KR100324967B1 - High Strength Zeolite And Powder Zeolite From Water Plant Sludges And Their Preparation Method - Google Patents

Abstract

The present invention relates to a high-strength zeolite and a powder zeolite using a water purification plant sludge, and a method for producing the same. More specifically, the water treatment plant sludge is used by heat treatment at 700 ° C. or higher in air, and the high-strength zeolite uses the heat treated sludge (150 μm) as a raw material for calcining. And a hydrothermal curing step of reacting the alkali component with a temperature of 50 to 200 ° C. for 2 hours or more, and a molding reaction step of putting the hydrothermally cured compound into a mold and reacting and drying at a temperature of 70 ° C. or higher for 24 hours or more. The heat treatment sludge and sodium hydroxide is composed of a reaction step of heating by heating at 70 ℃ or more for 5 hours or more. The present invention is effective in recycling the purified water sludge which is thrown away as wastes into a high value-added adsorbent for water treatment by producing a high-strength zeolite for various adsorbents and powdered zeolites from a water purification plant sludge in a simple and economical manner.

Description

High Strength Zeolite And Powder Zeolite From Water Plant Sludges And Their Preparation Method}

The present invention relates to a high-strength zeolite and a powder zeolite using a water treatment plant sludge, and a method for producing the same, and more particularly, to prepare a composite zeolite from a water treatment plant sludge by a dry method and a wet method and to use them as an adsorbent for water treatment, thereby providing a simple and economical method. The present invention relates to a method for recycling water purification sludge into a high value-added adsorbent for water treatment.

In general, organic wastes can be incinerated and harmless, while inorganic wastes are difficult to thermally decompose to prevent environmental pollution by blocking them from the surrounding environment through solidification treatment and landfilling. However, these methods are emerging as the development of appropriate treatment methods as environmental laws are strengthened. Therefore, unlike sewage sludge, sludge produced in water purification plant has low harmful contents and clay-like properties, and research for recycling has been conducted, and building bricks have been suggested as an alternative.

According to the results of the component analysis of the water treatment plant sludge to 700 ℃, it is known that the main components are SiO ₂ and Al ₂ O ₃ . It should be noted, however, that fly ash, which has very similar constituents, has recently been known to be zeolitable by reacting with sodium hydroxide, and studies have shown that it can be recycled as an adsorbent other than conventional cement mixtures. lost. In addition, unlike the conventional wet reaction method in which a large amount of basic wastewater is generated, it is known in Japan that a high-strength zeolite that can be molded by the dry ash method of coal ash is recently produced.

Motivation of the present invention was to show that similar water purification plant sludge can be recycled as a raw material of zeolite.

Therefore, the present inventors have completed the present invention in order to broaden the selection according to the intended use by heat treatment of the water purification plant sludge, and by the dry and wet reaction method to prepare a high-strength or powder zeolite and to form a variety of adsorbents.

The present invention has been made in view of the above-mentioned, a method for producing a high-strength zeolite by the dry method of mixing and reacting the sludge powder heat-treated 700 ℃ or more with a cement-based binder and a method for producing a powder zeolite obtained by a wet method treated with sodium hydroxide solution Through recycling of functional metals with ammonia nitrogen adsorption capacity as well as heavy metal and total organic carbon (TOC) adsorption capacity to water purification plant sludge, it becomes a substitute material of existing activated carbon and synthetic zeolite currently used in various industrial and environmental fields. The purpose is to drastically prepare the water treatment plant sludge treatment problem and to secure economic feasibility by making the most of the advantages that the water purification plant sludge, which is the basic raw material, does not have a cost burden.

In addition, by using a cement binder and sodium hydroxide to obtain a high-strength zeolite and a powder zeolite for the adsorbent with various properties and functionalities to overcome the limitations of the existing water treatment plant sludge treatment method using a simple solidification as a landfill or cover material Its purpose is to recycle waste into useful resources.

