KR102230941B1 - Method for manufacturing a porous composite for treating contaminated water using waste sludge, a porous composite manufactured therefrom - Google Patents

Abstract

The present invention relates to a method for preparing a porous composite for treating contaminated water using waste sludge and a porous composite prepared thereby. The present invention provides a method for preparing a porous composite for treating contaminated water using waste sludge and a porous composite prepared thereby, which comprises: a mixture preparation step of mixing waste sludge, zerovalent iron (Fe^0), an alginate binder and an admixture so that the waste sludge, zerovalent iron and admixture are attached to the alginate binder; and an alginate-zerovalent iron-waste sludge-admixture complex preparation step of heat-treating alginic acid to form a plurality of pores and form a three-dimensional support, in which the attached waste sludge, zerovalent iron and admixture form a complex. When the complex comes into contact with polluted water containing pollutants, the pollutants receive electrons from zerovalent iron and are reduced and decomposed, and adsorbed to the pores of the complex to remove the pollutants, thereby providing polluted water permeability and pollutant reactivity.

Description

[Method for manufacturing a porous composite for treating contaminated water using waste sludge, a porous composite manufactured therefrom}

The present invention relates to a method of manufacturing a porous composite for treating contaminated water using waste sludge, and to a porous composite manufactured therefrom.

As industries become diversified, advanced, and large-sized, new types of pollutants are emerging in each field, and they are spreading to a serious state even in industrial fields with low emissions and low pollution levels.

Among them, contaminated water such as industrial wastewater, contaminated groundwater, and acidic drainage from mines has relatively low emissions and high treatment efficiency compared to domestic sewage, but requires thorough management because it has a high pollution concentration and a large amount of pollution load.

The substances contained in contaminated water are chlorinated organic compounds, pesticides, cyanide compounds, nitrates, oils, nutrients, pathogenic microorganisms, suspended substances, color, heavy metals, acid and alkali detergents, etc., and have a high concentration.

In particular, the discharge of heavy metals or heavy metal active ingredients from landfill leachate, contaminated groundwater, and mine acid drainage and sewage, etc., is rapidly increasing, and heavy metals can have a fatal effect on humans if they penetrate the groundwater through the soil.

Currently, contaminants such as heavy metals and chlorinated organic compounds contained in various contaminated water are treated in a solution or solid phase using various technologies. The most commonly used processes include evaporation, chemical precipitation, electrolysis and recovery, and membranes. There are separation methods, solvent extraction methods, and ion exchange resin methods.

Among them, chemical precipitation is the most commonly used process. When heavy metals are contained in contaminated water, chemicals are added to change the physical state of dissolved or suspended heavy metals, or to precipitate.

However, the chemical precipitation method is greatly affected by the type and concentration of heavy metals, the concentration of total dissolved solids, the pH of the contaminated water, and the properties of the contaminated water, and there is a problem in that secondary contamination by chemical substances used as adsorbents occurs.

As a method for improving the chemical precipitation method, "Ammonia removal adsorbent including acidic mine drainage sludge and alginic acid, its manufacturing method, and ammonia removal method using the same (Publication No.: 10-2020-0059972)" describes acidic mine drainage sludge and There has been an attempt to purify the water quality by providing an adsorbent for removing ammonia containing alginic acid. However, since it can be used only if the iron content in the acid mine drainage sludge is 70% or more, the acid mine drainage sludge with an iron content of less than 70% becomes unnecessary, and there is a problem that the amount of sludge being disposed of is excessively increasing. .

Therefore, it is the time of desperate need for research on technology that can efficiently and economically treat pollutants contained in contaminated water.

Korean Patent Application Publication No. 10-2020-0059972, published on May 29, 2020.

The present invention was invented to solve the above problems, and it is a technical solution to provide a method for preparing a porous composite for treating contaminated water using zero-valent iron, an alginic acid binder, an admixture, and waste sludge, and a porous composite prepared therefrom. .

