AU2016397146B2 - Agent for treating cyanide-containing wastewater and method for treating cyanide-containing wastewater using same - Google Patents
Agent for treating cyanide-containing wastewater and method for treating cyanide-containing wastewater using same Download PDFInfo
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- AU2016397146B2 AU2016397146B2 AU2016397146A AU2016397146A AU2016397146B2 AU 2016397146 B2 AU2016397146 B2 AU 2016397146B2 AU 2016397146 A AU2016397146 A AU 2016397146A AU 2016397146 A AU2016397146 A AU 2016397146A AU 2016397146 B2 AU2016397146 B2 AU 2016397146B2
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- A—HUMAN NECESSITIES
- A62—LIFE-SAVING; FIRE-FIGHTING
- A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
- A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
- A62D3/30—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents
- A62D3/38—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by reacting with chemical agents by oxidation; by combustion
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/76—Treatment of water, waste water, or sewage by oxidation with halogens or compounds of halogens
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/18—Cyanides
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Abstract
An agent for treating cyanide-containing wastewater that is an N-chlorosulfamate- and/or N-bromosulfamate-containing aqueous solution or is prepared from a combination of two liquids, an N-chlorosulfamate- and/or N-bromosulfamate-containing aqueous solution and a hydrogen peroxide- or metal compound-containing aqueous solution, or a combination of three liquids, an N-chlorosulfamate- and/or N-bromosulfamate-containing aqueous solution, a hydrogen peroxide-containing aqueous solution, and a metal compound-containing aqueous solution.
Description
[0001] The present invention relates to an agent for treating cyanide containing wastewater, which allows safe removal of cyanide in wastewater by simple procedures while using as little chemicals as possible compared to conventional agents, and a method for treating cyanide-containing wastewater using the same. According to the present invention, cyanide in any form in wastewater, particularly cyanide ions can be treated by simple procedures.
[0002] Cyanides have a strong impact on the ecosystem, and thus cyanide-containing wastewater (hereinafter also referred to as "cyanide wastewater") must not be released to nature without treatment. The
level of cyanides in wastewater is controlled by the Water Pollution Prevention Act, and thus wastewater must be detoxified by cyanide removal treatment so as to fulfil the effluent standard (1 mg/L or less) before discharging into sewers and the like. In some areas, the
standard is stricter than the standard mentioned above, which is controlled by regulation of local government.
Cyanides are present in wastewater in three different forms, i.e., persistent cyano complexes, easily decomposable cyano complexes and cyanide ions, depending on the source of wastewater, the content of which may vary.
[0003] Various methods for removing cyanides from cyanide-containing wastewater have been proposed and put into practical use. The methods have, however, advantages and drawbacks and are used according to the status of wastewater. For example, the following methods may be mentioned: oxidative decomposition methods such as (1) an alkaline chlorination method in which cyanide-containing wastewater is adjusted to be alkaline followed by injection of chlorine to oxidatively decompose cyanide; (2) an ozone oxidation method in which cyanide is oxidatively decomposed to nitrogen gas and a hydrogen carbonate salt by strong oxidative power of ozone; and (3) an electrolytic oxidation method (electrolysis method) in which cyanide is decomposed by electric current with insoluble electrodes to perform oxidation reaction; insoluble complex methods such as (4) a Prussian blue method in which an iron-ion-providing compound such as ferrous sulfate is added to cyanide-containing wastewater to produce insoluble ferri/ferrocyanide which is precipitated and removed; (5) a zinc white method in which zinc chloride and a reducing agent are added and the produced insoluble complex is precipitated and removed and (6) a reduced copper method in which a copper(II) salt and a reducing agent are added and the produced insoluble complex is precipitated and removed; (7) a biological treatment method in which microorganisms (cyanide -decomposing bacteria) acclimatized to cyanides decompose cyanides; and hydrothermal reactions such as (8) a thermal hydrolysis method in which cyanide-containing wastewater is maintained at high temperature to allow hydrolysis of cyanide compounds to ammonia and formic acid and co-existing heavy metals are deposited in the form of elemental substances or oxides and (9) a wet oxidation method in which not only cyanide is decomposed but also organic pollution materials are oxidatively decomposed.
[0004] The applicant of the present invention has proposed the following methods for treating cyanide-containing wastewater: (A) a method for treating cyanide-containing wastewater by adding to cyanide-containing wastewater a manganese compound that is soluble in hypochlorites and water and can form a manganese ion in water, and removing a produced water-insoluble manganese salt from the wastewater to remove cyanide in the wastewater (see Japanese Patent No. 4106415: Patent Document 1); and (B) a method for treating cyanide compound-containing wastewater by conducting a first stage reaction of adding to cyanide compound-containing wastewater formaldehyde at an amount corresponding to 1.4 times or more of the amount in moles of the contained cyanide compound followed by a second stage reaction at pH 7.0 or higher by adding a substantially effective amount of hydrogen peroxide at 3.0 times or more of the amount in moles of the cyanide compound (see Japanese Unexamined Patent Application Publication No. H02(1990)-35991: Patent Document 2).
[0005] However, the conventional methods as above require complicated steps and procedures and accordingly may need more than one reaction vessel. In addition, depending on the type of wastewater such as wastewater containing thiocyanate ion and ammonium ion, cyanides may not be sufficiently removed, failing to comply with the effluent standard (1 mg/L or less) of the cyanide concentration in treated wastewater, thereby leading to incapability of discharge of treated wastewater into sewers in some cases. It is specified in the Water Pollution Prevention Act that the effluent standard of hydrogen ion concentration (pH) is 5.0 to 9.0 in the ocean area and 5.8 to 8.6 other than the ocean area. In the above conventional methods in which the pH of wastewater is adjusted to acidic or alkaline, not only the cyanides concentration in wastewater but also the pH needs to be adjusted to be within the effluent standard by neutralization treatment before discharge into sewers. The term "ocean area as used herein means the water area holding salt water (sea water) on the earth other than dry land, particularly around boarders with dry land from which wastewater is discharged, and specifically around estuaries or sea coasts. The term "other than the ocean area" means the water area of water (fresh water) other than the ocean area such as rivers and lakes. The boarders between the above areas in the water area containing brackish water or the water area including constructions such as ports, harbors and banks are defined according to various laws such as the Water Pollution Prevention Act.
[0006]
C:\Interwo n\NRPortbl\DCC\DAR\19639241-I.docx-I0/l2/2019
Patent Document 1: Japanese Patent No. 4106415 Patent Document 2: Japanese Unexamined Patent Application Publication No. H02(1990)-35991
[0007]
In the method (A) disclosed in Patent Document 1, for example, the cyanide concentration may be adjusted to be at or below the specified value by adding an excess amount of chemicals to cyanide
containing wastewater. However, there is a need for safe cyanides treatment by using as little chemicals as possible. The present invention seeks to provide an agent for treating cyanide-containing wastewater, which allows safe removal of cyanides in wastewater that contains cyanides, particularly cyanide-containing wastewater containing coexisting compounds such as thiocyanate ion or
ammonium ion by simple procedures while using as little chemicals as possible compared to conventional agents, and a method for treating
cyanide-containing wastewater using the agent.
[0008] It has been surprisingly found that by allowing existence of an N-chlorosulfamate and/or N-bromosulfamate or an N-chlorosulfamate and/or N-bromosulfamate and hydrogen peroxide and/or a metal compound
in cyanide-containing wastewater containing a coexisting substance, cyanides in the wastewater may be safely removed by simple procedures while using as little chemicals as possible compared to conventional agents. Thus, the inventors have completed the present invention.
[0009] Thus, the present invention provides an agent for treating cyanide-containing wastewater, which is an aqueous solution containing an N-chlorosulfamate and/or N-bromosulfamate. The present invention further provides an agent for treating cyanide-containing wastewater comprising a combination of two solutions of the above aqueous solution containing an N chlorosulfamate and/or N-bromosulfamate and an aqueous solution containing hydrogen peroxide or a metal compound, or a combination of three solutions of the above aqueous solution containing an N chlorosulfamate and/or N-bromosulfamate, an aqueous solution containing hydrogen peroxide and an aqueous solution containing a metal compound.
[0010] The present invention also provides a method for treating cyanide-containing wastewater, comprising allowing the agent for treating cyanide-containing wastewater to exist in cyanide-containing wastewater to decompose or insolubilize cyanides in the wastewater, thereby removing the cyanides from the wastewater.
[0011] The present invention can provide an agent for treating cyanide containing wastewater, which allows safe removal of cyanides in wastewater that contains cyanides, particularly cyanide-containing wastewater containing coexisting substances such as thiocyanate ion or ammonium ion by simple procedures while using as little chemicals as possible compared to conventional agents, and a method for treating cyanide-containing wastewater using the agent. Namely, according to the present invention, cyanides in any form in wastewater, particularly cyanide ion can be treated by simple procedures while using as little chemicals as possible compared to conventional methods. Therefore, the wastewater treated with the method of the present invention can be released to nature as it is with little impact on the environment. Thus, the method of the present invention is industrially extremely useful.
[00121 The inventors of the present invention believe that the
comprehensive excellent effect is obtained as a result of synergistic exhibition of cyanides removal effects respectively of the N chlorosulfamate or N-bromosulfamate, hydrogen peroxide and the metal compound contained in the agent for treating cyanide-containing wastewater according to the combinations of the present invention. Specifically, it is believed that (1) hydrogen peroxide suppresses production of chloro cyanide derived from the N-chlorosulfamate or N bromosulfamate; (2) the N-chlorosulfamate and N-bromosulfamate and hydrogen peroxide synergistically exhibit effects on cyanide removal; and (3) the metal compound insolubilize cyanide that could not be removed by other two components or that was insufficiently removed by the two components by metal complexation; and due to the comprehensive effects of the above, the present invention exhibits an excellent effect.
[0013] The agent for treating cyanide-containing wastewater of the present invention exhibits the above effect more strongly when any one of the following conditions is fulfilled: (1) the N-chlorosulfamate and N-bromosulfamate are reaction products of sulfamic acid and hypochlorous acid and/or hypobromous acid; and (2) the metal compound is a compound containing manganese, copper, zinc or iron.
[0014] The method for treating cyanide-containing wastewater of the present invention exhibits the above effect more strongly when any one of the following conditions is fulfilled: (3) the agent for treating cyanide-containing wastewater is allowed to exist so that an effective halogen concentration of the sum of the N chlorosulfamate and N-bromosulfamate is 0.2 molar equivalent or more relative to a cyanide content in the cyanide-containing wastewater; (4) the agent for treating cyanide-containing wastewater is allowed to exist so that a concentration of the hydrogen peroxide is 0.1 molar equivalent or more relative to a cyanide content in the cyanide containing wastewater; (5) the agent for treating cyanide-containing wastewater is allowed to exist so that a metal ion concentration of the metal compound is 0.1 molar equivalent or more relative to a cyanide content in the cyanide containing wastewater; (6) the cyanide-containing wastewater contains one or more coexisting substances selected from thiocyanic acid and salts thereof and ammonium ion; and (7) the cyanide-containing wastewater is adjusted to pH 6 to 11.
[0015] The phrase "the agent for treating cyanide-containing wastewater is allowed to exist so that a concentration of a specific component is at a specific molar equivalent or more relative to a cyanide content in the cyanide-containing wastewater" means that the agent is added so that a concentration or a converted concentration of a specific component, specifically an effective halogen concentration of the sum of the N-chlorosulfamate and N-bromosulfamate, a concentration of hydrogen peroxide or a metal ion concentration of the metal compound is at a specific molar equivalent or more relative to 1 molar equivalent of the total cyanide in the cyanide-containing wastewater.
[0016] (A) Agent for treating cyanide-containing wastewater The agent for treating cyanide-containing wastewater of the present invention is characterized in that the agent is an aqueous solution containing an N-chlorosulfamate and/or N-bromosulfamate (two components may be collectively referred to as "sulfamate(s)"). The agent for treating cyanide-containing wastewater of the present invention alternatively is characterized in that the agent comprises a combination of two solutions of the aqueous solution containing an N-chlorosulfamate and/or N-bromosulfamate and an aqueous solution containing hydrogen peroxide or a metal compound, or a combination of three solutions of the aqueous solution containing an N-chlorosulfamate and/or N-bromosulfamate, an aqueous solution containing hydrogen peroxide and an aqueous solution containing a metal compound.
[0017] (Sulfamates)
The sulfamates which are active components of cyanide treatment with the agent for treating cyanide-containing wastewater of the present invention may be prepared by a well-known method such as methods disclosed in Japanese Translation of PCT International Application No. 2003-503323, Japanese Unexamined Patent Publication No. 2006-022097, Japanese Translation of PCT International Application Nos. HEI 11(1999)-506139, 2001-501869, and 2003 507326 and Japanese Unexamined Patent Publication No. 2014 101251. The active component of the agent for treating cyanide containing wastewater of the present invention is more preferably an N chlorosulfamate in terms of the effect of cyanide removal. In the present invention, a reaction product of sulfamic acid and hypochlorous acid and/or hypobromous acid may be suitably used. Addition of the sulfamate(s) by the reaction is specifically described under the section of (B) Method for treating cyanide-containing wastewater hereinbelow.
[0018] The agent for treating cyanide-containing wastewater of the present invention is in the form of aqueous solution and the agent for treating cyanide-containing wastewater has an active component concentration, namely an effective halogen concentration of the sum of the sulfamates of 0.5 mg/L or more. When the agent for treating cyanide-containing wastewater has a high concentration, the agent may be appropriately diluted with water such as industrial water upon use. In cases where active components are produced by reaction in situ, the concentrations of the compounds in the aqueous solution(s) before reaction may be appropriately adjusted so that the concentrations after reaction fall within the treatment conditions. The agent for treating cyanide-containing wastewater of the present invention preferably has pH of 12 or more. However, the pH is not limited thereto when active components are produced by reaction in situ and the pH may be such that the acidity of sulfamic acid and salts thereof may be neutralized.
[0019] (Hydrogen peroxide) The hydrogen peroxide used in the present invention may be
hydrogen peroxide aqueous solutions having concentrations of 3 to 60% which are commercially available mainly for industrial use. Hydrogen peroxide generated from hydrogen peroxide-providing compounds (also referred to as "hydrogen peroxide-generating agent") and hydrogen peroxide generated by electrolysis of industrial water or
alkaline solutions may also be used. Examples of the hydrogen peroxide-providing compound include inorganic peracids that can release hydrogen peroxide in water such as percarbonic acid, perboric acid and peroxysulfuric acid; organic peracids such as peracetic acid; and salts thereof. Examples of the salt
include sodium percarbonate, sodium perborate and the like. The hydrogen peroxide and the hydrogen peroxide-providing compound may be used after diluting or dissolving in water such as industrial water so as to provide a desired hydrogen peroxide concentration upon addition.
[0020] (Metal compound) Examples of the metal compound used in the present invention
include metal compounds used for cyanide removal in the art and specific examples thereof include manganese compounds, copper compounds, zinc compounds, iron compounds and the like.
[0021] (Manganese compound) The manganese compound is not particularly limited as far as the compound is a water-soluble neutral salt, and examples thereof include manganese chloride, manganese sulfate, manganese nitrate, manganese borate, manganese acetate and the like. Among these, manganese chloride is particularly preferable in terms of the effect of removal of the cyanide compound and the cost for treatment of the cyanide wastewater.
[0022] (Copper compound) The copper compound is not particularly limited as far as the compound is soluble in water and can form cuprous or cupric ion in water. Examples thereof include cuprous chloride, cuprous fluoride, cuprous bromide, cuprous iodide, cupric chloride, cupric fluoride, copper nitrate and copper sulfate and the like. Among these, cuprous chloride, cupric chloride and copper sulfate are preferable and cuprous chloride and cupric chloride are particularly preferable in terms of the effect of removal of the cyanide compound and the cost for treatment of the cyanide wastewater. The copper compound in the form of solution is preferably added to the cyanide wastewater. However, when the cuprous compound is a cuprous salt, it is preferable to prepare a cuprous salt solution in a solvent which is hydrochloric acid, an alkali metal halide aqueous solution or ethanol because of the stability of the cuprous salt in solution.
[0023] (Zinc compound) The zinc compound is not particularly limited as far as the compound is soluble in water and can form a divalent zinc ion in water. Examples thereof include zinc chloride, zinc sulfate, zinc ammonium chloride (ammonium tetrachlorozincate), zinc nitrate, zinc thiocyanate, zinc acetate, zinc lactate, zinc citrate and the like. Among these, zinc chloride is particularly preferable in terms of the effect of removal of the cyanide compound and the cost for treatment of the cyanide wastewater.
[0024] (Iron compound) The iron compound is not particularly limited as far as the compound is soluble in water and can form a ferrous ion in water. Examples thereof include ferrous salts such as ferrous chloride, ferrous sulfate and ammonium iron(II) sulfate hexahydrate. Among these,
ferrous chloride is particularly preferable in terms of the effect of removal of the cyanide compound and the cost for treatment of the cyanide wastewater. In the method of the present invention, a compound that can form a ferrous ion in water encompasses a compound that can form a ferrous ion produced by adding a compound that can form a ferric ion together with a reducing agent to the cyanide-containing wastewater or by adding a compound that can form a ferric ion to reducing cyanide containing wastewater to reduce in the wastewater the compound that can form a ferric ion. Examples of the reducing agent include a sulfite, hydrazine and the like.
[0025] Among the metal compounds, a compound containing manganese, copper, zinc or iron is preferable and a compound containing manganese, copper or zinc is particularly preferable in terms of the effect of removal of the cyanide compound and the cost for treatment of the cyanide wastewater. Specifically, manganese chloride, cuprous chloride, cupric chloride, zinc chloride and ferrous chloride are mentioned, and manganese chloride, cuprous chloride, cupric chloride and zinc chloride are particularly preferable. The metal compound may be used by, similar to the sulfamates and hydrogen peroxide, dissolving in water such as industrial water at a desired concentration.
[0026] (Formulation) The agent for treating cyanide-containing wastewater of the present invention in combination includes combinations of two or three aqueous solutions indicated below. (1) a combination of three solutions of an aqueous solution containing a sulfamate, an aqueous solution containing hydrogen peroxide and an aqueous solution containing a metal compound; (2) a combination of two solutions of an aqueous solution containing a sulfamate and an aqueous solution containing hydrogen peroxide; and (3) a combination of two solutions of an aqueous solution containing a sulfamate and an aqueous solution containing a metal compound. Among the above combinations, the formulation (1) or (2) is particularly preferable in terms of the effect of the present invention and ease of operation of addition of the formulation.
[0027] The concentrations of the sulfamate(s), hydrogen peroxide and the metal compound in the aqueous solutions may be appropriately adjusted according to the solubility and pH of compounds, handling properties and the like.
[0028] (Cyanide-containing wastewater)
The cyanide-containing wastewater to be treated in the present invention may be cyanide-containing wastewater containing cyanide
compounds of metals, cyanide ions, cyano complexes and cyanide complex ions discharged from iron mills, chemical plants, metal plating plants, coke-making mills, metal surface treatment plants and the like; cyanide-containing wastewater discharged during radiation contaminated water treatment; and cyanide-containing wastewater discharged from soil treatment facilities. The method for treating
cyanide-containing wastewater of the present invention is particularly suitable for treatment of cyanide-containing wastewater having a high buffering effect such as coke oven wastewater, namely cyanide containing wastewater containing thiocyanic acid and salts thereof and ammonium ion.
[0029] The cyanide-containing wastewater contains various coexisting substances such as reducing substances that easily react with an oxidizing agent and may react in aeration treatment including sulfide ions, sulfite ions, nitrite ions, thiosulfate ions, hydrazines, ferrous ions and the like, and persistent substances that may react only with an oxidizing agent having a certain level or more of oxidizing power including cyanide ions, thiocyanate ions, ammonium ions, organic substances (formaldehyde, amino acids, proteins, microorganisms) and the like.
[0030] These substances and ions may react with an oxidizing agent
having high oxidizing power. Meanwhile, the active components for
cyanide treatment of the agent for treating cyanide-containing wastewater of the present invention, sulfamates, have low oxidizing power and may preferentially react only with substances that are easily oxidized such as cyanide ions (which may be referred to as "free cyanide") and thus may also be referred to as stabilized halogen containing oxidizing agents. The active components of the agent for treating cyanide containing wastewater of the present invention serve as stabilized halogen-containing oxidizing agents and preferentially react with cyanide ions, thereby exhibiting the effect of the present invention. In addition, a risk of corrosion or salt deposition in base materials of piping in devices due to an increased oxidation-reduction potential (ORP) or a high amount of residual halogen in the cyanide-containing wastewater may be decreased.
[0031] Therefore, the agent for treating cyanide-containing wastewater of the present invention may be suitably used for treatment of cyanide containing wastewater containing one or more coexisting substances selected from thiocyanic acid and salts thereof and ammonium ion.
[00321 The cyanide-containing wastewater may have pH 6 of more, specifically 6, 6.5, 7, 7.5, 8, 8.5, 9, 10 or 11, preferably pH 6 to 11 and more preferably pH 6 to 9 in terms of the effect of cyanides removal. When the cyanide-containing wastewater has less than pH 6, it may be dangerous because hazardous hydrogen cyanide gas may be volatilized. Meanwhile, when the cyanide-containing wastewater has above pH 11, a high amount of alkaline chemicals is required and pH needs to be adjusted to above pH 9 because it is above the effluent standard. The cyanide-containing wastewater to be treated generally is in the neutral to alkaline region. However, when the pH thereof is outside of the range, pH may be adjusted by adding an acid or alkali that does not inhibit the effect of the present invention such as sulfuric acid or sodium hydroxide to the wastewater to be treated.
[0033] (B) Method for treating cyanide-containing wastewater The method for treating cyanide-containing wastewater of the present invention is characterized in that the agent for treating cyanide containing wastewater of the present invention is allowed to exist in cyanide-containing wastewater to decompose or insolubilize cyanides in
the wastewater, thereby removing the cyanide from the wastewater.
[0034] The inventors of the present invention believe that "decomposition of cyanide in wastewater" is due to oxidation of cyanide with the added sulfamates and production of ammonium hydrogen
carbonate by hydrolyzation of the produced cyanic acid. The inventors of the present invention also believe that "insolubilization of cyanide in wastewater" is due to formation of water insoluble metal complex salt from the added metal compound with cyanide in the wastewater.
[0035] In the method for treating cyanide-containing wastewater of the present invention, a manner for allowing the sulfamate to exist in cyanide-containing wastewater is not particularly limited. Examples
include simultaneous or separate addition of an aqueous solution containing an alkali agent and a stabilizing agent selected from amino acids such as glycine, a-alanine, sodium glutamate, sodium aspartate, methionine and lysine hydrochloride, amides such as sulfamic acid, succinimide, caprolactam and maleimide and taurine and an aqueous solution containing hypochlorous acid and/or hypobromous acid; simultaneous or separate addition of an aqueous solution containing an alkali agent, sulfamic acid and sodium bromide and an aqueous solution containing hypochlorous acid; and the like
[0036] (Sulfamic acid) Sulfamic acid used in the present invention may be obtained by dissolving in water a compound that may produce sulfamic acid in water to react with hypochlorous acid and hypobromous acid. Examples of the compound include alkali metal salts of sulfamic acid such as sodium sulfamate and potassium sulfamate; and organic sulfamic acids and salts thereof such as methylsulfamic acid, sodium methylsulfamate, potassium methylsulfamate, ammonium methylsulfamate, phenylsulfamic acid, sodium phenylsulfamate, potassium phenylsulfamate and ammonium phenylsulfamate. Particularly, sodium sulfamate and potassium sulfamate are industrially easily available and are suitably used in the present invention.
[0037] (Hypochlorous acid and hypobromous acid) Hypochlorous acid and hypobromous acid used in the present invention may be obtained by dissolving in water compounds that may produce hypochlorous acid and hypobromous acid, respectively, to react with sulfamic acid. Examples of the compound include alkali metal salts and alkaline earth metal salts of hypochlorous acid and hypobromous acid such as sodium hypochlorite, potassium hypochlorite, calcium hypochlorite, magnesium hypochlorite, sodium hypobromite, potassium hypobromite, calcium hypobromite and magnesium hypobromite. Particularly, sodium hypochlorite, potassium hypochlorite, sodium hypobromite and potassium hypobromite are industrially easily available and are suitably used in the present invention. Hypochlorous acid may be obtained by electrolysis of salt solution or marine water in an electrolysis vessel.
[0038] (Alkali agent) The alkali agent used in the present invention has functions to neutralize sulfamic acid and salts thereof, to make pH of the aqueous solution of the sulfamic acid and salts thereof alkaline, and to contribute to the stability of an aqueous solution of an N chlorosulfamate or N-bromosulfamate which is a reaction product of a hypohalous acid and sulfamic acid. The alkali agent is not particularly
limited as far as the agent has the above functions, and examples thereof include sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate and the like. Particularly, sodium
hydroxide and potassium hydroxide are industrially easily available and are suitably used in the present invention.
[0039] (Addition amount and addition of sulfamate(s) only) The amount(s) of addition of the sulfamate(s) to the agent for treating cyanide-containing wastewater of the present invention (the amount to be allowed to exist in cyanide-containing wastewater) may be appropriately decided according to the conditions because the amount(s) is affected by the type and concentration of cyanide in cyanide-containing wastewater as well as the type and concentration of other metal ions in cyanide-containing wastewater. Specifically, the
amount(s) of the additive(s) may be decided based on the cyanide concentration or the like of cyanide-containing wastewater measured before the treatment.
[0040]
The cyanide concentration in cyanide-containing wastewater may be measured according to a well-known method. Examples of the method include methods defined in item 38 of JIS K0102:2013 "Testing methods for industrial water" such as pyridine-pyrazolone absorption spectrophotometry, 4-pyridinecarboxylic acid-pyrazolone absorption spectrophotometry, ion electrode method, and flow analysis, modified methods such as picric acid method, microdiffusion-ion electrode method, microdiffusion method using acetate buffer, flow injection-ion electrode method, flow injection-chemiluminescence method, fluorescence derivatization HPLC method, conductivity detection ion chromatography and electrochemical detection ion chromatography. Practically, the method may be appropriately selected according to the status of cyanide-containing wastewater and the like, and a total cyanide detector by picric acid method that is used in Examples may be used.
[0041] The amount of addition of the agent for treating cyanide containing wastewater of the present invention may vary according to the content of cyanide in cyanide-containing wastewater to be treated. The agent is preferably allowed to exist in cyanide-containing wastewater so that an effective halogen concentration of the sum of the sulfamates is 0.2 molar equivalent or more relative to the cyanide content in the wastewater. Specific effective halogen concentrations (molar equivalent) include 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 and 10. More preferably, the effective halogen concentration is 1 molar equivalent or more relative to the cyanide content in the cyanide containing wastewater.
When the effective halogen concentration is less than 0.2 molar equivalent, the reaction with cyanide ions may be insufficient, resulting in insufficient effect of cyanide removal. The upper limit of the amount of addition of the agent for treating cyanide-containing wastewater is not particularly limited; however, the amount of about 10 molar equivalent may provide sufficient effect of cyanide removal.
[0042] The cyanide content of the cyanide-containing wastewater to be treated in the present invention is not particularly limited; however, the cyanide-containing wastewaters described above generally have a total cyanide concentration of about 2 to 500 mg/L. When such cyanide
containing wastewater is treated, the alkali agent may be added so as to be 0.6 to 2000 mg/L, preferably 1 to 600 mg/L, the sulfamic acid compound may be added so as to be 0.05 to 1000 mg/L, preferably 0.08 to 300 mg/L, the hypochlorite salt and the hypobromite salt in total may be added so as to be 3 to 10000 mg/L, preferably 5 to 3000 mg/L to cyanide-containing wastewater.
[0043] (Addition amount and addition of sulfamate(s) in combination with other components) The amount of addition of the agent for treating cyanide containing wastewater of the present invention (the amount to be allowed to exist in cyanide-containing wastewater) may be appropriately decided according to the conditions because the amount is affected by the type and concentration of cyanide in cyanide-containing wastewater as well as the type and concentration of other metal ions in cyanide containing wastewater. Specifically, the amount(s) of the additive(s)
may be decided based on the cyanide concentration or the like of cyanide-containing wastewater measured before the treatment.
The cyanide concentration in cyanide-containing wastewater may be measured as described in "Addition amount and addition of sulfamate(s) only" above.
[0044] The amount of addition of the agent for treating cyanide containing wastewater of the present invention may vary according to the content of cyanide in cyanide-containing wastewater to be treated, and may be appropriately decided. The amount of sulfamate(s) may be lower than the case of addition of sulfamate(s) only because of an effect of combining use with other components. For example, the agent may be allowed to exist in cyanide-containing wastewater so that an effective halogen concentration of the sum of the sulfamates is 0.1 molar equivalent o r more relative to the cyanide content in the wastewater. Specific effective halogen concentrations (molar equivalent) include 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7,
7.5, 8, 8.5, 9, 9.5 and 10. More preferably, the effective halogen concentration is 0.5 molar equivalent or more relative to the cyanide content in cyanide-containing wastewater. When the effective concentration is less than 0.1 molar equivalent, the reaction with cyanide ions may be insufficient, resulting in insufficient effect of cyanide removal. The upper limit of the amount of addition of the agent for treating cyanide-containing wastewater is not particularly limited; however, the amount of about 10 molar equivalent may provide sufficient effect of cyanide removal.
[0045] It is also preferable that the agent is allowed to exist in cyanide containing wastewater so that hydrogen peroxide is 0.1 molar equivalent or more relative to the cyanide content in the wastewater. Specific hydrogen peroxide concentrations (molar equivalent) include 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 and 10. More preferably, the hydrogen peroxide concentration is 0.5 molar equivalent or more relative to the cyanide content in cyanide containing wastewater. When the hydrogen peroxide concentration is less than 0.1 molar equivalent, the reaction with cyanide ions may be insufficient, resulting in insufficient effect of cyanide removal. The upper limit of the amount of addition of the agent for treating cyanide-containing wastewater is not particularly limited; however, the amount of about 10 molar equivalent may provide sufficient effect of cyanide removal.
[00461 The metal compound is preferably allowed to exist in cyanide containing wastewater so that the metal ion concentration thereof is 0.1 molar equivalent or more relative to the cyanide content in the wastewater. Specific metal ion concentrations (molar equivalent) include 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 and 10. More preferably, the metal ion concentration is 0.5 molar
equivalent or more relative to the cyanide content in the wastewater. When the metal ion concentration is less than 1 molar equivalent, the reaction with cyanide ions may be insufficient, resulting in insufficient effect of cyanide removal. The upper limit of the amount
of addition of the agent for treating cyanide-containing wastewater is not particularly limited; however, the amount of about 10 molar equivalent may provide sufficient effect of cyanide removal.
[0047] The cyanide content in cyanide-containing wastewater to be treated in the present invention is not particularly limited; however, the cyanide-containing wastewaters described above generally have a total cyanide concentration of about 2 to 500 mg/L. When treating such cyanide-containing wastewater, the alkali agent may be added so as to be 0.3 to 2000 mg/L, preferably 0.5 to 600 mg/L, the sulfamic acid compound may be added so as to be 0.02 to 1000 mg/L, preferably 0.04 to 300 mg/L, the hypochlorite salt and the hypobromite salt in total may be added so as to be 1 to 10000 mg/L, preferably 2.5 to 3000 mg/L to cyanide-containing wastewater. Alternatively, hydrogen peroxide may be added so as to be 0.2 to 6500 mg/L, preferably 1 to 2000 mg/L, and the metal compound may be added so as to be 0.4 to 12000 mg/L, preferably 2 to 3600 mg/L to cyanide-containing wastewater.
[0048] In the method for treating cyanide-containing wastewater of the present invention, sulfamate(s) and hydrogen peroxide and/or the metal compound may be allowed to exist in cyanide-containing wastewater to be treated by simultaneously or separately adding the formulation containing the combination of two or three solutions to cyanide containing wastewater to be treated.
[0049] (Cyanide-containing wastewater) The cyanide-containing wastewater to be treated is as described in (A) Agent for treating cyanide-containing wastewater above and preferably contains one or more coexisting substances selected from thiocyanic acid and salts thereof and ammonium ion. The cyanide-containing wastewater to be treated preferably has pH 6 to 11. When pH is outside of the range, it is preferable that pH of the wastewater is adjusted with an acid or alkaline.
[0050] (Agitation) It is preferable that a mixed solution during addition of each compound and reaction of the added compounds with cyanide is agitated in terms of the effect of cyanides removal. It is preferable that
agitation is performed every time when a compound is added. For the purpose of promoting the reaction during agitation, it is preferable that the mixed solution is heated at some extent so that the added compound is not decomposed. The liquid temperature is about 20 to 60°C. The time required for the reaction during agitation may vary according to the amount of cyanide-containing wastewater, the type and concentration of cyanides, the form and scale of the treatment device, and may be appropriately decided so that cyanides is in sufficient contact with the added compound. Generally, the agitation time may
be 10 minutes or more and more preferably 20 to 60 minutes.
[0051] (Treatment and precipitation separation) For a series of operations including addition of compounds, mixing by agitation, sedimentation separation and removal of the water insoluble salt, well-known devices such as an additive vessel, a reaction treatment vessel, a thickener and a clarifier may be used. Existing
facilities may be converted for the purpose. In the method for treating cyanide-containing wastewater of the present invention, a well-known chemical such as a rust preventing agent, a corrosion inhibitor, a scale dispersing agent, a slime control agent, a metal scavenger and an antifoaming agent may also be used at a range that does not inhibit the effect of the present invention.
In sedimentation separation, a surfactant or a flocculant may be added at a range that does not inhibit the effect of the present invention. The method may be used in combination with a well-known chemical cyanides treatment method as described in Background Art or a well-known physical cyanides treatment method using infrared rays or ultraviolet rays. As used herein, "water-insoluble" means that a compound (salt) has a solubility of 1 g or less in 100 g water at 20°C and the insoluble content of the compound can be separated from a liquid phase by sedimentation separation or filtration.
[0052] According to the above treatment, cyanides in wastewater can be removed safely by simple procedures while using as little chemicals as possible compared to conventional methods from wastewater containing cyanides, particularly cyanide-containing wastewater containing coexisting substances such as thiocyanate ion or ammonium ion, the cyanide concentration (total cyanide content (mg/L)) before the treatment can be significantly reduced to at or lower than the effluent standard, and thus wastewater after the treatment can be discharged into sewers or recycled without requiring neutralization treatment. When the treated wastewater is released as it is, compounds may be added at such amounts that the total cyanide concentration is reduced at or below the effluent standard in the method of the present invention. When the treated wastewater is diluted in another wastewater before release, the compounds may be added at such amounts that the diluted wastewater has the total cyanide concentration at or below the effluent standard.
Generally, treated wastewater is released after diluting thereof with another wastewater at plants and the like. It is preferable to
control the amounts of active components by taking the cost effectiveness into account. Thus, it is understood that the present invention encompasses
the treatment which does not result in the total cyanide concentration after the treatment of 1 mg/L or lower such as the treatment which results in the concentration of generally 5 mg/L or less.
[0053] The present invention is specifically described by way of Formulation Examples and Test Examples which do not limit the present invention.
[0054] In the following Test Example 1-1, synthetic cyanide-containing
wastewater 1-A was used which was prepared from synthetic water (pH 8.2) prepared to have water quality indicated in Table 1 so as to have the contents of free cyanide (F-CN), thiocyanate ion (SCN-) and ammonium ion (NH4 +) indicated in Table 3. The synthetic cyanide-containing wastewater was prepared with a potassium ferrocyanide aqueous solution, a potassium cyanide aqueous solution, a potassium thiocyanate aqueous solution, a calcium chloride dihydrate aqueous solution, a sodium chloride aqueous solution, a sodium sulfate aqueous solution, an ammonium chloride aqueous solution and a sodium hydrogen carbonate aqueous solution.
[0055] Table 1
Item Concentration (mg/L) Sodium ion 947 Potassium ion 30 Calcium ion 80 Chloride ion 798 Sulfate ion 67 Hydrogencarbonate ion 610
[0056] In the following Test Example 1-2, cyanide-containing wastewater 1-B (pH 8.6) was used which was collected from a coke oven wastewater line at an iron mill and had water quality indicated in Table 2.
[0057] Table 2 Item Concentration (mg/L) Conductivity 402 mS/m Acid consumption (pH 4.8) 1100 CODMn 19 Total nitrogen 150 Ammonia nitrogen 140 Chloride ion 460 Sulfate ion 110 Calcium hardness 170 Thiocyanate ion 11 Zinc 12 Iron 5.6 Total cyanide 9.1
[0058] (Formulation Example 1-1: Preparation of N-chlorosulfamate) To a 500-mL beaker, 48.8 g of pure water, 23.8 g of sulfamic acid, 47.0 g of 48% sodium hydroxide aqueous solution and 130.5 g of 10.6% sodium hypochlorite aqueous solution were added and stirred to obtain N-chlorosulfamate aqueous solution (effective chlorine concentration: 5.5%).
[00591 (Formulation Example 1-2: Preparation of N-bromosulfamate) To a 500-mL beaker, 172 g of 10.6% sodium hypochlorite aqueous solution, 35 g of 48% sodium hydroxide aqueous solution and 40 g of sodium bromide were added and stirred in a water bath at 50C for 2 hours to obtain a yellow transparent aqueous solution. Separately, to a 200-mL beaker, 64.0 g of pure water, 31.2 g of sulfamic acid and 27 g of 48% sodium hydroxide aqueous solution were added and stirred to obtain transparent aqueous solution. The yellow transparent aqueous solution and the transparent aqueous solution were mixed at room temperature to obtain N-bromosulfamate aqueous solution (effective bromine concentration: 10.2%).
[0060] (Test Example 1-1) To respective 100-mL beakers, 100mL of cyanide-containing wastewater 1-A was placed, and one of sodium N-chlorosulfamate, sodium N-bromosulfamate, sodium hypochlorite and sodium hypobromite was respectively added so as to obtain the concentrations indicated in Table 3, thereby obtaining water samples. To some water samples, a sulfuric acid aqueous solution or a sodium hydroxide aqueous solution was added to adjust the pH of the water samples to the values indicated in Table 3. The obtained water samples were then agitated on an agitator (produced by AS ONE Corporation, magnetic stirrer, model: RS-4AR, stirrer: plane shape, the longest side: 30 mm) at a rotation speed of 250 rpm for 15 minutes. The water samples (treated solutions) were then measured for the total cyanide concentration (T-CN) according to the picric acid method with a total cyanide analyzer (produced by Kyoritsu Chemical
Check Lab. Corp., model: WA-CNT), thereby evaluating the effect of removal of cyanide compound in water samples. In the present test, a blank sample (Comparative Example 1-4) without addition of the agent was tested in parallel. The obtained results are shown in Table 3 together with the
compounds added and the amounts thereof and the pH of water samples.
v C\ `-r- r ro Lo x-r 0m C: C 6J: 6 C 6 6c: cP-a vf vI vUl 0 ~ & . wi m 0
cu
=- cu E - r- o r- - - C N- -r- P- 04 t- r
'0 *0
-E cu zm Cu
r- Cu4 0 CD
2o E)2 waEa) 0
E~cu a
C:Cu
0) .V . C4C)C C4C D 7
0 u
Z 2E 0)
Cu1 CN-N-? - *1 CL C CuC ? L"I
-- -~ - - - - - -)
0~C 0) 0X 0)-I LU~~~~~~ ~ ~~ a iQw0wQL + (= -
[0062] The test results in Table 3 indicate the following: treatment with the agents for treating cyanide-containing wastewater of the present invention exhibited sufficient effect of cyanide removal (Examples 1-1 to 1-11); when cyanide-containing wastewater containing coexisting substances (SCN-, NH 4 +)was treated with the agents for treating cyanide-containing wastewater of the present invention, sufficient effect of cyanide removal was exhibited (Examples 1-8 to 1-10); treatment of cyanide-containing wastewater containing coexisting substances (SCN-, NH4+) with an agent for treating cyanide containing wastewater containing sodium hypochlorite or sodium hypobromite did not provide sufficient effect of cyanide removal (Comparative Examples 1-1 to 1-3); and treatment of cyanide-containing wastewater containing coexisting substances (SCN-, NH4+) with an agent for treating cyanide containing wastewater containing sodium hypobromite did not provide sufficient effect of cyanide removal even when an excess amount of sodium hypobromite was used (Comparative Example 1-2).
[0063] (Test Example 1-2) To respective 100-mL beakers, 100 mL of cyanide-containing wastewater 1-B was placed, and one of sodium N-chlorosulfamate and sodium hypochlorite was respectively added so as to obtain the concentrations indicated in Table 4, thereby obtaining water samples. To some water samples, a sulfuric acid aqueous solution or a sodium hydroxide aqueous solution was added to adjust the pH of the water samples to the values indicated in Table 4. The obtained water samples were then agitated on an agitator
(produced by AS ONE Corporation, magnetic stirrer, model: RS-4AR, stirrer: plane shape, the longest side: 30 mm) at a rotation speed of 250 rpm for 15 minutes. The water samples (treated solutions) were then measured for the total cyanide concentration (T-CN) according to JIS K0102, thereby evaluating the effect of removal of cyanide compound in water samples. In the present test, a blank sample (Comparative Example 1-6) without addition of the agent was tested in parallel. The obtained results are shown in Table 4 together with the compounds added and the amounts thereof and the pH of water samples.
00 0
mmtt
Clo
CO *~ (nOD (D-%
CD cc
C) 01
an
ca. CD CL CD CL
00
rCC"
C=) 0
o 0
2
0
000
c-mc oo
[0065] The test results in Table 4 indicate the following: treatment with the agents for treating cyanide-containing wastewater of the present invention exhibited sufficient effect of cyanide s removal (Examples 1-12 and 1-13); and treatment of cyanide-containing wastewater containing coexisting substances (SCN-, NH 4 +) with an agent for treating cyanide containing wastewater containing sodium hypochlorite did not provide sufficient effect of cyanides removal (Comparative Example 1-5).