1 is a manufacturing process of a high-strength zeolite and a powder zeolite prepared by a wet method and a dry method according to the present invention,

Figure 2 is a result by the thermogravimetric analyzer (Thermo Gravimetric Analyzer-TGA) for the dry sludge used in the present invention,

3 is an analysis photograph of a scanning electron microscope (Scanning Electron Microscope-SEM),

4 is an analysis result of the X-ray diffractometer of the high-strength zeolite crystal phase according to the present invention,

5 is an analysis result of the X-ray diffractometer of the zeolite prepared by the dry method using the blast furnace slag,

Figure 6 shows the adsorption characteristics of ammonia nitrogen of the composite zeolite by the dry method and the wet method according to the present invention,

Figure 7 shows the total organic carbon (TOC) adsorption characteristics of the composite zeolite by the dry method and the wet method according to the present invention,

8 and 9 show the adsorption characteristics of heavy metals (Pb, Cd) of the composite zeolite by the heat treatment sludge itself, the dry method and the wet method according to the present invention.

In order to achieve the above object, the present invention comprises a heat treatment step of making the water treatment plant sludge to 700 ℃ or more about 150㎛ powder; Hydrothermal curing step of hydrocuring the calcined raw material and the alkali component at a temperature of 50 to 200 ° C. for at least 2 hours; It consists of a high-strength zeolite manufacturing process in which a hydrothermally cured compound is put into a mold and reacted and dried at 70 ° C. or more for 24 hours or more, and a powder zeolite process in which the heat-treated sludge is treated with a sodium hydroxide solution. It was.

Hereinafter, each manufacturing process illustrated in FIG. 1 will be described in detail.

I. Manufacturing process of high strength zeolite

(1) heat treatment process

The sludge is placed in a water treatment plant and heat-treated in the air at 700 ℃ or higher to make organic matter remaining in the sludge to 3% by weight or less, and then pulverized and classified to a size of 150㎛.

(2) hydrothermal curing process

100 parts by weight of the heat treated sludge and 10 to 50 parts by weight of the mixture of the calcined raw material and the alkali component are hydrothermally cured for 2 hours or more at a temperature of 50 to 200 ° C. At this time, CaO may be used as the lime raw material, and Na ₂ CO ₃ may be used as the alkali component, and their molar ratio is preferably 0.3 to 1.8. In addition, by utilizing the blast furnace slag containing both calcareous and alkali components, it is possible to recycle another waste resources.

(3) forming process

In order to obtain a high-strength zeolite of a certain type, hydrothermally cured mixtures are put into molds of various sizes, and then reacted and dried for 24 hours or more at a temperature of 70 ° C. or more. At this time, various types of molded bodies are also manufactured by various extrusion and injection molding techniques. can do.

According to the above (1), (2) and (3) soft dry process, it is possible to manufacture high-strength zeolites of various shapes without any generation of waste water, and the strength of the manufactured zeolite molded body (based on 5 × 5 × 5 cm) is It has a high compressive strength of 100 to 500 kgf / cm 2.

II. Manufacturing process of powder zeolite by sodium hydroxide solution reaction method

A low-carbon heat-treated sludge having a carbon content of 3 wt% or less obtained in step (1) above is heated in a sodium hydroxide solution at 70 ° C. or more for at least 5 hours, and filtered and dried to prepare a powder zeolite.

The powdered zeolite can be formed into a molded body by reacting with various types of molds with CaO, and further reacted with various binders and heat-treated at 100 ° C. or above in various (N ₂ , Ar, air) atmospheres to improve moldability and specific surface area. Can improve. At this time, the binder may be water glass, water pool, molasses, phenol resin, or the like.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the scope of the present invention is not limited by the following examples.

Example 1

The water treatment plant sludge was heat-treated at a temperature of 600 ° C. or higher to remove organic matter and to form ocherous sludge. Table 1 shows the results of component analysis by heat treatment of external water purification sludge.

