Heavy metal treatment agent, wastewater treatment method using same, and incineration ash treatment method

Abstract

Provided are: a novel heavy metal treatment agent which improves the treatment performance of a group 6-16 element or a compound thereof in the periodic table, such as wastewater treatment or incineration ash treatment; and a wastewater treatment method and an incineration ash treatment method using the heavy metal treatment agent. This heavy metal treatment agent contains the following component (A) and at least one selected from the group consisting of components (B)-(E). (A) A dithiocarbamate of at least one type of amine compound represented by any of formulae (I) to (III) (wherein each X independently represents a hydrogen atom or a 2-aminoethyl group, at least one of which is a 2-aminoethyl group). (B) a base; (C) at least one substance selected from the group consisting of aminocarboxylic acids, thiols, and phosphoramidates; (D) a dithiocarbamate of a polyethyleneimine; and (E) a sulfur-containing compound. [Chemical Formula 1] # imgabs0 # [Chemical Formula 2] # imgabs1 # [Chemical Formula 3] # imgabs2 #

Description

Technical Field

[0001] The present invention relates to a heavy metal treating agent. Background Art

[0002] Various treatments are performed to separate and recover heavy metals from water such as industrial wastewater and workplace wastewater to purify and render the water harmless and to reuse the heavy metals.

[0003] As the method in the past of removing the metal contained in the waste water etc., known for example have neutralization aggregation sedimentation method, ion flotation method, ion exchange method, electrolytic flotation method, electrodialysis method, adsorption method, reverse osmosis method etc.But in neutralization aggregation sedimentation method, there is the problem on the operation that the formation of flocculent material is insufficient or a large amount of metal hydroxide sludges that must be generated are processed, metal ions are dissolved into rivers, seawater etc. again from discarded sludge and cause secondary public hazards or are not easy for making the metal ion concentration in the waste water reach the following reference value that the country formulates, in addition, under the situations such as ion flotation method, ion exchange method, electrolytic flotation method, electrodialysis method, adsorption method, reverse osmosis method, the removal rate of metal, operability, running cost etc. exist problems.Therefore, widely used is to replace above these methods by using metal trapping agents such as organic chelating agents to capture the metal in the waste water and remove the method for described metal.

[0004] The incineration ash (fly ash (dust) and main ash (burnt slag)) produced when municipal garbage or industrial waste is incinerated sometimes contains heavy metals that are harmful to the human body. For example, the fly ash produced when municipal garbage is incinerated in a facility contains heavy metals. If these heavy metals are leached into groundwater, rivers, or seawater, serious environmental pollution will occur. Therefore, fly ash is treated as a special general waste and is required to be subjected to intermediate treatment such as chemical reagent treatment. Fly ash containing heavy metals will be eluted due to rainwater, etc. after being landfilled. Therefore, a method of fixing the heavy metals in the fly ash to suppress the elution is generally used. The method of treating with chemical agents is a method of mixing the agent, water, and fly ash to fix the harmful heavy metals. The agents used for this purpose include organic chelating agents such as dithiocarbamates and inorganic agents such as iron compounds.

[0005] Conventionally, in the treatment of heavy metals contained in wastewater, incineration fly ash (dust), and primary ash (slag), dithiocarbamates using amine compounds such as ethylenediamine, diethylenetriamine, and piperazine as raw materials have been used as heavy metal treatment agents (metal scavengers) (Patent Documents 1 to 3).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-154130.

[0009] Patent document 2: Japanese Patent Application Publication No. 2019-026793.

[0010] Patent Document 3: Japanese Patent Application Laid-Open No. 6-079254. Summary of the Invention

[0011] Problems to be solved by the invention

[0012] However, conventional technologies have focused on heavy metal treatment performance in wastewater treatment and incineration ash treatment, particularly in wastewater treatment, where improvements in heavy metal capture and floc formation are desired, and in incineration ash treatment, where further improvements are desired to suppress leaching from the ash. Furthermore, conventional dithiocarbamates of amine compounds precipitate when mixed with water containing minerals, resulting in insufficient stability. Therefore, a heavy metal treatment agent with both heavy metal capture and stability is desired.

[0013] The present invention has been made in view of the above circumstances, and its object is to provide a novel heavy metal treatment agent which improves the treatment performance of elements of Groups 6 to 16 of the periodic table or their compounds, particularly in wastewater treatment and incineration ash treatment, and which is excellent in flocculant formation ability, stability when mixed with water containing minerals, and flocculant stability, as well as a wastewater treatment method and incineration ash treatment method using the heavy metal treatment agent.

[0014] Methods for solving the problem

[0015] As a means for solving the above-mentioned problems, the following inventions are disclosed.

[0016] [1]. A heavy metal treatment agent, wherein:

[0017] The heavy metal treatment agent comprises the following component (A) and at least one selected from components (B) to (E),

[0018] (A) at least one dithiocarbamate of an amine compound represented by any one of the following formulas (I) to (III),

[0019] [Chemical Formula 1]

[0020]

[0021] In the formula, m represents an integer of 3 to 6,

[0022] [Chemical Formula 2]

[0023]

[0024] In the formula, n Xs are independently hydrogen or 2-aminoethyl, at least one of which is 2-aminoethyl, n is an integer of 1 to 3, and the total number of nitrogen atoms is 4 to 8.

[0025] [Chemical Formula 3]

[0026]

[0027] In the formula, o represents an integer of 0 to 2, p represents 0 or 1, q represents 0 or 1, r represents an integer of 0 to 3, the sum of o, p and r is 1 or more, and the total number of nitrogen atoms is 3 to 7.

[0028] (B) alkali,

[0029] (C) at least one selected from aminocarboxylic acids, thiols and aminophosphoric acids,

[0030] (D) dithiocarbamates of polyethyleneimine,

[0031] (E) Sulfur-containing compounds.

[0032] [2] The heavy metal treatment agent as described in [1], wherein

[0033] The amine compound includes an amine compound represented by the formula (III).

[0034] [3] The heavy metal treatment agent as described in [2], wherein

[0035] The amine compound includes at least one selected from various amine compounds represented by the following formula (IIIa), formula (IIIb) and formula (IIIc) as the amine compound represented by the formula (III),

[0036] [Chemical Formula 4]

[0037]

[0038] [4] The heavy metal treatment agent as described in [3], wherein

[0039] The amine compound includes various amine compounds represented by the following formula (IIIa) and formula (IIIb) as the amine compound represented by the formula (III).

[0040] [Chemical Formula 5]

[0041]

[0042] [5] The heavy metal treatment agent as described in [4], wherein

[0043] The aforementioned amine compound further includes an amine compound represented by the following formula (IIIc) as the amine compound represented by the above formula (III),

[0044] [Chemical Formula 6]

[0045]

[0046] [6]. The heavy metal treatment agent as described in [1], wherein

[0047] The aforementioned amine compound includes each of the amine compounds represented by the above formula (I), the above formula (II), and the above formula (III).

[0048] [7] The heavy metal treatment agent as described in [6], wherein

[0049] The amine compound includes each of the following amine compounds represented by formula (Ia), formula (IIa), formula (IIIa), and formula (IIIb) as the amine compound represented by any one of the above formulas (I) to (III),

[0050] [Chemical Formula 7]

[0051]

[0052] [8] The heavy metal treatment agent as described in [7], wherein

[0053] The aforementioned amine compound further includes an amine compound represented by the following formula (IIIc) as the amine compound represented by the above formula (III),

[0054] [Chemical Formula 8]

[0055]

[0056] [9]. The heavy metal treatment agent as described in [1], wherein

[0057] The amine compound includes an amine compound represented by the formula (III), and the amount of the amine compound represented by the formula (III) is 10.0% or more and 80.0% or less.

[0058]

[10] . The heavy metal treatment agent as described in [1], wherein

[0059] The amine compound comprises each of the amine compounds represented by the following formula (IIIa) and formula (IIIb) as the amine compound represented by the formula (III), and the total amount of the amine compound of the formula (IIIa) and the amine compound of the formula (IIIb) is 10.0% or more and 50.0% or less,

[0060] [Chemical Formula 9]

[0061]

[0062]

[11] . The heavy metal treatment agent as described in [1], wherein

[0063] The amine compound includes an amine compound represented by the formula (II), and the amount of the amine compound represented by the formula (II) is 5.0% or more and 30.0% or less.

[0064]

[12] . The heavy metal treatment agent as described in [1], wherein

[0065] The dithiocarbamate is dithiocarbamic acid sodium salt.

[0066]

[13] . The heavy metal treatment agent as described in [1], wherein

[0067] The heavy metal treatment agent includes the component (A), the component (B), and the component (C).

[0068]

[14] The heavy metal treatment agent according to any one of [1] to

[13] , wherein

[0069] The treatment targets are elements from Groups 6 to 16 of the periodic table or their compounds.

[0070]

[15] . A method for treating wastewater, wherein:

[0071] The wastewater treatment method includes the step of adding the heavy metal treatment agent described in any one of [1] to

[13] to water to be treated, wherein the wastewater contains an element of Groups 6 to 16 of the periodic table or a compound thereof.

[0072]

[16] The method for treating wastewater as described in

[15] , wherein

[0073] The wastewater treatment method further comprises the step of adding a polymer aggregating agent and / or an inorganic aggregating agent to the water to be treated.

[0074]

[17] . A method for treating incineration ash, wherein:

[0075] The incineration ash treatment method includes the step of adding the heavy metal treatment agent described in any one of [1] to

[13] to the incineration ash, wherein the incineration ash contains at least one element or a compound thereof in Groups 6, 12, and 14 of the periodic table.

[0076]

[18] The method for treating incineration ash as described in

[17] , wherein:

[0077] The pH of the eluate of the incineration ash according to the Japan Environment Agency Test No. 13 is 11.5 or higher.

[0078] Effects of the Invention

[0079] The heavy metal treatment agent of the present invention has excellent treatment performance for elements of Groups 6 to 16 of the periodic table or their compounds, including wastewater treatment and incineration ash treatment, and has excellent stability when mixed with water containing minerals, etc., and the generated flocs also have excellent stability. DETAILED DESCRIPTION

[0080] Hereinafter, specific embodiments of the present invention will be described.

[0081] The heavy metal treatment agent of the present invention comprises component (A) a dithiocarbamate of at least one amine compound represented by any one of formulae (I) to (III) and at least one selected from components (B) to (E) below.

[0082] (B) alkali,

[0083] (C) at least one selected from aminocarboxylic acids, thiols and aminophosphoric acids,

[0084] (D) dithiocarbamates of polyethyleneimine,

[0085] (E) Sulfur-containing compounds.

[0086] In the following description, the term "amine compound" refers to the amine compound in component (A) unless otherwise specified, except for the compound in component (B).

[0087] (A) Dithiocarbamates of amine compounds

[0088] In the present invention, "a dithiocarbamate of at least one amine compound represented by any one of formulae (I) to (III)" refers to a dithiocarbamate produced using at least one amine compound represented by any one of formulae (I) to (III) as a raw material. A dithiocarbamate is a compound in which a hydrogen atom bonded to a nitrogen atom of the raw amine compound is replaced with a dithioacid salt.

[0089] The amine compound represented by formula (I) is a linear chain. In the formula, m represents an integer of 3 to 6. From the perspective of excellent treatment of elements of Groups 6 to 16 of the periodic table or their compounds, or in addition to excellent treatment of at least one of dithiocarbamate stability in heavy metal treatment agents and floc formation in wastewater treatment, m is preferably 3 to 5, more preferably 3 to 4, and even more preferably 4. The amine compound represented by formula (I) may be used alone or in combination of two or more.

[0090] The amine compound represented by formula (I) is not particularly limited, and examples thereof include triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and hexaethyleneheptamine. Among these, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine are preferred, from the viewpoint of excellent treatment of elements of Groups 6 to 16 of the periodic table or compounds thereof, and from the viewpoint of excellent stability of dithiocarbamates in heavy metal treatment agents and excellent floc formation in wastewater treatment. Triethylenetetramine and tetraethylenepentamine are more preferred, and tetraethylenepentamine is even more preferred.

[0091] The amine compound represented by formula (II) is a straight chain. In the formula, n Xs are each independently a hydrogen atom or a 2-aminoethyl group, at least one of which is a 2-aminoethyl group, n is an integer of 1 to 3, and the total number of nitrogen atoms is 4 to 8. From the perspective of excellent treatment of elements of Groups 6 to 16 of the periodic table or their compounds, or from the perspective of excellent stability of dithiocarbamates in heavy metal treatment agents and floc formation in wastewater treatment, n is preferably 1 to 2, and more preferably 2. The total number of nitrogen atoms is preferably 4 to 6, and more preferably 5. The amine compound represented by formula (II) may be used alone or in combination of two or more.

[0092] The amine compound represented by formula (II) is not particularly limited, and examples thereof include tris(2-aminoethyl)amine, N,N,N'-tris(2-aminoethyl)ethane-1,2-diamine, N,N,N',N'-tetrakis(2-aminoethyl)ethane-1,2-diamine, N,N-bis-(2-aminoethyl)-N'-[2-[(2-aminoethyl)amino]ethyl]ethane-1,2-diamine, N 1 -(2-[(2-aminoethyl)-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl)ethane-1,2-diamine, N,N'-bis-(2-aminoethyl)-N-[2-[bis-(2-aminoethyl)amino]ethyl]ethane-1,2-diamine, N,N-bis-(2-aminoethyl)-N'-[2-[bis-(2-aminoethyl)amino]ethyl]ethane-1,2-diamine, and the like. Among them, from the viewpoint of excellent treatment of elements of Groups 6 to 16 of the periodic table or compounds thereof, or from the viewpoint of excellent stability of dithiocarbamates in heavy metal treatment agents and excellent floc formation in wastewater treatment, tris(2-aminoethyl)amine, N,N,N'-tris(2-aminoethyl)ethane-1,2-diamine, and N,N,N',N'-tetrakis(2-aminoethyl)ethane-1,2-diamine are preferred, and N,N,N'-tris(2-aminoethyl)ethane-1,2-diamine is more preferred.

[0093] The amine compound represented by formula (III) is a combination of a cyclic and a linear group. In the formula, o represents an integer from 0 to 2, p represents 0 or 1, q represents 0 or 1, and r represents an integer from 0 to 3, the sum of o, p, and r is 1 or greater, and the total number of nitrogen atoms is 3 to 7.

[0094] From the perspective of excellent treatment of elements from Groups 6 to 16 of the periodic table or their compounds, or from the perspective of excellent stability of dithiocarbamates in heavy metal treatment agents and floc formation in wastewater treatment, it is preferred that o is 0 or 1, p is 0 or 1, q is 0 or 1, and r is an integer from 0 to 3. More preferably, o is 0 or 1, p is 0, q is 0 or 1, and r is an integer from 0 to 3. More preferably, o is 0 or 1, p is 0, q is 0, and r is an integer from 2 to 3. On the other hand, the total number of nitrogen atoms is preferably 3 to 6, more preferably 4 to 5, and even more preferably 5.

[0095] The amine compound represented by formula (III) may be used alone or in combination of two or more.

[0096] The amine compound represented by formula (III) is not particularly limited, and examples thereof include aminoethylpiperazine, piperazine-1,4-diethylamine, N-(2-(1-piperazinyl)ethyl)ethylenediamine, N-[2-[4-(2-aminoethyl)piperazin-1-yl]ethyl]ethane-1,2-diamine, N-(2-aminoethyl)-N'-[2-(piperazin-1-yl)ethyl]ethane-1,2-diamine, 4-[2-(1-piperazinyl)ethyl]-1-piperazineethylamine, bis(2-(piperazin-1-yl)ethyl)amine, 1-[2-[[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]amino]ethyl ]-piperazine, N-[2-[(2-aminoethyl)amino]ethyl]-1,4-piperazinediethylamine, N,N'-bis(2-aminoethyl)-1,4-piperazinediethylamine, N-[2-(1-piperazinyl)ethyl]-1,4-piperazinediethylamine, N-[2-[(2-aminoethyl)amino]ethyl]-1,4-piperazinediethylamine, N-[2-[(2-aminoethyl)amino]ethyl]-1,4-piperazinediethylamine, N-[2-[(2-aminoethyl)amino]ethyl]-N'-[2-[4-(2-aminoethyl)-piperazin-1-yl]ethyl]ethane-1,2-diamine, 2-[4-[2-[2-[4-(2-aminoethyl)-piperazin-1-yl]ethylamino]ethyl]-piperazin-1-yl]ethylamine, and the like. Among them, from the viewpoint of excellent treatment of elements of Groups 6 to 16 of the periodic table or their compounds, or from the viewpoint of excellent stability of dithiocarbamates in heavy metal treatment agents and excellent floc formation in wastewater treatment, aminoethylpiperazine, piperazine-1,4-diethylamine, N-(2-aminoethyl)-N'-[2-(piperazin-1-yl)ethyl]ethane-1,2-diamine, N-[2-[4-(2-aminoethyl)piperazin-1-yl]ethyl]ethane-1,2-diamine, 4-[2-(l-piperazinyl)ethyl]-1-piperazineethylamine, bis(2-(piperazin-1-yl)ethyl)amine, 1-[2-[[2[[2-[(2-aminoethyl)amino]ethyl]amino] ]ethyl]amino]ethyl]-piperazine, N-[2-[(2-aminoethyl)amino]ethyl]-1,4-piperazinediethylamine, N-[2-(1-piperazinyl)ethyl]-1,4-piperazinediethylamine, more preferably N-(2-aminoethyl)-N'-[2-(piperazin-1-yl)ethyl]ethane-1,2-diamine, N-[2-[4-(2-aminoethyl)piperazin-1-yl]ethyl]ethane-1,2-diamine, 4-[2-(1-piperazinyl)ethyl]-1-piperazineethylamine, further preferably N-(2-aminoethyl)-N'-[2-(piperazin-1-yl)ethyl]ethane-1,2-diamine, or N-[2-[4-(2-aminoethyl)piperazin-1-yl]ethyl]ethane-1,2-diamine.

[0097] In a preferred embodiment, in the heavy metal treatment agent of the present invention, the amine compound includes an amine compound represented by formula (III).

[0098] From the viewpoint of excellent treatment of elements of Groups 6 to 16 of the periodic table or their compounds, or in addition from the viewpoint of excellent treatment of at least either one of stability of dithiocarbamates in heavy metal treatment agents and floc formation in wastewater treatment, it is preferred to include an amine compound represented by formula (III) having a combination of cyclic and linear structures in one molecule, as compared to an amine compound having only a linear structure or only a cyclic structure in one molecule, or a mixture of an amine compound consisting only of a linear structure and an amine compound consisting only of a cyclic structure. Among them, it is more preferred to include an amine compound represented by formula (III) having two or more cyclic structures in one molecule.

[0099] The heavy metal treatment agent preferably contains at least one selected from the group consisting of the amine compounds represented by the above formula (IIIa), the above formula (IIIb), and the above formula (IIIc) as the amine compound represented by the formula (III).

[0100] In this case, the heavy metal treatment agent preferably includes, as the amine compound represented by formula (III), various amine compounds represented by formula (IIIa) and formula (IIIb). In this case, the heavy metal treatment agent preferably includes, as the amine compound represented by formula (III), an amine compound represented by formula (IIIc).

[0101] In a preferred embodiment, the heavy metal treatment agent of the present invention comprises the amine compound represented by Formula (I), Formula (II), and Formula (III). If the amine compound comprises the amine compounds represented by Formula (I), Formula (II), and Formula (III), it is particularly suitable for treating elements from Groups 6 to 16 of the Periodic Table or compounds thereof, and is also suitable for at least one of improving the stability of dithiocarbamates in the heavy metal treatment agent, forming flocs in wastewater treatment, and improving the stability of the flocs.

[0102] In the heavy metal treatment agent, as the amine compound represented by any one of formulas (I) to (III), the amine compound preferably includes various amine compounds represented by formula (Ia), formula (Ila), formula (IIIa), and formula (IIIb). In this case, in the heavy metal treatment agent, as the amine compound represented by formula (III), the amine compound more preferably includes an amine compound represented by formula (IIIc).

[0103] A structure combining a cyclic and linear chain in one molecule, such as Formula (III), has fewer nitrogen atoms available for dithiocarbamate group introduction than Formula (I) with the same number of nitrogen atoms, resulting in fewer dithiocarbamate groups capable of bonding to heavy metals and the like. However, the rigid molecular structure allows for steric overlap due to intermolecular forces, resulting in excellent floc formation and effective heavy metal treatment. Amine compounds represented by Formula (IIIc) having two cyclic structures in one molecule are particularly excellent in this regard, exhibiting their effectiveness even when their content in the amine compound is 1.0% or less.

[0104] In the present invention, the amount (%) of the amine compound is the area percentage of the peak area of each amine compound in the total peak area excluding the peak of the solvent used in the analysis when the amine compound is analyzed by gas chromatography.

[0105] If the amount of the amine compound is within the following range, it is suitable for treating elements of Groups 6 to 16 of the periodic table or their compounds, and is also suitable for at least either improving the stability of dithiocarbamate in a heavy metal treatment agent or forming flocs in wastewater treatment.

[0106] The amount of the amine compound represented by formula (I) is preferably 0.0% to 80.0%, more preferably 20.0% to 80.0%, further preferably 20.0% to 55.0%, particularly preferably 25.0% to 55.0%, and even more preferably 40.0% to 55.0%.

[0107] The amount of the amine compound represented by formula (II) is preferably 0.0% to 50.0%, more preferably 5.0% to 30.0%, further preferably 5.0% to 25.0%, particularly preferably 15.0% to 25.0%, and even more preferably 15.0% to 20.0%.

[0108] The amount of the amine compound represented by formula (III) is preferably 10.0% or more and 100.0% or less, more preferably 10.0% or more and 80.0% or less, further preferably 10.0% or more and 65.0% or less, particularly preferably 20.0% or more and 65.0% or less, even more preferably 25.0% or more and 65.0% or less, still more preferably 27.0% or more and 65.0% or less, and most preferably 27.0% or more and 45.0% or less.

[0109] The amount of the amine compound represented by formula (IIIa) is preferably 0.0% to 40.0%, more preferably 10.0% to 40.0%, further preferably 10.0% to 35.0%, particularly preferably 22.0% to 30.0%.

[0110] The amount of the amine compound represented by formula (IIIb) is preferably 0.0% to 20.0%, more preferably 1.0% to 15.0%, further preferably 1.0% to 10.0%, particularly preferably 6.0% to 10.0%, and even more preferably more than 6.0% to 10.0%.

[0111] The total amount of the amine compound of formula (IIIa) and the amine compound of formula (IIIb) is preferably 0.0% or more and 50.0% or less, more preferably 10.0% or more and 50.0% or less, further preferably 13.0% or more and 40.0% or less, particularly preferably 17.0% or more and 40.0% or less, and even more preferably 27.0% or more and 40% or less.

[0112] The amount of the amine compound represented by formula (IIIc) is preferably 0.0% or more and 1.0% or less, and more preferably 0.1% or more and less than 1.0%.

[0113] The total amount of the amine compound of formula (IIIa), the amine compound of formula (IIIb) and the amine compound of formula (IIIc) is preferably 0.0% or more and 50.0% or less, more preferably 10.0% or more and 50.0% or less, further preferably 13.0% or more and 40.0% or less, particularly preferably 17.0% or more and 40.0% or less, and even more preferably 28.0% or more and 40.0% or less.

[0114] The method for producing the amine compounds represented by the above formulae (I) to (III) is not particularly limited, and they can be produced by a known method, which is preferably an inexpensive and simple method.

[0115] In the heavy metal treatment agent of the present invention, the dithiocarbamate is not particularly limited, and examples thereof include dithiocarbamates obtained by reacting an amine compound represented by any one of formulas (I) to (III), carbon disulfide, and a base such as a metal hydroxide.

[0116] The dithiocarbamate salt is not particularly limited, and examples thereof include alkali metal salts, alkaline earth metal salts, and ammonium salts of dithiocarbamic acid. Examples of the alkali metal salt include lithium salts, sodium salts, and potassium salts. Examples of the alkaline earth metal salt include magnesium salts and calcium salts. Among these, alkali metal salts are preferred, sodium salts and potassium salts are more preferred, and sodium salts are even more preferred.

[0117] In the heavy metal treatment agent of the present invention, the reaction molar ratio of the dithiocarbamate amine compound and the base, such as carbon disulfide or a metal hydroxide, is not particularly limited. A dithiocarbamate is a compound (salt-type functional group) formed by bonding a salt of a dithioacid group to the nitrogen atom of an amine compound. Furthermore, a compound containing two or more salts of dithiocarbamate groups introduced into one molecule of the amine compound is preferred. A single dithiocarbamate may be used alone, or two or more may be used in combination. From the perspective of improving heavy metal treatment performance, including incineration ash treatment and wastewater treatment, a substance obtained by reacting with 0.5 to 1 times the mole of carbon disulfide relative to the nitrogen atoms of the primary and secondary amino groups calculated based on the amount of the amine compound obtained by the above method is preferred, a substance obtained by reacting with 0.7 to 1 times the mole of carbon disulfide is more preferred, a substance obtained by reacting with 0.8 to 1 times the mole of carbon disulfide is further preferred, and a substance obtained by reacting with 0.9 to 1 times the mole of carbon disulfide is particularly preferred.

[0118] The method for producing a dithiocarbamate by reacting an amine compound, carbon disulfide, and a base is not particularly limited. For example, the method can be carried out by dissolving or suspending the amine compound and a base such as a metal hydroxide exemplified above as a salt in a solvent such as water, and then adding carbon disulfide to react. Unreacted carbon disulfide is removed as needed. If byproducts other than the dithiocarbamate are generated during the production of the dithiocarbamate, gases such as carbon disulfide gas may be generated from the byproducts during storage or use of the heavy metal treatment agent. To suppress such gas generation, it is preferable to use an excess of the amine compound during the production of the heavy metal treatment agent, thereby containing unreacted amine compound, or to add at least one selected from the group consisting of an amine compound and an amine derivative after the production of the dithiocarbamate.

[0119] The dosage form of the heavy metal treatment agent of the present invention is not particularly limited as long as it contains the above-mentioned component (A) and at least one selected from the above-mentioned components (B) to (E). For example, it can be a solid, liquid, or viscous body. From the perspective of operability, it is preferably used in the form of a liquid aqueous solution.

[0120] When the heavy metal treatment agent is used as an aqueous solution, the content of component (A) is not particularly limited. However, from the perspective of stability of the dithiocarbamate, the content of component (A) is preferably 20% to 60% by mass, more preferably 30% to 50% by mass, based on the total amount of the heavy metal treatment agent. From the perspective of stability during storage of the aqueous solution of the heavy metal treatment agent and suppression of crystallization, it is preferred that an amine compound be included.

[0121] (B) Alkali

[0122] The base is not particularly limited, and examples thereof include alkali metal compounds, alkaline earth metal compounds, and amine compounds.

[0123] The alkali metal compound is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate, etc. By including an alkali metal compound in the heavy metal treatment agent of the present invention, the precipitation of the dithiocarbamate in the aqueous solution of the dithiocarbamate (A) under low temperature conditions can be suppressed, the hydrolysis of the dithiocarbamate group can be suppressed, and the formation of precipitates (scale) when mixed with mineral-containing water can be suppressed, thereby improving the stability of the aqueous solution.

[0124] The amine compound is not particularly limited, and examples thereof include ammonia, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, ethylenediamine, piperazine, piperidine, the amine compounds represented by formula (I) to (III), polyethyleneamine, etc. By including an amine compound in the heavy metal treatment agent of the present invention, decomposition of carbon disulfide from the dithiocarbamate of the amine compound represented by formula (I) to (III) can be suppressed, and the formation of precipitates (scale) when mixed with mineral-containing water can be suppressed.

[0125] Heavy metal treatment agents containing an alkali inhibit the nitrogen atoms of the amine compound (A) from bonding with hydrogen ions in water in an aqueous solution, allowing the nitrogen atoms of the amine compound (A) to bond more readily with elements from Groups 6 to 16 or their compounds. This improves heavy metal treatment capabilities and enhances floc formation and stability. Consequently, these agents exhibit excellent treatment capabilities for elements from Groups 6 to 16 or their compounds, making them particularly useful for wastewater treatment.

[0126] From the viewpoints of suppressing the precipitation of dithiocarbamates under low temperature conditions, suppressing the hydrolysis of dithiocarbamate groups, and suppressing the formation of precipitates (scale) when mixed with mineral-containing water, the alkali content in the heavy metal treatment agent of the present invention is not particularly limited. For example, it can be 0.01% by mass or more and 20% by mass or less, preferably 0.1% by mass to 10% by mass, and more preferably 0.1% by mass to 5% by mass, relative to the aqueous solution of the dithiocarbamate (A).

[0127] (C) at least one selected from aminocarboxylic acids, thiols, and aminophosphoric acids

[0128] Examples of aminocarboxylic acids include aminocarboxylic acids or salts thereof. The aminocarboxylic acid is not particularly limited, and examples thereof include ethylenediaminetetraacetic acid, ethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, and aminophenoxyethanetetraacetic acid. Examples of aminocarboxylic acid salts include alkali metal, alkaline earth metal, and amine salts of aminocarboxylic acids. Among these, alkali metal salts of aminocarboxylic acids are preferred, sodium salts or potassium salts are more preferred, and sodium salts are even more preferred.

[0129] The thiols are not particularly limited, and examples thereof include compounds having a thiol group.

[0130] The aminophosphoric acids are not particularly limited, and examples thereof include compounds containing a nitrogen atom and a phosphoric acid group, or salts thereof.

[0131] These compounds are effective in stabilizing dithiocarbamates and inhibiting the hydrolysis of dithiocarbamate groups. In particular, they are effective in suppressing the formation of precipitates when an aqueous solution of the dithiocarbamate (A) is mixed with water containing minerals, etc. In view of these effects, aminocarboxylic acids and aminophosphoric acids are preferred, and aminocarboxylic acids are more preferred.

[0132] The content of the component (C) in the heavy metal treatment agent of the present invention is not particularly limited, but may be 0.001% by mass to 10% by mass, and preferably 0.01% by mass to 1% by mass.

[0133] (D) Dithiocarbamate of polyethyleneimine

[0134] Examples of dithiocarbamates of polyethyleneimine include dithiocarbamates of polyethyleneimine having a molecular weight of 2 to 1,000,000. The reaction molar ratio of the dithiocarbamic acid group relative to one ethyleneimine unit in the polyethyleneimine can be 0.5 to 1.0, preferably 0.6 to 0.8. There are no particular limitations on the dithiocarbamates, and examples include alkali metal salts, alkaline earth metal salts, and ammonium salts of dithiocarbamic acid. Examples of alkali metal salts include lithium salts, sodium salts, and potassium salts. Examples of alkaline earth metal salts include magnesium salts and calcium salts. Among these, alkali metal salts are preferred, sodium salts and potassium salts are more preferred, and sodium salts are still more preferred.

[0135] To improve stability, the dithiocarbamate of polyethyleneimine may contain a halogenated hydrocarbon, and a mixture of polyethyleneimine and a halogenated hydrocarbon, or a condensate of polyethyleneimine and a halogenated hydrocarbon may also be used. The halogenated hydrocarbon is not particularly limited, and examples thereof include benzyl chloride and benzyl bromide.

[0136] Polyethyleneimine dithiocarbamates are excellent at aggregating flocs formed by capturing heavy metals or their compounds. If the flocs are small, for example, when filtering out the flocs formed by adding a heavy metal treatment agent to wastewater in wastewater treatment, the flocs cannot be recovered, resulting in heavy metals remaining in the treated water. In incineration ash treatment, water is added to the fly ash at the same time as the heavy metal treatment agent, causing heavy metals and rainwater to flow out of the treated ash simultaneously after mixing. Low-molecular-weight amine dithiocarbamates are more effective in aggregating, particularly in their ability to form flocs in wastewater treatment.

[0137] By containing a dithiocarbamate of polyethyleneimine in the heavy metal treatment agent of the present invention and using it in combination with the dithiocarbamate of the amine compound (A) described above, the hydrolysis stability of the dithiocarbamate group, the suppression of precipitate (scale) formation when mixing with mineral-containing water, and the heavy metal treatment performance can be improved.

[0138] When used in combination, the proportions of the dithiocarbamates are not particularly limited. For example, the total amount of the dithiocarbamate of the amine compound (A) may be 5% by mass or more and 95% by mass or less, preferably 30% by mass or more and 80% by mass or less, and more preferably 50% by mass or more and 70% by mass or less. The total amount of the dithiocarbamate of the polyethyleneimine (D) may be 5% by mass or more and 95% by mass or less, preferably 10% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 50% by mass or less.

[0139] When the heavy metal treatment agent is used as an aqueous solution, the total amount of the dithiocarbamate of the (A) amine compound and the dithiocarbamate of the (D) polyethyleneimine can be 10% by mass or more and 50% by mass or less, preferably 20% by mass or more and 30% by mass or less.

[0140] (E) Sulfur-containing compounds

[0141] The sulfur-containing compound is not particularly limited, and examples thereof include sulfides such as sodium sulfide, potassium sulfide, sodium hydrosulfide, and sodium polysulfide; thiosulfates such as sodium thiosulfate and potassium thiosulfate, and salts thereof; and sulfurous acids such as sodium sulfite and salts thereof.

[0142] By incorporating a sulfur-containing compound into the heavy metal treatment agent of the present invention, heavy metals and the like can be treated efficiently.

[0143] When used in combination, the proportions of the respective compounds are not particularly limited. For example, the dithiocarbamate content of the amine compound (A) may be 5% by mass or more and 95% by mass or less, preferably 30% by mass or more and 80% by mass or less, and more preferably 50% by mass or more and 70% by mass or less. The sulfur-containing compound content may be 5% by mass or more and 95% by mass or less, preferably 10% by mass or more and 70% by mass or less, and more preferably 30% by mass or more and 50% by mass or less.

[0144] When the heavy metal treatment agent is used as an aqueous solution, the total amount of the dithiocarbamate of the (A) amine compound and the (E) sulfur-containing compound can be 10% by mass or more and 50% by mass or less, preferably 20% by mass or more and 30% by mass or less.

[0145] The heavy metal treatment agent of the present invention only needs to contain the component (A) and at least one selected from the components (B) to (E). The combination of the components is not particularly limited, and examples thereof include the following combinations.

[0146] A heavy metal treatment agent comprising component (A) and component (B).

[0147] A heavy metal treatment agent comprising components (A) and (C).

[0148] A heavy metal treatment agent comprising component (A) and component (D).

[0149] A heavy metal treatment agent comprising component (A) and component (E).

[0150] From the viewpoints of the hydrolysis stability of the dithiocarbamate group, the suppression of precipitate (scale) formation when mixed with mineral-containing water, and the heavy metal treatment performance, more preferred are heavy metal treatment agents comprising component (A), component (B), and component (C), heavy metal treatment agents comprising component (A), component (B), component (C), and component (D), and heavy metal treatment agents comprising component (A), component (B), component (D), and component (E).

[0151] (Hydrolytic stability)

[0152] The heavy metal treatment agent of the present invention, by containing component (A) and at least one selected from components (B) to (E), can inhibit hydrolysis and improve stability during storage, use, and mixing with water. Of components (B) to (E), any one of component (B), component (C), and component (D) is preferred, with component (B) being more preferred. The hydrolysis index is not particularly limited, but for example, in an aqueous solution containing 5 mg / L of dithiocarbamate groups in the dithiocarbamate salt of the amine compound (A), after standing at 25°C for 6 hours, the reduction rate of dithiocarbamate groups is preferably less than 25% by mass, more preferably less than 10% by mass, further preferably less than 5% by mass, and particularly preferably less than 4% by mass.

[0153] (Scale prevention)

[0154] The heavy metal treatment agent of the present invention, comprising component (A) and at least one selected from components (B) to (E), can suppress the formation of scale (insoluble matter) when mixed with water or other additives, thereby preventing malfunctioning of equipment. Scale may be formed, for example, by a reaction between minerals, metal ions, and the like in water and dithiocarbamate groups. From the perspective of preventing scale, among components (B) to (E), preferably any one of component (B), component (C), and component (D) is used, and more preferably components (C) and (D).

[0155] The heavy metal treatment agent of the present invention may contain other components as long as the effects of the present invention are not impaired. Examples of such other components include, but are not limited to, amine compounds, amine derivatives, ammonium salts, organic solvents, reducing agents, oxidizing agents, alkali metal hydroxides, pH adjusters, inorganic heavy metal treatment agents, aggregating agents, rust inhibitors, antiscaling agents, defoaming agents, stabilizers, gas suppressants, and surfactants.

[0156] Next, heavy metal treatment using the heavy metal treatment agent of the present invention will be described.

[0157] The heavy metal treatment agent of the present invention is mixed with a slurry of solid objects, liquid objects, or waste gas containing elements or compounds of Groups 6 to 16 of the Periodic Table listed below. The agent reacts with these elements or compounds to form water-insoluble insoluble substances, thereby reducing or preventing the dissolution of heavy metals from the solid objects and separating the insoluble substances from the liquid objects, thereby removing the elements or compounds of Groups 6 to 16 of the Periodic Table. The solid objects are not particularly limited, but examples include incineration ash (fly ash (dust) and main ash (burned slag)) generated at waste incineration plants, slag, sludge, soil, and shredder dust. The liquid objects are not particularly limited, but examples include wastewater, waste oil, liquid sludge, and waste gas cleaning wastewater.

[0158] The heavy metal treatment agent of the present invention targets elements of Groups 6 to 16 of the periodic table or compounds thereof.

[0159] Examples of Group 6 elements include chromium, molybdenum, tungsten,

[0160] Examples of Group 7 elements include manganese, technetium, rhenium,

[0161] Examples of Group 8 elements include iron, ruthenium, osmium,

[0162] Examples of Group 9 elements include cobalt, rhodium, iridium,

[0163] Examples of Group 10 elements include nickel, palladium, platinum,

[0164] Examples of Group 11 elements include copper, silver, gold,

[0165] Examples of Group 12 elements include zinc, cadmium, mercury,

[0166] Examples of Group 13 elements include boron, aluminum, gallium, indium, thallium,

[0167] Examples of Group 14 elements include carbon, silicon, germanium, tin, lead,

[0168] Examples of the Group 15 elements include nitrogen, phosphorus, arsenic, antimony, bismuth and magnesium.

[0169] Examples of Group 16 elements include oxygen, sulfur, selenium, tellurium, polonium,

[0170] Elements of the same family have the same outermost electron state and can therefore be treated in the same manner using the heavy metal treatment agent of the present invention.

[0171] Among the above elements, in particular, as elements of Group 6, chromium, molybdenum and tungsten can be mentioned; as elements of Group 7, manganese can be mentioned; as elements of Group 8, iron, ruthenium and osmium can be mentioned; as elements of Group 9, cobalt, rhodium and iridium can be mentioned; as elements of Group 10, nickel, palladium and platinum can be mentioned; as elements of Group 11, copper, silver and gold can be mentioned; as elements of Group 12, zinc, cadmium and mercury can be mentioned; as elements of Group 13, boron, gallium, indium and thallium can be mentioned; as elements of Group 14, germanium, tin and lead can be mentioned; as elements of Group 15, arsenic, antimony and bismuth can be mentioned; and as elements of Group 16, selenium and tellurium can be mentioned. Among them, chromium, manganese, iron, cobalt, nickel, copper, zinc, cadmium, mercury, aluminum, tin, lead, arsenic, selenium, or their compounds can be suitably treated, and chromium, manganese, iron, cobalt, nickel, copper, zinc, cadmium, mercury, aluminum, lead, arsenic, selenium, or their compounds can be more suitably treated. For example, chromium, manganese, iron, nickel, copper, zinc, cadmium, mercury, lead, arsenic, selenium, or their compounds that have been set to landfill or drainage standards can be further suitably treated.

[0172] Examples of compounds of the elements include substances formed by bonding the elements with other elements by covalent bonds, ionic bonds, coordinate bonds, etc., and there are no particular limitations on the compounds. Examples include oxides, hydroxides, oxygen-containing acids and salts thereof, halides, complexes, complex salts, etc.

[0173] (Wastewater Treatment)

[0174] Wastewater treatment using the heavy metal treatment agent of the present invention refers to the separation of elements of Groups 6 to 16 of the periodic table or their compounds from the water to be treated. Although there is no particular limitation, it includes, for example, the separation of insoluble floccules (aggregates or precipitates) produced by the reaction of the heavy metal treatment agent with the target element or its compound.

[0175] The heavy metal treating agent of the present invention has an excellent ability to form flocs, and facilitates the removal of the flocs, thereby being able to suitably treat the target element or its compound.

[0176] Wastewater treatment using heavy metal treatment agents is carried out by adding the heavy metal treatment agent to the water to be treated. The water to be treated is water containing the element or its compound to be treated, including water before and after the addition of the heavy metal treatment agent.

[0177] Even if the water to be treated contains elements or compounds other than the treatment target, it can be suitably treated. Furthermore, there are no particular limitations, and even if it contains complexing agents such as EDTA and citric acid, phosphoric acid compounds, amine compounds, and cyanides, oxidants, reducing agents, surfactants, salts, organic compounds, and inorganic compounds, it can be suitably treated.

[0178] The treatment conditions after addition are not particularly limited, and for example, stirring or standing can be used. Insoluble matter or solid matter can also be removed by separation after treatment. The method for removing insoluble matter or solid matter is not particularly limited, and examples thereof include filtration, centrifugation, and methods in which solid matter is allowed to precipitate and then separated from the supernatant.

[0179] There are no particular limitations on the apparatus and operation for stirring, and conventionally known apparatuses and operations can be used. For standing, no special apparatus is required, and any apparatus capable of solid-liquid separation, for example, by using a sedimentation separation tank or the like, can be used.

[0180] In treatment using the heavy metal treatment agent of the present invention, other ingredients, such as pH adjusters, flocculants, alkali metal hydroxides, inorganic heavy metal treatment agents, rust inhibitors, scale inhibitors, defoamers, adsorbents, surfactants, complexing agents, chelating agents, oxidizing agents, and reducing agents, may be added simultaneously with the addition of the heavy metal treatment agent and other ingredients to the treated water. By adding the pH adjuster and performing the treatment in an appropriate pH range, decomposition of the heavy metal treatment agent can be prevented, floc formation can be promoted, and thus, elements from Groups 6 to 16 of the periodic table or their compounds can be appropriately treated.

[0181] The pH adjuster is not particularly limited, and examples thereof include inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid, and inorganic bases such as sodium hydroxide, potassium hydroxide, and calcium hydroxide. Furthermore, the coagulants listed below may also be used as pH adjusters.

[0182] The sedimentation properties of the flocs are improved by adding a heavy metal treatment agent and a coagulant.

[0183] If necessary, a flocculant is added and stirred to separate the generated flocs. These methods can remove the target element or its compound contained in the wastewater.

[0184] The aggregating agent is not particularly limited, and examples thereof include polymer aggregating agents, inorganic aggregating agents, and minerals. Among them, polymer aggregating agents and inorganic aggregating agents are preferred, and polymer aggregating agents are more preferred.

[0185] As polymer aggregating agents, anionic aggregating agents, cationic aggregating agents, nonionic aggregating agents, and amphoteric aggregating agents can be used, and there is no particular limitation on them. Examples include anionic aggregating agents such as polyacrylamide aggregating agents, sodium polyacrylate aggregating agents, polyacrylic acid aggregating agents, and natural aggregating agents; cationic aggregating agents such as polymethacrylate aggregating agents, polyacrylate aggregating agents, polyamine aggregating agents, polydimethyldiallylammonium chloride aggregating agents, and dicyandiamide aggregating agents; nonionic aggregating agents such as polyacrylamide aggregating agents, polyethylene glycol, and polyvinyl alcohol; and amphoteric polymer aggregating agents such as polyacrylate-acrylic acid copolymer aggregating agents. Specific examples include sodium polyacrylate, sodium alginate, copolymers of acrylamide and sodium acrylate, copolymers of acrylamide and 2-acrylamido-2-methylpropanesulfonic acid (AMPS), copolymers of acrylamide, acrylic acid, and AMPS, polydimethylaminoethyl (meth)acrylate quaternary ammonium salt, copolymers of dimethylaminoethyl (meth)acrylate quaternary ammonium salt and acrylamide; polydimethyldiallylammonium chloride, copolymers of dimethyldiallylammonium chloride and acrylamide; polyamidine, epichlorohydrin dimethylamine condensate; dicyandiamide ammonium chloride formaldehyde condensate; polyacrylamide, polyethylene oxide, dimethylaminoethyl (meth)acrylate quaternary ammonium salt, and acrylic acid copolymers; and Hofmann decomposition products of polyacrylamide. Among these, anionic and cationic types are preferred, with anionic types being more preferred. Among anionic types, copolymers of sodium polyacrylate, acrylamide, and sodium acrylate are preferred, while among cationic types, copolymers of dimethyldiallylammonium chloride and acrylamide are preferred.

[0186] The inorganic aggregating agent is not particularly limited, and examples thereof include iron-based inorganic aggregating agents (ferric chloride, ferrous chloride, ferric sulfate, ferrous sulfate, polyferric sulfate, etc.), aluminum-based inorganic aggregating agents (aluminum sulfate, polyaluminum chloride, aluminum chloride, etc.), and alkali-based inorganic aggregating agents (calcium chloride, magnesium hydroxide, potassium aluminate, etc.). Among them, iron-based inorganic aggregating agents and aluminum-based inorganic aggregating agents are preferred, ferric chloride, ferrous sulfate, polyferric sulfate, aluminum sulfate, polyaluminum chloride, and calcium chloride are more preferred, and ferric chloride, ferrous sulfate, polyferric sulfate, aluminum sulfate, and polyaluminum chloride are even more preferred.

[0187] The above-mentioned aggregating agents may be used alone or in combination of two or more.

[0188] The minerals are not particularly limited, and examples thereof include carbonate minerals such as hydrotalcite, magnesite, and limestone; silicate minerals such as zeolite, montmorillonite, kaolin, bentonite, and silica; oxide minerals such as alumina; sulfate minerals such as gypsum; and phosphate minerals such as hydroxyapatite.

[0189] Aggregating agents may be used singly or in combination, and may be used once or twice or more. Combining an inorganic aggregating agent with a polymeric aggregating agent is also a preferred method. By combining a polymeric aggregating agent with an inorganic aggregating agent, elements or compounds of Groups 6, 10, 11, 12, 14, 15, and 16 can be suitably treated, among the elements or compounds of Groups 6 to 16 listed above.

[0190] (Incineration ash treatment)

[0191] The treatment of incineration ash using the heavy metal treatment agent of the present invention is not particularly limited. For example, the treatment targets include incineration ash (fly ash and main ash) generated from combustion facilities such as combustion furnaces and melting furnaces, such as municipal garbage, industrial waste, sludge, biomass boilers, paper sludge, coal, and waste solid fuel (RDF: refuse derived fuel or RPF: waste paper and plastic high density fuel); and incineration ash (fly ash and main ash) generated from combustion facilities such as electric furnaces for iron and steel making, roasting furnaces for metal refining, sintering furnaces, calcining furnaces, melting furnaces, converters, melting furnaces, and drying furnaces. In addition to incineration ash, the treatment targets include soil, sludge, slag, etc. containing elements from Groups 6 to 16 of the periodic table or their compounds.

[0192] The term "incineration ash" as used herein refers to the main ash (bottom ash) from the incinerator, which is the combustion residue, and the fly ash (dust) that floats along with the gas components generated by incineration. Fly ash also includes fly ash generated by melting (molten fly ash). Furthermore, fly ash also includes other types of waste gas treatment agents such as slaked lime and activated carbon. In the present invention, no particular distinction is made between these. Hereinafter, when referring to incineration ash, the main ash and fly ash are used interchangeably.

