JP2009274040A - Inorganic porous body, regeneration method of inorganic porous body, and manufacturing method of inorganic porous body - Google Patents

Abstract

An object of the present invention is to provide an inorganic porous body applicable to wastewater treatment and a method for producing the same. Moreover, it is provision of the inorganic porous body which provided phosphoric acid adsorption ability, and its manufacturing method. Furthermore, the present invention provides an inorganic porous material that can be easily regenerated after adsorbing phosphoric acid and a method for regenerating the same.
SOLUTION: A pore size distribution has a first maximum value in a region of 10 to 100 nm, a second maximum value in a region of pore size distribution of 10 to 100 μm, and the first maximum value is 0.05 cm ³ / g or more. If the second maximum value is 0.10 cm ³ / g or more and an inorganic porous material containing a calcium component is used, the amount of calcium on the surface of the inorganic porous material is increased, and water retention inside the inorganic porous material is further increased. Since it can be increased, it can be applied to the treatment of substances that can be adsorbed to calcium in waste water. In addition, phosphoric acid or phosphate radicals contained in the aqueous solution to be treated can be adsorbed efficiently, and can be easily regenerated by immersing the inorganic porous material adsorbing phosphoric acid in a sulfuric acid aqueous solution of 0.01 N or less.
[Selection] Figure 13

Description

  The present invention relates to an inorganic porous material used for wastewater treatment, a method for regenerating the inorganic porous material, and a method for producing the inorganic porous material, and particularly recovers phosphoric acid in wastewater and recycles it as phosphoric acid fertilizer. The present invention relates to an inorganic porous body that has a high phosphate adsorption ability and is easy to re-dissociate phosphoric acid, a method for regenerating an inorganic porous body, and a method for producing an inorganic porous body.

  In recent years, global environmental problems have occurred as a result of increased human industrial activities. From the viewpoint of protecting the global environment, regulations on the release of harmful substances in the atmosphere and water have been made, and there is an urgent need for purification of the atmosphere and water. Has been. For example, with regard to water areas, phosphoric acid derived from domestic wastewater, industrial wastewater, and other livestock excreta is a cause of water pollution and eutrophication of water systems, such as significant changes in ecosystems and disruption of food chains. Causes serious problems. In order to deal with this problem, the Water Pollution Control Law, the Lake Water Quality Special Measures Law, etc. have been enacted, and phosphoric acid emission standards have been established. In recent years, in order to more strictly regulate such water pollution, the 6th Total Water Quality Regulation (which sets a target for reducing the pollution load flowing into Tokyo Bay) has further reduced the concentration of phosphoric acid in wastewater. Is required.

Examples of methods for reducing the concentration of phosphoric acid in wastewater include biological treatment methods such as anaerobic / aerobic methods, coagulation precipitation methods, crystallization dephosphorylation methods, and adsorption methods.
The anaerobic / aerobic method has high phosphoric acid removal efficiency, but has the problem of high equipment installation costs. Further, the coagulation precipitation method is simple and inexpensive, but the reaction efficiency between phosphoric acid and the coagulant is low, and a large amount of sludge and sludge are generated.

  As for the crystallization dephosphorylation method, the removal efficiency of phosphoric acid is high, but the equipment introduction cost, the adjustment of reaction conditions and the maintenance management cost for removing the scale are expensive. The removal efficiency is high and simple, but disposal of the adsorbent after use for wastewater treatment is a problem. This is because the existing adsorbent strongly adsorbs phosphoric acid, so even if the adsorbent holding phosphoric acid is used as culture soil as it is, it is not easily absorbed by the plant, and the phosphate is removed from the adsorbent. This is because it is not easy to remove phosphoric acid even in the method of separating and using, and it is difficult to use it as a fertilizer.

  As described above, water quality regulations on wastewater have been strengthened in recent years, and further reduction of the phosphoric acid concentration in the wastewater has been demanded. However, the concentration of phosphoric acid in the actual wastewater (raw water) may fluctuate greatly even at one establishment. Even if one of the above treatment methods is used, the concentration of phosphoric acid in the treated water Fluctuates greatly with acid concentration.

  As a result, it is feared that the regulation value (reference value) may be exceeded temporarily, so that it will be used in the subsequent stage of the existing wastewater treatment facility in order to cope with such a transient regulation value excess. There is a need for a simple and simple treatment method with high phosphoric acid removal efficiency.

As this treatment method, application of the above adsorption method is conceivable, and in Patent Document 3 below, as an adsorbent for phosphoric acid, one or more selected from aluminum, ferrous iron, ferric iron or calcium sulfate and chloride There is disclosed a water-purifying granule that has a mother nucleus containing water and a coating layer formed around the core and has a particle diameter in the range of 0.5 to 40 mm.
JP 2007-169119 A JP-A-2005-97065 JP-A-9-103608

  According to the above adsorption method, the existing adsorbent must be treated with sulfuric acid having a high concentration of about 0.2 N in order to desorb and regenerate the adsorbed phosphoric acid, and disposal of the generated waste liquid is a problem. For example, according to Patent Document 3, for reuse of a filter medium in which a metal salt of phosphoric acid is captured, the metal of phosphoric acid is immersed in about 0.5% dilute sulfuric acid or dilute hydrochloric acid for about 2 minutes. It is described that salt can be removed.

  Phosphoric acid is a causative substance that causes water pollution and eutrophication of water systems, but is an essential element indispensable for plant growth and is also useful as a fertilizer for plant cultivation. Phosphate ore, the raw material for phosphate fertilizer, is a scarce resource that is in danger of being exhausted, and in recent years resource prices have soared. Therefore, the need for efficient recovery and recycling of phosphoric acid is increasing. Therefore, in order to recycle the adsorbed phosphoric acid as phosphate fertilizer, it is desirable that the adsorbent be easily regenerated / desorbed. Also, from the viewpoint of environmental problems, an adsorbent that can be recycled (recycled) is preferable.

  On the other hand, glass foam manufactured by pulverizing glass discharged from ordinary households and business establishments, mixing and firing materials that generate gas at high temperatures, is sold as a recycled glass product. This glass foam is mainly used as civil engineering and building materials, taking advantage of its light weight, porosity and heat insulation.

  And the present inventors previously revealed that the glass foam is an adsorbent capable of adsorbing phosphoric acid (hereinafter sometimes referred to as having a phosphoric acid adsorption ability) (Patent Document 2). However, phosphoric acid adsorption ability of existing glass foams is low, and it was not applicable to wastewater treatment. In this method, glass powder is mixed with calcium carbonate as a foaming agent and heated and cooled. This is because the existing glass foam is limited to the use of lightweight materials such as civil engineering and construction, and is still insufficient from the viewpoint of phosphate adsorption.