Analysis item Result value (% by weight) Ig. Loss 40.7 SiO ₂ 21.1 Al ₂ O ₃ 32.4 CaO 0.61 Fe ₂ O ₃ 2.24 K ₂ O 0.72 MgO 0.49 MnO 0.08 Na ₂ O 0.25 P ₂ O ₅ 1.12 TiO ₂ 0.18 N 1.68

From the elemental analysis results, only the sludge ash of the inorganic material was present as SiO ₂ and Al ₂ O ₃ . The toxic substance analysis experiment also showed below the standard value, which was different from the sewage sludge. However, according to the measurement results of Table 1, the ratio of SiO ₂ and Al ₂ O ₃ showed a difference according to the water purification plant and seasons.

Example 2

Thermal Characteristics of Dry Sludge

In order to determine the change according to the temperature of the dry sludge, the thermogravimetric analyzer (TGA 2050, TA Instruments) was measured up to 1000 ° C. (10 ° C./min) under nitrogen atmosphere (FIG. 2). When the sludge was naturally dried and then heat-treated in a nitrogen atmosphere, the weight loss of 11% by weight was generated below 100 ° C and the total weight loss of about 30% by weight was reached up to 700 ° C. At this time, various organic flocculants or other organic substances contained in the sludge were carbonized to show a black color. Compared with the phenomenon that the organic substance was completely burned during heat treatment in air, a high loss ratio of 30 to 50% by weight and yellowish white color were observed.

Example 3

100 parts by weight of the heat treatment sludge, 10.3 parts by weight of CaO, 22.2 parts by weight of Na ₂ CO ₃ After the reaction drying at 100 ℃ to prepare a high-strength zeolite.

The compressive strength of the zeolite thus prepared was measured (300 kgf / cm 2) (Table 2), and a high strength zeolite was produced by analyzing the crystal phase through a scanning electron microscope analysis (FIG. 3) and an X-ray diffractometer (FIG. 4). It was confirmed.

BET and strength measurements Sample name Surface area (㎡ / g) Pore size TS-Z 79.94 127.7 TS 157.85 93.28 F-Z 2.93 71.07 TS-Z: Zeolite Made of Sludge F-Z: Zeolite Made of Fly-Ash TS: Heat Treated Sludge (700 ° C)

Example 4

Except for using the blast furnace slag instead of CaO and the same as in Example 3, it was confirmed that a high-strength composite zeolite was produced through the result of the X-ray diffraction analysis (FIG. 5) of the crystal phase thus prepared.

Example 5

100 parts by weight of the heat treatment sludge used in Example 1, 20.6 parts by weight of CaO and 44.4 parts by weight of Na ₂ CO ₃ were hydrothermally cured at 100 ° C. for 2 hours, and then dried at 100 ° C. for reaction. The compressive strength was measured (500kgf / cm 2), The obtained crystal phase confirmed that a composite zeolite (dry method) was produced through the results of X-ray diffraction analysis.

Example 6

100 parts by weight of the heat treated sludge was reacted at 400 ° C. in 4N-NaOH solution at a temperature of 90 ° C. for 4 hours, and then filtered and dried at 110 ° C. The crystal phase thus obtained was confirmed to be a powdery composite zeolite through X-ray diffraction analysis (FIG. 4).

Example 7

NH ₄ -N adsorption characteristic

The standard solution was prepared by diluting 100 ml in 1000 ml using a 1000 ppm ammonia standard solution to prepare a 10 ppm standard solution. The zeolite prepared by the dry and wet method was added 100 ml of a 10 ppm solution of standard ammonium solution into a 250 ml Erlenmeyer flask, and then adsorbed at an initial concentration of 6 hours with stirring at 250 min ⁻¹ , followed by 0.45 at 30 minute intervals. After filtration with a membrane filter (membrane filter), the filtrate was taken and measured by an ultraviolet absorber by the Nesler method.

Zeolite prepared by dry method using blast furnace slag maintained pH of 10 and showed a maximum removal rate of 81% when the removal rate was 2 hours. The adsorption and desorption process was repeated over time, but the removal rate was 63-81%.

Compared with natural zeolites, natural zeolites had a maximum removal rate of 77% at 3 hours and 64% at 12 hours.

