JP2005329326A - Harmful gas removing adsorbent and absorption can using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adsorbent capable of effectively removing a specific harmful substance regulated by the soil pollution control law. <P>SOLUTION: The adsorbent is prepared by depositing an iodine compound further on activated carbon which has 500 cm<SP>2</SP>/g specific surface area and on which a copper compound, a silver compound, chromium compound and if need, triethylene diamine are deposited . <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an adsorbent for removing harmful gases and an absorbent can using the same, and more particularly to an adsorbent for adsorbing and removing specific harmful substances regulated by the Soil Contamination Countermeasures Law and an absorbent can using the adsorbent.

  The use of activated carbon to remove harmful gases has long been known. Also known are adsorbents in which various reactive substances are supported (impregnated / attached) on activated carbon for the purpose of removing harmful gases that cannot be removed by activated carbon alone by physical adsorption and chemical reaction. Examples of known publications disclosing the latter include Patent Literature 1, Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, Patent Literature 7, Patent Literature 8, Patent Literature 9, Patent Literature. 10, Patent Document 11, Patent Document 12, Patent Document 13, Patent Document 14, and Patent Document 15. These are effective in removing specific harmful gases (including steam) such as mercury, but are difficult to use for objects that can contain various harmful gases such as harmful gases from contaminated soil.

  So far, no adsorbent has been developed that can handle almost or all of the harmful gases indicated in the current Soil Contamination Countermeasures Law.

Japanese Patent Publication No. 1-57618 Japanese Patent Publication No. 1-59009 Japanese Patent Publication No. 1-59010 Japanese Patent Publication No.2-11300 Japanese Patent Publication No. 2-50771 Japanese Patent Publication No. 4-24092 Japanese Examined Patent Publication No. 4-24093 Japanese Examined Patent Publication No. 4-64734 Japanese Patent Publication No. 8-17938 Japanese Patent No. 3453923 Japanese Patent Laid-Open No. 61-238337 JP 62-114632 A Japanese Patent Laid-Open No. 3-114534 JP-A-9-239265 Japanese Patent Laid-Open No. 10-174842

  An object of the present invention is to provide an adsorbent and an absorption can which can be applied to the general removal of gaseous substances of specific organic substances regulated by the Soil Contamination Countermeasures Law (toxic gases including steam, hereinafter referred to as harmful gases) and soil. The object is to provide an absorption can that can be applied to the removal of all specified hazardous substances regulated by the Pollution Control Law.

A first aspect of the present invention is a harmful gas removing adsorbent characterized in that an iodine compound is further supported on activated carbon having a specific surface area of 500 cm ² / g or more formed by supporting a copper compound, a silver compound and a chromium compound. .

  Secondly, the present invention has a copper compound loading of 7 to 10 wt%, a silver compound loading of 0.01 to 0.5 wt%, and a chromium compound loading of 1 to 3 wt%, The adsorbent is an iodine compound loaded in an amount of 1 to 2% by weight.

  Thirdly, the present invention is the above adsorbent in which 3% by weight or less of triethylenediamine is previously supported on activated carbon in addition to the copper compound, the silver compound and the chromium compound.

  Fourthly, the present invention provides a gas mask absorbent can characterized by containing the above-mentioned adsorbent.

  5thly this invention is said absorption can which comprises the filter for dust prevention.

  According to the present invention, it is possible to effectively remove specific harmful substances regulated by the Soil Contamination Countermeasures Law, and it is possible to improve the safety of workers in processing work of contaminated soil.

The adsorbent of the present invention is a product in which an iodine compound is further supported on activated carbon having a specific surface area of 500 cm ² / g or more, which is previously supported (synonymous with impregnation / attachment) with a copper compound, a silver compound, a chromium compound, and optionally triethylenediamine. However, the activated carbon itself before loading the iodine compound has a capacity of 50 cc and is a national certification standard (gas mask regulations, Occupational Safety and Health Act (Act No. 57 of 1972), No. 42 as a direct-attached small gas mask can for organic gas. No .: Revision of September 18, 2001, Ministry of Health, Labor and Welfare Notification No. 299).

