JPS6341616B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for cleaning activated carbon for body fluid purification, which is used as it is without coating for use in artificial livers, artificial kidneys, etc. Conventionally, the activated carbon used in DHP columns for assisting artificial livers and artificial kidneys are coconut shell activated carbon and petroleum pitch activated carbon, but in most cases, this is not used as is, but the activated carbon is coated with collodion, hydrogel, cellulose, etc. on the surface. It is coated with a polymer membrane. The reason for coating is
This is to prevent fine particles (coal dust) from escaping from the activated carbon, as well as to prevent the adhesion of blood cells and the formation of blood clots caused by the fine particles, thereby imparting biocompatibility to the activated carbon. However, coated activated carbon has a low adsorption capacity because its surface is covered with a polymer film, and as a result, the amount of activated carbon used is large, making the device larger, and as a result, the amount of priming is large, making it difficult to perform extracorporeal circulation It places a heavy burden on patients and poses safety problems. Moreover, some organic solvent used during coating remains on the coated activated carbon, and the coating agent may be eluted during autoclave sterilization or long-term storage, which may have an adverse effect on living organisms. Apart from these, there is also a method in which uncoated coconut shell activated carbon is adhered to a tape to prevent the escape of fine particles. Since this product is not coated, it has a high adsorption capacity, but the equipment is complicated and the cost is high.Furthermore, since it uses an adhesive, there is a risk that impurities may be eluted from the adhesive when it comes into contact with blood. As described above, all conventional activated carbons for blood purification have problems with adsorption ability or biocompatibility. Therefore, the inventor conducted research to solve these problems, and as a result found the following. In other words, among activated carbons, coconut shell activated carbon has a very uneven surface and an extremely large amount of fine particles, but compared to this, oil pitch activated carbon has a smooth surface and a small amount of fine particles, and this activated carbon can be washed thoroughly. It was found that when the fine particles were peeled off and removed, there was no problem with biocompatibility even if the particles were used as they were without coating. The present invention has been made based on such knowledge, and it is possible to use activated carbon as it is without coating it to efficiently clean body fluids by effectively utilizing the cleaning liquid. The present invention provides a method for cleaning activated carbon for purification. That is, in the present invention, when cleaning petroleum pitch activated carbon with an ultrasonic cleaning machine to peel off and remove fine particles attached to the petroleum pitch activated carbon, a cleaning solution containing the fine particles removed from the petroleum pitch activated carbon with the cleaning machine is first washed. A step of filtering the fine particles to a predetermined size using a second filtering device, a step of further filtering the fine particles to a smaller size using a second filtering device, and a step of cleaning the fine particles in the first and second filtration steps. This method of cleaning activated carbon for body fluid purification is characterized by comprising a step of returning the cleaning liquid to the cleaning machine for circulation use. The present invention also provides an ultrasonic cleaning machine capable of storing a cleaning liquid and petroleum pitch activated carbon to be cleaned, and further having ultrasonic transmitting means, a cleaning liquid circulation circuit that communicates with the inside of the cleaning machine and circulates the cleaning liquid, and a cleaning liquid circulation circuit that communicates with the inside of the cleaning machine and circulates the cleaning liquid. a first filtration device that communicates with the inside of the circuit and filters particles contained in the cleaning solution to a predetermined size; and a second filtration device that further filters the particles to a smaller size. This is an activated carbon cleaning device for body fluid purification characterized by comprising a filtration device. The method and apparatus of the present invention will now be described with reference to illustrative embodiments. Figure 1 is an explanatory diagram showing the cleaning equipment used in this method. A cleaning liquid circulation path 5 is formed in. The ultrasonic cleaning machine 1 has a liquid inlet section 8 with a mesh and a liquid outlet section 9 of the cleaning liquid circulation path 5 disposed in a bathtub 7 equipped with an ultrasonic vibrator 6, and further has a stirring section driven by a motor 10. A propeller 11 is provided. This bath layer 7 is filled with a cleaning liquid 12 such as physiological saline, distilled water, dextran, etc., and petroleum pit activated carbon 13 is placed therein. The activated carbon 13 is preferably one that has high purity and hardness, and has few stray particles. Also, the first passing device 3 is
It is equipped with a 5μ cartridge filter, and the second filter device 4 is equipped with a 1μ cartridge filter. In this cleaning device, the ultrasonic vibrator 6 is operated to remove and clean fine particles and impurities adhering to the oil pit activated carbon 13, and during this cleaning, the propeller 11 is rotated to stir and improve the cleaning effect. The cleaning liquid 12 containing particulates and impurities flows into the first and second filtration devices 3 and 4 through the liquid inlet 8 by the action of the pump 2 . In the first filtration device 3, fine particles and impurities of 5μ or more are removed, and in the second filtration device 4, fine particles and impurities of 1μ to 5μ are removed, and the thus cleaned cleaning liquid 1
2 is returned into the bathtub 7 through the liquid outlet section 9.
