Apparatus for decomposing halogenated aliphatic hydrocarbon compounds or aromatic compounds

Abstract

A method for decomposing halogenated aliphatic hydrocarbon compounds or aromatic compounds characterized by contacting the compound to be decomposed with functional water under light irradiation, wherein the functional water is characterized by a hydrogen ion concentration (pH) of 1-4, an oxidation-reduction potential of 800-1500 mV (working electrode: platinum, reference electrode: silver-silver chloride) and a chlorine concentration of 5-150 mg/l, and the irradiation is carried out with light of a wavelength of 300 nm or more, with an intensity of 10 mW/cm 2 or less. This method is carried out at room temperature under the atmospheric pressure. An apparatus for the method is also provided.

What is claimed is:  
     
         1 . A method of decomposing a halogenated aliphatic hydrocarbon compound or an aromatic compound, comprising a step of contacting under irradiation with light a medium containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound with functional water produced by electrolysis of water containing an electrolyte.  
     
     
         2 . A decomposition method according to  claim 1 , wherein said functional water is acidic water produced around an anode when water containing an electrolyte is electrolyzed.  
     
     
         3 . A decomposition method according to  claim 1 , wherein said functional water is a mixture of acidic water produced around an anode and alkaline water produced around a cathode when water containing an electrolyte is electrolyzed.  
     
     
         4 . A decomposition method according to  claim 3 , wherein said mixture is obtained by mixing the acidic water and the alkaline water to a ratio of not greater than 1:1.  
     
     
         5 . A decomposition method according to  claim 1 , wherein said electrolyte includes at least one of sodium chloride and potassium chloride.  
     
     
         6 . A method of decomposing a halogenated aliphatic hydrocarbon compound or an aromatic compound, comprising a step of contacting under irradiation with light a medium containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound with functional water containing hypochlorous acid.  
     
     
         7 . A decomposition method according to  claim 6 , wherein said functional water is an aqueous solution of hypochlorite.  
     
     
         8 . A decomposition method according to  claim 7 , wherein said hypochlorite is at least one of sodium hypochlorite and potassium hypochlorite.  
     
     
         9 . A decomposition method according to  claim 6 , wherein the chlorine concentration of said functional water is between 2 and 2,000 mg/l.  
     
     
         10 . A decomposition method according to  claim 6 , wherein said aqueous solution further contains an inorganic acid or an organic acid.  
     
     
         11 . A decomposition method according to  claim 10 , wherein said inorganic acid or organic acid includes at least hydrochloric acid, oxalic acid, sulfuric acid, phosphoric acid, boric acid, acetic acid, formic acid, malic acid or citric acid,  
     
     
         12 . A decomposition method according to  claim 1  or  6 , wherein said functional water is characterized by a hydrogen ion concentration (pH) between 1 and 4, an oxidation-reduction potential between 800 and 1,500 mV (working electrode: platinum, reference electrode: silver-silver chloride), and a chlorine concentration between 5 and 150 mg/l.  
     
     
         13 . A decomposition method according to  claim 1  or  6 , wherein said functional water is characterized by a hydrogen ion concentration (pH) between 4 and 10, an oxidation-reduction potential between 300 and 1,100 mV (working electrode: platinum, reference electrode: silver-silver chloride), and a chlorine concentration between 2 and 100 mg/l.  
     
     
         14 . A decomposition method according to  claim 1  or  6 , wherein said light includes light in a wavelength range between 300 and 500 nm.  
     
     
         15 . A decomposition method according to  claim 14 , wherein said light includes light in a wavelength range between 350 and 450 nm.  
     
     
         16 . A decomposition method according to  claim 1  or  6 , wherein an intensity of irradiation is between 10 μW/cm 2  and 10 mW/cm 2 .  
     
     
         17 . A decomposition method according to  claim 16 , wherein the intensity of irradiation is between 50 μW/cm 2  and 5 mW/cm 2 .  
     
     
         18 . A decomposition method according to  claim 1 , wherein said step of contact comprises the steps of: 
 providing a container which comprises a pair of electrodes of an anode and a cathode and a power source for applying a potential between the electrodes and contains water containing an electrolyte therein,    providing a halogenated aliphatic hydrocarbon compound or an aromatic compound at least around the anode,    electrolyzing the water to produce functional water by applying a potential between the electrodes, and    irradiating the functional water with light.    
     