In order to solve the above technical problem, the present invention is a ^{mixture of waste sludge containing an organic carbon source, zero-valent iron (Fe 0} ), an alginic acid binder, and an admixture, so that the waste sludge, zero-valent iron, and admixture are attached to the alginic acid binder. To, a mixture preparation step; And heat treatment of the mixture to form a three-dimensional support by forming a plurality of pores in the alginic acid by the waste sludge, zero-valent iron, and admixture, but allowing the attached waste sludge, zero-valent iron and admixture to form a complex, alginic acid. Including, wherein when the complex contacts contaminated water containing contaminants, the contaminant is reduced and decomposed by donating electrons from the zero-valent iron and pores of the complex. The contaminated water is adsorbed to remove contaminants to have permeability and reactivity of contaminated water, and the pH of the contaminated water is in the range of 7.0 to 9.0, and the complex is in contact with contaminated water to oxidize the zero-valent iron to form divalent iron and hydroxide ions. It provides a method for producing a porous composite for treating contaminated water using waste sludge, characterized in that the contaminants are adsorbed to the pores and removed by adjusting the pH in the range of 8.3 to 8.5.

In the present invention, the step of preparing the mixture comprises mixing 10 to 60 parts by weight of the zero-valent iron, 1 to 80 parts by weight of the alginic acid binder, and 30 to 90 parts by weight of the admixture based on 1 part by weight of the waste sludge. do.

In the present invention, the alginate binder is characterized in that at least one of iron alginate, calcium alginate, and sodium alginate.

In the present invention, the admixture is characterized in that at least one of pumice stone, activated carbon, peat, kaolin, and bentonite.

In order to solve the above other technical problems, the present invention provides a porous composite, characterized in that it is manufactured by the above method.

According to the method of manufacturing a porous composite for treating contaminated water using waste sludge according to the solution to the above problem, waste sludge, zero-valent iron, and admixture are adhered to the alginic acid binder, and a number of pores are formed in the alganic acid through heat treatment. As a result, a porous structure is formed by forming a three-dimensional support, and since the zero-valent iron acts as an electron donor, there is an effect of manufacturing a multifunctional composite material capable of removing contaminants through an oxidation-reduction reaction.

1 is a flow chart showing a method of manufacturing a porous composite for treating contaminated water according to the present invention.
Figure 2 is a schematic diagram of a porous composite for treating contaminated water according to the present invention.
Figure 3 is a mechanism showing the reaction between the zero-valent iron and pollutants according to the present invention.

Hereinafter, the present invention will be described in detail.

1 is a flow chart showing a method of manufacturing a porous composite for treating contaminated water according to the present invention. Referring to Figure 1, the multifunctional porous composite of the present invention is a mixture of waste sludge, zero iron (Fe ⁰ ), alginic acid binder, and admixture, so that the waste sludge, zero iron, alginic acid binder, and admixture are attached to the alginic acid binder. The mixture manufacturing step (S10), alginic acid forming a three-dimensional support by heat treatment of the mixture to form a three-dimensional support, but attached waste sludge, zero iron and admixture to form a complex alginic acid-zero iron-waste sludge- It may be prepared through the admixture composite manufacturing step (S20).

However, the alginic acid-zero iron-waste sludge-admixture prepared in this way has multifunctionality.This multifunctionality is multifunctional because it can have adsorption activity to various contaminated waters such as industrial wastewater, contaminated groundwater, and acidic mine drainage. It can be said to have.

According to the above-described manufacturing method, first, the mixture preparation step is a step of mixing waste sludge, zero-valent iron (Fe ⁰ ), an alginic acid binder, and an admixture so that the waste sludge, zero-valent iron, and admixture are attached to the alginic acid binder (S10).

Prior to the explanation, most of the contaminated mine wastewater or groundwater contains chlorinated organic compounds and heavy metals that are harmful to the human body, so it is difficult to remove them by a general method. In other words, in order to manufacture an alginic acid-zero iron-waste sludge-admixture that enables the oxidation, sedimentation and adsorption of pollutants such as heavy metal ions or chlorinated organic compounds contained in contaminated water, waste sludge is collected from a sewage treatment plant A powdery mixture is prepared by physically mixing zero-valent iron, an alginic acid binder, and an admixture.

