JPH04110035A - Treating agent for adsorbing and decomposing contaminant and its production - Google Patents

Abstract

PURPOSE:To prevent the diffusion of contaminants by effective adsorption and to decompose the contaminants into harmless substances by using a treating agent contg. an adsorbing substance which adsorbs contaminants and a decomposition accelerating substance which accelerates the decomposition of the adsorbed contaminants. CONSTITUTION:A porous sintered body obtd. by firing a blend of silicon dioxide with one or more kinds of metal oxides selected among calcium oxide, aluminum oxide, iron oxide, manganese oxide, magnesium oxide and potassium oxide is crushed to obtain a granular decomposition accelerating substance and this substance is blended with a granular adsorbing substance such as activated carbon. When the resulting treating agent for adsorption and decomposition is used, the diffusion of contaminants is prevented by effective adsorption and the contaminants can be decomposed into harmless substances by the action of the treating agent itself or indirect action by which microorganisms are made active to accelerate biochemical decomposition action.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention aims to prevent contamination by pollutants, especially agricultural chemicals sprayed on soil, etc. by adsorbing these substances and by
The present invention relates to an agent for adsorbing and decomposing pollutants and a method for producing the same.

[Prior Art and Problems to be Solved by the Invention] The problem of pollution caused by chemical substances has been much discussed in the past. , heavy metal compounds, etc. are prohibited or regulated in their manufacture and use.

Furthermore, in recent years, with the growing debate on environmental issues, so-called agricultural chemicals such as insecticides and herbicides, whose toxicity has not been much of an issue in the past, have come to attract attention as pollutants. Particularly today, various chemicals used to protect lawns at golf courses and the like are sometimes sprayed concentratedly in a certain area, and before they are fully decomposed in the soil, they are mixed with rainwater, etc. in surrounding areas. This is causing problems such as leaking into the country, destroying the ecosystem, and threatening the lives of residents.

While the need for pesticide use still exists in this situation, the issues surrounding pesticide treatment after application are
Effective pollution prevention measures have not yet been established because they involve a wide range of issues, including not only technical issues but also economics, laws, etc.

For example, there are dozens of types of agricultural chemicals on the market, both domestically and internationally, and it is actually extremely difficult to take treatment measures for all of their basic ingredients. Also,
There are many ways to use pesticides, such as burying them, spraying them with water, and spraying them in the air. In practice, it is almost impossible to collect and decompose all of the pesticide components. To give a familiar example, it is impossible to predict which underground water route a pesticide component sprayed on a golf course will travel and to collect the pesticide component that has spread over a wide area. Furthermore, even if the pesticide components once sprayed are recovered using some kind of adsorbent,
There are no legal standards in place to treat this adsorbed waste.

The present invention was made in view of the above circumstances, and its purpose is to effectively adsorb pollutants and prevent their diffusion, and also to activate the activity of microorganisms based on their own action or by activating the activities of microorganisms. The object of the present invention is to provide a pollutant adsorption and decomposition agent that can decompose pollutants into harmless substances through an indirect action of promoting biochemical decomposition.

Furthermore, it is an object of the present invention to provide a manufacturing method that can reliably and inexpensively manufacture such a processing agent.

[Means and actions for solving the problem] In general, in the natural world, pollutants such as agricultural chemicals are degraded by surface catalytic action by colloidal clay contained in soil and biochemical decomposition action by various microorganisms such as bacteria. Or, it is decomposed by the decomposition effect of light such as ultraviolet rays and returned to the global environment. Furthermore, in the various decomposition actions described above, secondary factors such as temperature, humidity, oxygen concentration, and pressure influence the decomposition-reduction process in nature in a more complex manner.

The present inventors focused on such a self-purifying effect in the natural world, and attempted to solve the above problem by taking artificial means that can maximize this effect. That is, the pollutant adsorption and decomposition treatment agent of the present invention contains an adsorbent that adsorbs pollutants and a decomposition promoting substance that promotes the decomposition of the adsorbed pollutants.

Therefore, in the area where the treatment agent is sprayed, pollutants are adsorbed by the adsorbent in the treatment agent.