[0193] The amount of the heavy metal treatment agent used in the present invention is not particularly limited. However, the addition rate relative to the incineration ash is preferably 0.01% by mass or greater, more preferably 0.1% by mass or greater, even more preferably 0.5% by mass or greater, and particularly preferably 1% by mass or greater. Furthermore, the amount is preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less, and particularly preferably 10% by mass or less. A usage amount within this range is suitable for achieving the effects of the present invention. Excessive use of the heavy metal treatment agent may cause undissolved heavy metals to dissolve again due to the dithiocarbamate.

[0194] The heavy metal treatment agent of the present invention can suitably treat incineration ash containing an element or a compound thereof of at least any one of Groups 6, 12, and 14, among the elements or compounds thereof of Groups 6 to 16 listed above.

[0195] From the perspective of the reaction efficiency between heavy metals and the dithiocarbamate contained in the heavy metal treatment agent of the present invention, if the treated ash is in a dried powdered form, the heavy metal ions and the dithiocarbamate cannot move smoothly, the contact frequency is reduced, and the reaction does not proceed fully. If the treated ash is liquid, it requires a dehydration process, or the proportion of water in the treated ash increases during transportation, which is uneconomical. Therefore, to effectively treat heavy metals, it is desirable to add the optimal amount of water to form a powder, block, or slurry with appropriate moisture content, and it is more desirable to form a block. The water addition rate is not particularly limited; as a rate relative to the incineration ash, it is preferably 5% by mass or greater, more preferably 10% by mass or greater, even more preferably 15% by mass or greater, and particularly preferably 20% by mass or greater. Furthermore, the rate relative to the incineration ash is 150% by mass or less, preferably 100% by mass or less, more preferably 80% by mass or less, even more preferably 60% by mass or less, and particularly preferably 40% by mass or less. By maintaining the addition rate above a specific amount, the dithiocarbamate efficiently contacts the heavy metals in the incineration ash, promoting the formation of insoluble matter. If the water addition rate is excessive, the ash will not form a bulk and will instead form a slurry or liquid, making the ash handling and transportation process more complicated.

[0196] When mixing the heavy metal treatment agent of the present invention with water and incineration ash, the heavy metal treatment agent and water may be added to the incineration ash simultaneously or separately. Furthermore, the heavy metal treatment agent and water may be mixed before adding to the incineration ash. The order of adding and mixing the heavy metal treatment agent, water, and incineration ash may be arbitrary.

[0197] The heavy metal treatment agent of the present invention can treat any type of incineration ash, including alkaline, acidic, and neutral. It is particularly suitable for treating alkaline and neutral incineration ash, and is more suitable for treating alkaline incineration ash. The alkalinity and acidity of incineration ash can be measured using the pH of the ash eluate. From this point of view, the heavy metal treatment agent of the present invention can treat incineration ash whose pH in the eluate (sample solution) in the test method of Japan Environment Agency Notice No. 13 is preferably 6 or higher, more preferably 9 or higher, further preferably 11.5 or higher, and particularly preferably 12 or higher. In the treatment of incineration ash, in order to adjust the pH of the eluate, alkaline or acidic compounds, pH adjusters, etc. may be added to the incineration ash.

[0198] In the treatment of incineration ash using the heavy metal treatment agent of the present invention, other components may be used along with the heavy metal treatment agent and water, as long as the effects are not impaired. Such other components are not particularly limited, and examples thereof include aggregating agents, pH adjusters, rust inhibitors, reducing agents, oxidizing agents, surfactants, adsorbents, alkali metal hydroxides, cement, and water glass.

[0199] When the incineration ash is treated with a heavy metal treatment agent, for example, it can be mixed with water and then post-treated. The post-treatment can be carried out by standing or stirring, and these treatments can stably suppress the dissolution of heavy metals. In a waste incineration facility, the fly ash generated by the incineration in the incinerator is transferred to a bulkhead bag filter, a flow-through electrostatic precipitator, a cyclone, etc. together with the exhaust gas and captured. The captured fly ash is, for example, stored in a silo and then transported to a batch or continuous mixer, where a heavy metal treatment agent and water are added and uniformly mixed. The mixture taken out from the mixer is transported out via a conveying device and then sent to a groove. The mixture can be post-treated in a storage body such as a conveying device, a groove, etc. that transports and stores the mixture taken out from the mixer indoors, or a container.

[0200] The primary ash (burnt ash) produced by incineration in an incinerator is, for example, at a high temperature when taken out of the incinerator, and is therefore usually placed in a water tank to cool. Examples of such methods include adding the heavy metal treatment agent of the present invention to the primary ash in a water tank to cause a reaction therein for insolubilization, and insolubilizing the primary ash by adding a heavy metal treatment agent and water to the cooled and dehydrated primary ash after leaving it in its original state or pulverizing it, followed by stirring / mixing. Similar to fly ash, the insolubilized primary ash can be post-processed in indoor equipment such as conveying equipment, tanks, or containers for indoor transportation and storage.

[0201] As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to this embodiment, Various changes are possible within the range which does not deviate from the summary.

[0202] [Example]

[0203] Hereinafter, the present invention will be described in further detail with reference to Examples, but the present invention is not limited to these Examples.

[0204] <Amine compounds>

[0205] Amine compounds were generally commercially available products and reagents, and carbon disulfide and sodium hydroxide manufactured by Kanto Chemical Co., Ltd. were used.

[0206] The amount of the amine compound was analyzed by gas chromatography (GC) on a sample prepared by dissolving the amine compound in a solvent (methanol). The GC used a GC-2010 Plus (Shimadzu Corporation, Japan) and a capillary column TC-1 (length 15 m, inner diameter 0.25 mm, liquid phase film thickness 0.25 μm) (GL Sciences Company Limited). Measurements were performed under the following conditions.

[0207] SPL (vaporization chamber)

[0208] Temperature: 300℃Total flow rate: 45.1mL / min.

[0209] Pressure: 48.9kPa Column flow rate: 1.03mL / min.

[0210] Carrier gas: Helium Linear velocity: 30.2 cm / sec.

[0211] Split ratio: 40.0 Purge flow rate: 3.0 mL / min.

[0212] Heating conditions

[0213] Set temperature: 50℃, hold time: 3min.

[0214] Heating rate: 10.0℃ / min., set temperature: 160℃.

[0215] Heating rate: 20.0℃ / min., set temperature: 300℃, holding time: 10min.

[0216] FID (detector)

[0217] Temperature: 300℃.

[0218] Makeup gas: helium.

[0219] Tail blow flow rate: 30.0mL / min.

[0220] H2 flow rate: 40.0mL / min.

[0221] Air flow rate: 400.0mL / min.

[0222] The amount ("%") of each amine compound indicates the area ratio (area percentage) of each amine compound in the total peak area after excluding the peak of the solvent used for analysis in the GC chart.

[0223] The tetraethylene pentamine described below used a commercially available, generally commercially available industrial product (a mixture of linear, branched, cyclic, and linear amines). The above analysis of this tetraethylene pentamine revealed that the linear amine compound of formula (la) accounted for 48.2%, the branched amine compound of formula (IIa) accounted for 18.3%, and the cyclic and linear amine compound of formula (III) accounted for 32.7% (of which formula (IIIa) accounted for 25.5%, formula (IIIb) accounted for 6.4%, and formula (IIIc) accounted for 0.8%).

[0224] Heavy metal treatment agents

[0225] The following heavy metal treatment agents 1 to 14 were prepared according to the ratios shown in Table 1.

[0226] Heavy metal treatment agent 1

[0227] Heavy metal treatment agent 1 was obtained by dissolving 100 g of the following heavy metal treatment agent 11 as component (A) and 1.0 g of a 48.0% sodium hydroxide aqueous solution as component (B).

[0228] Heavy metal treatment agent 2

[0229] 100 g of the following heavy metal treatment agent 12 as the component (A) and 1.0 g of a 48.0% sodium hydroxide aqueous solution as the component (B) were dissolved to obtain a heavy metal treatment agent 2.

[0230] Heavy metal treatment agent 3

[0231] 100 g of the following heavy metal treatment agent 13 as the component (A) and 1.0 g of a 48.0% sodium hydroxide aqueous solution as the component (B) were dissolved to obtain a heavy metal treatment agent 3.

[0232] Heavy metal treatment agent 4

[0233] 100 g of the following heavy metal treatment agent 14 as the component (A) and 1.0 g of a 48.0% sodium hydroxide aqueous solution as the component (B) were dissolved to obtain a heavy metal treatment agent 4.

[0234] Heavy metal treatment agent 5

[0235] 100 g of the following heavy metal treatment agent 11 as the component (A) and 0.1 g of a 40% tetrasodium ethylenediaminetetraacetate (EDTA-4Na) aqueous solution as the component (C) were dissolved to obtain a heavy metal treatment agent 5.

[0236] Heavy metal treatment agent 6

[0237] 100 g of the following heavy metal treatment agent 12 as the component (A) and 0.1 g of a 40% aqueous solution of tetrasodium ethylenediaminetetraacetate (EDTA-4Na) as the component (C) were dissolved to obtain a heavy metal treatment agent 6.

[0238] Heavy metal treatment agent 7

[0239] Heavy metal treatment agent 7 was obtained by mixing 37.5 g of the following heavy metal treatment agent 12 as component (A), 12.5 g of ion-exchanged water, 26.0 g of polyethyleneimine (commercial product: average molecular weight 70,000) as component (D), and 50.0 g of a dithiocarbamate (20.0 mass % aqueous solution) obtained by reacting 9.5 g of carbon disulfide and 10.4 g of a 48.0% sodium hydroxide aqueous solution in 54.1 g of ion-exchanged water.

[0240] Heavy metal treatment agent 8

[0241] Heavy metal treatment agent 8 was obtained by mixing 37.5 g of the following heavy metal treatment agent 12 as component (A), 14.3 g of sodium hydrosulfide (NaHS: 70%) (manufactured by NAGAO Corporation) as component (E), and 48.2 g of ion-exchanged water.

[0242] Heavy metal treatment agent 9

[0243] Heavy metal treatment agent 9 was obtained by mixing 37.5 g of the following heavy metal treatment agent 12 as component (A), 30.8 g of sodium sulfide (Na2S) nonahydrate (manufactured by Kanto Chemical Co., Ltd.) as component (E), and 31.7 g of ion-exchanged water.

[0244] Heavy metal treatment agent 10

[0245] 100 g of the following heavy metal treatment agent 12 as component (A), 1.0 g of a 48.0% sodium hydroxide aqueous solution as component (B), and 0.1 g of a 40% EDTA-4Na aqueous solution as component (C) were dissolved to obtain a heavy metal treatment agent 10.

[0246] Heavy metal treatment agent 11

[0247] As component (A), a dithiocarbamate (40.0 mass % aqueous solution) was used, obtained by reacting 15.9 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), 18.7 g of carbon disulfide, and 20.5 g of a 48.0% sodium hydroxide aqueous solution in 44.9 g of ion-exchanged water (the molar amount of carbon disulfide was 1 times the molar amount relative to the nitrogen atoms of the primary and secondary amino groups of the amine compound). In N-(2-aminoethyl)piperazine, the amine compound of formula (III), which is a combination of cyclic and linear compounds, accounted for 100.0%.

[0248] Heavy metal treatment agent 12

[0249] As component (A), a dithiocarbamate (40.0 mass % aqueous solution) obtained by reacting 13.0 g of tetraethylenepentamine (commercially available: a mixture of linear, branched, and cyclic and linear forms), 20.9 g of carbon disulfide, and 22.9 g of a 48.0% sodium hydroxide aqueous solution in 43.2 g of ion-exchanged water was used (the mole of carbon disulfide was 1 times the mole of the nitrogen atoms of the primary and secondary amino groups calculated from the amount of the amine compound obtained by the above-mentioned GC analysis method).

[0250] Heavy metal treatment agent 13

[0251] As component (A), a dithiocarbamate (40.0 mass % aqueous solution) obtained by reacting 5.3 g of N-(2-aminoethyl)piperazine (manufactured by Tokyo Chemical Industry Co., Ltd.), 8.7 g of tetraethylenepentamine (commercially available: a mixture of linear, branched, and cyclic and linear forms), 20.2 g of carbon disulfide, and 22.1 g of a 48.0% aqueous sodium hydroxide solution in 43.7 g of ion-exchanged water was used (the mole of carbon disulfide was 1 times the mole of the nitrogen atoms of the primary and secondary amino groups calculated from the amount of the amine compound obtained by the above-mentioned GC analysis method). Regarding the amount of amine compounds, the linear amine compound of formula (Ia) accounted for 32.1%, the branched amine compound of formula (IIa) accounted for 12.2%, and the amine compound of formula (III) which is a combination of cyclic and linear amine compounds accounted for 55.2% (among which, formula (IIIa) accounted for 17.0%, formula (IIIb) accounted for 4.3%, formula (IIIc) accounted for 0.6%, and N-(2-aminoethyl)piperazine accounted for 33.3%).