     
         19 . A decomposition method according to  claim 18 , wherein said container further comprises a diaphragm for preventing functional water produced around the anode and functional water produced around the cathode by electrolysis from being mixed with each other.  
     
     
         20 . A decomposition method according to  claim 19 , wherein said medium containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound is a gas, and at least one of halogenated aliphatic hydrocarbon compounds and aromatic compounds is provided around the anode by bubbling the water around the anode with said medium.  
     
     
         21 . A decomposition method according to  claim 20 , wherein said bubbling is conducted after the functional water was produced around the anode.  
     
     
         22 . A decomposition method according to  claim 19 , wherein said medium containing at least one of halogenated aliphatic hydrocarbon compounds and aromatic compounds is a liquid, and at least one of halogenated aliphatic hydrocarbon compounds and aromatic compounds is provided around the anode by feeding the medium around the anode.  
     
     
         23 . A decomposition method according to  claim 22 , wherein said feeding is conducted after the functional water was produced around the anode.  
     
     
         24 . A decomposition method according to claim  1 , further comprising the steps of: 
 supplying the functional water which was produced around the anode by electrolyzing water containing an electrolyte to a container,    supplying a medium containing at least one of halogenated aliphatic hydrocarbon compounds and aromatic compounds to the container, and    irradiating the container with light.    
     
     
         25 . A decomposition method according to  claim 1  or  6 , wherein said halogenated aliphatic hydrocarbon compound is a halogenated aliphatic hydrocarbon compound substituted with at least one of chlorine and fluorine.  
     
     
         26 . A decomposition method according to  claim 25 , wherein said halogenated aliphatic hydrocarbon compound is at least one of: 
 trichloromethane, dichloromethane, trichlorofluoromethane, dichlorodifluoromethane, chlorotrifluoromethane, dichlorofluoromethane, chlorodifluoromethane, trifluoromethane, 1,1,1-trichloroethane, 1,2-difluoro-1,1,2,2-tetrachloroethane, 1,1,2-trichloro-1,2,2-trifluoroethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, 2,2-dichloro-1,1,1-trifluoroethane, chlorodifluoroethane, 1,1-difluoroethane, tetrafluoroethane, chloropentafluoroethane, hexafluoroethane, chloroethylene, dichloroethylene (1,1-dichloroethylene, cis-1,2-dichloroethylene, trans-1,2-dichloroethylene), trichloroethylene and tetrachloroethylene.    
     
     
         27 . A decomposition method according to  claim 1  or  6 , wherein said aromatic compound is at least one of benzene, chlorinated benzene and phenol.  
     
     
         28 . A decomposition method according to  claim 27 , wherein said chlorinated benzene is at least one of chlorobenzene, 1,4-dichlorobenzene (p-dichlorobenzene), 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, tetrachlorobenzene and hexachlorobenzene.  
     
     
         29 . A decomposition method according to  claim 1  or  6 , wherein said aromatic compound has a biphenyl bond or a biphenyl skeleton.  
     
     
         30 . A decomposition method according to  claim 29 , wherein said compound having a biphenyl bond or a biphenyl skeleton is selected from a group consisting of biphenyl, dehydrodivanillic acid, 2-chlorobiphenyl, 3-chlorobiphenyl, 4-chlorobiphenyl, 2,2′-dichlorobiphenyl, 3,3′-dichlorobiphenyl, 4,4′-dichlorobiphenyl, 2,4′-dichlorobiphenyl, 2,3-dichlorobiphenyl, 2,4-dichlorobiphenyl, 2,5-dichlorobiphenyl, 2,6-dichlorobiphenyl, 3,4-dichlorobiphenyl, 3,5-dichlorobiphenyl, 2,4,4′-trichlorobiphenyl, 2,2′,5-trichlorobiphenyl, 2,3′,5-trichlorobiphenyl, 2,4′,5-trichlorobiphenyl, 2′,3,4-trichlorobiphenyl, 2,3,4-trichlorobiphenyl, 2,3,6-trichlorobiphenyl, 2,4,5-trichlorobiphenyl, 2,4,6-trichlorobiphenyl and compounds having a biphenyl bond and derivatives thereof where at least one chlorine atoms is substituted by a fluorine or bromine atom.  
     