  In Patent Document 1, as an improvement of the MAP (magnesium ammonium phosphate) method for removing and collecting phosphate ions in waste water as crystals, glass powder, a powder containing a magnesium component, and a foaming agent are mixed. A technique for efficiently producing a foamed glass material having a small particle diameter is disclosed by a firing step of heating and a rapid cooling step of cooling the fired product. And the invention of the said patent document 1 is made to adsorb | suck the phosphorus (phosphoric acid) of to-be-processed water by exposing a magnesium component to the surface of a foamed glass material, and a cavity inner wall surface.

The MAP method is a method of precipitating phosphoric acid as a double salt of ammonium and magnesium. Although the processing efficiency is high, it is necessary to introduce a processing device for adjusting the reaction conditions, and therefore it takes an initial cost. There is a problem that the maintenance of the apparatus is also expensive. In the invention described in Patent Document 1, magnesium may be eluted from the adsorbent and may be precipitated as magnesium phosphate in the supernatant. Phosphoric acid is actually supported on the adsorbent, and the adsorbed phosphorus It has not been confirmed whether the acid can be dissociated or recovered.
In addition, even if the inside of the foamed glass material is not sufficiently porous, phosphorous acid (phosphoric acid) is only adsorbed on the surface, even if the foamed glass material has a small particle size. I cannot expect much improvement.

  The subject of this invention is solving the said problem, and provision of the inorganic porous body which can be applied to waste water treatment, and its manufacturing method. Another object of the present invention is to provide an inorganic porous material imparted with phosphate adsorption ability and a method for producing the same, and to recycle and recover the collected phosphoric acid as a fertilizer. It is to provide a possible inorganic porous material and a method for regenerating the same.

Specifically, the present invention can be achieved by adopting the following configuration.
The invention according to claim 1 has a first maximum value in a region where the pore size distribution is 10 to 100 nm, a second maximum value in a region where the pore size distribution is 10 to 100 μm, and the first maximum value is 0.05 cm. ³ / g or more, the second maximum value is 0.10 cm ³ / g or more, and the inorganic porous body contains a calcium component.

  The invention according to claim 2 is the inorganic porous body according to claim 1 for adsorbing phosphoric acid or phosphate radical contained in the aqueous solution to be treated.

  The invention according to claim 3 uses the inorganic porous material according to claim 1 for adsorption of phosphoric acid, and then immerses the inorganic porous material adsorbed with phosphoric acid in a sulfuric acid aqueous solution of 0.01 N or less. The method for regenerating an inorganic porous material according to claim 1, wherein the adsorbed phosphoric acid is dissociated and regenerated.

  In the invention according to claim 4, (a) inorganic powder and (b) calcium magnesium carbonate or dolomite, which is a foaming agent, and (c) sodium carbonate are mixed, baked, foamed, and then immersed in water. This is a method for producing an inorganic porous body from which sodium carbonate has been removed.

  Invention of Claim 5 is a manufacturing method of the inorganic porous body of Claim 4 which uses glass powder as said (a) inorganic particle body.

(Function)
The principle of the present invention will be described. As a harmful substance that is contained in domestic wastewater and industrial wastewater and is a treatment target, for example, phosphoric acid, which is a causative substance for water pollution and aqueous eutrophication, is representative.
According to the conventional method of adsorbing phosphoric acid, it is necessary to treat with about 0.2 N sulfuric acid in order to desorb and regenerate the adsorbed phosphoric acid, and disposal of the generated waste liquid is a problem. . This is because the adsorption of phosphoric acid is due to the chemical adsorption of aluminum or iron on the surface of the adsorbent, and these elements and phosphoric acid are strongly adsorbed, requiring high concentrations of sulfuric acid to dissociate. It is thought that.

However, in addition to aluminum and iron, calcium is an element that reacts with phosphoric acid. Chemically, when the solubility of phosphate with each metal ion of aluminum, iron, and calcium is compared, calcium phosphate is about 10 ⁻⁷ mol / liter, iron phosphate is about 10 ⁻⁸ mol / liter, aluminum phosphate Is increased in the order of about 10 ⁻¹¹ mol / liter, and is considered to be strongly bonded to phosphoric acid in the order of aluminum, iron, and calcium. This solubility relationship is a phenomenon related to the interaction between each metal ion and phosphoric acid in an aqueous solution, but when these metals are present on the surface of the adsorbent, the same phenomenon occurs. Inferred.
Therefore, the present inventors thought that calcium, unlike aluminum and iron, could be dissociated by a low concentration acid that can be easily treated with a waste liquid, by adsorbing slowly with phosphoric acid. The inventors of the present invention believe that the problem of wastewater treatment using the above adsorbent can be solved if an inorganic porous adsorbent enriched on the surface of the calcium component can be produced. We have eagerly studied how to enrich the surface with calcium component by increasing the surface area of the material.

That is, the present inventors speculated that the performance of the adsorbent is defined by the amount of reactive groups (calcium) present on the adsorbent surface and the surface area.
For example, when carbonate such as calcium carbonate containing calcium and glass powder, which is an example of an inorganic powder, are mixed and heated and fired, calcium carbonate releases carbon dioxide at a high temperature range, and the softened glass passes through the softened glass. Holes and voids are formed by the passage of bubbles. The manufacturing method of the glass foam which uses a typical calcium carbonate as a foaming agent goes through the process of mixing calcium carbonate with glass powder, heating and cooling.

In FIG. 18, the conceptual diagram showing the manufacturing process of the conventional glass foam is shown.
The surface area of the glass foam is closely related to the amount of voids generated by the foaming reaction. For example, when the temperature of the mixture of the glass powder 1 and the foaming agent (calcium carbonate) 2 is raised, as shown in FIG. 18, the softening of the glass starts at around 730 ° C. Decomposition / foaming reaction of calcium 2 occurs, and pores (voids) 3 are formed. When the mixture of the glass powder 1 and the foaming agent 2 is heated, the softening temperature of the glass 1 is about 730 ° C., and the foaming temperature of the calcium carbonate 2 is 800 ° C. to 900 ° C., so further heating from 730 ° C. Thus, it is necessary to raise the foaming temperature to cause foaming. Thus, the softening of the glass 1 and the foaming reaction do not start simultaneously in the production process of the glass foam 4, and the foaming reaction occurs in a higher temperature range.

  For this reason, even if the foaming agent 2 is foamed in a high temperature region to form a large number of voids 3, the difference between the softening temperature of the glass 1 and the foaming temperature of the calcium carbonate 2 in the process of lowering the temperature thereafter. Because of its large size, the pores 3 and the voids 3 generated by the foaming agent 2 are blocked, the foaming reaction is slowed and the amount of voids is reduced. It is thought that.