  The amount of each supported component is 7.0 to 10.0% copper compound, 0.01 to 0.5% silver compound, 1.0 to 3.0% chromium compound, 0.0 to 3.0% triethylenediamine. Is preferred.

  The loading of the copper compound, silver compound, and chromium compound can be appropriately performed by a known method. Usually, it is supported by impregnating activated carbon into an aqueous solution of the above water-soluble metal salt that generates decomposition gas by heating, such as sulfate, nitrate, carbonate, and the like, followed by drying and heat treatment. The above metal components and triethylenediamine are usually impregnated in the form of a mixture.

  In the present invention, it is important to support the iodine compound after supporting the above components on activated carbon in advance.

  Examples of the iodine compound further supported on the activated carbon on which the above components are previously supported include copper iodide, silver iodide, sodium iodide, potassium iodide and the like, and these are usually supported in the form of an aqueous solution. The supported amount is preferably 1.0 to 2.0%. By supporting the iodine compound, the initial detoxification ability of the activated carbon can be suppressed to about ½, and further gas adsorption ability can be imparted.

  The adsorbent of the present invention can effectively adsorb noxious gas regulated by the Soil Contamination Countermeasures Law, and an absorption can using the adsorbent satisfies the above-mentioned standards for gas masks. Moreover, the particulate matter which can coexist can be effectively removed by providing a dustproof filter in this absorption can. The specific organic substances regulated by the Soil Contamination Countermeasures Law contain particulate substances such as lead, hexavalent chromium and cadmium in addition to harmful gases, and these can be removed together with a dust filter, so that the present invention The absorption can with dust filter can handle virtually all specified hazardous substances regulated by the Soil Contamination Countermeasures Law. As the dustproof filter, an appropriate filter such as a glass fiber nonwoven fabric capable of removing the particulate matter as described above can be used. A well-known structure and shape of the absorber can be used as appropriate.

  The invention will now be illustrated by examples.

  The evaluation was in accordance with the gas mask standard described above. Some of these are summarized below.

Detoxification test:
The absorption can is passed at a flow rate of 300 ppm of cyclohexane, and the time until the permeation concentration on the downstream side of the absorption can reaches 5 ppm is measured. In this case, the test humidity is 50 ± 5%. Judgment criteria: 50 minutes or more

Performance of absorbent can with dust prevention function:
The gas mask standard stipulates the S classification for the purpose of respiratory protection against solid particles and the L classification for the purpose of respiratory protection from solid particles and oil mist as classification of the absorbent can having a dustproof function. Moreover, three ranks of 1, 2, and 3 are defined for each performance (collection efficiency, ventilation resistance) for each division. The provisions of the three L categories targeted in the present invention are as follows.

Particle collection efficiency test:
Inside the absorption can attached to the particle collection efficiency measuring instrument, dioctyl phthalate-containing air (median particle size distribution of dioctyl phthalate mist is 0.15 μm or more and 0.25 μm or less, and its geometric standard deviation is 1 0.6 or less, and the dioctyl phthalate concentration is 100 mg / m ³ or less and the fluctuation is ± 15% or less.) At a flow rate of 85 lpm, and phthalic acid supplied to the absorber In the process until dioctyl reaches 200 mg, the concentration of dioctyl phthalate before and after passing through the absorption can is continuously measured by a dioctyl phthalate concentration measuring device using a scattered light method.
Judgment criteria: 99.9% or more

Ventilation resistance test:
Attach an absorption can to the ventilation resistance tester (including an intake valve for an absorption can equipped with an intake valve), pass air at a flow rate of 40 lpm, and measure the pressure difference between the inside and outside of the absorption can.
Judgment criteria: 370 Pa or less (in the case of a direct-coupled small-sized absorbent can having a dust prevention function (L three categories))

Example:
A specific surface area of 500 cm ² in which 1.0 to 3.0 g of potassium iodide is dissolved in 100 cc of solvent in a resin vat, and the amount of the copper compound, silver compound, chromium compound and triethylenediamine carried in Table 1 is supported in this solution. Add 100 g of activated carbon with / g or more. Next, the activated carbon is left in this solution at room temperature for 3 hours, and is preliminarily dried at 25 to 60 ° C. for 120 to 12 hours in a dryer. Thereafter, it is dried at 100 ° C. for 12 hours. The iodine carrying amount of the activated carbon produced by this process is 1.0 to 3.0%. The proportion of the activated carbon support material is analyzed by EPMA.

