JP2002253962A - Adsorbent and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive adsorbent having high performance. SOLUTION: An adsorbent in which a reaction product obtained by a cross- linking reaction of polyethylene-polyamines having low molecular weight is fixed to the surface of a porous carrier is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adsorbent effective for adsorbing and removing acidic gases, odor components, surfactants, heavy metal ions and the like which cause environmental pollution. More specifically, the present invention particularly relates to an adsorbent having high affinity for heavy metal ions and selectively adsorbing the same, and a method for producing the same.

[0002]

2. Description of the Related Art Strict regulations are set for metals harmful to the human body contained in wastewater and the like, and various methods have been proposed to remove them.

[0003] As a method for removing metals contained in wastewater and the like, for example, neutralization coagulation sedimentation method, ion flotation method, ion exchange method, electrolytic flotation method, electrodialysis method, adsorption method, reverse osmosis method and the like. It has been known. However, in the neutralization coagulation sedimentation method, there is an operational problem that it is necessary to treat a large amount of generated metal hydroxide sludge, and metal ions are generated from discarded metal hydroxide sludge in rivers, lakes, seawater, etc. Redissolved in water and could cause secondary pollution.
Methods such as the ion flotation method, ion exchange method, electrolytic flotation method, electrodialysis method, adsorption method, and reverse osmosis method have problems in terms of metal ion removal rate, operability, running cost, and the like, and are not always satisfied. It was not a processing method.

[0004] For this reason, a metal removal method using an adsorbent has been widely used instead of the above-mentioned method. The adsorbent is capable of adsorbing not only metals in wastewater but also surfactants in solution, and exhaust gas containing gasified metals such as flue gas from garbage incineration plants, environmental For the adsorption of gases such as acid gas and odorous components that cause pollution, and also for the treatment of solid waste containing metals such as incineration ash, slag, sludge, contaminated soil, etc. generated in refuse incineration plants. It is available and is becoming widely used.

[0005] As such an adsorbent, an adsorbent in which an amino group is introduced and immobilized on various carriers is known. Polyamines such as polyethyleneimine are converted to acid gases and odor components such as carbon dioxide, sulfur dioxide, hydrogen sulfide, aldehydes and mercaptans, nonionic or anionic surfactants, and heavy metal ions such as copper and mercury. It is generally known that it has a high affinity for the polymer. For example, a heavy metal adsorbent obtained by impregnating a reaction product of polyethyleneimine and carbon disulfide on activated carbon (Japanese Patent Application Laid-Open No. 58-150424, etc.), a porous resin Adsorbent for environmental purification comprising polyethyleneimine having a molecular weight of 5000 or more supported on
Japanese Patent Application Laid-Open No. 62-225244, etc.), an adsorbent obtained by reacting a cross-linking agent with a carrier obtained by adsorbing and supporting polyethylene imine on a porous carrier (eg, JP-A-62-225244) In addition, materials in which polyethyleneimine is supported on various carriers have been proposed.

[0006]

However, since polyethyleneimine is an expensive material for these adsorbents, the adsorbents themselves have a problem of high cost, and the adsorbing / removing rate of metal ions is not sufficient. Was hard to say.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive and high-performance adsorbent and a method for producing the same.

[0008]

Means for Solving the Problems The present inventors have intensively studied to develop an inexpensive and high-performance adsorbent, and as a result, a reaction product obtained by a cross-linking reaction of low molecular weight polyethylene polyamines was used as a porous carrier. The present inventors have found an adsorbent immobilized on the surface, and have completed the present invention.

That is, the present invention relates to an adsorbent in which a reaction product obtained by a cross-linking reaction of low molecular weight polyethylene polyamines is immobilized on the surface of a porous carrier, and a method for producing the same.

Hereinafter, the present invention will be described in detail.

The adsorbent of the present invention is characterized in that a reaction product obtained by a cross-linking reaction of low molecular weight polyethylene polyamines is immobilized on the surface of a porous carrier.