  Therefore, in this method, since the difference between the softening temperature of the glass 1 and the foaming temperature of the calcium carbonate 2 is large, the holes 3 and the voids 3 generated by the foaming agent 2 are blocked during the cooling process, and the glass The foam 4 becomes insufficiently porous.

  Thus, grasping how many times the carbonate is decomposed is important in considering the production of an inorganic porous material such as a glass foam. Therefore, the present inventors considered that it is effective to use carbonates that foam more gently near the softening temperature of glass (about 730 ° C.) in order to avoid this phenomenon. Dolomite (magnesium calcium carbonate) was examined as a carbonate that contains calcium (calcium component) as an adsorbing group, and the same carbonate, sodium carbonate, was used as a sample. Differential thermal analysis was performed on Chemical Co., Ltd. (special grade reagent), Dolomite (Takeno Kuni no Kokume lime) and sodium carbonate (Kanto Chemical Co., Ltd. special grade reagent).

  Dolomite means calcium and magnesium double carbonate CaMg (CO3) 2 or a rock mainly composed thereof (Source: Chemical Dictionary Popular Edition Morikita Publishing Co., Ltd., page 881, January 26, 1985) Issue).

  A differential thermal analyzer (Model TG8120, manufactured by Rigaku Corporation) was used for the differential thermal analysis. As measurement conditions, 10 mg of the above reagent was measured at 900 ° C. while increasing the temperature at 10 ° C./min. The above reagent was used for analysis without any pretreatment such as grinding.

  The measurement result of this differential thermal analysis is shown in FIG. According to FIG. 1, the foaming of calcium carbonate (indicated by the alternate long and short dash line) started from around 620 ° C. and completely finished at around 790 ° C. On the other hand, foaming of dolomite (indicated by a dotted line) started from around 600 ° C., the foaming rate increased around 700 ° C., and ended around 770 ° C. From these results, the present inventors solved the problem that the pores and voids generated by the foaming agent were blocked during the above cooling process because the foaming temperature of dolomite and the softening temperature of glass were relatively close. I found out.

  Thus, by using dolomite instead of calcium carbonate as a foaming agent for glass foam, blockage of pores and voids in the cooling process can be prevented, but further, the foam of the glass foam is increased to make it porous. If it can, the surface area will increase and the adsorption performance of phosphoric acid is expected to improve.

  According to FIG. 1, it can be seen that sodium carbonate (shown by a solid line) does not show any foaming up to around 830 ° C. and starts around 850 ° C. Sodium carbonate does not decompose near the softening temperature of glass, but is easily dissolved in water. Therefore, the present inventors added not only the foaming agent but also sodium carbonate to the glass powder, mixed, heated, fired, foamed, and then immersed in water to elute the sodium carbonate in the mixture. It was thought that pores (voids) after the sodium carbonate was removed from the foamed material, and that further porosity could be achieved, and the present invention was completed.

In FIG. 2, the conceptual diagram showing the manufacturing process of the inorganic porous body of this invention is shown.
That is, a mixture of glass powder 1, foaming agent 2 and sodium carbonate 5 is heated and fired by using sodium carbonate 5 which does not decompose at a high temperature near the softening temperature of glass 1 and is water-soluble as a template substance. Further, after foaming, it is immersed in water and the sodium carbonate 5 as a template material is removed from the glass foam 4 to make it more porous.

Thus, the manufacturing method of the inorganic porous body of the present invention includes a step of mixing calcium magnesium carbonate (or dolomite) and sodium carbonate as a foaming agent in an inorganic powder and baking, foaming, and water immersion. It passes.
Due to the foaming action of calcium magnesium carbonate or dolomite which is a foaming agent, the inorganic porous material of the present invention takes a maximum value (first maximum value) in a region where the pore diameter distribution is 10 to 100 nm. The pore size in the vicinity is a pore size distribution important for the adsorption reaction of phosphorus (phosphoric acid). In addition, the pores after sodium carbonate is eluted and removed from the water have a maximum value (second maximum value) in a region where the pore size distribution is 10 to 100 μm. It is thought that the pore diameter near this contributes to water retention. When the water absorption increases, the phosphoric acid adsorption ability is improved by facilitating the contact of the phosphoric acid aqueous solution with the pore surface inside the inorganic porous body.

And 1st maximum value is 0.05 cm < ³ > / g or more larger than the pore volume in the hole diameter of 10-100 nm of the glass foam at the time of using the conventional calcium carbonate as a foaming agent, and 2nd maximum value is In the case of using only dolomite without adding sodium carbonate, each pore has a pore diameter of 0.05 cm ³ / g or more, which is larger than the pore volume in a pore diameter of 10 to 100 μm, as compared with a conventional glass foam. Since the pore volume of the diameter is large, a glass foam excellent in phosphate adsorption ability can be obtained.

Furthermore, since the inorganic porous material according to the present invention contains a Ca (calcium) component, it is adsorbed slowly with phosphoric acid, so that it can be dissociated and regenerated by a low-concentration acid that can be easily treated with waste liquid.
The inorganic porous material may be any material that can carry a Ca component and has a certain level of strength that can be used. For example, silica, activated alumina, zeolite, microporous silica, An inorganic porous material such as an inorganic mesoporous material, smectite, titanium oxide, zirconia oxide, or vanadium oxide may be used.

Therefore, according to the first aspect of the present invention, the amount of calcium on the surface of the inorganic porous body can be increased by increasing the pore volume of the pore diameter of 10 to 100 nm and the pore diameter of 10 to 100 μm. In addition, since the first maximum value and the second maximum value having different pore diameters and the first maximum value is 0.05 cm ³ / g or more, the surface area of the inorganic porous body is increased and the second maximum value is obtained. The water retention in an inorganic porous body can be improved because a value is 0.10 cm < ³ > / g or more. The substance to be adsorbed easily enters the inside of the inorganic porous body from the pore diameter of the second maximum value, and is easily adsorbed by calcium within the pore diameter of the first maximum value.
Further, as the substance to be adsorbed other than phosphoric acid, organic phosphoric acid, phosphorous acid, polyphosphoric acid and the like that can be adsorbed to the Ca component are conceivable.

According to the invention described in claim 2, in addition to the action of the invention described in claim 1, the inorganic porous material described in claim 1 is used for adsorption of phosphoric acid or phosphate radicals contained in the aqueous solution to be treated. Thus, phosphoric acid and the like are more likely to enter the inorganic porous body from the pore diameter of the second maximum value, and are easily adsorbed by calcium within the pore diameter of the first maximum value. Therefore, it is effective and suitable for the removal of phosphoric acid which is a causative substance of water pollution and aqueous eutrophication. Note that the phosphate ^radical, H2 PO4 ^-, HPO4 2-, is a generic term such as ^{PO4 3-,} is intended to include organic Phosphate in or phosphorous acid, and polyphosphoric acid.