  When iodine compounds are mixed with copper compounds, chromium compounds, and silver compounds, metal iodides (silver iodide, copper iodide, chromium iodide) are produced, resulting in a decrease in gas performance. It is necessary to support after supporting other metal compounds.

About 50 cc of the above activated carbon was filled in a container having an inner diameter of φ75, and the gas performance was measured. As the test gas, five kinds of volatile organic compounds, hydrocyanic acid, mercury, hydrogen arsenide, and hydrogen fluoride, which are frequently detected as causative substances of soil contamination, were used. Further, as a performance evaluation method for volatile organic compounds, cyclohexane, which is a standard test gas for gas masks for organic gas, was used. All tests were performed at a temperature of 20 ° C., a relative humidity of 50% RH, and a flow rate of 30 lpm. The test gas concentration and breakthrough concentration were cyclohexane, hydrocyanic acid, mercury, hydrogen arsenide, hydrogen fluoride, chlorine, hydrogen chloride, sulfur dioxide, hydrogen sulfide in the order of 300 ppm and 5 ppm, 300 ppm and 4.7 ppm, and 3 mg / m, respectively. ³ and 0.05 mg / m ³ , 10 ppm and 0.05 ppm, 100 ppm and 3 ppm, 200 ppm and 1 ppm, 300 ppm and 5 ppm, 300 ppm and 5 ppm, 200 ppm and 10 ppm.

  Quantitative analysis of the test gas was performed using cyclohexane and cyanide gas with a gas chromatograph equipped with a hydrogen ionization detector (FID), and mercury, hydrogen arsenide, hydrogen fluoride, chlorine, hydrogen chloride, sulfur dioxide, and hydrogen sulfide with a detector tube. . Note that the breakthrough standard for the cyanide gas was the sum of hydrocyanic acid and its by-product dicyan. Table 2 shows the test results. From the test results, it was confirmed that the present invention has an effective adsorption capacity for all the test gases, and proved to be an adsorbent for specific harmful substances in the soil contamination countermeasure method.

  If the absorbent case for a gas mask is filled with the adsorbent of the present invention, the gas mask can can be used effectively for soil contamination treatment. In addition, by attaching a mechanical filter molded with glass fiber as a main component or an electrostatic filter carrying an electrostatic resin on wool on the upstream side or downstream side of the absorption can, the standards in the gas mask as shown in Table 3 Satisfies the standard of an absorption can equipped with a filter of L three sections.

  Furthermore, if the adsorbent of the present invention is filled in a gas adsorption layer such as a local exhaust device, it can also serve as an exhaust gas treatment filter when heat-purifying contaminated soil.

Claims (5)

A harmful gas removal adsorbent characterized by further supporting an iodine compound on activated carbon having a specific surface area of 500 cm ² / g or more formed by supporting a copper compound, a silver compound and a chromium compound.   The supported amount of copper compound is 7 to 10% by weight, the supported amount of silver compound is 0.01 to 0.5% by weight, the supported amount of chromium compound is 1 to 3% by weight, and the supported amount of iodine compound is 1 to 1%. The adsorbent according to claim 1, which is 2% by weight.   The adsorbent according to claim 1 or 2, wherein in addition to the copper compound, the silver compound and the chromium compound, 3% by weight or less of triethylenediamine is previously supported on the activated carbon.   A gas mask absorbent can comprising the adsorbent according to claim 1.   The absorbent can according to claim 4, comprising a dustproof filter.