[0252] Heavy metal treatment agent 14

[0253] As component (A), a dithiocarbamate (40.0 mass % aqueous solution) obtained by reacting 2.2 g of triethylenetetramine (manufactured by Sigma-Aldrich Japan Co., LLC), 10.4 g of tetraethylenepentamine (commercially available: a mixture of linear, branched, and cyclic and linear forms), 21.2 g of carbon disulfide, and 23.4 g of a 48.0% aqueous sodium hydroxide solution in 42.8 g of ion-exchanged water was used (the amount of carbon disulfide was 1 mole relative to the nitrogen atoms of the primary and secondary amino groups calculated from the amount of the amine compound obtained by the above-mentioned GC analysis method). Of the amount of amine compounds, the amine compound of formula (I) as a straight chain accounted for 58.6% (of which formula (la) accounted for 38.6% and triethylenetetramine accounted for 20.0%), the amine compound of formula (IIa) as a branched chain accounted for 14.6%, and the amine compound of formula (III) as a combination of cyclic and straight chains accounted for 26.2% (of which formula (IIIa) accounted for 20.4%, formula (IIIb) accounted for 5.1%, and formula (IIIc) accounted for 0.7%).

[0254] [Table 1]

[0255]

[0256] (Hydrolysis stability test)

[0257] The hydrolysis stability test of the heavy metal treatment agent shown in Table 2 was conducted as follows. (A) was diluted with ion-exchanged water so that the dithiocarbamate group content in the dithiocarbamate salt became 5 mg / L, thereby preparing a test sample. Using a UV-visible spectrophotometer (UH4510, Hitachi High-Tech Science Co., Ltd.), the absorbance of the test sample immediately after dilution and the test sample after standing at 25°C for 6 hours were measured. The reduction rate of the dithiocarbamate group was calculated based on the absorbance at 286 nm, which indicates the absorption of the dithiocarbamate group before and after standing. The lower the reduction rate, the better the hydrolysis stability.

[0258] [Table 2]

[0259]

[0260] Table 2 confirms that the heavy metal treatment agent of the present invention exhibits a lower rate of decrease in absorbance at 286 nm and excellent hydrolytic stability compared to the comparative examples. In the examples, a comparison of Example 1 and Example 2 confirms that the use of tetraethylenepentamine (a mixture of linear, branched, and cyclic / linear) as component (A) exhibits excellent hydrolytic stability.

[0261] When Example 1 was compared with Examples 2 to 4, it was confirmed that Examples 2 to 4 had a low rate of decrease in absorbance at 286 nm, and that the dithiocarbamates of amine compounds comprising any one of the amine compounds of Formula (IIIa), Formula (IIIb), and Formula (IIIc), particularly the dithiocarbamates comprising the amine compounds of Formula (IIIa), Formula (IIIb), and Formula (IIIc), had excellent hydrolytic stability. Furthermore, the dithiocarbamates of amine compounds comprising the amine compounds of Formula (I), Formula (II), and Formula (III), particularly the dithiocarbamates comprising the amine compounds of Formula (Ia), Formula (IIa), Formula (IIIa), Formula (IIIb), and Formula (IIIc), had excellent hydrolytic stability.

[0262] In the comparison between Examples 2 and 3 and Example 4, Examples 2 and 3 have a low rate of reduction in absorbance at 286 nm. In the mixed system of Formula (I) to Formula (III), if the amount of the amine compound of Formula (III) is greater than 27.0% and less than 65.0%, it shows a tendency to have excellent hydrolysis stability.

[0263] Furthermore, in the comparison between Example 2 and Example 3, Example 2 has a lower rate of decrease in absorbance at 286 nm, which suggests that if the amount of the amine compound of formula (III) is greater than 27.0% and less than 45.0%, the hydrolysis stability is excellent. In addition, if the total amount of the amine compounds of formula (IIIa) and formula (IIIb) is greater than 27.0% and less than 40%, the hydrolysis stability is excellent.

[0264] In addition, a comparison of Examples 2, 5 to 8 confirmed that the use of (B) a base, (C) an aminocarboxylic acid, and (D) a dithiocarbamate of polyethyleneimine as additives resulted in even better hydrolytic stability. A comparison of Examples 2, 5, and 10 confirmed that the heavy metal treatment agent comprising components (A), (B), and (C) exhibited even better hydrolytic stability.

[0265] This suggests that the heavy metal treatment agent of the present invention can suppress the decomposition of dithiocarbamate groups due to hydrolysis during storage, use, and mixing with water, thereby preventing a decrease in heavy metal treatment capability.

[0266] (Scale prevention test)

[0267] The heavy metal treatment agent shown in Table 3 was diluted with tap water (hardness 78) to 10% by mass. The mixture was allowed to stand at 25°C, and the precipitation (scale) was visually observed over time. The absence of scale precipitation was evaluated as "○," while the presence of scale precipitation was evaluated as "×."

[0268] [Table 3]

[0269]

[0270] As shown in Table 3, in Comparative Example 2, precipitation was observed after one day, but in Examples 10 to 16, no precipitation was observed even after one day or more, indicating that the heavy metal treatment agent of the present invention has excellent anti-scaling performance. According to Table 3, it was also confirmed that in the examples, in the comparison between Example 11 and Example 12 containing aminocarboxylic acids (C), no precipitation was observed in Example 12 even after 10 days. When tetraethylenepentamine (a combination mixture of linear, branched, and cyclic and linear) is contained as the (A) component, the stability is excellent. In addition, when a dithiocarbamate of an amine compound containing any one of the amine compounds of Formula (IIIa), Formula (IIIb), and Formula (IIIc) is contained, in particular, a dithiocarbamate containing an amine compound of Formula (IIIa), Formula (IIIb) and also containing Formula (IIIc) is excellent in scale prevention performance. In addition, when a dithiocarbamate of an amine compound containing an amine compound of Formula (I), Formula (II), or Formula (III) is contained, in particular, a dithiocarbamate containing an amine compound of Formula (Ia), Formula (IIa), Formula (IIIa), Formula (IIIb), and also containing Formula (IIIc) is excellent in scale prevention performance.

[0271] In the comparison of Examples 10, 12, and 16, it was confirmed that the heavy metal treatment agent containing the components (A), (B), and (C) was excellent in both the antiscaling performance and the hydrolysis stability.

[0272] (Wastewater treatment test)

[0273] The following reagents were used to prepare the test solution to be treated: A hydrochloric acid aqueous solution or a sodium hydroxide aqueous solution was used to adjust the pH when preparing the test solution.

[0274] Chromium (III) chloride hexahydrate (manufactured by Kanto Chemical Co., Ltd., Japan).

[0275] Manganese (II) chloride tetrahydrate (manufactured by Kanto Chemical Co., Ltd., Japan).

[0276] Cobalt (II) chloride hexahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Japan).

[0277] Iron (III) chloride hexahydrate (manufactured by Kanto Chemical Co., Ltd., Japan).

[0278] Copper (II) chloride dihydrate (manufactured by Nihon Kokusho Chemical Co., Ltd.).

[0279] Zinc (II) chloride (manufactured by Nihon Kokusho Chemical Co., Ltd.).

[0280] Aluminum sulfate 14-18 hydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Japan).

[0281] Cadmium chloride (I1) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Japan).

[0282] Lead (II) chloride (manufactured by Kanto Chemical Co., Ltd., Japan).

[0283] Mercury (II) chloride (manufactured by Kanto Chemical Co., Ltd., Japan).

[0284] Arsenic (III) oxide (manufactured by Kanto Chemical Co., Ltd., Japan).

[0285] Sodium selenite (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Japan).

[0286] In addition, the following substances were used as the aggregating agent.

[0287] Aluminum sulfate aqueous solution (manufactured by Daimei Chemical Industry Co., Ltd., Japan).

[0288] 38% ferric chloride aqueous solution (manufactured by Hayashi Junyao Industry Co., Ltd.)

[0289] Polymer aggregating agent (anionic polymer aggregating agent: MIYOFLOC AP-800 (manufactured by Miyoshi Oils & Fats Co., Ltd., Japan)

[0290] [Treatment of copper-containing wastewater]

[0291] An aqueous solution containing 20 mg / L of copper (Group 11) was prepared as test wastewater (treated water), and the wastewater was treated and evaluated according to the following procedures.

[0292] 200 mL of the test wastewater was stirred at 200 rpm. The heavy metal treatment agent (A) was added in an amount shown in Table 4, such that the dithiocarbamate content of the agent was equal to that of the wastewater. The mixture was stirred for 10 minutes. After stirring, the mixture was allowed to stand for 10 minutes, and the flocculent material was filtered out using filter paper (JIS P3801 5 type A). The copper concentration in the test wastewater and filtrate was measured using an ICP emission spectrometer (ICPE-9820, Shimadzu Corporation, Japan). The results are shown in Table 4.

[0293] [Table 4]

[0294]

[0295] Table 4 shows that when the heavy metal treatment agent was added so that the dithiocarbamate group content of component (A) in the added heavy metal treatment agent became equal, the concentration of copper (Group 11) in the filtrate was lower in Examples 17 to 24 and 61 than in Comparative Examples 3 to 6, indicating that the heavy metal treatment agent of the present invention has high treatment performance for Group 11 elements.

[0296] Comparing Example 17 with Comparative Example 3, Example 18 with Comparative Example 4, Example 19 with Comparative Example 5, and Example 20 with Comparative Example 6, respectively, it was confirmed that the copper concentration of the filtrates of Examples 17 to 20 was low, and the heavy metal treatment agent containing the (B) base had excellent performance in treating Group 11 elements or their compounds.

[0297] When Examples 22 to 24 are compared with Examples 18 and 21, it was confirmed that the copper concentration of the filtrates of Examples 22 to 24 was low, and the heavy metal treatment agent containing (D) dithiocarbamate of polyethyleneimine or (E) sulfur-containing compound had excellent performance in treating elements of Group 11 or their compounds. Among them, the heavy metal treatment agent containing sulfur-containing compound had excellent performance in treating elements of Group 11 or their compounds.

[0298] When Example 17 is compared with Examples 18 to 20, it was confirmed that the copper concentration of the filtrate of Examples 18 to 20 was low, and the dithiocarbamate of an amine compound containing any one of the amine compounds of Formula (IIIa), Formula (IIIb), and Formula (IIIc), in particular, the dithiocarbamate containing an amine compound of Formula (IIIa), Formula (IIIb) and Formula (IIIc), was excellent in treating elements of Group 11 or their compounds. In addition, the dithiocarbamate of an amine compound containing an amine compound of Formula (I), Formula (II), or Formula (III), in particular, the dithiocarbamate containing an amine compound of Formula (Ia), Formula (IIa), Formula (IIIa), Formula (IIIb), and Formula (IIIc), was excellent in treating elements of Group 11 or their compounds.

[0299] In the comparison between Examples 18 and 19 and Example 20, the copper concentration of the filtrate of Examples 18 and 19 was low, showing the following tendency: in the mixed system of Formula (I) to Formula (III), the greater the amount of the amine compound of Formula (III), the better the performance of treating the elements or their compounds of Group 11.

[0300] Furthermore, in the comparison between Example 18 and Examples 19 and 20, the copper concentration of the filtrate of Example 18 was low, suggesting that the greater the total amount of the amine compounds of Formula (IIIa) and Formula (IIIb), the better the performance in treating the target element or its compound.