  In addition, according to the invention described in claim 3, since the inorganic porous body described in claim 1 contains Ca component, it is adsorbed slowly with phosphoric acid. The phosphoric acid that has been adsorbed can be easily dissociated by immersing in, and the inorganic porous body according to claim 1 can be easily regenerated and reused.

  According to the invention described in claim 4, (a) inorganic powder and (b) calcium magnesium carbonate or dolomite (these are foaming agents) and (c) sodium carbonate are mixed and baked and foamed. By soaking in water, both pores derived from (b) calcium magnesium carbonate or dolomite and (c) pores derived from sodium carbonate having different pore size distributions can be formed in the inorganic porous body.

  According to the invention described in claim 5, in addition to the action of the invention described in claim 4, an inexpensive inorganic porous body can be produced by using glass powder. The glass powder is not limited to window glass or bottle glass, and the glass component may be borosilicate glass, soda lime glass, or other glass.

  The present invention is effective in adsorbing and removing harmful substances contained in domestic wastewater and industrial wastewater, and specifically has the following effects.

  According to the first aspect of the present invention, the substance to be adsorbed is more likely to enter the inside of the inorganic porous body due to the pore diameter of the second maximum value, and is further easily adsorbed to calcium within the pore diameter of the first maximum value. . Thus, the adsorption performance of the substance to be adsorbed is improved by the synergistic effect of having two different maximum values.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, since phosphoric acid can be adsorbed efficiently, water quality regulation of phosphoric acid that is being strengthened (regulation of phosphoric acid concentration in waste water) Can be easily accommodated.

  According to the invention described in claim 3, the inorganic porous body described in claim 1 can be easily regenerated and reused, and phosphoric acid can be recycled as phosphate fertilizer. Therefore, it also leads to the creation of phosphate resources that are feared to be depleted.

  According to the invention described in claim 4, by using calcium magnesium carbonate or dolomite as a foaming agent, and further using sodium carbonate, the inorganic porous material having pores having different pore size distributions easily and inexpensively and having excellent adsorption performance. The body can be manufactured.

  According to the invention described in claim 5, in addition to the effect of the invention described in claim 4, by using glass powder as the inorganic powder, it is possible to produce an inorganic porous body that is further inexpensive and has excellent adsorption performance. For example, if a glass foam made from waste glass is used, it promotes the reuse of glass and contributes to the formation of a recycling-oriented society.

  Embodiments of the present invention will be described with reference to the drawings. A glass foam using glass powder was produced as an example of an inorganic powder of an inorganic porous body. In addition to the glass powder, inorganic porous particles such as silica gel, activated alumina, zeolite, microporous silica, inorganic mesoporous material, smectite, titanium oxide, zirconia oxide, or vanadium oxide may be used. By supporting the Ca component on these inorganic particles, a substance that can be adsorbed on the Ca component can be treated.

FIG. 3 shows a flow showing a manufacturing process of a glass foam which is an embodiment of the present invention.
As shown in FIG. 3, the manufacturing process of the glass foam includes a foreign matter removal process from a glass container (for example, waste glass), a pulverization process (coarse pulverization, fine powder), dolomite (or calcium magnesium carbonate), sodium carbonate, etc. It is roughly divided into a mixing process, a firing process, and a water washing / drying process. It shows below about the preparation method of the glass powder (glass ground material) used by the present Example and the following comparative example.

A glass container (waste glass) discharged from a general household was used as a raw material for glass powder. Foreign substances such as labels and metal crowns were removed from the glass container, washed with water, dried, and coarsely pulverized to a particle size of about 10 mm using a hammer.
Then, it grind | pulverized to the particle size of 1000 micrometers or less using the stamp mill (Nissho Science Co., Ltd. ANS143). As for the particle size composition of the prepared glass, 1000 to 500 μm is 16.3%, 500 to 250 μm is 22.0%, 250 to 150 μm is 14.9, 150 to 90 μm is 11.3%, and 90 μm or less is 35.5. %Met. The component composition of the raw glass was measured by a fluorescent X-ray analysis method (apparatus name: scanning X-ray fluorescence analyzer, model ZSX Primus II, manufactured by Rigaku Corporation). SiO2: 68.9%, Na2O: 13.6%, CaO : 13.3%, Al2O3: 1.96%, K2O: 1.42%, and other components were 0.82%. In addition, unless otherwise indicated,% of a component represents weight%.

  Moreover, as a kind of glass used as a raw material, borosilicate glass may be used in addition to soda lime glass which is a raw material of bottle glass. Further, quartz glass, 96% silica glass, lead alkali silicate glass, aluminosilicate glass, and the like may be used, and the present invention is not limited to these types, and a mixture thereof may be used. Moreover, if waste glass is used as a raw material, it promotes the reuse of glass and contributes to the formation of a recycling-oriented society.

Although the glass foam of the Example of this invention is manufactured based on the flow shown in FIG. 3, the present inventors are phosphoric acid contained in domestic waste water, industrial waste water, etc. as a substance which can adsorb | suck to Ca component. In order to confirm the difference in the phosphate adsorption performance between dolomite and calcium carbonate, we first sought and examined the conditions for adding calcium carbonate with high phosphate adsorption performance.
Since it is considered that the amount of calcium distribution on the surface of the adsorbent is related to the phosphate adsorption of glass foams, glass foams with different amounts of calcium carbonate are prepared and their phosphate adsorption capacities are compared. Thus, the relationship between the calcium content and the phosphate adsorption capacity was examined.

  Therefore, first, a glass foam when calcium carbonate is used as a foaming agent without using calcium magnesium carbonate (dolomite) and sodium carbonate will be described below as Comparative Example 1.

Comparative Example 1

(Preparation of glass foam A)
Calcium carbonate (special grade reagent manufactured by Kanto Chemical Co., Ltd.), which is a carbonate, is pulverized in advance to a particle size of 500 μm or less by a stamp mill in the same manner as the above pulverized product, and the pulverized product and calcium carbonate are uniformly distributed. After mixing, the mixture was transferred to an alumina container and placed in a muffle furnace (model FO710 manufactured by YAMATO Co., Ltd.) and baked.

  The concentration of calcium carbonate to be mixed with the glass powder pulverized to a particle size of 1000 μm or less is 0.5, 1, 2.5, 5, 7.5, and 10% by weight. / Min, with a maximum temperature of 900 ° C. for 30 minutes and a temperature drop rate of 10 ° C./min. The produced glass foam A was pulverized to a particle size of 2 to 4 mm, washed with water and dried, and was subjected to a phosphate adsorption test.