     
         31 . A method for purifying an exhaust gas, comprising a step of contacting an exhaust gas containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound with functional water produced by electrolyzing water containing an electrolyte, under light irradiation to decompose said halogenated aliphatic hydrocarbon compound or aromatic compound.  
     
     
         32 . A purifing method according to  claim 31 , wherein said functional water is acidic water produced around an anode by electrolyzing water containing an electrolyte.  
     
     
         33 . A purifying method for purifying an exhaust gas, comprising a step of contacting an exhaust gas containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound with functional water containing hypochlorous acid under irradiation with light to decompose the halogenated aliphatic hydrocarbon compound or aromatic compound.  
     
     
         34 . A purifying method according to  claim 33 , wherein the chlorine concentration of said functional water is between 2 and 2,000 mg/l.  
     
     
         35 . A purifying method according to  claim 31  or  33 , wherein said functional water is characterized by a hydrogen ion concentration (pH) of 1-4, an oxidation-reduction potential of 800-1500 mV (working electrode: platinum, reference electrode: silver-silver chloride) and a chlorine concentration of 5-150 mg/l.  
     
     
         36 . A purifying method according to  claim 31  or  33 , wherein said functional water is characterized by a hydrogen ion concentration (pH) of 4-10, an oxidation-reduction potential of 300-1100 mV (working electrode: platinum, reference electrode: silver-silver chloride) and a chlorine concentration of 2-100 mg/l.  
     
     
         37 . A purifying method according to  claim 31  or  33 , wherein said contact step comprises the steps of: 
 contacting an exhaust gas to pass through a reaction container filled with a filler, and  
 supplying the functional water to the reaction container.  
 
     
     
         38 . A purifying method according to  claim 31  or  33 , wherein said halogenated aliphatic hydrocarbon compound or aromatic compound is an organochlorinated compound.  
     
     
         39 . An apparatus for decomposing a halogenated aliphatic hydrocarbon compound or an aromatic compound, comprising a container having a pair of electrodes of an anode and a cathode, and a power source for applying a voltage to the electrodes, means for supplying the container with water containing an electrolyte dissolved therein, light irradiation means and means for supplying a medium containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound.  
     
     
         40 . A decomposition apparatus according to  claim 39 , further comprising means for supplying a medium containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound to the anode side of said electrodes.  
     
     
         41 . A decomposition apparatus according to  claim 39 , further comprising a diaphragm arranged between said pair of electrodes.  
     
     
         42 . A decomposition apparatus according to  claim 41 , wherein said diaphragm is an ion exchange membrane or a fine porous membrane.  
     
     
         43 . An apparatus for decomposing a halogenated aliphatic hydrocarbon compound or an aromatic compound, comprising a decomposition treatment tank, means for supplying functional water produced by electrolyzing water to the decomposition treatment tank, means for supplying a halogenated aliphatic hydrocarbon compound or an aromatic compound to be decomposed and means for irradiating the decomposition tank with light.  
     
     
         44 . A decomposition apparatus according to  claim 43 , wherein said means for supplying functional water produced by electrolysis of water is means for supplying functional water produced around the anode by electrolysis of water.  
     
     
         45 . A decomposition apparatus according to  claim 43 , wherein said decomposition treatment tank is provided with agitating means.  
     
     
         46 . An apparatus for decomposing a halogenated aliphatic hydrocarbon compound or an aromatic compound comprising a container for containing functional water which contains hypochlorous acid, means for irradiating the container with light and means for supplying the container with a medium containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound.  
     
     
         47 . An apparatus for purifying an exhaust gas containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound, comprising a reaction container having inlet ports and discharge ports for an exhaust gas and functional water, and being filled with a filler from the inlet ports to the discharge ports, means for introducing the exhaust gas into the reaction container, means for introducing functional water obtained by electrolysis of water containing an electrolyte into the reaction container, and means for irradiating the inside of the reaction container with light.  
     
     
         48 . An apparatus for purifying an exhaust gas containing at least one of a halogenated aliphatic hydrocarbon compound and an aromatic compound, comprising a reaction container having inlet ports and discharge ports for an exhaust gas and functional water, and being filled with a filler from the inlet ports to the discharge ports, means for introducing the exhaust gas into the reaction container, means for introducing functional water containing hypochlorous acid into the reaction container, and means for irradiating the inside of the reaction container with light.