It is desirable to mix waste sludge, zero-valent iron, alginic acid binder, and admixture at room temperature for 10 minutes to 1 hour to make a dough state.If the mixture is mixed within 10 minutes, the dough is not uniform, and the resulting porous composite has the adsorption activity of contaminants. There is a disadvantage in that it cannot be maximized, and if it is mixed for more than 1 hour, this also has a disadvantage that the adsorption activity of contaminants decreases.

Waste sludge is composed of organic carbon source as a major component, and it is intended to be useful by recycling the sludge that has been disposed of in a sewage treatment plant.Since it can help the adsorption activity of pollutants, reuse of waste sludge causes pollution. It acts to increase the adsorption power with substances.

The moisture content of the waste sludge is preferably 10 to 90% by weight. If the water content of the waste sludge is less than 10% by weight, the sludge is stiff and it is difficult to achieve a uniform mixing process with the zero-valent iron, the alginic acid binder, and the admixture. On the other hand, when the moisture content of the waste sludge exceeds 90% by weight, there is a disadvantage that the process is not easy, as well as the occurrence of bad odor due to too much moisture.

If the density of the waste sludge is less than 1.1g/cm3, the shape of the porous composite will not be maintained in a spherical shape in the future, and if the density exceeds 3.5g/cm3, the miscibility with zero iron, alginic acid binder and admixture is poor. Since it cannot be combined with zero-valent iron, alginic acid binder, and admixture, it is preferable to use waste sludge having a density in the range of 1.1 to 3.5 g/cm 3.

_{Zero-valent iron is a pure iron powder that does not have oxygen molecules from iron oxides (FeO, Fe 2} O ₃ , Fe ₃ O ₄ ) generated in the steel industry and other natural sources, and uses the strong oxidizing power of the surface to produce heavy metal ions and chlorinated organic compounds. It acts to decompose the same contaminants.

Zero-valent iron is an iron of a low-cost and non-toxic metal, has a large surface area, and is capable of being precipitated after adsorbing and decomposing contaminants due to high efficiency derived from the active site.

Usually, the pH of the contaminated water is in the range of 7.0 to 9.0, and since the zero-valent iron is oxidized when the porous composite is in contact with the contaminated water and is produced as divalent iron and hydroxide ions, the pH of the porous composite is adjusted to 8.3-8.5. That is, only when the pH of the porous composite is in the range of 8.3 to 8.5, contaminants contained in contaminated water under alkaline conditions can be removed.

If zero-valent iron is not separately added, the required amount of divalent iron and hydroxide ions are not generated, so the pH of the porous composite is rather lowered to the acidic range, which is a factor that lowers the adsorption efficiency of contaminants.

It is preferable that the zero-valent iron has a particle size of 0.04 to 1 mm and a density of 2 to 3.5 g/cm 3. The smaller the particle size of the zero-valent iron is, the more easily agglomeration between the particles occurs, resulting in poor dispersibility and stability. Therefore, it is difficult to directly apply it to contaminated water. Therefore, the particle size of zero-valent iron is preferably 0.04mm or more.

In other words, if the particle size of the zero-valent iron is less than 0.04mm, irregular agglomeration of the mixture is likely to occur, and the size of the zero-valent iron is too small to make enough pores in the alginic acid binder, resulting in insufficient space for contaminants to be adsorbed. There is a disadvantage that it cannot be increased.

Conversely, when the particle size of the zero-valent iron exceeds 1 mm, the particle size is too large to cut the alginic acid binder, and thus waste sludge, zero-valent iron, and admixture cannot be attached around the alginic acid binder.

Accordingly, the amount of contaminants adsorbed to the porous composite by making pores sufficiently in the alginic acid-zero iron-waste sludge-admixture complex to form a porous structure only when the particle size of zero-valent iron is made of a powder in the range of 0.04 to 1 mm. Will be able to increase.

In the case of zero-valent iron density, if the density is less than 2g/cm3, the density of the mixture is also lowered, making it impossible to manufacture a spherical porous composite with hard physical properties, and if it exceeds 3.5g/cm3, it is easy to combine with waste sludge, alginic acid binder, and admixture. There is a disadvantage that it is difficult to make pores of uniform size because it is not possible.

These zero-valent irons are based on 1 part by weight of waste sludge, and if they are mixed in less than 10 parts by weight, the reduction and decomposition of pollutants is not easy due to the lack of electrons that can be donated by the pollutants. It becomes difficult to fit. If zero-valent iron is mixed in excess of 60 parts by weight based on 1 part by weight of waste sludge, the amount of zero-valent iron is too large, causing breakage in the alginic acid binder, which results in poor adsorbing activity of pollutants in the porous composite, making it not suitable for reducing and decomposing pollutants. Can not do it.

For this reason, the zero-valent iron should be mixed in an amount of 10 to 60 parts by weight based on 1 part by weight of waste sludge, but the pH of the porous composite can be adjusted to 8.3 to 8.5, so that the permeability to alkaline contaminated water is increased, and the reactivity to pollutants is also increased. .

Alginic acid binders are natural polymers with low toxicity, and become a porous scaffold that acts as a porous support, thereby helping the adsorption of contaminants in the porous composite.

This alginic acid binder is due to the formation of a scaffold because D-mannuronic acid and L-gluronic acid form a block copolymer, and L-gluronic acid can combine with a cation to form a hydrogel. Preferably, the alginate binder may be at least one of iron alginate, calcium alginate, and sodium alginate. For example, sodium alginate is an alginic acid formed by bonding with sodium cations, and is a long polymeric material formed by successively bonding molecules, and has good film-forming ability, enabling rapid bonding with contaminants contained in contaminated water.

Through the mixing process, waste sludge, zero-valent iron, and admixture are attached to the alginic acid binder, thereby forming mutual bonding. At this time, pores may be formed in waste sludge and admixture attached to the alginic acid binder by the zero-valent iron attached to the alginic acid binder.

Through the subsequent heat treatment, the space created by the adhesion of the waste sludge, the zero iron and the admixture forms pores, so that the alginic acid-zero iron-waste sludge-admixture composite can have a porous structure.

That is, since waste sludge, zero-valent iron, and admixture are attached around the alginic acid binder through the mixing process, the porous composite can maintain a three-dimensional sphere. In addition, it is possible to increase the adhesion of contaminants through the pores generated by the waste sludge attached to the alginic acid binder through the subsequent heat treatment, the zero-valent iron, and the admixture.

The alginic acid binder may be used by adjusting its amount according to the density of zero-valent iron, and may be added in the range of 1 to 80 parts by weight based on 1 part by weight of waste sludge. If the alginic acid binder is added in an amount of less than 1 part by weight, a space in which the waste sludge, the zero iron and the admixture can be attached may not be created, so that the waste sludge, the zero iron and the admixture may clump together. On the other hand, if the alginic acid binder is added in excess of 80 parts by weight, a space in which waste sludge, zero iron and admixture can be sufficiently attached may be created, but there is a disadvantage that pore formation becomes difficult if the alginic acid binder is added in an excessive amount. .

In addition, the alginic acid binder has a particle size of 100 ~ 500㎛. If the size of alginic acid is less than 100㎛, it does not function properly as a porous scaffold, so the space for attaching zero iron, waste sludge and admixture becomes narrow. If it exceeds 500㎛, the alginic acid binder is too large, which also acts as a porous scaffold. It is not desirable to

For reference, heavy metal ions among pollutants are heavy elements with a specific gravity of 4.5 or more, and copper ions (Cu ²⁺ ), cobalt ions (Co ²⁺ ), zinc ions (Zn ²⁺ ), cadmium ions (Cd ²⁺ ), It may be one or more selected from the group consisting of lead ions (Pb ²⁺ ) and mercury ions (Hg ^2+). That is, divalent heavy metal ions are contained in the contaminated water, and alginic acid has a high binding power to divalent heavy metal ions. However, the heavy metal ions that can be removed by the porous composite of the present invention are not only +2, but also +3.

The admixture is composed of any one or more of pumice, activated carbon, peat, kaolin, lapillus such as volcanic gravel, and bentonite, and acts to allow the adsorption and precipitation of contaminants.

If the admixture is less than 30 parts by weight based on 1 part by weight of waste sludge, there is not enough space for pores in the admixture, and it is not helpful for the sedimentation of the porous composite adsorbed with contaminants. If it exceeds 90 parts by weight, the amount of admixture There are too many parts in which zero-valent iron cannot be bonded to the admixture, making it difficult to make the admixture into a porous structure.

Here, the admixture and the zero-valent iron have a particle size of 0.5 to 2 mm, and the particle size ranges are different from each other. In particular, the particles of the admixture are preferably larger than the zero-valent iron particles. In other words, it is preferable that the particle size of the zero-valent iron is smaller than the particle size of the admixture. This is to make it possible to create a porous structure by allowing a large number of pores to be formed in the admixture as the zero-valent iron having a relatively small particle size is attached to the admixture having a relatively large particle size.

Next, in the step of preparing the alginic acid-zero iron-waste sludge-admixture complex, the mixture is heat-treated to form a three-dimensional support with alginic acid forming a large number of pores, but the attached waste sludge, zero-valent iron, and the admixture form a complex. It is a step (S2).

Prior to the heat treatment, it is preferred to dry the mixture. That is, drying is a pretreatment process for later heat treatment, and it can be said that during heat treatment, pores formed in waste sludge, alginic acid binder, and admixture can be maintained by zero-valent iron.

To this end, by drying so that the amount of moisture contained in the mixture is less than 30% by weight for 10 minutes to 1 hour within the range of room temperature from 15℃ to 80℃, the adsorption activity of pollutants of the porous composite can be increased. It is desirable.

Drying the mixture below 15°C may cause the mixture to freeze, so the moisture content will increase depending on the melting after a period of time, and if it exceeds 80°C, the properties of the mixture will change, resulting in satisfactory adsorption activity of the porous composite. There is a drawback of not being able to do so.

If the mixture is dried within 10 minutes, the drying time is too short and the moisture content of the mixture is not sufficient to reach 30% by weight or less, so that the adsorption activity of contaminants such as heavy metal ions cannot be maximized, and the drying time exceeds 1 hour. In the case of making it, compared to the case of drying in a shorter period of time, there is a disadvantage in that a more excellent effect is not drawn in adsorbing contaminants, and thus only the processing time is consumed.

Following drying, when chemical heat treatment is performed, a number of pores are formed in the alginic acid binder, thereby forming a three-dimensional support, thereby forming a porous structure and forming a spherical alginic acid-zero iron-waste sludge-admixture. Referring to the photo of FIG. 2, the pores formed in the porous composite in which the alginic acid binder, zero-valent iron, waste sludge, and admixture are bonded together, and the porous structure created through these pores can be confirmed. Porosity through the pores formed in the alginic acid binder It can be seen that the area in which contaminants can be adsorbed is increased by the structure.

With this structure, zero-valent iron acts as an electron donor, and pollutants contained in contaminated water act as electron acceptors, so when the complex comes into contact with contaminated water containing pollutants, the pollutants receive electrons from zero-valent iron. As it is reduced and decomposed, it is adsorbed to the pores of the complex to remove contaminants, thereby having contaminated water permeability and contaminant reactivity.