In this way, the petroleum pit activated carbon 13 is thoroughly washed while using the cleaning liquid 12 in circulation. In this cleaning method, the cleaning conditions vary depending on the properties of the activated carbon, characteristics of the equipment, scale, etc., but normally when cleaning 1 kg of petroleum pitch activated carbon, the flow rate is
Run at 0.5 to 5.0/min for about 1 to 4 hours to reduce the number of particles of 2μ or more in the cleaning solution to 100 particles/ml or less.
Purify the number of particles with a size of 5μ or more to 0/ml. After repeating decantation washing several times, the petroleum pit activated carbon 13 that has been thoroughly ultrasonically cleaned in this manner is filled into a column 14 as shown in Fig. 2, and sterilized in an autoclave to produce an artificial liver and an artificial kidney. A blood purification device for use is obtained. This device has the function of removing middle-molecular poisons and organic substances contained in the blood, such as creatinine, inulin, agricultural chemicals, and sleeping pills, by adsorbing them onto the activated carbon 13. In this case, since fine particles and impurities have been peeled off and removed from the petroleum pitch activated carbon 13, blood cells such as platelets hardly adhere thereto, and the fine particles do not flow into the living body, preventing the formation of blood clots. Its biocompatibility can be similar to that of conventional coatings. Moreover, since it is not coated, the adsorption capacity is high and the device can be miniaturized, and problems such as residual organic solvent and elution of the coating agent due to coating can be solved. Furthermore, petroleum pitch activated carbon is similar to graphite, which has been evaluated as an antithrombotic material, and from this point of view, it is advantageous to use petroleum pitch activated carbon as it is without coating. In addition, in the present invention, petroleum pitch activated carbon is used,
The reason why coconut shell activated carbon was not used is as follows. In other words, coconut shell activated carbon has a highly uneven surface and contains many fine particles, and its hardness is so low that it is practically impossible to remove it by ultrasonic cleaning, whereas oil pitch activated carbon has a smooth surface. This is because there are few fine particles and the hardness is high, so they can be easily peeled off and removed by ultrasonic cleaning. In the above embodiment, fine particles were removed using 2μ and 5μ cartridge filters, but the present invention is not limited to this combination, nor is the number of cartridge filters to be limited to this. Furthermore, the filtration device is not limited to a cartridge filter, but may be any device capable of removing particulates and impurities, such as a reverse osmosis device or an ultrafiltration device. Furthermore, the column filled with petroleum pit activated carbon can be used not only for blood washing but also for purifying the liquid separated by, for example, a blood filtering device for an artificial kidney. Next, examples of the method of the present invention will be described. In the cleaning apparatus shown in Fig. 1, a Solid State 600 manufactured by Ultrasonic Industries Co., Ltd. is used as an ultrasonic cleaning machine, and a cartridge filter (1μ
and 5 μ), put 1 kg of petroleum pitch activated carbon (BAC-MU-ND-LE, manufactured by Kureha Chemical Co., Ltd., trade name) into this ultrasonic cleaner, add sterile physiological saline solution, and wash at a flow rate of 3/min. Washed continuously for 3 hours. When each cartridge filter was observed after completing this cleaning operation, it was found that the filters turned black due to the escaped particles, and it was confirmed that the particles were captured there. In addition, the number of particles in the physiological saline flowing out from the liquid outlet was measured using a Coulter counter (Model ZB, manufactured by Coulter Electronics, Incorporated).The results showed that the number of particles larger than 2μ was less than 100 particles/ml, and the number of particles larger than 5μ was 100 particles/ml. 0 pieces/ml
It was clean and warm. Furthermore, as a result of scanning electron micrographs of the activated carbon surface before and after cleaning, it was found that many fine particles were scattered on the surface of the activated carbon before cleaning, as shown in Figure 3, while that of the activated carbon after cleaning was shown in Figure 4. As shown, no fine particles were observed, indicating that sufficient cleaning was possible. Petroleum pitch activated carbon 100 washed in this way
g was packed into a column and sterilized in an autoclave. After that, a clean physiological saline solution that had been passed twice through a pore membrane filter (0.22μ) was flowed through this column at a flow rate of 200 ml/min, and after 5 minutes, the particles in the physiological saline solution that had flowed out were measured using a Coulter counter. The results are shown in Table 1. Next, an AV shunt was created in the carotid artery and vein of a 24-28 kg mongrel dog, and the whole body was heparinized to form a blood circulation circuit for an artificial kidney.The above column was connected to this circuit, and an extracorporeal circulation experiment was performed. . Fluctuations in the number of platelets during the extracorporeal circulation experiment were measured, and the results are shown in the graph of FIG. 5 by broken line _a1 . In addition, vitamin
A solution of 20 mg/dl B ₁₂ was flowed in a single pass at a flow rate of 200 ml/min. Measure the change in clearance K _T at this time, and plot the results as a broken line in the graph of Figure 6.