(Phosphate adsorption test)
1 g of the glass foam A produced by the above method is immersed in 100 ml of 1 mg PO4-P / liter phosphoric acid aqueous solution, and the phosphoric acid concentration of the supernatant after standing at room temperature for 24 hours is determined by molybdenum blue absorptiometry (according to JIS K0102). Colorimetric determination. This method and conditions were the same in Comparative Example 2 and Examples described later except for the standing time.

The results of this phosphate adsorption test are shown in FIG.
Phosphoric acid adsorption capacity was shown as a relative value with the maximum value (calcium carbonate addition amount 5 wt%, P2O 5140 mg adsorption per 1 kg of glass foam) taken as 100%. In addition, each measured value has shown the average value +/- standard deviation, and it is the same also about the result of the phosphate adsorption test in the following comparative examples 2 and an Example.

  Up to 5% by weight of calcium carbonate, the phosphate adsorption capacity increases as the added amount increases, and the phosphate adsorption capacity at 5% by weight increases to about 35 times that of 0.5% by weight. did. The reason why the phosphate adsorption ability is improved by increasing the amount of calcium carbonate added in this way is presumed that the added calcium carbonate is desorbed by firing, and the remaining calcium reacts with phosphoric acid. The

  On the other hand, when 7.5% by weight or more was added, no foam structure was observed, and a foaming agent that could not be taken into the glass foam was deposited on the surface. For this reason, it was considered that addition of 7.5% by weight or more reduced the phosphate adsorption capacity. It is considered that the amount of calcium in the foam regulates the phosphate adsorption capacity under the condition that the foam is sufficiently foamed and the surface area is secured.

(Effects of glass powder particle size, firing temperature, firing time on phosphate adsorption capacity of glass foam when calcium carbonate is used)
Next, the influence of the particle size, firing temperature, and firing time of the glass powder on the phosphate adsorption ability of the glass foam was examined. The basic conditions for the preparation of the glass foam are as follows: glass powder particle size of 500 μm or less (mixture of particle sizes of 500 μm or less), firing conditions of heating rate of 10 ° C./min, maximum temperature of 900 ° C. for 30 minutes, cooling rate of 10 ° C. / The amount of calcium carbonate added was set to 5% by weight. For example, when examining the influence of the glass powder particle size, the glass powder particle size alone is replaced with a glass powder of 1000 to 500 μm, 500 to 250 μm, 250 to 150 μm, 150 to 90 μm, 90 μm or less among the above basic conditions. A foam was prepared. Similarly, the influence of firing temperature and firing time was also examined. The firing temperature was 750 to 920 ° C., and the firing time was 5 to 30 minutes (no adsorption at 60 minutes).

The influence of the glass powder particle size is shown in FIG. 5, the influence of the firing temperature is shown in FIG. 6, and the influence of the firing time is shown in FIG.
In FIG. 5, the phosphate adsorption capacity is shown as a relative value with the maximum value (value when glass particle diameter is 500 to 250 μm, P2O 5167 mg adsorbed per 1 kg of glass foam) being 100%. Further, in FIG. 6, the phosphate adsorption capacity is shown as a relative value with the maximum value (the value when the firing temperature is 900 ° C. and P2O 5140 mg adsorbed per 1 kg of the glass foam) being 100%. Further, in FIG. 7, the phosphate adsorption capacity is shown as a relative value with the maximum value (the value when the firing time is 30 minutes and P2O 5140 mg adsorbed per 1 kg of the glass foam) being 100%.

  According to the result of FIG. 5, when the glass particle size is 500 to 250 μm, the phosphate adsorption ability is the highest, and the phosphate adsorption ability decreases as the particle diameter becomes finer. On the other hand, even when a mixture having a particle size of 500 μm or less was used as a raw material, the phosphoric acid adsorption ability was the same as when 500 to 250 μm was used. Although not shown, the phosphate adsorption capacity of the mixture having a glass particle size of 500 μm or less was about 102% when a glass particle size of 500 to 250 μm was used as a raw material.

  Therefore, as for the particle size of the glass raw material, coarse particles exceeding 500 μm should be excluded and the content ratio of fine particles having a size of 150 μm or less should be avoided from being extremely increased. From the results shown in FIGS. 6 and 7, the optimum firing temperature was 900 ° C., and the preferred firing time was 30 minutes.

Comparative Example 2

(Preparation of glass foam B)
Next, in order to improve the phosphate adsorption capacity of the glass foam, an attempt was made to improve the porosity. That is, since the performance of the adsorbent is considered to be defined by the abundance and surface area of the reactive group (calcium) on the adsorbent surface, the calcium carbonate shown in Comparative Example 1 as a foaming agent is used to increase the surface area. Instead of dolomite (magnesium calcium carbonate) having a foaming temperature relatively close to the softening temperature of glass was used. An example using dolomite as the foaming agent will be described below as Comparative Example 2. The glass foam production conditions were the same as in Comparative Example 1 unless otherwise specified.

  Dolomite (Domestic limestone lime) was added to the above crushed glass as a foaming agent instead of calcium carbonate of Comparative Example 1 to prepare Glass Foam B. Dolomite was previously pulverized under a particle size of 500 μm by a stamp mill in the same manner as in Comparative Example 1, and was uniformly mixed with the above pulverized glass, and the mixture was transferred to an alumina container. And baked.

  The production conditions of the glass foam are as follows: glass powder particle size of 1000 μm or less (mixture of particle sizes of 1000 μm or less), firing conditions of temperature rising rate 10 ° C./min, maximum temperature 750 ° C. for 15 minutes, temperature falling rate 10 ° C./min, The added amount of dolomite was set to 5 to 12.5% by weight. Other conditions were the same as in Comparative Example 1, and a glass foam B was produced.

(Effect of added amount of dolomite on phosphate adsorption capacity of glass foam)
The produced glass foam B was pulverized to a particle size of 2 to 4 mm, washed with water and dried, and subjected to a phosphate adsorption test under the same conditions as in Comparative Example 1 except that the standing time was 12 hours. Here, the stationary time was set to 12 hours shorter than Comparative Example 1 (24 hours) because, when using dolomite, most of the phosphoric acid in the solution was adsorbed when reacted for 24 hours. This is because it was difficult to compare the performance.

The result of the phosphoric acid adsorption test of the glass foam B is shown in FIG.
In FIG. 8, the phosphate adsorption capacity is shown as a relative value with the maximum value (the value when the added amount of dolomite is 10% by weight, adsorption of P2O5124 mg per kg of glass foam) being 100%. The value of 124 mg is lower than 167 mg and 140 mg, which are the adsorption amounts shown in FIGS. 5 to 7 when calcium carbonate is used (Comparative Example 1). In Comparative Example 2, Comparative Example 1 The reaction time is shortened from 24 hours to 12 hours as compared with the above, so that the amount of adsorption is also considered to have decreased.

