 6: Cavitation bubble permeation Inner tank with membrane 7: Object to be cleaned

Claims (13)

  A cavitation increasing method characterized by increasing cavitation bubbles by causing a solid substance to exist in a liquid under ultrasonic irradiation.   2. The method according to claim 1, wherein the generation of OH radicals and hydrogen peroxide is promoted by increasing the cavitation.   3. The method according to claim 2, wherein reaction sites in a chemical reaction are increased by promoting generation of the OH radical and hydrogen peroxide.   2. The method according to claim 1, wherein metal ions are present in the liquid.   The method according to claim 2, wherein the reaction rate of a chemical reaction is improved by increasing the number of reaction sites.   A method for lowering a cavitation threshold, wherein the cavitation threshold is lowered by an increase in cavitation in the liquid according to the method according to claim 1.   2. The method according to claim 1, wherein the cavitation increase rate is improved by increasing the surface area of the solid substance or by providing irregularities on the surface thereof.   2. The method according to claim 1, wherein particles are added as a solid substance into the reaction solution as an external component of the predetermined reaction system.   A method for increasing a shock wave and a micro jet in a liquid, wherein the shock wave and the micro jet accompanying bubble contraction are increased by increasing cavitation in the liquid according to the method of claim 1.   A method for increasing microstreaming in a liquid, comprising increasing the microstreaming around bubbles by increasing cavitation in the liquid according to the method of claim 1.   A method for promoting dispersion or emulsification of a liquid, wherein the dispersion or emulsification of the liquid is promoted by increasing cavitation in the liquid by the method according to claim 1.   A method for promoting dispersion of fine particles, comprising dispersing fine particles in a liquid by increasing cavitation in the liquid according to the method according to claim 1. A means for ultrasonically cleaning an object to be cleaned using the cavitation increasing method comprising increasing a cavitation bubble by causing a solid substance to exist in a liquid under ultrasonic irradiation according to claim 1. An ultrasonic cleaning bath equipped with an ultrasonic transducer capable of ultrasonic vibration, a cavitation bubble permeable membrane for separating a first tank containing a treatment liquid and additive particles and a second tank containing a treatment liquid An ultrasonic cleaning apparatus characterized in that an inner tank is included as a component, and an object to be cleaned is placed in a second tank containing the treatment liquid to perform ultrasonic cleaning.

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