JP2015107477A - Solution, method, and system for decomposition and/or removal of odor material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a system for decomposition and/or removal of an odor material.SOLUTION: Provided is the method for decomposition and/or removal of an odor material. The method includes a step for decomposing and/or removing the odor material by bringing hypochlorite solution into contact to the odor material. The hypochlorite solution includes sodium hypochlorite and/or potassium hypochlorite by 350 ppm or more in terms of effective chlorite concentration, and has pH within a range of 3.0-5.5 or 8-10, and is saturated by sodium chloride and/or potassium chloride.

Description

  The present invention relates to a solution, method and system for decomposing and / or removing odorous substances in a gas.

  Smoking is not only harming the health of smokers alone, but there is also a risk of harming the health of others by smoking by secondhand smoke, so smoking is being promoted worldwide.

  As a means for smoking separation, a highly airtight smoking room or smoking booth is often installed. In any case, in order to protect smokers' health and to remove cigarette smoke and odors, mechanisms / devices for removing cigarette smoke and odor substances are provided in smoking rooms or smoking booths.

  In addition, not only tobacco smoke and exhaust, but also exhaust and smoke that generate an unpleasant odor may be emitted from restaurants, hospitals, sewage, nursing homes, factories, etc., and these exhaust and smoke There has been a need for a method and system for decomposing and / or removing unpleasant odors and harmful volatile substances therein.

  Although it is possible to simply release fumes such as cigarettes and exhaust gas into the atmosphere by ventilation, there is a problem with neighboring residents, etc., so tobacco smoke and odor substances are fundamentally There is a need for an apparatus that decomposes or removes, and various proposals have been made.

  As a method for removing these odorous substances, for example, removal with zeolite or activated carbon (Patent Document 1), removal with strong electrolyzed water (for example, Patent Document 2), removal by electrostatic adsorption (Patent Document 3), etc. Although it has been proposed, no one has been developed that can sufficiently remove the flue gas such as tobacco and the unpleasant odor in the exhaust.

  This is thought to be due to the fact that all odorous substances cannot be adsorbed, decomposed or removed by the same system due to the variety of odorous substances. For example, perennials belonging to the genus Tobacco are used for tobacco, but there are about 50 species in the genus Tobacco, and the components contained vary depending on the variety, production area, etc., and the volatile components that actually accompany the burning of tobacco Since more than 3000 kinds of odor components are included, it is difficult to remove all odor components, and development of a method for decomposing and / or removing odor substances more efficiently has been demanded.

  In addition, there is a technique called masking in order to avoid feeling smoke and unpleasant odors such as cigarettes. This is a method of cheating with a citrus smell such as orange. However, although this method can eliminate the unpleasant odor, it cannot eliminate the fundamental health hazard, and therefore it has been desired to remove the volatile substance containing the unpleasant odor by adsorption or decomposition.

  Further, even in the absorption / adsorption method of activated carbon or the like, there remains a problem in the regeneration and disposal of activated carbon after adsorption, so that a solution, method or system for decomposing odorous substances has been demanded.

Patent Document 1 Japanese Patent No. 4948325 Patent Document 2 Japanese Patent Application Laid-Open No. 2004-290713
Patent Document 3 JP 2012-96162 A

  Solutions, methods and systems are provided for degrading and / or removing odorous substances.

As a result of intensive studies on the above problems, the inventors have discovered a method for efficiently decomposing and / or removing odorous substances and completed the invention. According to this specification, the following invention is provided.
(1) A method for decomposing and / or removing odorous substances, containing 350 ppm or more of sodium hypochlorite and / or potassium hypochlorite, and having a pH of 3.0-5.5 or 8.0- A method comprising decomposing and / or removing an odorous substance by bringing a hypochlorous acid solution saturated with sodium chloride and / or potassium chloride ions in the range of 10.0 into contact with the odorous substance. The solution is prepared by adding sodium chloride or sodium hydroxide to a sodium hypochlorite solution of 350 ppm or more. Here 350 ppm represents the effective chlorine concentration. A more preferable effective chlorine concentration is 500 ppm or more, more preferably 700 ppm or more, and particularly preferably 1000 ppm or more. The upper limit of the effective chlorine concentration is a commercially available stock solution of hypochlorous acid, that is, an effective chlorine concentration of 12% or less. Further, a potassium salt (potassium chloride, potassium hypochlorite, potassium hydroxide, etc.) can be used instead of the sodium salt.