Indicated by a ₂ . The clearance K _T is expressed by the formula below. T _T = C _i − C ₀ / C _i ×Q _B where K _T : Clearance (ml/min) C _i : Column inlet concentration (mg%) C ₀ : Column outlet concentration (〃) Q _B : Liquid flow rate (ml /min) Comparative Example Using poly-hydroxyethyl methacrylate as a coating agent, this coating agent 15
After putting 1 kg of petroleum pitch activated carbon into 2 ml of ethanol and dissolving it by heating, 1 kg of petroleum pitch activated carbon was added and the ethanol was evaporated under hot air. After the solution had run out, the mixture was left in an oven at 90°C for 2 days to produce coated petroleum pit activated carbon. 100 g of the activated carbon thus obtained was packed into a column and sterilized in an autoclave in the same manner as in the example. After that, a physiological saline solution was poured in to measure the particulates in the solution, and the results are also listed in Table 1. . Similar experiments were also conducted using petroleum pit activated carbon that was not washed in the above example, and the results are also shown in Table 1. Furthermore, the same extracorporeal circulation experiment as in the above example was conducted using a column packed with coated petroleum pit activated carbon and _a column packed with unwashed petroleum pitch activated carbon. It is shown by broken line C (not washed). Further, the change in clearance was measured for the coated material under the same experimental conditions as in the example, and the results are shown in FIG. 6 by broken line _b2 .

[Table] From Table 1 and Fig. 5, the petroleum pit activated carbon according to the method of the present invention does not release fine particles or cause a small decrease in platelets even when used as it is without coating, and is superior to conventional methods in terms of biocompatibility. It was confirmed that there was no inferiority to that coated with . Furthermore, from the experimental results shown in FIG. 6, it was confirmed that by using the petroleum pit activated carbon according to the method of the present invention, the clearance could be maintained higher than that of the coated carbon, and the adsorption capacity was significantly improved to about twice that. As explained above, according to the method of the present invention, petroleum pitch activated carbon, which is used without coating, can be cleaned efficiently and by effectively utilizing the cleaning liquid. Moreover, since the petroleum pitch activated carbon obtained by this method is used without being coated, it has a high adsorption capacity and the device can be made smaller.As the device is made smaller, the amount of priming is reduced, and the burden on the patient during extracorporeal circulation can be reduced. In addition, the problem of organic solvent residue and coating agent elution due to coating can be solved.Furthermore, since the amount of activated carbon used is small, costs can be reduced, and since there is no coating operation, there are fewer production steps, making production easier. It has various remarkable effects. Furthermore, according to the apparatus of the present invention, the method of the present invention having the above effects can be carried out reliably and easily.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the cleaning device used in the method of the present invention, FIG. 2 is a schematic sectional view showing a column filled with petroleum pitch activated carbon cleaned by the method of the present invention, and FIG. The figure is a micrograph of petroleum pitch activated carbon observed before washing using a scanning electron microscope. Figure 4 is a micrograph of petroleum pitch activated carbon observed after washing using a scanning electron microscope.
Figure 6 is a characteristic diagram showing the changes in the amount of platelets over time using the same column as a broken line along with that of a comparative example. FIG. 1... Ultrasonic cleaner, 2... Pump, 3... First filtering device, 4... Second filtering device, 12...
Cleaning liquid, 13... Petroleum pitch activated carbon, 14... Column.

Claims (1)

[Scope of Claims] 1. When cleaning petroleum pit activated carbon with an ultrasonic cleaner to peel off and remove fine particles attached to the petroleum pitch activated carbon, a cleaning solution containing the fine particles removed from the petroleum pitch activated carbon with the cleaning machine is used. a step of filtering fine particles to a predetermined size using a first filtration device;
It consists of a step of further filtering the fine particles to smaller particles in a second filtration device, and a step of returning the cleaning liquid cleaned in the first and second filtration steps to the washing machine for circulation use. A method for cleaning activated carbon for body fluid purification, characterized by: 2. An ultrasonic cleaning machine capable of storing cleaning liquid and petroleum pitch activated carbon to be cleaned, and further having ultrasonic transmitting means, a cleaning liquid circulation circuit that communicates with the interior of the cleaning machine and circulates the cleaning liquid, and an ultrasonic cleaning machine installed in the circuit. A cleaning liquid circulation pump, a first filtration device that communicates with the inside of the circuit and filters particulates contained in the cleaning liquid to a predetermined size, and a second filtration device that further filters the particulates to a smaller size. An activated carbon cleaning device for body fluid purification characterized by: