Environmental purification material and method for manufacturing the environmental purification material

Abstract

To provide an environment purifying material that is effective in suppressing the proliferation of coliform for a long time and a method for producing an environment purifying material.SOLUTION: An environment purifying material comprises clinker ash with a particle size of 2 mm or less as the main component.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to an environmental purification material having an inhibitory effect on the growth of coliform bacteria and a method for producing the environmental purification material. [Background technology]

[0002] One of the environmental standards specifies the number of coliform bacteria in rivers and lakes. In recent years, although the water quality of rivers and lakes throughout Japan has improved due to advancements in sewage treatment technology in ordinary households, it is not uncommon to detect coliform bacteria counts exceeding the environmental standards. To remove coliform bacteria released into rivers and lakes from sources such as livestock farms and closed water bodies, antimicrobial agents have been developed in which highly antimicrobial metal ions such as silver ions, copper ions, and zinc ions are supported on inorganic carriers.

[0003] For example, the antibacterial material described in Patent Document 1 is made by crushing fly ash, which is coal ash generated at coal-fired power plants and factories, to an average particle size of 1 to 10 μm, washing it with an acidic solution to dissolve and remove impurities such as iron, then heating and stirring it in an alkaline aqueous solution to form a zeolite through a hydrothermal synthesis reaction, on which metal ions, such as silver ions, are supported by ion exchange, and then forming it into fine particles by applying a low pressure that does not destroy the particles. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 9-241017 (pages 3 to 5) [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Conventionally, antimicrobial agents like the one described in Reference 1 generate metal salts from some of the metal ions supported on the zeolite during use. These metal salts not only lack antimicrobial properties but also cover a portion of the zeolite surface, inhibiting the antimicrobial action of the metal ions present in the covered area. Furthermore, these metal salts grow over time, resulting in a decrease in the antimicrobial effect of the agent over time. In addition, while the antimicrobial agent in Reference 1 improves the persistence of its antimicrobial properties by crushing fly ash and exposing the fine pores on the crushed surface, the spherical shape of fly ash inherently results in a low porosity of the crushed surface, leading to a short duration of antimicrobial activity. Moreover, because the antimicrobial agent is in the form of fine particles, using it in flowing water such as rivers and lakes poses a risk of the agent being washed away. Furthermore, if the particles clump together in stagnant areas, the efficiency of contact with water decreases, potentially inhibiting the antimicrobial action that should function across the entire zeolite surface, making it difficult to handle. Furthermore, when antibacterial microparticles are integrated with a binder, the binder can clog the micropores, potentially reducing their antibacterial properties.

[0006] The inventors discovered that contacting coliform bacteria with clinker ash, which is coal ash generated at coal-fired power plants and factories and has a larger particle size than fly ash, can suppress the growth of coliform bacteria. This is presumed to be partly due to the fact that clinker ash has a fine porosity structure and a very large specific surface area. Furthermore, the inventors found that by treating clinker ash under specific conditions, the excellent coliform bacteria growth suppression effect of clinker ash can be maintained for a long period of time, even when used as a roadbed material for civil engineering structures.

[0007] This invention addresses these problems and aims to provide an environmental purification material and a method for producing an environmental purification material that exhibits excellent long-term inhibitory effects on coliform bacteria growth. [Means for solving the problem]

[0008] To solve the aforementioned problems, the environmental purification material of the present invention is It is characterized by containing clinker ash with a particle size of 2 mm or less as its main component. According to this characteristic, the fine pore structure on the surface of clinker ash with particle sizes of 2 mm or less results in optimal total pore volume and specific surface area, allowing for the maintenance of a state of excellent inhibition of growth due to contact with coliform bacteria over a long period of time.

[0009] It is characterized by containing clinker ash with a particle size of 1 mm or less as its main component. According to this characteristic, the fine pore structure on the surface of clinker ash with particle sizes of 1 mm or less further optimizes the total pore volume and specific surface area, allowing for the maintenance of a state with excellent inhibitory effect on the growth of coliform bacteria over a long period of time.