(2) The solution is a solution produced by a method including a step of adding sodium ion to a sodium hypochlorite solution in a supersaturated state and adjusting the effective chlorine concentration to be 350 ppm or more. The method of (1). In this case, if the volume that increases with the amount of sodium chloride added is known, it can be calculated so that the effective chlorine concentration can finally be 350 ppm or higher. A sodium hypochlorite solution can be prepared. The solution thus prepared is also included in the solution of the present invention (1) or (2). Here, for “increasing sodium ions”, sodium chloride or sodium sulfate may be added and dissolved, but is not limited thereto. In short, it is only necessary that the dissociation equilibrium of NaClO shifts in the non-dissociation direction as the sodium ions increase. That is, in the formula [NaClO] ⇔ [Na ⁺ ] + [ClO ⁻ ], the [NaClO] concentration should be increased by increasing the concentration of sodium ions based on the Le Chatelier's principle. Alternatively, after the sodium hypochlorite solution reaches equilibrium, the dissociation equilibrium of NaClO may be shifted to the left side by adding sodium chloride, sodium sulfate, sodium nitrate, or the like.

(3) The method according to (1) or (2), further comprising an electric dust collection step.
(4) The method according to any one of (1) to (3), further comprising an adsorption treatment process of odorous substances with activated carbon.
(5) A system for decomposing and / or removing odorous substances, containing 350 ppm or more of sodium hypochlorite and / or potassium hypochlorite and having a pH in the range of 3-5.5 or 8-10. Means for preparing a hypochlorous acid solution saturated with sodium chloride and / or potassium chloride, a storage tank for storing the solution, a means for introducing a gas containing an odor substance, and the solution containing the odor substance. A system comprising means for decomposing and / or removing an odorous substance in contact with a gas contained therein and means for discharging a gas obtained by decomposing and / or removing the odorous substance.

(6) The solution contains 350 ppm or more of sodium hypochlorite in saturated saline solution, and after reaching an equilibrium state, the sodium ion is increased to increase the dissociation state of sodium hypochlorite. (5) The system according to (5), which is a solution produced by a preparation means including a means for moving to a state side.
(7) The deodorizing system according to (5) or (6), further comprising an electric dust collecting means.
(8) The deodorization system according to any one of (5) to (7), further including an odorous substance adsorption treatment unit using activated carbon.
(9) Hypochlorite saturated with sodium chloride and / or potassium chloride containing 350 ppm or more of sodium hypochlorite and / or potassium hypochlorite and having a pH in the range of 3-5.5 or 8-10 Acid solution. Here, this solution is preferably used to decompose and / or remove tobacco odorants and / or smoke.
(10) The step of bringing the dissociation state of the sodium hypochlorite solution and / or the potassium hypochlorite solution into an equilibrium state, and the equilibrium state is not dissociated by increasing sodium ions or potassium ions after reaching the equilibrium state. (9) The hypochlorous acid solution produced by a method having a step of moving in the direction of. Here, in order to increase sodium ions or potassium ions, for example, sodium chloride (or potassium chloride), sodium sulfate (or potassium sulfate), sodium nitrate (or potassium nitrate) or the like may be added and dissolved. Thereby, for example, the dissociation equilibrium of sodium hypochlorite moves in the non-dissociation (left side) direction, so that non-dissociated sodium hypochlorite increases.

According to the present invention, odorous substances can be efficiently decomposed and / or removed.

FIG. 1 is a diagram showing the procedure of a deodorization experiment for cigarette smoke and the like. FIG. 2 shows an experimental apparatus for decomposing and / or removing tobacco smoke and odorous substances. FIG. 3 is a diagram showing an outline of a system according to one embodiment of the present invention. FIG. 4 is a diagram showing the structure of a system according to one embodiment of the present invention.

  As a result of intensive studies on the above problems, the inventors have discovered a method for efficiently decomposing and / or removing odorous substances.

  In the present specification, the term “odorous substance” refers to foul odors of exhaust or smoke, foul odors such as grilled meat and grilled fish, oil mist, lively, exhaust from automobiles, exhaust from incinerators, cigarette smoke, aging odors, This includes, but is not limited to, odors of germs, exhausts from hospitals and nursing homes, manure treatment plants, sewage treatment plants, leather, pulp, feed, fertilizer, livestock, animals, plastics, rubber, building materials, garbage, etc. Absent. Moreover, what is harmful to the human body, harmless, and beneficial is also included in the odorous substance as long as it has an odor felt by humans.

  Examples of “odor substances” include fatty acid and protein oxides, decomposition products, amines, ammonia, methyl mercaptan, hydrogen sulfide, methyl sulfide, sulfur oxide, nitrogen oxide, trimethylamine, acetaldehyde, formaldehyde, isocyanate, Phthalate esters, phosphate esters, organophosphorus or organochlorine compounds, isopropyl alcohol, ethanol, toluene, xylol, benzine, chlorofluorocarbon, propionic acid, normal butyric acid, carbon monoxide, nicotine, etc. and mixtures containing a plurality thereof However, it is not limited to these.

  In the present invention, oxidative decomposition is adopted as a decomposition method. That is, as a method for decomposing and / or removing odorous substances used in the present invention, oxidative decomposition using hydrogen peroxide, ozone, chlorine, hypochlorous acid, or the like is preferably used. Typically, decomposition with sodium hypochlorite or hypochlorous acid is particularly preferably used.

As the hypochlorous acid-based solution, for example, a strongly acidic electrolytic aqueous solution or a weak acidic electrolytic water prepared by electrolysis of a solution containing chlorine ions such as a sodium chloride solution is used. A solution prepared by passing chlorine into a sodium hydroxide solution can also be used. In addition to these, sodium hypochlorite solutions and the like generally sold as research reagents and bleaching agents can also be used. The strongly acidic electrolytic aqueous solution contains chlorine gas and non-dissociated HClO (hypochlorous acid), and the pH of the sodium hypochlorite solution is adjusted to 3-5.5 with weakly acidic electrolytic water (or hydrochloric acid or the like). Although these may be adjusted to those described in detail below, non-dissociated HClO (hypochlorous acid) is mainly contained, and sodium hypochlorite is ClO ⁻ (hypochlorous acid) in the solution. Acid ions), which are considered to be oxidants and oxidatively decompose odorous substances.

  Tobacco smoke was put in a vacuum collection bottle and brought into contact with a 350 ppm hypochlorous acid-saturated sodium chloride saturated solution previously added to decompose or adsorb odorous substances and remove them. As a means for bringing the odor substance into contact with the solution, for example, a method of bringing the solution into contact with mist is preferably used. When the odorous substance was brought into contact with the solution of the present invention, it was found that the malodor of cigarette smoke could be decomposed in a short period of time. The pH is preferably 3.0 to 5.5 or 8 to 10. More preferably, they are pH 4.5-5.5 and pH 8-9. In particular, when a sodium hypochlorite solution adjusted to pH 9.0 by adding sodium hydroxide was used, it was found that odorous substances could be decomposed even at a concentration of 350 ppm (Example 1, Table 1).

  As means for bringing the odorous substance into contact with the hypochlorous acid solution, techniques such as packed tower, spray tower, urekabe tower, plate tower, bubble tower, etc. used in the deodorizing tower can be used.

In the present specification, hypochlorous acid concentration (ppm) was measured as follows. ClO ^- concentration was measured as an active chlorine concentration. This effective chlorine concentration can be measured by methods well known to those skilled in the art, such as DPD colorimetric method, DPD absorptiometric method, polarographic method, and iodine reduction titration method. In the present invention, the effective chlorine concentration is measured by the iodine reduction titration method, but is not limited thereto.

The iodine reduction titration method is a titration method that uses iodine, which has both the properties of an oxidizing agent and a reducing agent, as a reducing agent. Potassium iodide is added to an aqueous solution containing an oxidizing substance to generate I _2. This is an indirect titration method in which I ₂ is titrated with sodium thiosulfate titrant as a reducing agent. . When potassium iodide is added to a solution containing hypochlorite ions, the following reaction occurs. At this time, the solution turns yellow.

ClO ⁻ + 2I ⁻ + 2H ⁺ → Cl ⁻ + I ₂ + H ₂ O (1)
As described above, since H ⁺ is required for the reaction, titration must be performed after adding potassium iodide and then adding sulfuric acid. The reaction during titration is as follows.