The heat treatment can be performed within the range of room temperature from 15℃ to 500℃. If the heat treatment is less than 15℃, it is difficult to increase the density in the dried mixture, making it difficult to manufacture a porous composite with strong physical properties, and zero-valent iron acts as an electron donor. It is not possible to activate the adsorption of pollutants. If heat treatment is performed at a temperature exceeding 500°C, the dried mixture is underfired, and the porous composite cannot be maintained in a perfect spherical shape. At this time, the heat treatment atmosphere may be formed in air or carbon dioxide atmosphere.

Figure 3 shows the reaction between the zero-valent iron and pollutants according to the present invention as a mechanism. Referring to FIG. 3, in the porous composite manufactured through heat treatment, the zero-valent iron acts as an electron donor, and, for example, the zero-valent iron is oxidized in the same manner as in Equation 1 below. That is, zero-valent iron (Fe ⁰ ) is oxidized to divalent iron (Fe ²⁺ ) or trivalent iron (Fe ³⁺ ), thereby donating electrons.

[Equation 1]

_{^{Fe 0 + 2H 2 O → Fe}} 2+ + H 2 + 2OH -

When the contaminant is nitrate, reactions such as the following Equations 2, 3, and 4 may be performed. In relation to the formula (2), a nitrate, a zero-valent iron is reduced to nitrogen by reaction with decomposition ^{_{xFe 2+ + yNO 3+ zH 2 O}} → xFe 3+ + y / 2N 2 + 2zOH contained in the polluted water ^- can be reacted It can be said that it is an equation that is achieved because of this.

[Equation 2]

^{_{10Fe 2+ + 2NO 3+ 6H 2 O}} → 10Fe 3+ + N 2 + 12OH -

[Equation 3]

_{^{4Fe 0 + NO 3 - + 7H}} 2 O → 4Fe 2+ + NH 4 + + 10OH -

[Equation 4]

_{^{5Fe 0 + 2NO 3 - + 6H}} 2 O → 5Fe 2+ + N 2 + 12OH -

When the contaminant is cyan, reactions such as the following Equations 5, 6, and 7 may be performed. However, Me means a heavy metal.

[Equation 5]

^{Fe 2+ + 6CN - + Me 2+} → Fe (CN) 6 2-

[Equation 6]

^{3Fe 2+ + 2Fe 3+ + 12CN -} → Fe 3 [Fe (CN) 6] 2

[Equation 7]

^{Fe 2+ + 6CN - + Me 2+} + 2H + → MeH 2 Fe (CN) 6

Among pollutants, chlorinated hydrocarbons, which are a kind of chlorinated organic compounds, are reduced by accepting electrons emitted in [Equation 1], which is shown in Equation 8.

[Equation 8]

RCl + H ⁺ + 2 ^e- → RH + Cl

The overall reaction of Equations 1 and 8 is the same as Equation 9.

[Equation 9]

^{RCl + Fe 0 + H + →} RH + Fe 2+ + Cl -

When the pollutant is a heavy metal, reactions such as Equations 10, 11, 12, 13, 14, and 15 are performed.

[Equation 10]

_{^{Fe 0 + 2H 2 O → Fe}} 2+ + H 2 + 2OH - + 2e -

[Equation 11]

4Fe(OH) ₂ + O ₂ + 2H ₂ O → 4Fe(OH) ₃

[Equation 12]

Fe ⁰ + H ₂ O + (O ₂ ) → H ₂ + (FeO,Fe ₃ O ₄ ,FeOOH)

[Equation 13]

2Fe ⁰ + 3Pb ²⁺ + 4H ₂ O → 2Fe(OH) ₂ + 3Pb ⁰ + 2H ⁺

[Equation 14]

2Fe ⁰ + 3Ni ²⁺ + 4H ₂ O → 2Fe(OH) ₂ + 3Ni ⁰ + 2H ⁺

[Equation 15]

Zn ²⁺ + FeOOH → [Zn ²⁺ ≡FeOOH] (sediment)

Alternatively, a reaction such as Equation 16 is also possible.