[0066] The agent for treating cyanide-containing wastewater of the present invention may be a 2-component formulation or a 3-component formulation of aqueous solutions of the compounds having certain concentrations as indicated below in Formulation Examples 2-1 to 2 11. (Formulation Example 2-1) - 35% N-chlorosulfamate aqueous solution - 3% hydrogen peroxide aqueous solution - 30% manganese chloride aqueous solution (Formulation Example 2-2) - 25% N-chlorosulfamate aqueous solution - 10% hydrogen peroxide aqueous solution - 15% cuprous chloride aqueous solution (Formulation Example 2-3) - 20% N-chlorosulfamate aqueous solution - 15% hydrogen peroxide aqueous solution
- 25% cupric chloride aqueous solution (Formulation Example 2-4)
- 15% N-chlorosulfamate aqueous solution - 35% hydrogen peroxide aqueous solution - 40% zinc chloride aqueous solution (Formulation Example 2-5) - 5% N-chlorosulfamate aqueous solution - 45% hydrogen peroxide aqueous solution - 25% ferrous chloride aqueous solution
[0067] (Formulation Example 2-6) - 20% N-chlorosulfamate aqueous solution - 35% hydrogen peroxide aqueous solution (Formulation Example 2-7) - 25% N-chlorosulfamate aqueous solution - 30% manganese chloride aqueous solution (Formulation Example 2-8) - 25% N-chlorosulfamate aqueous solution - 15% cuprous chloride aqueous solution (Formulation Example 2-9) - 20% N-chlorosulfamate aqueous solution - 25% cupric chloride aqueous solution (Formulation Example 2-10) - 20% N-chlorosulfamate aqueous solution - 40% zinc chloride aqueous solution (Formulation Example 2-11) - 25% N-chlorosulfamate aqueous solution - 25% ferrous chloride aqueous solution
[0068] In the following Test Example 2-1 and Test Example 2-3, synthetic cyanide-containing wastewater 2-A was used which was prepared from synthetic water (pH 8.2) prepared to have water quality indicated in Table 5 so as to have the contents of cyanide ion (free cyanide: F-CN), cyano complex, thiocyanate ion (SCN-) and ammonium ion (NH 4 +) indicated in Table 5. The synthetic cyanide-containing wastewater was prepared with a potassium ferrocyanide aqueous solution, a potassium cyanide aqueous solution, a potassium thiocyanate aqueous solution, a calcium chloride dihydrate aqueous solution, a sodium chloride aqueous solution, a sodium sulfate aqueous solution, an ammonium chloride aqueous solution and a sodium hydrogen carbonate aqueous solution.
[0069] Table 5 Item Concentration (mg/L) Sodium ion 717 Potassium ion 90 Calcium ion 80 Chloride ion 1193 Sulfate ion 67 Hydrogencarbonate ion 610 Ammonium ion (NH4+) 201 Thiocyanate ion (SCN-) 93 Cyanide ion 14 (free cyanide: F-CN) Cyano complex 6.0
[0070] In the following Test Example 2-2, cyanide-containing wastewater 2-B (pH 7.1) was used which was collected from a coke oven wastewater line at an iron mill and had water quality indicated in Table 6.
[0071]
Table 6 Item Concentration (mg/L) Conductivity 92.7 mS/m Acid consumption (pH 4.8) 280 CODMn 16 Total nitrogen 84 Ammonium ion 91 Chloride ion 66 Sulfate ion 63 Calcium hardness 49 Thiocyanate ion 4.1 Zinc 0.5 Iron 0.5 Total cyanide 3.0
[0072] (Formulation Example 2-A: Preparation of N-chlorosulfamate) Same as in Formulation Example 1-1. (Formulation Example 2-B: Preparation of N-bromosulfamate) Same as Formulation Example 1-2.
[0073] (Test Example 2-1) To respective 100-mL beakers, 100 mL of cyanide-containing wastewater 2-A was placed, and one of N-chlorosulfamate, N bromosulfamate and a combination of sodium hypochlorite and sulfamic acid, and hydrogen peroxide and manganese chloride were respectively added so as to obtain the concentrations indicated in Table 7, thereby obtaining water samples. To some water samples, a sulfuric acid aqueous solution or a sodium hydroxide aqueous solution was added to adjust the pH of the water samples to the values indicated in Table 7.
[0074] The obtained water samples were then agitated on an agitator (produced by AS ONE Corporation, magnetic stirrer, model: RS-4AR, stirrer: plane shape, the longest side: 30 mm) at a rotation speed of 250 rpm. Specifically, the solution was agitated for 1 minute after addition of N-chlorosulfamate, N-bromosulfamate or a combination of sodium hypochlorite and sulfamic acid, for 1 minute after addition of hydrogen peroxide and for 15 minutes after addition of manganese chloride. After the test, the water samples were filtered through filter paper (produced by Toyo Roshi Kaisha, Ltd. (ADVANTEC), product name: No. 5C) and the filtrates were obtained as treated solutions.
[0075] The water samples (treated solutions) were then measured for the total cyanide concentration (T-CN) according to the picric acid method with a total cyanide analyzer (produced by Kyoritsu Chemical Check Lab. Corp., model: WA-CNT), thereby evaluating the effect of removal of cyanide compound in water samples. In the present test, a blank sample (Comparative Example 2-4) without addition of the agent was tested in parallel. The obtained results are shown in Table 7 together with the compounds added and the amounts thereof and the pH of water samples.
[0076] The test results in Table 7 indicate the following: treatment with the agents for treating cyanide-containing wastewater of the present invention exhibited sufficient effect of cyanide removal (Examples 2-1 to 2-7); and treatment with an agent for treating cyanide-containing wastewater containing only manganese chloride, or manganese chloride and sodium hypochlorite and/or hydrogen peroxide did not provide sufficient effect of cyanides removal (Comparative Examples 2-1 to 2-5).
mcnmomjmomomomo Mmmmmm M 2 3 3 '3 S'fB3rB2 r s po 3 c
~C 20
o~ a
0 m o (.&) rC ) 0 ) rCDN
33
-3
cCnr-J--4-4 C E SC C) =~ CD
a-3 cc o O
0) Cicn C,,D
Lnx CC o r -a
:3 A a
- z )
[0078] (Test Example 2-2) To respective 300-mL beakers, 300 mL of cyanide-containing wastewater B was placed, and N-chlorosulfamate and hydrogen peroxide were added so as to obtain the concentrations indicated in Table 8, thereby obtaining water samples. To some water samples, a sulfuric acid aqueous solution or a sodium hydroxide aqueous solution was added to adjust the pH of the water samples to the values indicated in Table 8.
[0079] The obtained water samples were then agitated on an agitator (produced by AS ONE Corporation, magnetic stirrer, model: RS-4AR, stirrer: plane shape, the longest side: 30 mm) at a rotation speed of 250 rpm. Specifically, the solution was agitated for 10 minutes after addition of hydrogen peroxide (first stage) and then for 40 minutes after addition of N-chlorosulfamate (second stage). After the test, the water
samples were filtered through filter paper (produced by Toyo Roshi Kaisha, Ltd. (ADVANTEC), product name: No. 5C) and the filtrates were obtained as treated solutions.
[0080] The water samples (treated solutions) were then measured for the total cyanide concentration (T-CN) according to JIS K0102, thereby evaluating the effect of removal of cyanide compound in water samples. In the present test, a blank sample (Comparative Example 2-7) without addition of the agent and a sample (Reference Example) to which only N-chlorosulfamate was added were tested in parallel. The obtained results are shown in Table 8 together with the
compounds added and the amounts thereof and the pH of water samples.
CD P) CD 00
C) X m CD 0 ?< mnr N) CO
C aa CDD
X -n a CD
-c CD 0
CDw
CD -a
0o CD
CD En
0D
[0082] The test results in Table 8 indicate the following: treatment with the agent for treating cyanide-containing wastewater of the present invention (Example 2-8) exhibited sufficient effect of cyanides removal and exhibited superior effect of cyanides removal to the treatment with only N-chlorosulfamate (Reference Example); and
[0083] (Test Example 2-3) To respective 100-mL beakers, 100 mL of cyanide-containing wastewater A was placed, and N-chlorosulfamate, hydrogen peroxide and a metal compound selected from cuprous chloride, cupric chloride and zinc chloride were respectively added so as to obtain the concentrations indicated in Table 9, thereby obtaining water samples. With the obtained water samples, the effect of removal of cyanide compound in the water samples was evaluated in the same manner as in Test Example 2-1. In the present test, a blank sample (Comparative Example 2-8) without addition of the agent was tested in parallel. The obtained results are shown in Table 9 together with the compounds added and the amounts thereof and the pH of water samples.
[0084] The test result in Table 9 indicate the following; treatment with the agents for treating cyanide-containing wastewater of the present invention exhibited sufficient effect of cyanides removal (Examples 2-9 to 2-12).
C:\Interwo n\NRPortb\DCC\DAR\19639241- .docx-l0/12/2019
[0085] Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood
to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.
[0086] The reference in this specification to any prior publication (or information derived from it), or to any matter which
is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.
- 43A- rrrN, . 00 w) 0
CD 0
C)a CL
C- -o C
+CD
PQ N37 ' a -CL CD
CD =
IDD +CDa-.o a
C0 2 bo 4 0 C0
Claims (10)
1. An agent for treating cyanide-containing wastewater, which is
an aqueous solution containing an N-chlorosulfamate and/or N bromosulfamate.
2. The agent for treating cyanide-containing wastewater according
to claim 1, wherein the N-chlorosulfamate and N-bromosulfamate are reaction products of sulfamic acid and hypochlorous acid and/or
hypobromous acid.
3. The agent for treating cyanide-containing wastewater according to claim 1, comprising a combination of two solutions of the aqueous solution containing the N-chlorosulfamate and/or N-bromosulfamate and an aqueous solution containing hydrogen peroxide or a metal compound,
or a combination of three solutions of the aqueous solution containing the N-chlorosulfamate and/or N-bromosulfamate, an aqueous
solution containing hydrogen peroxide and an aqueous solution containing a metal compound.
4. The agent for treating cyanide-containing wastewater according to claim 3, wherein the metal compound is a compound containing manganese, copper, zinc or iron.
5. A method for treating cyanide-containing wastewater, comprising allowing the agent for treating cyanide-containing wastewater
according to claim 1 or 3 to exist in cyanide-containing wastewater to decompose or insolubilize cyanide in the wastewater, thereby removing the cyanide from the wastewater.
6. The method for treating cyanide-containing wastewater according to claim 5, wherein the agent for treating cyanide-containing
wastewater is allowed to exist so that an effective halogen concentration of the sum of the N-chlorosulfamate and N bromosulfamate is 0.2 molar equivalent or more relative to a cyanide
content in the cyanide-containing wastewater.
C:\Interwo n\NRPortb\DCC\DAR\19639241- .docx-l0/12/2019
7. The method for treating cyanide-containing wastewater according to claim 5, wherein the agent for treating cyanide-containing wastewater is allowed to exist so that a concentration of the
hydrogen peroxide is 0.1 molar equivalent or more relative to a cyanide content in the cyanide-containing wastewater.
8. The method for treating cyanide-containing wastewater according to claim 5, wherein the agent for treating cyanide-containing wastewater is allowed to exist so that a metal ion concentration of
the metal compound is 0.1 molar equivalent or more relative to a cyanide content in the cyanide-containing wastewater.
9. The method for treating cyanide-containing wastewater according to claim 5, wherein the cyanide-containing wastewater contains one or more coexisting substances selected from thiocyanic acid and salts
thereof and ammonium ion.
10. The method for treating cyanide-containing wastewater according to claim 5, wherein the cyanide-containing wastewater is adjusted to pH 6 to 11.
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| JP2016-048486 | 2016-03-11 | ||
| JP2016048486A JP5990717B1 (en) | 2016-03-11 | 2016-03-11 | Cyanogen-containing wastewater treatment agent and cyanide-containing wastewater treatment method using the same |
| JP2016-164880 | 2016-08-25 | ||
| JP2016164880A JP6578561B2 (en) | 2016-08-25 | 2016-08-25 | Cyanogen-containing wastewater treatment agent and cyanide-containing wastewater treatment method using the same |
| PCT/JP2016/076992 WO2017154243A1 (en) | 2016-03-11 | 2016-09-13 | Agent for treating cyanide-containing wastewater and method for treating cyanide-containing wastewater using same |
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| CN110318066B (en) * | 2019-06-20 | 2024-08-02 | 青岛鼎海电化学科技有限公司 | Preparation method of tetraalkylammonium hydroxide |
| CN114163843B (en) * | 2021-12-02 | 2022-11-25 | 中国科学院上海硅酸盐研究所 | A preparation method of HMPB, Prussian blue-based fluorescent probe and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5155774A (en) * | 1974-11-11 | 1976-05-17 | Asahi Chemical Ind | Haiekino shoriho |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS59169914A (en) * | 1983-03-11 | 1984-09-26 | Sumikin Coke Co Ltd | Production of ammonium sulfamate |
| CN1007041B (en) * | 1987-12-31 | 1990-03-07 | 冶金工业部建筑研究总院 | Comprehensive treatment method for sulfur dioxide-containing waste flue gas and cyanide-containing waste water |
| JPH0235991A (en) | 1988-07-22 | 1990-02-06 | Katayama Chem Works Co Ltd | Treatment of waste water containing cyanic compound |
| US5922745A (en) * | 1997-11-03 | 1999-07-13 | Nalco Chemical Company | Composition and method for inhibiting the growth of microorganisms including stabilized sodium hypobromite and isothiazolones |
| JP4106415B2 (en) | 2000-04-21 | 2008-06-25 | 株式会社片山化学工業研究所 | Treatment method of wastewater containing cyanide |
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| WO2007142618A2 (en) * | 2005-06-10 | 2007-12-13 | Albemarle Corporation | High concentrated, biocidally active compositions and aqueous mixtures and methods of making the same |
| CN103053613A (en) | 2011-10-21 | 2013-04-24 | 纳尔科公司 | Improved biological control through the use of chlorine-stabilizer mixtures |
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| JP2014176799A (en) * | 2013-03-14 | 2014-09-25 | Kurita Water Ind Ltd | Reverse osmotic membrane separation method |
| CN105152391A (en) * | 2015-08-13 | 2015-12-16 | 浙江捷华电子有限公司 | Electroplating wastewater treatment method |
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2016
- 2016-09-13 CN CN201680083212.8A patent/CN108779008B/en not_active Expired - Fee Related
- 2016-09-13 AU AU2016397146A patent/AU2016397146B2/en not_active Ceased
- 2016-09-13 WO PCT/JP2016/076992 patent/WO2017154243A1/en not_active Ceased
- 2016-09-13 KR KR1020187028529A patent/KR102117850B1/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5155774A (en) * | 1974-11-11 | 1976-05-17 | Asahi Chemical Ind | Haiekino shoriho |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108779008B (en) | 2021-08-24 |
| KR20180118759A (en) | 2018-10-31 |
| WO2017154243A1 (en) | 2017-09-14 |
| CN108779008A (en) | 2018-11-09 |
| KR102117850B1 (en) | 2020-06-02 |
| AU2016397146A1 (en) | 2018-10-04 |
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