2Na ₂ S ₂ O ₃ + I ₂ → 2NaI + Na ₂ S ₄ O ₆ (2)
By this reaction, iodine is liberated, so that the solution changes from yellow to colorless and transparent.

Comparing the number of moles of each chemical species, it can be seen from the formula (1) that the number of moles of hypochlorite ion and generated iodine is 1: 1. Further, from the formula (2), it can be seen that the number of moles of hypochlorite ion and the number of moles of sodium thiosulfate are 1: 2. Therefore, the formula for obtaining the effective chlorine concentration can be expressed as follows. Here, W is the weight of the sample, N is the concentration of the sodium thiosulfate titrant (N standard), and T is the drop amount (ml). In addition, this value is the hypochlorous acid oxidation power converted to chlorine,
[{(N × T) ÷ 1000 × 1/2 × (35.45 × 2)} ÷ W] × 10 ⁶ ppm (3)
(ppm) (3)
The iodine titration reaction is very sensitive and is said to be able to detect approximately ^10-5 mol / L iodine at room temperature (Yoshi Imaizumi et al., Basic Analytical Chemistry, p82, Chemistry). Doujin, 1998).

  Hereinafter, the present invention will be described using examples, but these examples do not limit the present invention.

  An outline of the odor substance decomposition and / or removal experiment is shown in FIG. As shown in FIG. 1, a 1000 ml branch Erlenmeyer flask is evacuated using a vacuum pump, and a lit cigarette (Mild Seven, manufactured by JT) is connected to the branch of the Erlenmeyer flask. Contain smoke and odorous substances (since the Erlenmeyer flask is evacuated, cigarette smoke etc. is sucked into the container and trapped), adjust the pH to a commercially available sodium hypochlorite solution in an Erlenmeyer funnel attached to the upper part of the Erlenmeyer flask After adding 200 ml of a solution adjusted to 3, 5, and 7 using hydrochloric acid as the agent and adjusting the effective chlorine concentration to 100, 200, 350, 500 ppm, the cock is opened, and after contact with the cigarette smoke in the Erlenmeyer flask , Held by hand and stirred several times with the container. The degree of reduction of odorous substances and smoke was evaluated by visual observation and visual observation of five people after stirring. The pH 9 sodium hypochlorite solution was prepared by adjusting the pH with NaOH when the original solution was acidic. As the reagent used for pH adjustment, any basic solution can be used without limitation. When the original solution is basic, a solution such as hydrochloric acid or sulfuric acid is preferably used, but is not limited thereto. After the pH adjustment, a solution in which sodium chloride was added and dissolved until saturation was prepared, and the solution was brought into contact with tobacco smoke, and the decomposition and / or removal effect of odorous substances was measured. The results are shown in Table 1.

  From the results in Table 1, it was found that the solutions of pH 3, pH 5.5, and pH 9 having an effective chlorine concentration of 500 ppm were able to remove smoke and odorous substances. In the case of pH 9, odorous substances and smoke could be removed even at 350 ppm. As a result of this experiment, it was possible to remove odorous substances and smoke even when pH 9 which increased dissociation equilibrium in the direction of non-dissociation by increasing sodium ions was 350 ppm. It turns out to be effective.

  However, the pH value at this time was 9, and when this value was set to 10, the effect was slightly lowered, and when it was 11 or more, the effect was lost. The effect decreased gradually when it was 8 or less. Therefore, it was found that the pH can be exhibited at pH 8-10. These were totally unexpected results.

  In Example 1, since the chlorine odor was quite strong at pH 3, the possibility of masking with chlorine gas was also considered. Therefore, chlorine gas and ammonia gas were measured. It is known that ammonia gas is contained as a main component of tobacco odor substances. Thus, measurement of ammonia can be used as a measure of whether or not the odorous substance component has been decomposed. The measurement results are shown in Tables 2 and 3.

  As a result, the chlorine gas concentration was so high that the pH = 3 could not be measured with the detector tube used (40 ppm), and the pH = 5 was 15 ppm. Ammonia was not detected, and the odorous substance component seems to be decomposed by the chemical solution. However, those having a pH of 3 are not preferred for use because of the high chlorine gas concentration. This is because chlorine gas is a toxic gas and a combustion-supporting gas. From the viewpoint of the chlorine gas concentration, it was found that a pH of 5 is effective.

  When the pH was 4 or less, the chlorine gas concentration was high, and when the pH was 6 or more, the effect of removing odorous substances was weak. Therefore, it was found that between 4 and 6 was effective in actual use. This time, the pH was adjusted using a commercially available sodium hypochlorite solution, but similar results were obtained using electrolyzed water that can be prepared by electrolysis of a solution containing chlorine such as a sodium chloride solution.

It was also found out that the detection of chlorine gas is due to the poor stability of the solution, that is, due to the decrease in effective chlorine concentration over time.
From Tables 2 and 3, it can be seen that the solution near pH 5 has the stability of effective chlorine and has the ability to decompose odor, and this value is particularly effective.

Next, the influence of hypochlorous acid or dissociated state of sodium hypochlorite on the decomposition of odorous substances was investigated. In the sodium hypochlorite solution, a certain proportion of NaClO is dissociated into hypochlorite ions (ClO ⁻ ).
NaClO + H ₂ O⇔ClO ⁻ + Na ⁺ + OH ⁻
Because this hypochlorite ion is negatively charged, cigarette smoke and odorous substances, which are also considered to be negatively charged, did not approach this hypochlorite ion, and the odorous substances could not be decomposed and / or removed efficiently. I guessed that.

  Therefore, in the above reaction formula, if sodium hypochlorite (NaClO) remains in the aqueous solution (non-dissociated state and electrically neutral), it was thought that odorous substances could be removed. Therefore, it was considered that non-dissociated sodium hypochlorite can be produced according to Le Chatelier's law by adding sodium chloride (sodium chloride) to the above formula in excess (saturation).

  The solution was prepared as follows.

  Salt saturated sodium hypochlorite solution is diluted with sodium hypochlorite solution (Wako Pure Chemical Industries, Ltd., chemical, effective chlorine 5 +%), salt is added to supersaturation, a stir bar is added and a stirrer is added. To pH 9 and 508 ppm.

As the salt-saturated electrolyzed water, a super-saturated saline solution was prepared, and electrolysis was performed using a platinum-coated titanium plate as an electrode to obtain a salt-supersaturated sodium hypochlorite solution having a pH of 9,524 ppm.
The results are shown in Table 4.

  1% saline electrolyzed water was prepared as 1% saline and electrolyzed using a platinum-coated titanium plate as an electrode to obtain a sodium hypochlorite solution having a pH of 11, 515 ppm.

  As shown in Table 4, in the sodium supersaturated sodium hypochlorite solution, a very strong deodorizing effect was observed in which the odorous substance was removed 1 minute after the dropping of the solution. This is a very strong deodorizing effect that cannot be obtained with saline supersaturated electrolyzed water or 1% salt electrolyzed water.

  Moreover, since smoke and odorous substances are considered to be negatively charged, there is a possibility that smoke can be removed by increasing the positive pole by electrostatic dust collection. Then, when the electrostatic precipitator shown in FIG. 2 was tested, it was found that smoke could be roughly removed visually. However, odorous substances could not be removed.

  Therefore, when only the smoke was taken with this electrostatic precipitator and the odorous substance was decomposed and / or removed with the chemical solution shown above, the concentration was lowered to 350 ppm in the hypochlorous acid solution at pH 5 as shown in Table 5. However, the odorous substance was sufficiently decomposed and / or removed. The pH 9 sodium hypochlorite solution was able to halve the amount of the chemical.

Therefore, the present inventors have found that a highly efficient system capable of removing cigarette smoke and odorous substances can be constructed by pretreatment with an electrostatic precipitator and treatment with the above-described chemical solution.
Furthermore, it was found that exhaust gas can be made non-brominated by using activated carbon for the final treatment of this system.

  An outline of the system of this apparatus is shown in FIG. This apparatus is installed in a smoking booth or the like, and the smoke of the smoker is pretreated with the electrostatic precipitator (the area of the positive electrode is increased) shown in FIG. This removes most of the smoke. However, all the smoke is not removed and the odorous substance is hardly removed.

  Subsequently, the chemical | medical solution of this invention was made to contact some smoke and the gas of an odorous substance. This allowed all odorous substances and smoke to be decomposed and / or removed. However, an activated carbon filter was further passed in order to remove cracked gas components, trace amounts of chlorine gas components, and the like. This removed cigarette smoke and odorous substances.

  An overview of the present invention is shown in FIG. The gas 5 containing an odorous substance is introduced into the electrostatic adsorption means 2 and the particulate matter in the smoke is removed by electrostatic adsorption. Thereafter, the gas moves from the upper part of the treated water tank 18 toward the decomposition treatment tower 9. Meanwhile, a sodium chloride saturated sodium hypochlorite solution is sprayed in a mist form from the mist nozzle 6 to decompose and / or remove odorous substances. The treated gas is further subjected to adsorption removal of odorous substances by the activated carbon treatment means 7 and discharged into the atmosphere (10).

A sodium chloride saturated hypochlorous acid solution is prepared in a hypochlorous acid solution tank 16 by mixing sodium chloride 13, hypochlorous acid solution 14 and water 15. First, water is sent to the tank 12 by a pump (not shown), and a fixed amount is introduced by a flow meter (not shown). Next, a certain amount of hypochlorous acid is fed by a pump and a flow meter (not shown) and mixed with water. Thereafter, an amount sufficient to saturate sodium chloride is added, and the stirring means 16 produces a sodium hypochlorite solution saturated with sodium chloride. The stirred solution is sent to the mist nozzle 6 by the pump 11 and sprayed on the decomposition treatment tower 9 in the mist state. The sprayed hypochlorous acid aqueous solution is collected in the treated water tank 18 and appropriately discharged, and is reused or treated with waste water as necessary.
In addition, 18 treated water is electrolyzed to prepare a sodium hypochlorite solution, and this solution is mixed with sodium chloride to move the dissociation equilibrium to the left side to create a sodium chloride supersaturated hypochlorous acid aqueous solution. However, it can also be used for decomposition and / or removal of odorous substances.

1 Funnel with stopcock 2 Electrostatic adsorption device 3 Vacuum pump 4 Collection bottle (branch flask with branch)
5 Gas containing odorous substances (cigarette smoke, etc.)
6 mist nozzle 7 activated carbon treatment means 8 fan 9 decomposition treatment tower 10 exhaust 11 pump 12 sodium chloride saturated hypochlorous acid solution tank 13 salt tank 14 hypochlorous acid solution tank 15 water tank 16 stirring means 17 18 treatment to water treatment means water tank

Claims (9)

  A method for decomposing and / or removing odorous substances, comprising sodium hypochlorite and / or potassium hypochlorite of 350 ppm or more and having a pH in the range of 3-5.5 or 8-10 And / or a method of decomposing and / or removing odorous substances by contacting a hypochlorous acid solution saturated with potassium chloride with the odorous substances.   The hypochlorous acid solution contains sodium hypochlorite so as to have a final concentration of 350 ppm or more. After reaching the equilibrium state, the sodium ion is increased to increase the equilibrium state of the sodium hypochlorite dissociation state. The method according to claim 1, wherein the solution is produced by a method including a step of moving the salt to the non-dissociated state.   Furthermore, the method of Claim 1 or 2 which has an electrical dust collection process.   Furthermore, the method of any one of Claim 1 thru | or 3 which has an adsorption treatment process of the odorous substance by activated carbon.   A system for decomposing and / or removing odorous substances, which contains 350 ppm or more of sodium hypochlorite and / or potassium hypochlorite and has a pH in the range of 3-5.5 or 8-10. Means for preparing a hypochlorous acid solution saturated with sodium and / or potassium chloride, a storage tank for storing the solution, a means for introducing a gas containing an odorous substance, and a gas containing the odorous substance. A system comprising: a means for contacting and decomposing and / or removing an odor substance; and a means for discharging a gas obtained by decomposing and / or removing the odor substance.   After the solution contains 350 ppm or more of sodium hypochlorite in saturated saline and reaches the equilibrium state, the sodium ion is increased to bring the equilibrium of the dissociated state of sodium hypochlorite to the non-dissociated state side. 6. The system of claim 5, wherein the system is a solution produced by a preparation means including a means for transferring.   Furthermore, the deodorizing system of Claim 5 or 6 provided with an electrical dust collection means.   Furthermore, the deodorizing system of any one of Claim 5 thru | or 7 provided with the adsorption processing means of the odorous substance by activated carbon.   A hypochlorous acid solution saturated with sodium chloride and / or potassium chloride, containing 350 ppm or more of sodium hypochlorite and / or potassium hypochlorite and having a pH in the range of 3-5.5 or 8-10.