The pollutants collected by this adsorbent are
It is decomposed and rendered harmless by a surface catalytic action similar to that of colloidal clay caused by a decomposition promoting substance and by the biochemical decomposition action of microorganisms activated by the decomposition promoting substance.

Hereinafter, the present invention will be explained in more detail. Examples of the adsorbent include activated carbon and the like.

Activated carbon is particularly preferred because of its large adsorption capacity.

As the decomposition promoting substance, calcium oxide (Cab)
, basic oxides such as iron oxide (FezOs), manganese oxide (MnO), magnesium oxide (MgO), and potassium oxide (KzO), amphoteric oxides such as aluminum oxide (Al□Oz), silicon dioxide (SiO, etc.) acidic oxides.

The above-mentioned basic oxides and amphoteric oxides act as basic substances in acidic soil and acidic water, and neutralize the soil and water. On the other hand, the amphoteric oxide and acidic oxide are
Acts as an acidic substance in basic soil and basic water, neutralizing soil and water. As a result, the pH of this treatment agent or the sprayed soil or water is always maintained near neutrality, and the activity of microorganisms living in the area is activated, resulting in contamination due to biochemical decomposition. Substances are efficiently decomposed. In particular, when soil etc. becomes acidic, fungi that inhibit these activities become more active than bacteria that are useful for decomposing pollutants, so this is also beneficial from this point of view.

In addition, the above oxides are also components of colloidal clay that exists in soil, and each metal oxide particle acts as a catalyst.
Decomposition reactions of pollutants are promoted on the surface. Therefore, in order to artificially reproduce the surface catalytic action of colloidal clay in the natural world and to minimize the disturbance of the substance distribution in the natural world by spraying this treatment agent, when using a combination of multiple metal oxides, It is preferable to set the blending ratio close to the abundance ratio in nature.

Furthermore, since the basic oxide can generate alkali, it acts effectively in decomposing agricultural chemical components that are generally easily decomposed by alkali.

Furthermore, since the metals constituting the metal oxides are minerals essential for plant growth, the present treatment agent is also effective as a mineral supply source.

It is preferable that at least one of the adsorbing substance and the decomposition promoting substance is supported in a porous body containing silicon dioxide.

This porous body containing silicon dioxide is produced by wet-mixing silicon dioxide with at least one metal oxide selected from calcium oxide, aluminum oxide, iron oxide, manganese oxide, magnesium oxide, and potassium oxide. ,
It is preferable that silicon dioxide is made to support a decomposition promoting substance by curing at room temperature, followed by a pressure crystallization step, and then firing. In this way, the decomposition promoting substance can be allowed to remain semi-permanently in the area where the treatment agent is sprayed, and the effect of the treatment agent can be exerted over a long period of time.

When forming this sintered body, silicon dioxide powder and the above-mentioned metal oxides may be separately procured and used as raw materials, but when considering the ease of obtaining raw materials and the cost of raw materials, Trilime (3CaO・5iOz), dicalcium silicate (2
It is preferable to use silicic lime such as CaO-3iCh). Then, to this silicate lime, Cao, Fe
Metal oxides such as z O3, Mno, MgO, Kz O, A 120x, etc. are blended as necessary, and aluminum powder (At) is blended, and the mixture is kneaded while adding water until the whole becomes a slurry state. At this time, a hydration reaction occurs between silicate lime, the calcium oxide contained therein, and water at room temperature, producing calcium hydroxide and colloidal crystals (3Ca0.2sioz.3H
20) is produced, and the crystals harden to form an insoluble molded body.

On the other hand, the aluminum powder also reacts with water and the calcium hydroxide to produce aluminum hydroxide and a hydrated composite crystal of alumina and lime (3CaO-A1□03.6H20). At this time, along with the production of aluminum hydroxide, hydrogen gas is produced as a by-product, and this gas is released from the uncured molded body, thereby forming continuous pores within the molded body and forming the prototype of the porous body. Ru.

The pressure crystallization step following this curing step is preferably carried out using an autoclave or the like under conditions of 10 atm and 180° C. for 24 hours. As a result, the molded body cured at room temperature is subjected to saturated steam curing. That is, the diffusion of silicon dioxide (Si02) contained in the raw material to the surface of the molded body is promoted, and this 5iCh and the crystal (3Ca 0 ・2
S i O2 3H20) causes a chemical reaction in the surface layer of the molded body, and tobermorite crystals (
5Ca0, 6SiO2, 5H20) is generated.