  As can be seen from FIG. 8, as the amount of dolomite added increases, the phosphate adsorption capacity increases, reaches a maximum at an addition amount of 10% by weight, and decreases at 12.5% by weight. However, if the amount of dolomite added is 5% to 12.5% by weight, the phosphate adsorption capacity will be 50% or more, so the amount of dolomite added should be 5% to 12.5% by weight. It is considered that sufficient adsorption performance can be obtained.

  And the phosphate adsorption capacity when the addition amount of dolomite was 10% by weight was improved about twice as much as the adsorption capacity when the addition amount of calcium carbonate was 5% by weight. This improvement in phosphoric acid adsorption capacity is because the foaming temperature of dolomite and the softening temperature of glass are relatively close, so that the pores and voids generated by the foaming agent are not blocked during the above cooling step. This is probably due to the increased surface area.

(Effects of glass powder particle size, firing temperature, firing time on phosphate adsorption capacity of glass foam when dolomite is used)
Also in the case of using dolomite, the influence of the particle size, firing temperature, and firing time of the glass powder on the phosphate adsorption ability of the glass foam was examined. The basic conditions for preparing the glass foam are as described above (production of glass foam B).

  The examination method was the same as in Comparative Example 1. For example, when examining the influence of the glass powder particle size, the glass powder particle size alone is replaced with a glass powder of 1000 to 500 μm, 500 to 250 μm, 250 to 150 μm, 150 to 90 μm, 90 μm or less among the above basic conditions. A foam was prepared. Similarly, the influence of firing temperature and firing time was also examined. The baking temperature was 700 to 900 ° C., and the baking time was 5 to 60 minutes.

The influence of the glass powder particle size is shown in FIG. 9, the influence of the firing temperature is shown in FIG. 10, and the influence of the firing time is shown in FIG.
In FIG. 9, the phosphate adsorption capacity is shown as a relative value with the maximum value (the value when the glass particle diameter is 1000 to 500 μm, P2O 5124 mg adsorbed per 1 kg of the glass foam) being 100%. Further, in FIG. 10, the phosphate adsorption capacity is shown as a relative value with the maximum value (value when the firing temperature is 750 ° C., adsorption of P 2 O 5134 mg per kg of glass foam) being 100%. Further, in FIG. 11, the phosphate adsorption capacity is shown as a relative value with the maximum value (the value when the firing time is 15 minutes and P2O 5134 mg adsorbed per 1 kg of the glass foam) being 100%.

  According to FIG. 9, about glass particle size, phosphoric acid adsorption ability fell, so that the particle size was fine. Therefore, it is desirable to keep the content of the raw material glass having a small particle size low. The conditions of 750 ° C. for the firing temperature and 15 minutes for the firing temperature were optimum, 150 ° C. lower and 15 minutes shorter than those for calcium carbonate. This result is considered to correlate with the result of the differential thermal analysis shown in FIG. From this result, it is expected that the use of dolomite rather than calcium carbonate can reduce the power cost during production.

And according to the present Example, in order to make the glass foam more porous, in addition to the dolomite (magnesium calcium carbonate) used in Comparative Example 2, sodium carbonate was further added to form the glass foam C. Manufactured. According to the result of FIG. 1, since sodium carbonate was not decomposed | disassembled even at high temperature, it turns out that the sodium carbonate added in the glass foam remains without being decomposed | disassembled by baking.
And after mixing dolomite and sodium carbonate into glass powder and baking, it is possible to remove water-soluble sodium carbonate by washing with water, so that after this sodium carbonate is removed, voids are formed, resulting in a porous structure Was expected. Therefore, the influence of the addition of sodium carbonate on the phosphate adsorption capacity of the glass foam was examined. Also in this example, the production conditions of the glass foam were the same as those in Comparative Example 1 and Comparative Example 2 unless otherwise specified.

(Preparation of glass foam C)
The basic conditions for the preparation of the glass foam are as follows: glass powder particle size of 1000 μm or less (mixture of particles having a particle size of 1000 μm or less), firing conditions of temperature increase rate of 10 ° C./min, maximum temperature of 750 ° C. for 15 minutes, temperature decrease rate of 10 ° C. / Minutes, the amount of dolomite added was set to 10% by weight. In addition, these conditions select the conditions when the phosphate adsorption ability was the best in the comparative example 2.

  Dolomite (Kokudo Kokudo lime) and sodium carbonate (Kanto Chemical Co., Ltd. special grade reagent) were previously pulverized by a stamp mill under a particle size of 500 μm in the same manner as in Comparative Example 1, and the above The pulverized glass (mixture having a particle size of 1000 μm or less), dolomite and sodium carbonate were uniformly mixed, the mixture was transferred to an alumina container, and placed in a muffle furnace (model FO710 manufactured by Yamato Scientific Co., Ltd.) and baked. Either dolomite and sodium carbonate can be mixed first. The amount of sodium carbonate added was 1-12.5% by weight.

  Then, after immersing in 10 ml of pure water per 1 g of the prepared glass foam at room temperature for 2 hours, sodium carbonate was removed by repeating the operation of removing the supernatant 5 times. As a measure for removing sodium carbonate, the pH of the supernatant was measured with a pH meter (Model F-52, manufactured by Horiba, Ltd.), and the above operation was performed until the pH reached about 10.5.

Then, the glass foam C was produced by using a drying furnace (model STPH-100M manufactured by Tabai Espec Co., Ltd.) and drying at 105 ° C. for 2 hours.
At this time, a glass foam produced by adding 10% by weight sodium carbonate was immersed in pure water at room temperature for 2 hours, then ventilated and dried, and a weight loss of 10% by weight was observed. It was confirmed that sodium carbonate was not decomposed during the firing process and remained in the produced glass foam.

(Effect of added amount of sodium carbonate on phosphate adsorption capacity of glass foam made with dolomite)
And the produced glass foam C is grind | pulverized to a particle size of 2-4 mm, washed with water, dried, and the phosphoric acid adsorption test of the glass foam C on the same conditions except the said comparative example 1 and the stationary time having been 12 hours. Went. Also in the examples, like the comparative example 2, the standing time was set to 12 hours shorter than the comparative example 1 (24 hours) when the reaction was performed for 24 hours when dolomite and sodium carbonate were used. Because most of the phosphoric acid was adsorbed, it was difficult to compare the performance.