[0301] [Treatment of chromium-containing wastewater]

[0302] An aqueous solution containing 10 mg / L of chromium (Group 6) was prepared as test wastewater (treated water), and the wastewater was treated according to the following steps and evaluated. 200 mL of the test wastewater was stirred at 200 rpm, and a heavy metal treatment agent was added at the same time, in which the dithiocarbamate content of component (A) in the heavy metal treatment agent was added in an amount shown in Table 5 relative to the wastewater, and stirred for 10 minutes. Then, the pH was adjusted to 8 using an aqueous sodium hydroxide solution. Thereafter, a polymer aggregating agent was added and stirred for 2 minutes at a rotation speed of 20 rpm. After the stirring was completed, the mixture was allowed to stand for 10 minutes and the flocs were filtered out with filter paper. The chromium concentration in the test wastewater and the filtrate was measured using an ICP emission spectrophotometer. The results are shown in Table 5.

[0303] [Table 5]

[0304]

[0305] Table 5 shows that, for Examples 25 to 27, although the dithiocarbamate group content of component (A) in the added heavy metal treatment agent was half that of Comparative Example 7, the chromium (Group 6) concentration in the filtrate was still low, and the heavy metal treatment agent of the present invention had high treatment performance for Group 6 elements.

[0306] [Treatment of manganese-containing wastewater]

[0307] An aqueous solution containing 10 mg / L of manganese (Group 7) was prepared as test wastewater (treated water). The wastewater was treated and evaluated according to the following steps. 200 mL of this test wastewater was stirred at 200 rpm. A heavy metal treatment agent (component (A)) was added at an amount corresponding to the dithiocarbamate content of the heavy metal treatment agent shown in Table 6 relative to the wastewater, and stirred for 10 minutes. After stirring, the mixture was allowed to stand for 10 minutes, and the flocs were filtered out using filter paper. The manganese concentrations in the test wastewater and filtrate were measured using an ICP emission spectrometer. The results are shown in Table 6.

[0308] [Table 6]

[0309]

[0310] Table 6 shows that, for Examples 28 to 30, the manganese (Group 7) concentration in the filtrate was low compared to Comparative Example 8, despite the low dithiocarbamate group content of component (A) in the added heavy metal treatment agent. This indicates that the heavy metal treatment agent of the present invention has high performance in treating Group 7 elements.

[0311] [Treatment of iron-containing wastewater]

[0312] An aqueous solution containing 10 mg / L of iron (Group VIII) was prepared as test wastewater (treated water). The wastewater was treated and evaluated according to the following steps. 200 mL of this test wastewater was stirred at 200 rpm. A heavy metal treatment agent (component (A)) was added at an amount corresponding to the dithiocarbamate content of the heavy metal treatment agent shown in Table 7 relative to the wastewater, and stirred for 10 minutes. After stirring, the mixture was allowed to stand for 10 minutes, and the flocs were filtered out using filter paper. The iron concentrations in the test wastewater and filtrate were measured using an ICP emission spectrometer. The results are shown in Table 7.

[0313] [Table 7]

[0314]

[0315] According to Table 7, it can be confirmed that for Examples 31 to 33, although the dithiocarbamate group content of component (A) in the added heavy metal treatment agent is small compared with Comparative Example 9, the iron (Group 8) concentration of the filtrate is still low, and the heavy metal treatment agent of the present invention has high treatment performance for Group 8 elements.

[0316] [Treatment of cobalt-containing wastewater]

[0317] An aqueous solution containing 10 mg / L of cobalt (Group 9) was prepared as test wastewater (treated water). The wastewater was treated and evaluated according to the following steps. 200 mL of this test wastewater was stirred at 200 rpm. A heavy metal treatment agent (component (A)) was added at an amount corresponding to the dithiocarbamate content of the heavy metal treatment agent shown in Table 8 relative to the wastewater, and stirred for 10 minutes. After stirring, the mixture was allowed to stand for 10 minutes, and the flocs were filtered out using filter paper. The cobalt concentrations in the wastewater and filtrate were measured using an ICP emission spectrometer. The results are shown in Table 8.

[0318] [Table 8]

[0319]

[0320] According to Table 8, it can be confirmed that for Examples 34 to 36, although the dithiocarbamate group content of component (A) in the added heavy metal treatment agent is small compared with Comparative Example 10, the cobalt (Group 9) concentration of the filtrate is still low, and the heavy metal treatment agent of the present invention has high treatment performance for Group 9 elements.

[0321] [Treatment of aluminum-containing wastewater]

[0322] An aqueous solution containing 10 mg / L of aluminum (Group 13) was prepared as test wastewater (treated water), and the wastewater was treated according to the following steps and evaluated. 200 mL of the test wastewater was stirred at 200 rpm, and at the same time, a heavy metal treatment agent was added in which the dithiocarbamate content of component (A) in the heavy metal treatment agent was added in an amount shown in Table 9 relative to the wastewater, and stirred for 10 minutes. Then, a sodium hydroxide aqueous solution was used to adjust the pH to 8. Thereafter, a polymer aggregating agent was added and stirred for 2 minutes at a rotation speed of 20 rpm. After the stirring was completed, the mixture was allowed to stand for 10 minutes and the flocs were filtered out with filter paper. The aluminum concentration in the test wastewater and the filtrate was measured using an ICP emission spectrometer. The results are shown in Table 9.

[0323] [Table 9]

[0324]

[0325] According to Table 9, it can be confirmed that for Examples 37 to 39, although the dithiocarbamate group content of component (A) in the added heavy metal treatment agent is small compared to Comparative Example 11, the aluminum (Group 13) concentration of the filtrate is still low, and the heavy metal treatment agent of the present invention has high treatment performance for Group 13 elements.

[0326] [Treatment of wastewater containing nickel and zinc 1]

[0327] Test wastewater having a nickel concentration (Group 10) of 10 mg / L and a zinc concentration (Group 12) of 10 mg / L was prepared in advance.

[0328] 200 mL of the above test wastewater was stirred at 200 rpm. The heavy metal treatment agent was added in the amount shown in Table 10, such that the dithiocarbamate content of component (A) in the heavy metal treatment agent was equal to that in the wastewater, and stirred for 10 minutes. A 38% aqueous solution of ferric chloride or an aqueous solution of aluminum sulfate was added as an inorganic flocculant in the amount shown in Table 10, and stirred for 5 minutes. The pH was then adjusted to 8 using an aqueous sodium hydroxide solution (pH adjustment). A polymer flocculant was then added and stirred for 2 minutes at 20 rpm. After stirring, the mixture was allowed to stand for 10 minutes, the flocculants were filtered out using filter paper, and the nickel and zinc concentrations in the filtrate were measured. The nickel and zinc concentrations in the filtrate were measured using an ICP emission spectrometer. In Examples 40 and 41, and Comparative Example 12, no pH adjustment was performed. In Example 44, the same procedures were followed, except that the polymer flocculant was not added. The results are shown in Table 10.

[0329] [Table 10]

[0330]

[0331] Table 10 shows that Examples 40 to 44, 62, and 63 have lower nickel and zinc concentrations in the filtrate than Comparative Examples 12 and 13, and that the heavy metal treatment agent of the present invention has higher performance in treating Group 10 and Group 12 elements or their compounds.

[0332] According to Table 10, it can also be confirmed that if Example 42 is compared with Example 44, the nickel and zinc concentrations in the filtrate of Example 42 in which a polymer aggregating agent is added are lower. By using the heavy metal treatment agent of the present invention and the polymer aggregating agent and the inorganic aggregating agent in combination, the treatment effect of the heavy metal treatment agent of the present invention on the elements or their compounds of Groups 10 and 12 is improved.

[0333] According to Table 10, it can be further confirmed that when Example 40 is compared with Example 42, and Example 41 with Example 43, the nickel and zinc concentrations in the filtrate of Examples 42 and 43, which were subjected to pH adjustment, are lower. By using the heavy metal treatment agent of the present invention in combination with a polymer aggregating agent, an inorganic aggregating agent, and a pH adjuster, the treatment effect of the heavy metal treatment agent of the present invention on elements of Groups 10 and 12 or their compounds is improved.

[0334] According to Table 10, it can be confirmed that when Example 40 is compared with Example 41, and Example 42 with Example 43, it is confirmed that the nickel and zinc concentrations in the filtrate of Examples 41 and 43 using aluminum sulfate as the inorganic aggregating agent are lower. Among the heavy metal treatment agent, polymer aggregating agent, inorganic aggregating agent and pH adjuster of the present invention, the treatment effect of the heavy metal treatment agent of the present invention on the elements or their compounds of Groups 10 and 12 is improved by using aluminum sulfate as the inorganic aggregating agent.

[0335] [Treatment of wastewater containing nickel and zinc 2]

[0336] Test wastewater containing nickel (Group 10) at a concentration of 10 mg / L and zinc (Group 12) at a concentration of 10 mg / L was prepared in advance.

[0337] 200 mL of the above test wastewater was stirred at 200 rpm, and a 38% aqueous solution of ferric chloride or aluminum sulfate was added as an inorganic flocculant in the amount shown in Table 11, and stirred for 5 minutes. A heavy metal treatment agent was then added in an amount corresponding to the dithiocarbamate content of component (A) in the wastewater, and stirred for 10 minutes. The pH was then adjusted to 8 using an aqueous sodium hydroxide solution (pH adjustment). A polymer flocculant was then added and stirred for 2 minutes at 20 rpm. After stirring, the mixture was allowed to stand for 10 minutes, the flocs were filtered out using filter paper, and the nickel and zinc concentrations of the filtrate were measured. The nickel and zinc concentrations in the filtrate were measured using an ICP emission spectrometer. In Examples 45 and 46 and Comparative Example 14, the same procedures were followed, except that the pH adjustment was not performed. The results are shown in Table 11.

[0338] [Table 11]

[0339]

[0340] According to Table 11, it can be confirmed that the nickel and zinc concentrations in the filtrates of Examples 45 to 48 are low compared with Comparative Examples 14 and 15, and the heavy metal treatment agent of the present invention has high treatment performance for elements of Group 10 and Group 12 or their compounds. Moreover, regardless of the order of addition of the heavy metal treatment agent and the inorganic aggregating agent of the present invention, the treatment performance for elements of Group 10 and Group 12 or their compounds is high.

[0341] From Tables 10 and 11, it was confirmed that the order of adding the heavy metal treatment agent of the present invention and the inorganic aggregating agent is preferably to add the heavy metal treatment agent of the present invention first.

[0342] Furthermore, it is suggested that the treatment using the heavy metal treatment agent of the present invention according to the above system can be applied to wastewater from plating plants.

[0343] [Treatment of wastewater containing complex elements]

[0344] Test wastewater containing chromium (Group 6) with a concentration of 0.5 mg / L, copper (Group 11) with a concentration of 0.5 mg / L, cadmium (Group 12) with a concentration of 0.2 mg / L, mercury (Group 12) with a concentration of 1.0 mg / L, lead (Group 14) with a concentration of 1.5 mg / L, arsenic (Group 15) with a concentration of 0.5 mg / L, selenium (Group 16) with a concentration of 0.5 mg / L and sodium chloride with a concentration of 50 g / L was prepared in advance.

[0345] In Example 49, 200 mL of the above-mentioned test wastewater was stirred at a rotation speed of 200 rpm and adjusted to pH 6 using a sodium hydroxide aqueous solution (pH adjustment (1)). A heavy metal treatment agent was added in an amount such that the dithiocarbamate content of component (A) in the heavy metal treatment agent was the amount shown in Table 12 relative to the wastewater, and the mixture was stirred for 10 minutes. Thereafter, a 38% ferric chloride aqueous solution was added as an inorganic aggregating agent in an amount shown in Table 12, and the mixture was stirred for 5 minutes. Next, the pH was adjusted to 8 using a sodium hydroxide aqueous solution (pH adjustment (2)). Then, a polymer aggregating agent was added and stirred for 2 minutes at a rotation speed of 20 rpm. After the stirring was completed, the mixture was allowed to stand for 10 minutes, the flocs were filtered out with filter paper, and the concentrations of each element in the filtrate were measured.