This tobermorite crystal is a plate-shaped crystal that improves the mechanical strength of the porous body.

The porous body thus obtained has a porosity of 70 to 8.
0%, compressive strength is 40 to 45 kgf/crl,
When the ratio of each component in the porous body is analyzed, the ratios are as shown in Table 1.

Table-I Component ratio (wt%) ho2 aO Al 2 o3 e203 nO gO K,O 50゜25゜2゜2゜0゜1゜14゜0~6 0~2 5~ 0~ 8~ 5~ 8~ 0~l Now, the porous sintered body obtained as described above is pulverized into granules to be used as a decomposition accelerating substance, and by adding the granular adsorbent as described above to this, the pollutants can be removed. Adsorption and decomposition treatment agents can be easily produced.

This decomposition promoting substance is a porous body with high porosity and can retain moisture inside, with a maximum water absorption rate of 2.
It reaches around 00%. Therefore, the decomposition accelerator that has absorbed moisture continues to supply moisture necessary for hydrolysis of pollutants and microbial activity over a long period of time, thereby maintaining appropriate humidity in the soil.

In addition, in addition to the decomposition-promoting substance being porous, this treatment agent is a mixture of the decomposition-promoting substance and the adsorbent in granular form, making it possible to secure a large amount of voids in the buried soil. can. Therefore, this treatment agent not only ensures air permeability in the soil, but also acts as a heat insulator to alleviate temperature changes in the soil and protect the activities of microorganisms.

Thus, according to the processing agent manufactured by the above method,
Environmental factors such as humidity in the soil, PH1 temperature of moisture, and ventilation can be optimally adjusted for microorganisms, thereby activating microbial activity and promoting the decomposition of pollutants.

The blending ratio of the adsorbent and decomposition promoting substance is not particularly limited, but the adsorbent is increased or decreased in consideration of pollutant adsorption capacity and cost, so the ratio of the two is generally 4/6 to 6/4.
It is blended within the range of. Further, the size of the particulate adsorbent and decomposition promoting substance is not particularly limited, but the average particle size is preferably about several tens of micrometers so that the treatment agent as a whole is bulky and has good air permeability.

In addition, in order to further improve the mechanical strength of the decomposition accelerator obtained by pulverizing the porous sintered body into granules, the decomposition accelerating substance is heat-treated again after pulverization to seal fine cracks on the surface of the pulverized particles. Alternatively, at the same time, tobermorite crystals may be further generated in each surface layer to ensure strength.

Further, the adsorption and decomposition treatment agent of the present invention is formed by kneading a decomposition promoting substance obtained by pulverizing the porous sintered body into granules and a granular adsorbing substance together with a binder that disappears by firing, and then forming the adsorption and decomposition treatment agent. It may be manufactured by firing at a temperature of 65,000 ℃ or less.

Binders that disappear by firing include ethylene glycol and stearic acid containing 10 to 20% paraffin.
%, and those that are decomposed or evaporated at a temperature of 650°C or lower, particularly 200 to 300°C, are preferred. This binder is used mainly in consideration of workability during firing, and is not particularly limited to the above-mentioned substances as long as it is eliminated by firing. The blending ratio of the binder is 10 to 20 parts by weight based on 100 parts by weight of the total amount of the decomposition promoting substance and the adsorbing substance, and this range is the appropriate amount necessary for molding.

It is preferable to form this raw material mixture into a spherical or pellet shape with a size of several mm and sinter it at a temperature of 650°C or lower in a non-oxidizing atmosphere, thereby obtaining a spherical or pellet-shaped processing agent. It will be done.

The purpose of performing the above-mentioned calcination in a non-oxidizing atmosphere is to prevent the carbonaceous material from being oxidized and lost, especially when activated carbon is used as the adsorbent. .

In addition, in order to simplify the baking equipment, the molded product is placed in a heat-resistant container with a relatively small scrap removal hole, and the inside of the heat-resistant container is made to be in an oxygen-deficient state when heated to the baking temperature. You can.