[Equation 16]

^{Zn 2+ + 2OH - → Zn (} OH) 2

Referring to Equations 1 to 16, the pH of the contaminated water is usually in the range of 7.0 to 9.0, so that contaminants can be removed under alkaline conditions of pH 8.3 to 8.5. That is, since zero-valent iron is oxidized to ^{produce divalent iron (Fe 2+} ) and 2OH ^- , the pH increases, so that the pH of the porous composite can be adjusted to 8.3-8.5.

If zero-valent iron does not exist separately in the porous composite, 20H ^- cannot be generated, and the pH of the porous composite is in the acidic range, so zero-valent iron can play an important role. Porous composites that have fulfilled the role of removing contaminants are automatically adjusted in the range of pH 6.8 to 7.0.

In summary, the present invention provides a method of manufacturing a porous composite for treating contaminated water using waste sludge, and a porous composite manufactured therefrom. According to this, in manufacturing an adsorbent by mixing waste sludge, zero-valent iron, alginic acid binder, and admixture, drying and heat treatment, the waste sludge, zero-valent iron and admixture are attached to the alginic acid binder, and the alginate binder A number of pores are formed, and pores may also be formed in waste sludge and admixture together, so that a composite having a porous structure can be made.

Therefore, when the porous composite of the present invention comes into contact with contaminated water containing pollutants, the zero-valent iron acts as an electron donor and the pollutant acts as an electron acceptor so that the pollutant is reduced and decomposed by donating electrons from zero-valent iron. By being adsorbed into the pores formed in the composite, there is an advantage of separating and removing the composite in the form of a precipitate in which contaminants of contaminated water are adsorbed.

Hereinafter, an embodiment of the present invention will be described in more detail as follows. However, the following examples are merely illustrative to aid in understanding of the present invention, and the scope of the present invention is not limited thereby.

<Example 1>

Based on 1 part by weight of the waste sludge, 50 parts by weight of zero-valent iron, 10 parts by weight of an alginic acid binder, and 60 parts by weight of an admixture were mixed to prepare a mixture. The mixture was dried at 60° C. for 30 minutes so that the moisture content was 30% by weight or less, and then heat-treated in air at 150° C. to prepare a porous composite, thereby completing a multifunctional composite material.

<Test Example 1>

After collecting drugs contained in the same way as pollutants contained in contaminated groundwater, 200 ml of raw water containing the collected drugs was put into an Erlenmeyer flask, and then 2 g of the multifunctional composite material prepared according to Example 1 was added, The initial concentration of raw water and the concentration after treatment were compared and experimented. The experimental method was carried out for 60 minutes as a batch experiment, and the results are shown in Table 1 below.

pollutant Applied chemicals Raw water initial concentration
(Mg/ℓ) Concentration after treatment
(Mg/ℓ) Remark medium
gold
genus Al Aluminum chloride
[AlCl ₃ ·6H ₂ O] 15 Not detected Analyzer: ICP-OES Zn Zinc cyanide
(ZnCN ₂ ) 15 Not detected Ni Nickel nitrate
[Ni(NO ₃ ) ₂ ] 15 Not detected As Arsenic(III)Oxide 0.1 Not detected Pb Lead nitrate
[Pb(NO ₃ ) ₂ ] 15 Not detected Cyanide Zinc cyanide
(ZnCN ₂ ) 15 0.001 Analysis method: Water pollution process test standard (Ministry of Environment Notice No. 2017-4) nitrate Lead nitrate
[Pb(NO ₃ ) ₂ ]
Nickel nitrate
[Ni(NO ₃ ) ₂ ] 15 Not detected Analysis method: Water pollution process test standard (Ministry of Environment Notice No. 2017-4) dense non-aqueous phase liquid Ethylene tetrachloride
(C ₂ Cl ₄ ) 10 0.001 Analyzer: HPLC Haloacetic acid Monochloroacetic acid Monochloroacetic acid
[C ₂ HCl ₃ O ₂ ] 10 0.05 Analyzer: HPLC Trichloroacetic acid Trichloroacetic acid
[C ₂ HClO ₂ ] 10 Not detected Chloroamine Chloroamine-T 30 Not detected Analyzer: HPLC

Referring to Table 1, after adding the multifunctional composite material prepared according to Example 1 to raw water containing the same pollutant contained in contaminated groundwater, the initial concentration of raw water and the concentration after treatment through a batch experiment for 60 minutes. You can check the result of comparing.