In the present invention, the low molecular weight polyethylene polyamines are not particularly limited,
Polyethylene polyamines having a molecular weight of 250 or less are preferable, and specific examples thereof include aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine. Although the detailed reason is unknown, the adsorbent of the present invention obtained using such low-molecular-weight polyethylene polyamines as polyethylene polyamines can be obtained using high-molecular-weight amines such as polyethylene imine. The metal ion adsorption capacity is higher than that of the adsorbent, and the performance is high. For this reason, in the present invention, it is important to use low molecular weight polyethylene polyamines. The low-molecular-weight polyethylene polyamines used in the present invention have a low viscosity, and are not more than about 100 mPa · s at 30 ° C. In contrast, high molecular weight amines have a high viscosity. For example, in the case of polyethylene amine having a molecular weight of 600,
00 to 2,500 mPa · s. As described above, in the present invention, the use of low-viscosity, low-molecular-weight polyethylene polyamines also has an advantage that handling is easy and operability is improved.

In the present invention, the porous carrier which is a component of the adsorbent is not particularly limited, and for example, a known porous inorganic compound, a porous resin or the like may be used. Examples of such a porous inorganic compound include silica, alumina, titania, zirconia, and aluminosilicate, and these can be used alone or as a mixture.
Examples of the porous resin include a resin having a styrene skeleton represented by polystyrene, a resin having a (meth) acryl skeleton represented by methyl (meth) acrylate, and a resin having a phenol skeleton represented by a phenol resin. And these can be used alone or as a mixture. Although the powder physical properties of the porous carrier are not particularly limited, the average particle diameter is 1 μm to 1 mm, the porosity is 20 to 90%, the average pore diameter is 10 nm to 5 μm, and BE
The T specific surface area may be about 50 to 500 m ² / g.

The amount of the reaction product obtained by crosslinking the low-molecular-weight polyethylene polyamines immobilized in the adsorbent of the present invention is not particularly limited, but may be 10 to 50% by weight of the adsorbent. A range is preferred. If the amount of the reaction product immobilized is less than 10% by weight, the amount of adsorbed metal may be low. If the amount exceeds 50% by weight, the reaction product may be separated from the porous carrier.

Next, a method for producing the adsorbent of the present invention will be described.

The method for producing the adsorbent of the present invention is not particularly limited. For example, a solution containing a low-molecular-weight polyethylene polyamine is mixed with a porous carrier, and the solvent is distilled off to obtain a low-molecular-weight. After producing a support carrying polyethylenepolyamines, a solution containing a crosslinking agent and the support are mixed, or a solution containing a low-molecular-weight polyethylene polyamine and a crosslinker and the support are mixed. It can be easily produced by mixing and allowing a low molecular weight polyethylene polyamine to undergo a crosslinking reaction on the surface of the porous carrier.

In the method of the present invention, the solvent used for supporting the low molecular weight polyethylene polyamines on the porous carrier is a solvent capable of dissolving the low molecular weight polyethylene polyamines, Any material can be used without any particular limitation as long as it does not change the physical properties such as the pore structure. Specific examples include aliphatic lower alcohols such as methanol, ethanol, isopropanol and n-butanol, ketones such as acetone and methyl ethyl ketone, cellosolps such as methyl cellosolve, and water. In terms of easy removal of the solvent, an aliphatic lower alcohol having a low boiling point is particularly preferable. The amount of the solvent is not particularly limited as long as the porous carrier and the low molecular weight polyethylene polyamines can be uniformly mixed.

In the method of the present invention, the amount of the low molecular weight polyethylene polyamines to be supported on the porous carrier is not particularly limited, but may be 100 parts by weight or less based on 100 parts by weight of the porous carrier. Since the entire amount of low molecular weight polyethylene polyamines used in this step is supported on the porous carrier, the performance of the adsorbent finally obtained,
The supported amount can be arbitrarily selected according to the use and purpose of use.

Next, the obtained carrier is mixed with a solvent containing a cross-linking agent or with a solution containing a low-molecular-weight polyethylene polyamine and a cross-linking agent. A cross-linking reaction is performed on the surface of the carrier.

In the method of the present invention, the crosslinking agent is not particularly limited as long as it has two or more functional groups capable of forming a chemical bond with a low molecular weight polyethylene polyamine. For example, dialdehydes such as glutaraldehyde, ring-opening polymers such as epichlorohydrin,
Examples thereof include diisocyanates such as tolylene diisocyanate and isophorone diisocyanate, acid anhydrides such as phthalic anhydride and maleic anhydride, and polyfunctional epoxy compounds. Preferred are polyfunctional epoxy compounds. Examples of the polyfunctional epoxy compound include bifunctional epoxy compounds such as ethylene glycol diglycidyl ether and propylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, Sorbitol polyglycidyl ether is exemplified.