The result is shown in FIG. In FIG. 12, the phosphate adsorption capacity is shown as a relative value with the maximum value (value when the amount of sodium carbonate added is 10% by weight, adsorption of P2O5201 mg per kg of glass foam) being 100%. .
As shown in FIG. 12, as the amount of sodium carbonate added increased, the phosphoric acid adsorption ability improved, reaching a maximum at an addition amount of 10% by weight, and decreasing at 12.5% by weight. When the amount of sodium carbonate added is 2.5% by weight or more, the adsorption performance of phosphoric acid is 50% or more. Therefore, if the amount of sodium carbonate added is 2.5% by weight to 12.5% by weight, sufficient adsorption performance is achieved. Can be obtained.

  The phosphate adsorption capacity at 10% by weight of sodium carbonate is 2 as compared with the adsorption performance of glass foam B only with dolomite (showing the value at 0% by weight of sodium carbonate in FIG. 12). It improved about twice. The adsorption performance is about 1.6 times that of the value when the amount of dolomite shown in FIG. 8 is 10% by weight (P 2 O 5124 mg per 1 kg of the glass foam), but this is slightly different from the room temperature at the time of measurement. This is considered to be an effect.

  When 1 g of this foam was immersed in 100 ml of an aqueous solution (each 1 mg / liter) of Cd (cadmium), As (arsenic), Pb (lead), and Cr (chromium) for 24 hours, adsorption of these ions was observed. It was estimated that the selectivity of the substance to be adsorbed was high. Therefore, it was confirmed that the selectivity of the adsorption ability of phosphoric acid is high, and it can be said that the glass foam C according to the present example is optimal as the inorganic porous body used for the adsorption of phosphoric acid.

(Pore diameter distribution of glass foam prepared using sodium carbonate and dolomite)
The pore size distribution of the glass foam C of this example using glass foam A of Comparative Example 1, glass foam B of Comparative Example 2, and dolomite and sodium carbonate was measured and compared by mercury porosimetry. Each foam was selected with high phosphate adsorption performance under each condition. In Table 1, each condition of the glass foam A, the glass foam B, and the glass foam C used for the measurement is shown.

  In addition, a mercury intrusion meter (capacitance type PORE SIZER 9320 manufactured by Shimadzu Corporation) was used as a measuring apparatus, and the measurement conditions were a contact angle of 140 degrees and a surface tension of 484 (dves / cm). The measurement result of the pore diameter distribution of each glass foam is shown in FIG. Moreover, in FIG. 14, the conceptual diagram of the glass foam A and the glass foam C is shown.

  The glass foam A using calcium carbonate (Comparative Example 1, indicated by a one-dot chain line) mainly has a pore diameter of several μm inside or outside, but the glass foam B using dolomite (Comparative Example 2, indicated by a dotted line) It was possible to enrich the pores in the mesopore region inside and outside the tens of nm, which is important for the adsorption reaction. The pore size in the vicinity is a pore size distribution important for the adsorption reaction of phosphorus (phosphoric acid).

  In the glass foam C (Example, solid line) using dolomite and sodium carbonate, the pore size distribution has maximum values (first maximum value and second maximum value) in the region of 10 to 100 nm and the region of 10 to 100 μm, respectively. It was confirmed. Further, in the glass foam C, the pore size distribution (first maximum value) in the mesopore region inside and outside the tens of nm due to the glass foam B was further enriched. Furthermore, the pores (second maximum value) around 20 μm were also increased. Since the pores in this region are thought to contribute to water retention, there is a possibility that the penetration of the phosphoric acid aqueous solution into the glass foam is promoted.

  As shown in FIG. 14, in the glass foam A, phosphoric acid enters the coarse pores 6 derived from calcium carbonate and is adsorbed by the calcium component. However, in the glass foam C, the pore size distribution is caused by the foaming action of dolomite. The surface area of the pores (gap) 7 in the region of 10 to 100 nm increases, and phosphoric acid enters from the pores 8 having a pore size distribution derived from sodium carbonate of 10 to 100 μm. Therefore, it is considered that the amount of calcium on the surface of the glass foam C is increased and the phosphate adsorption ability is improved.

  Then, in order to investigate the relationship between the pore 8 derived from sodium carbonate and the water retention of the glass foam, the water absorption rate of two types of glass foams, glass foam B and glass foam C, was measured. The measurement method was a method for obtaining a change in weight after immersing the glass foam B and glass foam C in pure water 10 times by weight at room temperature for 6 hours. As a result, the glass foam B using only dolomite had a water absorption of about 12%, whereas the glass foam C using dolomite and sodium carbonate increased to about 22%.

  On the other hand, the water absorption of the glass foam A to which 5.0% by weight of calcium carbonate was added was about 9%. The increase in water absorption facilitates the contact of the phosphoric acid aqueous solution with the pore surface inside the glass foam, thereby improving the phosphate adsorption ability. In addition, since it was confirmed that the water retention was increased by the addition of sodium carbonate, the glass foam C according to the present example can be expected to be applied to a rooftop greening material (water retention medium such as mat plant).

And from FIG. 13, when the 1st maximum value of the glass foam C is 0.05 cm < ³ > / g or more, the pore in 10-100 nm of pore diameters of the glass foam A which used the conventional calcium carbonate as a foaming agent. It becomes larger than the volume, and when the second maximum value of the glass foam C is 0.10 cm ³ / g or more, it becomes larger than the pore volume at a pore diameter of 10 to 100 μm of the glass foam B using only dolomite. . Accordingly, if the glass foam has a pore volume at a pore diameter of 10 to 100 nm of 0.05 cm ³ / g or more and a pore volume at a pore diameter of 10 to 100 μm of 0.10 cm ³ / g or more, a more conventional glass It can be said that the adsorption performance of phosphoric acid is superior to the foam.
On the other hand, since the glass foam C according to the present example contains a calcium component, it can be adsorbed slowly with phosphoric acid and dissociated by a low-concentration acid that can be easily treated with waste liquid.

(Phosphate adsorption capacity of glass foam prepared using sodium carbonate and dolomite)
Next, the maximum retention amount of phosphoric acid adsorption of the glass foam C was measured. 1 g of glass foam C was immersed in 100 ml of 1000 mg PO4-P / liter phosphoric acid aqueous solution for 24 hours, and this operation was repeated 8 times. As a result of measuring the phosphoric acid concentration in the supernatant each time, 1.2% by weight of P2O5 could be retained. In addition, the first time was 0.19%, the second time was 0.28%, the third time was 0.43% (hereinafter omitted), and the value after repeating eight times reached a peak at 1.2% by weight. .

(Method of removing phosphoric acid from glass foam and recycling of phosphoric acid)
Furthermore, the effect of sulfuric acid treatment for desorbing phosphoric acid adsorbed on the glass foam on phosphoric acid desorption from the glass foam was investigated. The glass foam C holding 1.2% by weight of P2O5 was used as the foam on which phosphoric acid was adsorbed.