[0010] The aforementioned clinker ash is characterized by being solidified with the addition of 5-10% by mass of a binder to 90-95% by mass. According to these characteristics, when granular clinker ash is solidified with a binder, the fine pore structure on the surface of the clinker ash is sufficiently exposed, and it has water permeability, allowing it to maintain a state of excellent inhibition of growth due to contact with coliform bacteria for a long period of time. In addition, because the environmental purification material is solidified, it is easy to handle when used as a road base material or in civil engineering structures.

[0011] The aforementioned binder is characterized by being slaked lime. According to this characteristic, the solution present in the pores is maintained in an alkaline state, which facilitates the dissolution of aluminum ions from clinker ash into the solution and the formation of complex ions. This allows for the maintenance of a state that is highly effective in inhibiting the growth of coliform bacteria through contact, over a long period of time.

[0012] The method for producing the environmental purification material of the present invention is: A step to sort clinker ash into particles of 2 mm or less, The method is characterized by comprising the step of adding a binder to the clinker ash whose particle size has been sorted. According to this feature, in the state where a binder is added to clinker ash whose particle size is selected to be 2 mm or less, preferably 1 mm or less, and solidified, the fine pore structure on the surface of the clinker ash is sufficiently exposed, and it has water permeability, and an environmental purification material capable of maintaining a state excellent in the growth inhibitory effect due to contact with coliform bacteria over a long period of time can be obtained.

[0013] It is characterized by using clinker ash washed with water. According to this feature, harmful substances such as boron contained in the clinker ash can be removed, and the impact on the environment can be reduced.

[0014] The water is characterized by having a pH of 4 to 7. According to this feature, by washing the clinker ash with water having a pH of 4 to 7, the clinker ash can be neutralized to lower the pH, so the environmental load can be suppressed. In addition, since the clinker ash can be washed using rainwater, the manufacturing cost can be reduced.

Brief Description of the Drawings

[0015] [Figure 1] It is a graph showing the results of Experiment 1 indicating the growth inhibitory effect of coliform bacteria in sample water by the addition of clinker ash and treated clinker ash in an embodiment of the present invention. [Figure 2] It is a graph showing the results of Experiment 2 indicating the growth inhibitory effect of coliform bacteria in sample water by the addition amount of clinker ash in an embodiment. [Figure 3] It is a graph showing the results of Experiment 3 indicating the growth inhibitory effect of coliform bacteria in sample water by pH adjustment in an embodiment. [Figure 4] It is a graph showing the results of Experiment 4 indicating the growth inhibitory effect of coliform bacteria in sample water by washing the clinker ash in an embodiment. [Figure 5] It is a graph showing the results of Experiment 5 indicating the growth inhibitory effect of coliform bacteria in sample water by the particle size of clinker ash in an embodiment. [Figure 6]This figure shows the experimental apparatus used in Experiment 6, which investigated the range of the coliform growth inhibitory effect of clinker ash in the examples. (a) shows the experimental apparatus filled with clinker ash (CA), and (b) shows the experimental apparatus filled with glass beads. [Figure 7] This graph shows the results of Experiment 6 regarding the range of the coliform growth inhibitory effect of clinker ash in the examples. [Modes for carrying out the invention]

[0016] The inventors discovered that clinker ash, which is coal ash generated by burning coal in thermal power plants and factories, is an excellent material for suppressing the growth of coliform bacteria in water. Research revealed that focusing on the components and structure of clinker ash was significant, so this will be explained first.

[0017] Furthermore, coliform bacteria are aerobic or facultative anaerobic, Gram-negative, non-spore-forming rod-shaped bacteria that break down lactose to produce acid and gas.

[0018] The environmental purification material is described below. The environmental purification material is a molded body solidified by adding 5 to 10% by mass of slaked lime (Ca(OH)2) as a binder to 90 to 95% by mass of clinker ash with a particle size of 2 mm or less, more preferably 1 mm or less. It is preferable that the environmental purification material be solidified into a plate or lump, but it may also be molded into granules.