In the method of the present invention, the solvent used for the crosslinking reaction of the low-molecular-weight polyethylene polyamines is a cross-linking agent or a solvent capable of dissolving the low-molecular-weight polyethylene polyamines and the cross-linking agent. The carrier can be used without any particular limitation as long as it does not change the physical properties such as the pore structure of the carrier. Specifically, methanol, ethanol, isopropanol, aliphatic lower alcohols such as n-butanol, acetone, ketones such as methyl ethyl ketone, esters such as ethyl acetate,
Ethers such as tetrahydrofuran and dioxane, n-
Hexane, aliphatic hydrocarbons such as cyclohexane, benzene, aromatic hydrocarbons such as toluene, methylene chloride,
Examples thereof include halogenated hydrocarbons such as chloroform and chlorobenzene, and one or more of these organic solvents.
Further, it is possible to use a mixed solvent in which water is partially mixed. The amount of the solvent is not particularly limited as long as the porous carrier and the crosslinking agent, or the porous carrier and the low molecular weight polyethylene polyamines and the crosslinking agent can be uniformly mixed.

In the method of the present invention, the amount of the crosslinking agent used at the time of the crosslinking reaction is not particularly limited as long as the crosslinking reaction proceeds well on the surface of the porous carrier. For example, in the case of a polyfunctional epoxy compound, the amount may be such that the amount of active hydrogen of low molecular weight polyethylene polyamines is about 1 to 10 per epoxy group. The temperature at the time of the crosslinking reaction is not particularly limited as long as the temperature allows the crosslinking reaction to proceed well on the surface of the porous carrier. For example, it may be in the range of room temperature to the boiling point of the solvent. The time for the crosslinking reaction is not particularly limited, but may be in the range of several to several tens of hours.

After the crosslinking reaction of the low molecular weight polyethylene polyamines is completed, the solvent is separated and removed to obtain the adsorbent of the present invention. The method for separating and removing the solvent is not particularly limited, and may be, for example, a mechanical separation method such as filtration or centrifugation, or a thermal separation method such as distillation or drying.

[0024]

The adsorbent of the present invention has the following effects, and can be used in an extremely wide range as, for example, an adsorbent for environmental purification. (1) Since the adsorbent of the present invention uses low molecular weight polyethylene polyamines as a raw material, the cost is lower than that of a conventional adsorbent using polyethyleneimine as a raw material. (2) The adsorbent of the present invention is excellent in metal ion adsorption ability as compared with a conventional adsorbent using polyethyleneimine as a raw material. (3) The adsorbent of the present invention is capable of adsorbing not only metal ions in wastewater but also surfactants and the like in a solution, and is capable of adsorbing gas such as smoke from a garbage incineration plant. Exhaust gas containing converted metal, adsorption of gases such as acid gas and odor components causing environmental pollution, and solids containing metals such as incineration ash, slag, sludge, contaminated soil, etc. generated in waste incineration plants It can also be used for waste disposal.

[0025]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

In the examples, TG-DTA was measured as follows.

Apparatus: "TGD700" manufactured by Vacuum Riko Co., Ltd.
0 "Measurement conditions: Atmosphere: in a dry air stream (50 ml / min) Heating rate: 10 ° C./min Calculation of supported amount: Calculated assuming that the weight loss at 150 to 1000 ° C. is due to decomposition and evaporation of organic components. .

Example 1 10 g of pentaethylenehexamine (manufactured by Tosoh) was added to 25
In addition to 0 g of methanol, 50 g of silica gel (trade name: CARiACTQ-1 manufactured by Fuji Silysia Chemical Ltd.)
0 ") and mixed at room temperature. After mixing, methanol was distilled off under reduced pressure at a temperature of 40 ° C. to produce silica gel carrying pentaethylenehexamine. TG-
As a result of measuring the weight loss by DTA analysis, the content of pentaethylenehexamine was 16.7% by weight.

1 g of pentaethylenehexamine (manufactured by Tosoh Corporation) and 3 g of glycerol polyglycidyl ether (manufactured by Nagase Kasei Kogyo Co., Ltd., trade name "Denacol EX-314") are added to 30 g of dioxane to form a uniform solution. The silica gel supporting 10 g of pentaethylenehexamine obtained in the above was added and stirred at 60 ° C. for 8 hours.
The reaction was allowed to proceed for a period of time to crosslink pentaethylenehexamine. After the crosslinking reaction, the supernatant was removed, and water washing by decantation was repeated to obtain an adsorbent.