[0346] In Example 50, 200 mL of the above-mentioned test wastewater was stirred at a rotation speed of 200 rpm, and the above-mentioned test wastewater was adjusted to pH 6 using a sodium hydroxide aqueous solution (pH adjustment (1)). A 38% ferric chloride aqueous solution was added as an inorganic aggregating agent in an amount as shown in Table 12, and stirred for 5 minutes. Then, a heavy metal treatment agent was added in an amount such that the dithiocarbamate group content of component (A) in the heavy metal treatment agent was the amount shown in Table 12 relative to the wastewater, and stirred for 10 minutes. Then, the pH was adjusted to 8 using a sodium hydroxide aqueous solution (pH adjustment (2)). Thereafter, a polymer aggregating agent was added and stirred for 2 minutes at a rotation speed of 20 rpm. After the stirring was completed, the mixture was allowed to stand for 10 minutes, the flocs were filtered out with filter paper, and the concentrations of each element in the filtrate were measured.

[0347] In Example 51, 200 mL of the test wastewater was stirred at 200 rpm and adjusted to pH 6 using a sodium hydroxide aqueous solution (pH adjustment (1)). A heavy metal treatment agent was added to the wastewater in an amount corresponding to the dithiocarbamate content of component (A) in the heavy metal treatment agent, and a 38% ferric chloride aqueous solution was added as an inorganic aggregating agent in an amount corresponding to the amount described in Table 12, and stirred for 10 minutes. Next, the pH was adjusted to 8 using a sodium hydroxide aqueous solution (pH adjustment (2)). Thereafter, a polymer aggregating agent was added and stirred for 2 minutes at a rotational speed of 20 rpm. After the stirring was completed, the mixture was allowed to stand for 10 minutes, the flocs were filtered out using filter paper, and the concentrations of each element in the filtrate were measured.

[0348] In Example 52, 200 mL of the test wastewater was stirred at 200 rpm and adjusted to pH 6 using an aqueous sodium hydroxide solution (pH adjustment (1)). A heavy metal treatment agent was added to the wastewater in an amount such that the dithiocarbamate content of component (A) was as shown in Table 12, and the mixture was stirred for 10 minutes. Subsequently, a 38% aqueous ferric chloride solution was added as an inorganic flocculant in an amount as shown in Table 12, and the mixture was stirred for 5 minutes. Next, the pH was adjusted to pH 8 using an aqueous sodium hydroxide solution (pH adjustment (2)). After the stirring was completed, the mixture was allowed to stand for 10 minutes, the flocs were filtered out using filter paper, and the concentrations of the various elements in the filtrate were measured.

[0349] The chromium, copper, cadmium, lead, arsenic, and selenium concentrations in the filtrate were measured using an ICP emission spectrometer, and the mercury concentration was measured using a mercury analyzer (Nippon Instruments Corporation, MA-3000). The results are shown in Table 12.

[0350] [Table 12]

[0351]

[0352] Table 12 confirms that, in Examples 49-51, regardless of the order in which the heavy metal treatment agent and inorganic flocculant of the present invention were added, the concentrations of chromium, copper, cadmium, mercury, lead, arsenic, and selenium in the wastewater were reduced to below the lower limit of quantification. Table 12 also confirms that the heavy metal treatment agent of the present invention can effectively treat elements or compounds of Groups 6, 11, 12, 14, 15, and 16. Furthermore, Table 12 confirms that, in Example 52, even without the addition of a polymer flocculant, the heavy metal treatment agent of the present invention can effectively treat elements or compounds of Groups 6, 11, 12, 14, 15, and 16.

[0353] This suggests that the treatment using the heavy metal treatment agent of the present invention according to the above system can be applied to the smoke washing wastewater of urban garbage incineration plants.

[0354] (Incineration ash treatment test)

[0355] Using a porcelain mortar as a container, a heavy metal treatment agent and water were added to 100 g of incineration ash generated in a municipal waste incineration plant (fly ash captured by a bag filter) at the addition rate shown in Table 13, so that the dithiocarbamate group content of the (A) component in the added heavy metal treatment agent was equal to the incineration ash, and kneaded for 10 minutes to mix it until it was uniform. As a blank test, the same treatment as in the example was carried out except that only water was added. The incineration ash (treated ash) after treatment in the example and the blank test was properly processed into a block shape. According to the test method No. 13 of the Japan Environment Agency Notice, the elution concentrations of chromium, mercury and lead obtained were measured. The results are shown in Table 13. The concentrations of chromium (Group 6) and lead (Group 14) in the eluate were measured using an ICP emission spectrometer, and the concentration of mercury (Group 12) was measured using a mercury analyzer. In addition, the pH value of the eluate was also measured.

[0356] [Table 13]

[0357]

[0358] Table 13 shows that the incineration ashes treated in Examples 53 to 60 and 64 all had chromium (Group 6), mercury (Group 12), and lead (Group 14) levels below landfill standards, demonstrating excellent performance in treating elements or compounds of Groups 6, 12, and 14. In particular, in Examples 58 to 60, although the dithiocarbamate group content of component (A) in the added heavy metal treatment agent was lower than that in Examples 54 and 57, the eluted concentrations of chromium, mercury, and lead were low. Furthermore, the heavy metal treatment agent containing (D) a dithiocarbamate salt of polyethyleneimine or (E) a sulfur-containing compound exhibited excellent performance in treating elements or compounds of Groups 6, 12, and 14.

[0359] Furthermore, it was confirmed that the incineration ashes treated in Examples 53 to 60 and 64 had cadmium (Group 12), arsenic (Group 15), and selenium (Group 16) levels were all below the landfill standards.

[0360] In addition, the pH of the eluates of the untreated incineration ash, the examples, and the blank test was 12.4, which suggests that if the pH of the incineration ash treatment liquid is 11.5 or above, incineration ash containing elements of Groups 6 to 16 or their compounds can be treated with the heavy metal treatment agent of the present invention.

[0361] In summary, it is suggested that the heavy metal treatment agent of the present invention has excellent performance in treating elements of Groups 6 to 16 or compounds thereof.

[0362] The above results suggest that the heavy metal treatment agent of the present invention has excellent stability when mixed with water containing minerals, etc., and due to the characteristics of its structure, it can react well with elements or compounds of Groups 6 to 16 to form water-insoluble aggregates (flocs). It has excellent treatment performance and the stability of the generated flocs is also excellent. Therefore, it has high practicality.

[0363] (Stability test of flocculants)

[0364] Test wastewater containing nickel (Group 10) at a concentration of 50 mg / L, copper (Group 11) at a concentration of 50 mg / L, zinc (Group 12) at a concentration of 0.2 mg / L, and lead (Group 14) at a concentration of 1.5 mg / L was prepared in advance.

[0365] 10L of the above-mentioned test wastewater was stirred at 200rpm, and at the same time, a heavy metal treatment agent was added in an amount such that the dithiocarbamate content of component (A) in the heavy metal treatment agent became the addition amount shown in Table 14 relative to the wastewater, and the mixture was stirred for 10 minutes. Next, a 38% ferric chloride aqueous solution was added as an inorganic coagulant in an amount as shown in Table 14, and the mixture was stirred for 5 minutes. Next, the pH was adjusted to 8 using a sodium hydroxide aqueous solution (pH adjustment). Thereafter, a polymer coagulant was added and stirred for 2 minutes at a rotation speed of 20rpm. After the stirring was completed, the mixture was allowed to stand for 10 minutes, the flocs were filtered out with filter paper, and the concentrations of each element in the filtrate were measured. In addition, the elution concentrations of each element were measured for the generated flocs according to the test method No. 13 of the Japan Environmental Agency Notice. The results are shown in Table 14.

[0366] [Table 14]

[0367]

[0368] Table 14 confirms that the concentrations of nickel, zinc, copper, and lead in the filtrates of Examples 65 to 68 were all lower than those of Comparative Example 16, and that the filtrates of Examples 65 to 68 exhibited excellent performance in treating elements from Groups 10, 11, 12, and 14 or their compounds. Furthermore, it was confirmed that the concentrations of the elements eluted from the generated flocs in Examples 65 to 68 were lower than those in Comparative Example 16, that the re-elution of the elements from the flocs was suppressed, and that the flocs treated with the heavy metal treatment agent of the present invention exhibited excellent stability.

Claims

1. A heavy metal treatment agent, wherein The heavy metal treatment agent comprises the following component (A) and at least one selected from components (B) to (E), (A) at least one dithiocarbamate of an amine compound represented by any one of the following formulas (I) to (III), [Chemical Formula 1] In the formula, m represents an integer of 3 to 6, [Chemical Formula 2] In the formula, n Xs are independently hydrogen or 2-aminoethyl, at least one of which is 2-aminoethyl, n is an integer of 1 to 3, and the total number of nitrogen atoms is 4 to 8. [Chemical Formula 3] In the formula, o represents an integer of 0 to 2, p represents 0 or 1, q represents 0 or 1, r represents an integer of 0 to 3, the sum of o, p and r is 1 or more, and the total number of nitrogen atoms is 3 to 7. (B) alkali, (C) at least one selected from aminocarboxylic acids, thiols and aminophosphoric acids, (D) dithiocarbamates of polyethyleneimine, (E) Sulfur-containing compounds.

2. The heavy metal treatment agent according to claim 1, wherein The amine compound includes an amine compound represented by the formula (III).

3. The heavy metal treatment agent according to claim 2, wherein The amine compound includes at least one selected from various amine compounds represented by the following formula (IIIa), formula (IIIb) and formula (IIIc) as the amine compound represented by the formula (III), [Chemical Formula 4] 4. The heavy metal treatment agent according to claim 3, wherein The amine compound includes various amine compounds represented by the following formula (IIIa) and formula (IIIb) as the amine compound represented by the formula (III). [Chemical Formula 5] 5. The heavy metal treatment agent according to claim 4, wherein The amine compound further includes an amine compound represented by the following formula (IIIc) as the amine compound represented by the formula (III), [Chemical Formula 6] 6. The heavy metal treatment agent according to claim 1, wherein The amine compound includes amine compounds represented by the formula (I), the formula (II), and the formula (III).

7. The heavy metal treatment agent according to claim 6, wherein The amine compound includes each of the following amine compounds represented by formula (Ia), formula (IIa), formula (IIIa), and formula (IIIb) as the amine compound represented by any one of the above formulas (I) to (III), [Chemical Formula 7] 8. The heavy metal treatment agent according to claim 7, wherein The amine compound further includes an amine compound represented by the following formula (IIIc) as the amine compound represented by the formula (III), [Chemical Formula 8] 9. The heavy metal treatment agent according to claim 1, wherein The amine compound includes an amine compound represented by the formula (III), and the amount of the amine compound represented by the formula (III) is 10.0% or more and 80.0% or less.

10. The heavy metal treatment agent according to claim 1, wherein The amine compound comprises each of the amine compounds represented by the following formula (IIIa) and formula (IIIb) as the amine compound represented by the formula (III), and the total amount of the amine compound of the formula (IIIa) and the amine compound of the formula (IIIb) is 10.0% or more and 50.0% or less, [Chemical Formula 9] 11. The heavy metal treatment agent according to claim 1, wherein The amine compound includes an amine compound represented by the formula (II), and the amount of the amine compound represented by the formula (II) is 5.0% or more and 30.0% or less.

12. The heavy metal treatment agent according to claim 1, wherein The dithiocarbamate is dithiocarbamic acid sodium salt.

13. The heavy metal treatment agent according to claim 1, wherein The heavy metal treatment agent includes the component (A), the component (B), and the component (C).

14. The heavy metal treatment agent according to any one of claims 1 to 13, wherein The treatment targets are elements from Groups 6 to 16 of the periodic table or their compounds.

15. A method for treating wastewater, wherein: The wastewater treatment method comprises the step of adding the heavy metal treatment agent according to any one of claims 1 to 13 to water to be treated, wherein the wastewater contains an element of Groups 6 to 16 of the periodic table or a compound thereof.

16. The method for treating wastewater according to claim 15, wherein The wastewater treatment method further comprises the step of adding a polymer aggregating agent and / or an inorganic aggregating agent to the water to be treated.

17. A method for treating incineration ash, wherein: The method for treating incineration ash comprises the step of adding the heavy metal treatment agent according to any one of claims 1 to 13 to incineration ash containing at least one element of Groups 6, 12, and 14 of the periodic table or a compound thereof.

18. The method for treating incineration ash according to claim 17, wherein: The pH of the eluate of the incineration ash according to the Japan Environment Agency Test No. 13 is 11.5 or higher.

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