[0019] This section explains the mechanism by which the environmental purification material inhibits the growth of coliform bacteria. The main component of the environmental purification material, clinker ash, has countless pores on its surface with an average diameter of approximately 5 nm, and a specific surface area of ​​3.2 m². 2It has such a degree and a large specific surface area, so it has excellent physical adsorbability for coliform bacteria that have entered the pores due to van der Waals forces and hydrogen bonds, and also has excellent water permeability. Incidentally, the clinker ash should have a particle size of 2 mm or less, more preferably 1 mm or less, so that the total pore volume and specific surface area are suitable, and a state excellent in the growth inhibitory effect due to contact with coliform bacteria can be maintained. Furthermore, in this specification, the main component means a component composition ratio of 50% by mass or more with respect to the total amount of the environmental purification material. That is, the environmental purification material of the present invention contains 50% by mass or more of clinker ash having a particle size of 2 mm or less.

[0020] In addition, the clinker ash has a larger permeability coefficient and better water permeability than the true sand and shirasu known as general soil. This is presumably because, unlike true sand and shirasu in which innumerable concave pores are formed on the surface, the clinker ash has a pore structure that penetrates the particles. Incidentally, the clinker ash in this specification has a permeability coefficient of about 2×10 -2 cm / s when 10% by mass of slaked lime is added to 90% by mass of the clinker ash and solidified, and the permeability coefficient when rolling pressure is applied as a paving material is about 2×10 -4 cm / s.

[0021] Furthermore, the clinker ash has a high composition ratio of Al2O3 (aluminum oxide) and exhibits hydrophilicity. After absorbing water, ionized Al 3+ (aluminum ion) shows high chemical bonding (chemical reactivity) with PO4 3- (phosphate ion) that constitutes the surface (hydrophilic group of phospholipid) of the cell membrane of coliform bacteria, and insoluble AlPO4 (aluminum phosphate) is generated. The chemical formula of the chemical bond between ionized Al 3+ and PO4 3- is shown in Chemical Formula 1 below.

[0022] [Chemical Formula 1] Al 3+ +PO4 3- →AlPO4

[0023] This ionized Al 3+ and PO4 3- It is thought that the chemical bonding with Al inhibits the growth of coliform bacteria, reducing the number of coliform bacteria in the water, i.e., it has bacteriostatic effects. Furthermore, it is known that when clinker ash is immersed in water, the pH rises to around 8.5, but Al 3+ When the pH is above 7, H + Because it is an amphoteric hydroxide that releases a negatively charged complex ion and dissolves in water, it is presumed to be able to exert an inhibitory effect on the growth of coliform bacteria even in alkaline environments.

[0024] In this way, the environmental purification material physically adsorbs coliform bacteria through its countless pores, and also ionizes Al 3+ PO4 is a component of the cell membrane of coliform bacteria. 3- By exhibiting high chemical bonding properties and generating AlPO4, it is possible to efficiently adsorb or bacteriostatically adsorb coliform bacteria and suppress their growth. In other words, the structure and components (Al2O3) of the clinker ash itself exert a coliform growth inhibitory effect in the environmental purification material. Furthermore, by forming a solidified molded body with a mixing ratio of 90-95% by mass of clinker ash with particle size of 2 mm or less and 5-10% by mass of slaked lime, the physical adsorption properties of clinker ash to coliform bacteria can be maintained in a good state for a long period of time.

[0025] The embodiments for implementing the environmental purification material according to the present invention will be described below based on examples. In these examples, the test results such as the component composition ratio are the average values ​​for a sample size of 3 or more.

[0026] The environmental purification material is a molded body formed by drying clinker ash A, collected in 2019, and clinker ash B, collected in 2020, from Factory A in Miyazaki Prefecture at 105°C. After drying each at 105°C, they are passed through a 2 mm sieve (JIS metal mesh sieve for testing, JIS Z 8801-1:2000), and then through a sieve of 2 mm or less, more preferably 1 mm (JIS metal mesh sieve for testing, JIS Z 8801-1:2000), to separate them into particles of 1 mm or less. After mixing 90-95% by mass of clinker ash, 5-10% by mass of slaked lime, and 10-30% by mass of water, the mixture is naturally dried and solidified. This molded body contains 90-95% by mass of clinker ash, 5-10% by mass of slaked lime, and small amounts of unavoidable impurities. Furthermore, in the particle size sorting described above, clinker ash with a particle size of 2 mm or larger was crushed using a mortar and pestle, then sieved again to adjust the particle size to 2 mm or less, and more preferably 1 mm or less, before use.

[0027] The component composition ratios of clinker ash A and B are shown in Table 1 below. The component composition ratios were analyzed using an X-ray fluorescence analyzer (Shimadzu EDX-720).

[0028] [Table 1]

[0029] Furthermore, clinker ash contains trace amounts of impurities such as boron (B) and boron compounds, which are organic compounds specified in soil environmental standards. These harmful substances could be removed by washing the clinker ash with water. Specifically, it was confirmed that the proportion of boron and boron compounds in the surface of the clinker ash particles was lower than that in the interior of the particles. This reduces the environmental impact when using it as an environmental remediation material.

[0030] The component composition ratio of the washed clinker ash B after washing the above clinker ash B with distilled water (pH 6-7) was as shown in Table 2 below.

[0031] [Table 2]

[0032] Furthermore, the component composition ratio of the washed clinker ash B after washing the above clinker ash B with water adjusted to pH 4 by adding nitric acid was as shown in Table 3 below.

[0033] [Table 3]

[0034] According to this, since the composition ratio of clinker ash remains largely unchanged even when harmful substances such as boron (B) are removed by washing with distilled water (pH 6-7) or water adjusted to pH 4, clinker ash can be washed using rainwater, which is generally slightly acidic, thus reducing manufacturing costs. Furthermore, washing clinker ash with water before crushing makes it easier to retain aluminum components on the crushed surface.

[0035] The environmental purification material of the present invention is formed by adding 5 to 10% by mass of slaked lime to 90 to 95% by mass of clinker ash with a particle size of 2 mm or less, more preferably 1 mm or less, and solidifying it. In this state, the fine porosity structure of the surface of the clinker ash is sufficiently exposed, and it has water permeability, allowing it to maintain an excellent inhibitory effect on the growth of coliform bacteria over a long period of time. Furthermore, because the environmental purification material is solidified into a mass, it is less affected by the environment of use compared to granular material, and can fully exert its function, making it easy to handle when used as a roadbed material for civil engineering structures, or as revetments and structures for rivers and lakes.

[0036] Furthermore, the environmental purification material uses slaked lime as a binder, and the solution present in the pores of the clinker ash is maintained at an alkaline level, which, as mentioned above, allows Al to be released from the clinker ash. 3+The substance dissolves in the solution and readily forms complex ions with water, allowing for the maintenance of a state of excellent inhibition of growth due to contact with coliform bacteria over a long period of time. Furthermore, the environmental purification material has excellent water permeability even when clinker ash is solidified with added slaked lime. As the solution passes through the pores, the products of the reaction with coliform bacteria are discharged outside the pores along with the solution inside the pores, preventing accumulation on the surface of the clinker ash. Thus, a state of excellent inhibition of growth due to contact with coliform bacteria can be maintained over a long period of time.

[0037] Furthermore, while the environmental purification material has slightly lower apparent porosity and water absorption than clinker ash itself due to the addition of a small amount of slaked lime during solidification, when used as an environmental purification material, its excellent water permeability makes it less likely for the pozzolanic reaction to occur in the solution within the pores, and the Al derived from clinker ash is less likely to occur. 3+ This allows for a full inhibition of growth through contact with coliform bacteria. Specifically, clinker ash has excellent water permeability, and some of the slaked lime added to the clinker ash reacts with carbon dioxide (carbonic acid) to produce sparingly soluble calcium carbonate and water. This suppresses the rise in pH of the solution in the pores due to the effect of slaked lime, and the solution in the pores stabilizes at around pH 8.5 due to the immersion of the clinker ash itself, thus preventing the release of SiO4 from the clinker ash. 4- (Silicate ions) become less likely to dissolve, and calcium ions and SiO4 in the solution within the pores 4- , Al 3+ The pozzolanic reaction is inhibited, and the Al dissolves from the clinker ash. 3+ It is thought that the inhibitory effect on the growth of coliform bacteria through contact is preferentially exerted.

[0038] Furthermore, because environmental purification materials are alkaline, boron is more easily leached out compared to acidic materials. Therefore, the environmental impact may be reduced by further removing boron by washing the environmental purification material with water after manufacturing.

[0039] Thus, the environmental purification material is composed of a molded body made by adding 5-10% by mass of slaked lime to 90-95% by mass of clinker ash, which is waste generated by burning coal at thermal power plants and factories, and then solidifying it. This allows for a high inhibitory effect on the growth of coliform bacteria over a long period of time, while being inexpensive and minimizing the burden on the environment. The clinker ash used as the environmental purification material is not limited to that collected from Factory A in Miyazaki Prefecture, as long as it is generated by burning coal. Furthermore, the environmental purification material may be composed of clinker ash alone, in which case it is preferable to use it as a paving material for sidewalks and other areas where high strength is not required.

[0040] Furthermore, the clinker ash A and B used in the following examples are those with the components described above. [Examples]

[0041] (Experimental conditions and methods) 1. Experiment on inhibiting coliform growth using clinker ash and clinker ash-treated materials. 200 ml of sample water, prepared by diluting treated wastewater (before disinfection) collected from the K wastewater treatment plant in Miyazaki City 100 times with distilled water, was placed in a 250 ml plastic bottle. 20 g of clinker ash B, sorted to a particle size of 2 mm or less, was added, and the plastic bottle was incubated at 37°C for 2 days. The container was stirred about twice a day during incubation. Afterwards, 100 ml of the solution was taken, and the number of coliform bacteria was measured using the BGLB (Brilliant Green Lactose Bile Broth) method. The same experiment was also performed on 20 g of clinker ash B treated material, which is the environmental purification material of the present invention, prepared by adding 2 g (10% by mass) of slaked lime to 18 g (90% by mass) of clinker ash B. The experiment was repeated 3 times in each case. Furthermore, the amount of clinker ash, etc., added to 200 ml of sample water was determined to be an appropriate amount based on the viscosity of the sample.

[0042] The following results for measuring coliform bacteria counts under each experimental condition were calculated by determining the ratio of coliform bacteria counts in the sample to the control (without clinker ash addition), and expressed as the coliform bacteria count reduction rate (%). In addition, the treated wastewater used for the sample water was freshly collected from the K wastewater treatment plant in Miyazaki City for each experiment, and the coliform bacteria count reduction rate (%) was calculated for each sample water.

[0043] (Experimental results) As shown in the graph in Figure 1, the reduction rate of coliform bacteria in both Sample 1 (S1), which had 20g of clinker ash B with particle size of 2mm or less added to 200ml of sample water, and Sample 2 (S2), which had 20g of clinker ash B treated material added, was 100%. This confirmed that contact with a solution containing coliform bacteria significantly suppresses the growth of coliform bacteria. Furthermore, it was confirmed that a 100% coliform bacteria growth inhibitory effect was obtained even with clinker ash B treated material, which is intended for actual construction (paving materials, etc.). It is presumed that the mechanism of the coliform bacteria growth inhibitory effect by clinker ash and clinker ash treated material is either due to the presence of coliform bacteria in the 2mm or smaller portion of the clinker ash or is dependent on its specific surface area.

[0044] (Experimental conditions and methods) 2. Experiment on inhibiting coliform bacterial growth by adding clinker ash 200 ml of sample water, obtained by diluting treated wastewater 100-fold with distilled water, was placed in a 250 ml plastic bottle. 4 g, 10 g, and 20 g of clinker ash A, sorted to a particle size of 2 mm or less, were added to each bottle, and the plastic bottles were incubated at 37°C for 2 days. The incubation method and the method for measuring the number of coliform bacteria were the same as in Experiment 1 described above.

[0045] (Experimental results) As shown in the graph in Figure 2, the reduction rate of coliform bacteria in Sample 3 (S3), to which 4g of clinker ash A with a particle size of 2mm or less was added to 200ml of sample water, was 68.0%. The reduction rates of coliform bacteria in Sample 4 (S4), to which 10g of clinker ash A was added, and in Sample 5 (S5), to which 20g of clinker ash A was added, were both 100%. This confirmed that the greater the amount of clinker ash added to the sample water, the greater the inhibitory effect on the growth of coliform bacteria.

[0046] (Experimental conditions and methods) 3. Experiment on inhibiting coliform bacterial growth by pH adjustment When 200 ml of sample water, prepared by diluting treated wastewater 100-fold with distilled water, was placed in a 250 ml plastic bottle and 20 g of clinker ash B with particle size of 2 mm or less was immersed in the sample water, the pH rose to approximately 8.5. To clarify the increase or decrease in coliform bacteria due to the rise in pH, 200 ml of pH 8.5 adjusted solution was prepared by adjusting the sample water to pH 8.5 with NaOH (sodium hydroxide) without adding clinker ash B. The static culture method and the method for measuring the number of coliform bacteria were the same as in experiments 1 and 2 described above.

[0047] (Experimental results) As shown in the graph in Figure 3, sample 6 (S6), to which 20g of clinker ash B with particle size of 2mm or less was added to 200ml of sample water, showed a 98.6% reduction in the number of coliform bacteria. Sample 7 (S7), a pH 8.5 adjusted solution, showed a -30.0% reduction in the number of coliform bacteria, meaning the number of coliform bacteria increased by 130%. Thus, it was confirmed that the inhibitory effect of adding clinker ash on the growth of coliform bacteria is not due to an increase in pH due to the elution of alkaline components from the clinker ash, but rather to the structure and components of the clinker ash itself.

[0048] (Experimental conditions and methods) 4. Experiment on inhibiting coliform bacterial growth using washing clinker ash. Washing was performed by filling a cylindrical column with an inner diameter of 5 cm and a length of 50 cm with uncrushed clinker ash B, and spraying 960 ml of distilled water from the top once a week. After spraying four times over one month, the clinker ash B inside the column was collected. After drying at 105°C, it was sorted to a particle size of 2 mm or less. 200 ml of sample water, obtained by diluting treated wastewater 100 times with distilled water, was placed in a 250 ml plastic bottle, and 20 g of washed clinker ash B sorted to a particle size of 2 mm or less was added. The plastic bottle was then incubated at 37°C for two days. The incubation method and the method for measuring the number of coliform bacteria were the same as in experiments 1 to 3 described above.

[0049] (Experimental results) As shown in the graph in Figure 4, the reduction rate of coliform bacteria in sample 8 (S8), to which 20g of clinker ash B with particle size of 2mm or less was added to 200ml of sample water, was 98.6%, and the reduction rate of coliform bacteria in sample 9 (S9), to which 20g of washed clinker ash B was added, was 83.9%. This confirmed that even washed clinker ash, which has had harmful substances such as boron removed by washing with water, has a significant inhibitory effect on coliform bacteria growth, thereby reducing its environmental impact. Furthermore, the post-experimental solution pH of clinker ash B washed by spraying with distilled water was 9.4, which was lower than the post-experimental solution pH of 9.9 for unwashed clinker ash B, confirming that washing clinker ash can also reduce its environmental impact.

[0050] (Experimental conditions and methods) 5. Experiment on inhibiting coliform growth based on the particle size of clinker ash 200 ml of sample water, obtained by diluting treated wastewater 100 times with distilled water, was placed in a 250 ml plastic bottle. 20 mg each of clinker ash B, sorted to a particle size of 1 mm or less, 1-2 mm or less, 2-4.75 mm or less, and 4.75 mm or larger, was added to the bottle, and the plastic bottle was incubated at 37°C for 2 days. The incubation method and the method for measuring the number of coliform bacteria were the same as in experiments 1-4 described above. The clinker ash of each particle size was not crushed, but was sorted by hand using sieves of 1 mm, 2 mm, and 4.75 mm (JIS metal mesh sieves for testing, JIS Z 8801-1:2000) and added as is.

[0051] (Experimental results) As shown in the graph in Figure 5, sample 10 (S10), to which 20g of clinker ash B with particle size of 1 mm or less was added to 200 ml of sample water, showed a 100% reduction in coliform bacteria count. Sample 11 (S11), to which 20g of clinker ash B with particle size of 1-2 mm was added, showed a 78.1% reduction in coliform bacteria count. Sample 12 (S12), to which 20g of clinker ash B with particle size of 2-4.75 mm was added, showed a 70.2% reduction in coliform bacteria count. Sample 13 (S13), to which 20g of clinker ash B with particle size of 4.75 mm or larger was added, showed a 79.8% reduction in coliform bacteria count. This confirmed that clinker ash with particle size of 1 mm or less showed a greater reduction in coliform bacteria count than clinker ash with particle sizes of 1-2 mm, 2-4.75 mm, and 4.75 mm or larger. Furthermore, the mechanism by which clinker ash inhibits the growth of coliform bacteria is presumed to be related to the particle size of clinker ash (less than 1 mm) or to its specific surface area.

[0052] (Experimental conditions and methods) 6. Experiment on the range of the inhibitory effect of clinker ash on coliform bacteria growth. As shown in Figure 6(a), 600g of clinker ash B sorted to a particle size of 2mm or less was packed into a polyvinyl chloride pipe with an inner diameter of 10cm and a height of 1m (filling height approximately 10cm). 6L of sample water, diluted 100-fold with distilled water, was gently added from the top of the pipe. After standing for 24 hours (day 1), 3, and 8 days, samples were collected from three locations: approximately 80cm (top) above the surface of the diluted sample water, i.e., 55cm (middle) and 15cm (bottom) above the surface of the packed clinker ash B. The method for measuring the number of coliform bacteria was the same as in experiments 1-5 described above. For comparison with clinker ash, a control experiment was similarly conducted using 600g of glass beads with a particle size of 2mm, as shown in Figure 6(b). Each experiment was repeated twice.

[0053] The effect of reducing coliform bacteria under these experimental conditions was calculated by determining the ratio of the experimental result (coliform bacteria count) A (MPN / 100ml) of the experimental result (coliform bacteria count) of the clinker ash B-filled container to the experimental result (coliform bacteria count) C (MPN / 100ml) of the control-filled container (coliform bacteria count) (glass beads-filled container), and this ratio was defined as the coliform bacteria reduction effect E (%). The formula for calculating the coliform bacteria reduction effect E is shown in Equation 1.

[0054] [Mathematics 1] E = ((C - A) ÷ C) × 100 (%)

[0055] (Experimental results) As shown in the graph in Figure 7, samples taken from the upper, middle, and lower parts (water depths) of the experimental apparatus filled with clinker ash B showed a reduction in coliform bacteria count on days 1, 3, and 8 after standing. In particular, the coliform bacteria count reduction effect E exceeded 50% from day 1 for samples taken from the upper and lower parts. Although the coliform bacteria count reduction effect E on day 1 for samples taken from the middle part was slightly below 50%, the coliform bacteria count reduction effect E exceeded 80% on days 3 and 8. This confirmed that the coliform bacteria growth inhibitory effect appears relatively early (on day 1) in the experimental apparatus filled with clinker ash B. Furthermore, the high coliform bacteria reduction effect E was observed even at the upper part (water surface of the diluted test water) approximately 80 cm away from the filled clinker ash B. This confirmed that the clinker ash placed at the bottom could exert its coliform bacteria growth inhibitory effect all the way up to the water surface, even in an environment with a water depth of approximately 90 cm. It is also thought that convection occurs in the diluted sample water within the experimental apparatus, and that coliform bacteria move over distances of 10-35 μm / s using their flagella. Therefore, it is presumed that the coliform bacteria that were in the upper and middle parts moved to the bottom due to these factors, and came into contact with the surface of the clinker ash, thereby exerting the coliform bacteria growth inhibitory effect.

[0056] In the control experiment with glass beads, the coliform bacteria count was approximately 3500-5000 (MPN / 100ml) in samples collected from the upper, middle, and lower parts of the water tank on day 1, but increased significantly to approximately 16000 (MPN / 100ml) in all samples by day 3. In contrast, in the experiment with clinker ash B, the coliform bacteria count was approximately 1500-2500 (MPN / 100ml) in samples collected from the upper, middle, and lower parts of the water tank on day 1, which was lower than in the control experiment. Furthermore, by day 3, the coliform bacteria count decreased to approximately 1500 (MPN / 100ml) in all samples, or their growth was suppressed.

[0057] Furthermore, based on the experimental results described above, it is presumed that environmental purification materials using clinker ash can effectively inhibit the growth of coliform bacteria not only in flowing waters such as rivers and lakes, but also in stagnant, enclosed bodies of water.

[0058] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0059] For example, in the above embodiment, an example was described in which alkaline slaked lime was added as a binder to the environmental purification material, but the example is not limited to this, and neutral or acidic binders may also be used. [Industrial application fields]

[0060] 1. This technology can be applied to riverbanks and structures in rivers and lakes where the proliferation of coliform bacteria is a concern, thereby suppressing the growth of coliform bacteria in water and contributing to environmental conservation. 2. By using it as a paving material in places that are sources of coliform bacteria, such as livestock farms, it can contribute to reducing the environmental impact caused by the outflow of coliform bacteria from livestock farms.

Claims

1. An environmental purification material characterized by being a molded body with a water permeability coefficient of 2 × 10⁻² cm / s or more, which is solidified by adding 5 to 10% by mass of a binder to 90 to 95% by mass of clinker ash, which has been sorted to a particle size of 2 mm or less by a 2 mm sieve (JIS test metal mesh sieve JIS Z 8801-1:2000).

2. An environmental purification material characterized by being a molded body with a water permeability coefficient of 2 × 10⁻² cm / s or more, which is solidified by adding 5 to 10% by mass of a binder to 90 to 95% by mass of clinker ash, which has been sorted to a particle size of 1 mm or less by a 1 mm sieve (JIS test metal mesh sieve JIS Z 8801-1:2000).

3. The environmental purification material according to claim 1 or 2, characterized in that the binder is slaked lime.

4. The clinker ash is sorted into particles of 2 mm or less using a 2 mm sieve (JIS test metal mesh sieve JIS Z8801-1:2000), The steps include adding a binder to the clinker ash whose particle size has been sorted, A method for producing an environmental purification material, characterized by comprising the steps of adding water to the clinker ash with sorted particle size and the binder, stirring and mixing, and then allowing it to air dry and solidify.

5. A step of sorting clinker ash to a particle size of 1 mm or less using a 1 mm sieve (JIS test metal mesh sieve JIS Z8801-1:2000), The steps include adding a binder to the clinker ash whose particle size has been sorted, A method for producing an environmental purification material, characterized by comprising the steps of adding water to the clinker ash with sorted particle size and the binder, stirring and mixing, and then allowing it to air dry and solidify.

6. A method for producing an environmental purification material according to claim 4 or 5, characterized in that clinker ash washed with water is used.

7. The method for producing an environmental purification material according to claim 6, characterized in that the water has a pH of 4 to 7.

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