Furthermore, the reason why the firing temperature was set at 650°C or less is because if it exceeds 650°C, low-temperature crystals such as silicon dioxide may undergo transformation, resulting in a large change in the strength of the crystal structure, which may cause the molded product to collapse. be.

In this way, by using a binder to form a granular or pellet-like treatment agent, it can be packed into a netted basket and submerged in an aquarium, etc., and then placed in each basket as needed. Recovery of processing agents that can be taken out from
It is easier to replace and handle.

[Example] An example embodying the present invention will be described in detail below.

(Preparation of adsorption and decomposition treatment agent) First, in order to provide one decomposition promoting substance, each raw material powder was mixed according to the formulation listed in Table 2, and then water was gradually added to this mixed powder and kneaded. A raw material slurry was prepared from shina.

Table 2 3Ca○"5iOz 2CaO-S 102 Cab (Additional portion) e203 nO g O Al2O2 I Water parts by weight parts by weight parts by weight parts by weight parts by weight parts by weight parts by weight parts by weight After preparing the raw material slurry, When the slurry was left to stand for 24 hours and hardened, the molded body was transferred to an autoclave and subjected to saturated steam curing at 180° C. and 10 atm for 24 hours to obtain a lumpy molded body.

The compressive strength of this molded body was 45 kgf/ci.

Next, this lump-like molded body was treated with a pulverizer, and then sieved to take out only the pulverized particles having a particle size in the range of about 0.6 to 2.0 mm, which were used as a decomposition promoting substance.

Then, 50 parts by weight of activated carbon having a size similar to that of this decomposition promoting substance was blended with 50 parts by weight of this decomposition promoting substance and mixed uniformly to prepare an adsorption and decomposition treatment agent. The average bulk density of the obtained treatment agent was 0.45 g/c
nl, average porosity is 70%, average specific surface area is 280.0
It was rn'/g.

Furthermore, as a result of analyzing this treatment agent, each component was quantified as shown in Table 3.

Table-3 Component ratio (wt%) C (carbon content) 50.0 8iOz 25.0Ca0
12.5AI203
1.3Fe2 u3 1.0Mn
0 0.5Mg0
0. 8 to 20
0.5820 8.4 Next, an example using this processing agent will be described.

(Experimental Example I) As shown in Figure 1, the diameter is 26 cm (cross-sectional area = 5,
The adsorption and decomposition treatment agent 2 is packed in a column 1 of 3 x 10 "rn') (filling length, about 3 cm), and a pesticide aqueous solution containing a pesticide at a concentration of 10 ppm is poured from above the column 1. , 50-60m/', /min
The aqueous solution treated with the treatment agent was collected by dropping it through the column 1 at a rate of . Then, the main components of the pesticide remaining in the collected aqueous solution were quantified by GC-ECD method. Table 4 shows the measurement results for each pesticide.

The dropping speed of the aqueous pesticide solution was set assuming that the pesticide sprayed on the soil due to heavy rain flows out in large quantities with rainwater, and is calculated as 94% per durability.
0 to 1130 J/min.

Table-4 Pesticide name daconil 1000 Roblar Cyanox Kirbar benomyl main component Concentration after treatment TPN” iprodione C.Y.A.P. bamidothione benlate N,　D” N,　D” 0.026ppm N,　D” N,　D” : (Table-4 notes) TPN is tetrachloroisophthalonitrile.

N and D mean not detected.

From the results in Table 4, it can be seen that this treatment agent removes most of the main components of the pesticide contained in the aqueous pesticide solution with an initial concentration of 10ppm.

Based on the above results, consider the case where this treatment agent is actually applied to soil. If Daconil 1000 is used as a pesticide, the concentration should be 1000 ppI11 according to the usage method.
Daconil aqueous solution prepared in
51 per ') will be distributed. Pesticide spraying is carried out three times a year, so the annual total amount of spraying per Irr1' is 15
This means 0cc.

On the other hand, the annual precipitation is estimated to be much smaller than 200.
+n+n/year, and if the annual total amount of application per lrn' is 150 cc, then 5 ppm of daconil aqueous solution per lrd will be treated throughout the year.