Zeolite prepared by dry method (CaO) was maintained at pH 11 and the removal rate was 51 ~ 71% showed a maximum removal rate of 71% (Fig. 6) at 30 minutes. Zeolite prepared by the wet method was maintained at pH 12 and the removal rate was 15 to 22% removal rate (Fig. 6).

Example 8

Adsorption Characteristics of Total Organic Carbon (TOC)

Zeolites prepared by dry and wet methods were measured and tested for 300 ppm solution by dissolving 0.3 g of humic acid in 1 liter of water or influent sewage treatment plant with 300 ppm total organic carbon (TOC) concentration. 1 to 7 g of the sample ground to a size of about 150 ml was put in 250 ml Erlenmeyer flasks and stirred for 3 hours at 250 min ⁻¹ with an automatic stirrer to perform adsorption experiments. In order to analyze the adsorption performance, the mixed solution was filtered through a 0.45㎛ membrane filter and then diluted 100-fold to measure total organic carbon (TOC). In order to compare the adsorption capacity of the commercial activated carbon currently used in the water treatment process, the experiment was conducted using the same particle size sample. Zeolite made from blast furnace slag by the dry method showed a removal rate of 44% at 7 g.

Zeolite prepared by dry method (CaO) was maintained at pH 11 and the removal rate was 63% at 5g. Zeolite prepared by the wet method was maintained at pH 12 and showed a removal rate of 78% (Fig. 7) at 5g. Zeolites prepared by the dry method (Fly-ash) showed a removal rate of 53% at 7 g.

Example 9

Heavy metal measurement

The zeolite prepared by the dry and wet method was put into 2 ml of 250 ml Erlenmeyer flask in 1000 ppm Pb and 10 ppm of Cd standard solution, and 250 min ^-1 for 4, 8 and 24 hours using an automatic stirrer at room temperature. After adsorbing with each other and measuring the respective pH, the filtrate was filtered and the residual concentration was measured by atomic analyzer (AA). Heat-treated sludge removed 100% of Pb but showed desorption of 20% after 24 hours. The pH was kept constant at about 4 (FIGS. 7, 8).

As can be seen from the above embodiment, the high-strength zeolite and the powder zeolite of the present invention can be seen that the adsorption capacity of heavy metals and total organic carbon (TOC) as well as the ammonia nitrogen adsorption properties are excellent and through this use in various industrial and environmental fields As well as the replacement of existing activated carbon and synthetic zeolite, it is possible to solve the problem of water treatment sludge treatment drastically, and it can be seen that the water purification plant sludge, which is a basic raw material, can maximize the cost-free advantage and secure economic feasibility. In addition, the high-strength composite zeolite by the dry method of the manufacturing method of the present invention can be molded and manufactured during the manufacturing process, the hydrothermal curing conditions during the manufacturing can be obtained the effect of simplifying wastewater problems and processes.

Claims (5)

10 parts by weight to 10 parts by weight of the mixture of the calcined raw material and the alkaline component were mixed with 100 parts by weight of the water purification plant sludge heat-treated at 700 ° C. or more, and hydrothermally cured at a temperature of 50 to 200 ° C. for 2 hours or more, and thus the obtained compound was molded into various sizes. And reacting and drying at a temperature of 70 ° C. or higher for 24 hours or more. The method of claim 1, The calcareous raw material is CaO, the alkali component is a method for producing a high-strength zeolite using water purification plant sludge, characterized in that Na ₂ CO ₃ . The method of claim 2, Method for producing a high-strength zeolite using water purification plant sludge, characterized in that the molar ratio of CaO and Na ₂ CO ₃ is 0.3 to 1.8. The method according to any one of claims 1 to 3, The calcined raw material is a method for producing high strength zeolite using water purification plant sludge, characterized in that the blast furnace slag. A method for producing powder zeolite using water purification sludge, which is characterized in that the purified water sludge heat-treated at 700 ° C. or higher is heated at a temperature of 70 ° C. or higher for 5 hours or more, followed by filtration and drying.