From the result of measuring the weight loss by TG-DTA analysis, the content of the crosslinked product of pentaethylenehexamine was 33.7% by weight.

The adsorption capacity of the adsorbent obtained by the above-mentioned method with respect to Cu was evaluated according to the following method.

200 m of an aqueous solution containing 10 ppm of Cu
Approximately 0.2 g of a wet adsorbent is added to the mixture under stirring.
The adsorption experiment was performed at a temperature of 25 ° C. for 24 hours. After the adsorption experiment, solid-liquid separation was performed, the adsorbent was dried, and the dry weight was measured. The concentration of Cu remaining in the solution was determined by ICP,
The adsorption capacity for Cu was evaluated as the adsorption amount per unit dry weight of the adsorbent. The adsorption capacity for Cu is 0.24
mmol / g.

Example 2 Using silica gel supporting pentaethylenehexamine obtained in the same manner as in Example 1, a crosslinking reaction of pentaethylenehexamine was carried out according to the following method. 45
g of dioxane and 1.5 g of pentaethylenehexamine (manufactured by Tosoh Corporation), 4.5 g of glycerol polyglycidyl ether (manufactured by Nagase Kasei Kogyo, trade name "Denacol E
X-314 ") to make a homogeneous solution, and then 10 g of silica gel supporting pentaethylenehexamine obtained in the same manner as in Example 1 was added.
For 8 hours. After the crosslinking reaction, the supernatant is removed,
Water washing by decantation was repeated to obtain an adsorbent.

From the result of measuring the weight loss by TG-DTA analysis, the content of the crosslinked product of pentaethylenehexamine was 39.3% by weight.

The adsorption capacity of the adsorbent obtained by the above-mentioned method for Cu was evaluated in the same manner as in Example 1. Cu
The adsorption capacity was 0.23 mmol / g.

Comparative Example 1 10 g of polyethyleneimine (trade name "Epomin SP-006" manufactured by Nippon Shokubai) was added to 150 g of methanol, and 100 g of silica gel (manufactured by Fuji Silysia Chemical Ltd.) was added.
(Trade name: CARiACT Q-10)) and mixed at room temperature. After mixing, methanol was distilled off under reduced pressure at a temperature of 40 ° C. to produce a silica gel supporting polyethyleneimine. From the measurement result of the weight loss by TG-DTA, the content of polyethyleneimine was 9.1% by weight.

In 15 g of dioxane, 0.5 g of polyethyleneimine (trade name "Epomin SP-0" manufactured by Nippon Shokubai)
06 "), 1 g of glycerol polyglycidyl ether (trade name" Denacol EX-31, manufactured by Nagase Kasei Kogyo Co., Ltd.)
4)) to obtain a homogeneous solution, 10 g of silica gel supporting polyethyleneimine obtained by the above method was added, and the mixture was reacted at 60 ° C. for 8 hours with stirring to crosslink the polyethyleneimine. After the crosslinking reaction, the supernatant was removed, and water washing by decantation was repeated to obtain an adsorbent.

From the result of the measurement of the weight loss by TG-DTA analysis, the content of the crosslinked product of polyethyleneimine was 1%.
It was 7.3% by weight.

The adsorption capacity of the adsorbent obtained by the above-mentioned method for Cu was evaluated in the same manner as in Example 1. Cu
The adsorption capacity was 0.09 mmol / g.

Claims (4)

[Claims] 1. An adsorbent characterized in that a reaction product obtained by subjecting a low molecular weight polyethylene polyamine to a crosslinking reaction is immobilized on the surface of a porous carrier. 2. The adsorbent according to claim 1, wherein the porous carrier is a porous inorganic compound. 3. A solution containing a low-molecular-weight polyethylene polyamine and a porous carrier are mixed, and the solvent is distilled off to produce a support carrying the low-molecular-weight polyethylene polyamine. Or a mixture containing a low-molecular-weight polyethylene polyamine and a crosslinking agent and a solution containing a crosslinking agent, and the low-molecular-weight polyethylene polyamines are cross-linked on the surface of the porous carrier. The method for producing an adsorbent according to claim 1 or 2, wherein 4. The method according to claim 3, wherein the crosslinking agent is a polyfunctional epoxy compound.