As shown in Table 1, heavy metals, nitrates, trichloroacetic acid, and chloroamine were not detected after treatment with the multifunctional complex, and cyanide was initially 15 mg/l, whereas after treatment, it was detected in trace amounts of 0.001 mg/l. In contrast, the dense non-aqueous phase liquid was initially 10 mg/l, whereas after treatment, it was detected as a trace amount of 0.001 mg/l. In the case of monochloroacetic acid, it was initially 10 mg/l, whereas after treatment, it was detected in a trace amount of 0.05 mg/l.

From the results of the above-described Examples and Test Examples, the present invention relates to a method of manufacturing a porous composite for treating contaminated water using waste sludge, and to a porous composite prepared therefrom. After allowing the sludge, zero iron and admixture to adhere to the alginic acid binder, a number of pores are formed in the alginic acid binder through drying and heat treatment, resulting in a porous structure of alginic acid-zero iron-waste sludge-admixture composite. There is this.

As described above, in the present invention, zero-valent iron acts as an electron donor and pollutants in contaminated water act as electron acceptors, so that the pollutants receive electrons from zero-valent iron and are reduced and decomposed to be adsorbed into the pores of the complex, thereby removing the pollutants. And it is of great significance in that it can have pollutant reactivity.

Therefore, according to the porous composite of the present invention, contaminants such as heavy metals, cyan salts, nitrates, dense non-aqueous phase liquids, haloacetic acid, and chloroamine can be reduced and decomposed through redox reactions. It is expected to be able to efficiently treat contaminated water.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the claims, and all technical thoughts within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (5)

Mixing the waste sludge containing an organic carbon source, zero-valent iron (Fe ⁰ ), an alginic acid binder, and an admixture so that the waste sludge, zero-valent iron, and an admixture adhere to the alginic acid binder; And
Alginic acid, which heat-treats the mixture so that the waste sludge, the zero-valent iron, and the admixture form a three-dimensional support with the alginic acid forming a three-dimensional support, and the attached waste sludge, the zero-valent iron, and the admixture form a complex. Including; zero-valent iron-waste sludge-admixture manufacturing step;
When the complex is in contact with contaminated water containing contaminants, the contaminant is reduced and decomposed by donating electrons from the zero-valent iron, and adsorbed to the pores of the complex to remove contaminated water permeability and contaminant reactivity. Have,
The pH of the contaminated water is in the range of 7.0 to 9.0, and the complex is produced as divalent iron and hydroxide ions as the zero-valent iron is oxidized in contact with the contaminated water, and the contaminant is adsorbed to the pores by adjusting the pH to the range of 8.3 to 8.5. Characterized in that to be removed,
A method of manufacturing a porous composite for treating contaminated water using waste sludge. The method of claim 1,
The step of preparing the mixture,
Based on 1 part by weight of the waste sludge, characterized in that mixing 10 to 60 parts by weight of the zero-valent iron, 1 to 80 parts by weight of the alginic acid binder, and 30 to 90 parts by weight of the admixture,
Method for producing a porous composite for treating contaminated water using waste sludge. The method of claim 1,
The alginic acid binder,
Characterized in that at least one of iron alginate, calcium alginate and sodium alginate,
Method for producing a porous composite for treating contaminated water using waste sludge. The method of claim 1,
The admixture is,
It is characterized in that any one or more of pumice stone, activated carbon, peat, kaolin and bentonite,
Method for producing a porous composite for treating contaminated water using waste sludge. It characterized in that it is produced by the method of any one of claims 1 to 4,
Porous composite.

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