From the above experimental results, it can be said that if this treatment agent is buried in the soil in advance in a layer of about 3 cm, Daconil can be treated with sufficient margin.

Furthermore, considering that pesticides themselves have the property of decomposing over time and that the annual rainfall in Japan is higher than the above assumption, it is certain that the actual concentration of pesticides in rainwater will be even lower. It is believed that the amount of processing agent used can be significantly reduced.

(Experimental Example 2) As in Experimental Example 1, 100 g of the adsorption and decomposition agent was packed in a column with a diameter of 2 am (filling length: about 55 c+n), and the concentration was measured from above the column. A pesticide aqueous solution containing loooppm of CYAP was added to
The 1 which passed through the column and came out was supplied intermittently every liter.
CYAP contained in the aqueous solution for each recovered aqueous solution
The concentration of was determined by GC-ECD method. When the CYAP concentration in the recovered water began to show an almost constant value,
It was determined that the adsorption capacity of the processing agent in the column was saturated. The amount of water recovered until this saturation was reached was 70-801. Then, the maximum adsorption capacity per tg of the treatment agent was calculated to be 400 mg/g based on the concentration data of each collected water collected every 11 times.

The adsorption capacity per 100 g of this treatment agent based on this calculation result is equivalent to the amount of agricultural chemicals sprayed on the soil for 25 years. Therefore, when this processing agent is actually used, assuming that 1 kg, which is a commercial transaction unit, is used as is, the period during which the processing agent effectively acts can be said to be semi-permanent.

As described above, according to the adsorption and decomposition treatment agent of this example, pollutants such as agricultural chemicals can be efficiently adsorbed and treated without adversely affecting the ecosystem. In addition, the adsorption capacity is very large, so if the amount of pesticide sprayed is normal, just by burying a predetermined amount of this treatment agent in the soil.
Can be used semi-permanently. Furthermore, many of the raw materials for this processing agent are available at low cost, and manufacturing can be simplified, so there is an advantage that this processing agent can be provided at a low cost.

[Effects of the Invention] As detailed above, the pollutant adsorption and decomposition treatment agent of the present invention effectively adsorbs pollutants and prevents their diffusion, and also acts based on its own action or It has the excellent effect of decomposing pollutants collected by adsorption into harmless substances through the indirect action of activating their activity and promoting their biochemical decomposition effects.

Moreover, according to the manufacturing method of the present invention, there is an excellent effect that the above-mentioned processing agent can be manufactured reliably and at low cost.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an experimental example in an embodiment embodying the present invention. Patent Applicant: Takehiko Yajima Market, Masami Wakahara, Tanuetsu

Claims (1)

[Scope of Claims] 1. A pollutant adsorption and decomposition treatment agent characterized by containing an adsorbent that adsorbs pollutants and a decomposition promoting substance that promotes decomposition of the adsorbed pollutants. 2. The agent for adsorbing and decomposing pollutants according to claim 1, wherein the adsorbent is activated carbon. 3. Claim 1, wherein the decomposition promoting substance contains at least one metal oxide selected from calcium oxide, iron oxide, manganese oxide, magnesium oxide, potassium oxide, aluminum oxide, and silicon dioxide.
or the pollutant adsorption and decomposition treatment agent according to 2. 4. Adsorption and decomposition of pollutants according to any one of claims 1 to 3, wherein at least one of the adsorbent and the decomposition promoting substance is supported in a porous body containing silicon dioxide. Processing agent. 5 A porous sintered body obtained by blending silicon dioxide with at least one metal oxide selected from calcium oxide, aluminum oxide, iron oxide, manganese oxide, magnesium oxide, and potassium oxide and firing the mixture is pulverized into particles. 1. A method for producing a pollutant adsorption and decomposition treatment agent, characterized in that a granular adsorption material is blended with the decomposition promoting substance. 6. A decomposition promoting substance obtained by pulverizing the porous sintered body into granules and a granular adsorbent substance are kneaded and formed together with a binder that is eliminated by firing, and then fired at a temperature of 650°C or less. The method for producing a pollutant adsorption and decomposition treatment agent according to claim 5.