  1 g of this glass foam C was immersed in 200 ml of sulfuric acid aqueous solution at room temperature with stirring for 2 hours. Then, the phosphoric acid concentration in the supernatant of the sulfuric acid aqueous solution was measured. The sulfuric acid concentration was compared and examined in the range of 0.001N to 0.1N. The eluate in the supernatant of the sulfuric acid aqueous solution was filtered through a 0.45 μm membrane filter, and the phosphoric acid concentration in the filtrate was measured by molybdenum blue absorptiometry (according to JIS K0102).

The measurement result of the phosphoric acid elution rate in the sulfuric acid aqueous solution of the glass foam C is shown in FIG.
All of the adsorbed phosphoric acid was eluted in the 0.01N sulfuric acid aqueous solution. When hydrochloric acid was used instead of sulfuric acid, it was not possible to elute all phosphoric acid even at high concentrations (0.05 N, elution rate 79%). This is presumably due to the ion exchange action of sulfate ions.

  Chemically, as described above, the phosphate solubility with each metal ion of aluminum, iron, and calcium increases in the order of calcium phosphate, iron phosphate, and aluminum phosphate. It is thought that they are strongly bound to phosphoric acid in this order. This solubility relationship is a phenomenon related to the interaction between each metal ion and phosphoric acid in an aqueous solution, but when these metals are present on the surface of the adsorbent, the same phenomenon occurs. Inferred.

  And in order to collect | recover this eluted phosphoric acid, pH was raised by adding an alkali and it precipitated as calcium phosphate. That is, a 1N sodium hydroxide aqueous solution was dropped into a phosphoric acid aqueous solution eluted with a 0.01N sulfuric acid aqueous solution, and the phosphoric acid concentration and pH in the supernatant of the phosphoric acid aqueous solution were measured. The pH was measured using a pH meter (Model F-52 manufactured by Horiba, Ltd.).

FIG. 16 shows the relationship between the phosphoric acid residual rate in the supernatant and pH.
By setting the pH of the supernatant of the aqueous phosphoric acid solution to 11, all of the eluted phosphoric acid could be recovered as a precipitate.
In addition, as a regeneration treatment of the glass foam adsorbed with phosphoric acid, the influence of repeated 0.01N sulfuric acid treatment on the phosphate adsorption ability of the glass foam was examined. The sulfuric acid treatment was performed 1 to 3 times, and the phosphate adsorption capacity was measured by the phosphate adsorption test shown in Comparative Example 2. The measurement results of this phosphate adsorption test are shown in FIG.
According to FIG. 17, when the sulfuric acid treatment was repeated three times, the phosphoric acid adsorption ability was lowered, but the degree of the decline was lower than that of the twice treatment. Therefore, it was confirmed that the glass foam C by a present Example can be repeatedly used and recycled for waste water treatment. As described above, the glass foam C according to the present example is easy to regenerate and reuse and can be recycled as phosphoric acid fertilizer, which leads to the creation of phosphoric acid resources that are feared to be depleted. It is expected.

  INDUSTRIAL APPLICABILITY The present invention can be utilized and used for the subsequent treatment of wastewater treatment facilities at business establishments that require wastewater treatment. In addition, the regenerated inorganic porous material can be used as a rooftop greening material, and can be used in various technical fields such as environmental fields and architectural fields other than wastewater treatment.

It is the figure which showed the measurement result of the differential thermal analysis of carbonate. It is a conceptual diagram showing the manufacturing process of the inorganic porous body of this invention. It is the flow which showed the manufacturing process of the glass foam which is embodiment of this invention. It is the figure which showed the result of the phosphate adsorption test of the comparative example 1 at the time of changing the density | concentration of calcium carbonate. It is the figure which showed the result of the phosphoric acid adsorption test of the comparative example 1 at the time of changing glass powder particle size. It is the figure which showed the result of the phosphoric acid adsorption test of the comparative example 1 at the time of changing baking temperature. It is the figure which showed the result of the phosphoric acid adsorption test of the comparative example 1 at the time of changing baking time. It is the figure which showed the result of the phosphate adsorption test of the comparative example 2 at the time of changing the addition amount of a dolomite. It is the figure which showed the result of the phosphoric acid adsorption test of the comparative example 2 at the time of changing a glass powder particle size. It is the figure which showed the result of the phosphoric acid adsorption test of the comparative example 2 at the time of changing baking temperature. It is the figure which showed the result of the phosphoric acid adsorption test of the comparative example 2 at the time of changing baking time. It is the figure which showed the result of the phosphate adsorption test of the Example of this invention when the addition amount of sodium carbonate is changed. It is the figure which showed the measurement result of the pore diameter distribution of the glass foam of the comparative example 1, the comparative example 2, and the Example of this invention. It is a conceptual diagram of the glass foam of the comparative example 1 and the glass foam of the Example of this invention. It is the figure which showed the measurement result of the phosphoric acid elution rate in the sulfuric acid aqueous solution of the glass foam of the Example of this invention which made phosphoric acid adsorb | suck. An aqueous sodium hydroxide solution was dropped into an aqueous phosphoric acid solution eluted from an aqueous sulfuric acid solution from the glass foam of the example of the present invention in which phosphoric acid was adsorbed, and the relationship between the residual phosphoric acid rate in the supernatant and pH was shown. FIG. It is the result of investigating the influence which the frequency | count of sulfuric acid treatment of the glass foam of the Example of this invention has on phosphoric acid adsorption ability. It is a conceptual diagram showing the manufacturing process of the conventional glass foam.

Explanation of symbols

1 Glass powder 2 Foaming agent 3 Hole (void)
4 Glass foam 5 Sodium carbonate 6 Pore derived from calcium carbonate 7 Pore derived from dolomite 8 Pore derived from sodium carbonate

Claims (5)

The first maximum value is in a region where the pore size distribution is 10 to 100 nm, the second maximum value is in a region where the pore size distribution is 10 to 100 μm, and the first maximum value is 0.05 cm ³ / g or more, An inorganic porous body having a maximum value of 0.10 cm ³ / g or more and containing a calcium component.   The inorganic porous body according to claim 1 for adsorbing phosphoric acid or a phosphate group contained in the aqueous solution to be treated.   After using the inorganic porous material according to claim 1 for adsorption of phosphoric acid, the adsorbed phosphoric acid is dissociated by immersing the inorganic porous material adsorbing the phosphoric acid in a sulfuric acid aqueous solution of 0.01 N or less, The method for regenerating an inorganic porous material according to claim 1, wherein the material is regenerated.   (A) Calcium magnesium carbonate or dolomite, which is a foaming agent, and (c) sodium carbonate are mixed and fired, foamed and then immersed in water to remove sodium carbonate from the foam. A method for producing an inorganic porous material.   The method for producing an inorganic porous body according to claim 4, wherein glass powder is used as the inorganic powder (a).

Images