KR102199224B1 - Method for producing granular adsorbent for removing ionic pollutants using alum sludge and granular adsorbent produced thereby - Google Patents

Abstract

Disclosed are a method for preparing a granular adsorbent for removing harmful ions using alum sludge, and a granular adsorbent prepared thereby. The method for preparing the adsorbent according to the present invention and the granular adsorbent prepared thereby form the adsorbent in the form of granules. Then, even if the adsorbent is applied and used in the field, the adsorbent does not clump, so there may be an effect of preventing water channeling and blockage of the flow path of the product with the adsorbent installed. There may be an effect. In addition, since the adsorbent is formed in the form of granules, it is possible to prevent the adsorbent from flowing out of the part of the product where the adsorbent is installed. Then, since there is no need for an operation to treat the spilled adsorbent, there may be a convenient effect. And, since the prepared granular adsorbent is dried and then heat treated, there may be an effect of further improving adsorption performance.

Description

Method for producing granular adsorbent for removing ionic pollutants using alum sludge and granular adsorbent produced thereby}

The present invention relates to a method for producing a granular adsorbent for removing harmful ions present in water using alum sludge, and to a granular adsorbent prepared thereby.

Harmful substances contained in drinking water are removed by various methods such as reverse osmosis, coagulation, oxidation, precipitation, electrodialysis, or adsorption. And, because the adsorption method is simple, effective, and economical, it is widely used.

Alum is widely used for drinking water purification, and is added as a coagulant to remove suspended substances and natural organic substances. When alum is added to water, amorphous aluminum hydroxide, which is a kind of alum sludge, can be produced, and since aluminum hydroxide is a porous material, it is used as a soil improver or soil substitute.

As the amount of water increases, the amount of alum used in the water treatment process increases. Then, since a large amount of alum sludge is generated, a method for treating alum sludge is also required.

As a result of making great efforts to develop a technology capable of treating alum sludge, the present applicants obtained a patent right (Registration No. 10-1344235) for "Adsorbent for removing harmful ions using alum sludge and its manufacturing method". .

The adsorbent disclosed in Patent Publication No. 10-1344235 is in powder form.

However, when the adsorbent in the form of powder is applied and used in the field, agglomeration occurs. Then, there is a problem that a channeling phenomenon of water occurs due to the lumped adsorbent, and the flow path of the product in which the adsorbent is installed is blocked.

In addition, since the powdered adsorbent may leak out of the part of the product where the adsorbent is installed, the flow rate must be limited or the leaked adsorbent must be treated to prevent leakage. Therefore, there is an inconvenient problem.

An object of the present invention may be to provide a method for manufacturing a granular adsorbent capable of solving all the problems of the prior art as described above, and a granular adsorbent prepared thereby.

Another object of the present invention is to provide a method for producing a granular adsorbent capable of preventing the channeling of water and clogging of the flow path of a product installed with the adsorbent by forming the adsorbent in the form of granules, and to provide a granular adsorbent manufactured thereby. Can be.

Another object of the present invention may be to provide a method for producing a granular adsorbent that can be conveniently used by preventing the adsorbent from leaking out of the part of the product where the adsorbent is installed, and to provide a granular adsorbent prepared thereby.

Still another object of the present invention may be to provide a method for producing a granular adsorbent capable of further improving adsorption performance, and a granular adsorbent prepared thereby.

In the method for producing a granular adsorbent according to the present invention, in the adsorbent manufacturing method for adsorbing and removing at least one of arsenic (As) ions, fluorine (F) ions, and selenium (Se) ions, (A) aluminum ( Removing impurities from Alum Sludge containing Al), manganese (Mn) and iron (Fe), drying the alum sludge from which the impurities have been removed for 23 to 25 hours at 100 to 115°C, and then pulverizing ; (B) adding a binder to the alum sludge pulverized in (A) and stirring by adding water; (C) hardening the solution stirred in (B) to form granules; (D) drying the granules cured in (C) after washing; (E) It may include the step of heat-treating the granules dried in (D).

In addition, the granular adsorbent according to the present invention may be prepared by the method according to any one of claims 1 to 7.

In the method of manufacturing the granular adsorbent according to the present embodiment and the granular adsorbent prepared thereby, the adsorbent is formed in a granular form. Then, even if the adsorbent is applied and used in the field, the adsorbent does not clump, so there may be an effect of preventing water channeling and blockage of the flow path of the product with the adsorbent installed. There may be an effect.

In addition, since the adsorbent is formed in the form of granules, it is possible to prevent the adsorbent from flowing out of the part of the product where the adsorbent is installed. Then, since there is no need for an operation to treat the spilled adsorbent, there may be a convenient effect.

And, since the prepared granular adsorbent is dried and then heat treated, there may be an effect of further improving adsorption performance.

1 is a photograph showing a granular adsorbent prepared by a manufacturing method according to an embodiment of the present invention.
Figure 2 is a flow chart showing a method of manufacturing a granular adsorbent according to an embodiment of the present invention.
3A and 3B are graphs showing the Langmuir Adsorption Iisotherm and the Freundlich Adsorption Isotherm of the present adsorbent according to an embodiment of the present invention.
4A and 4B show a Pseudo-first order kinetic model and a Pseudo-second order kinetic model of the present adsorbent according to an embodiment of the present invention. graph.
5A and 5B are graphs showing the results of column experiments of the adsorbent according to an embodiment of the present invention.

The meaning of the terms described in this specification should be understood as follows.

Singular expressions should be understood as including plural expressions unless clearly defined differently in context, and terms such as “first” and “second” are used to distinguish one element from other elements, The scope of rights should not be limited by these terms.

It is to be understood that terms such as "comprise" or "have" do not preclude the presence or addition of one or more other features or numbers, steps, actions, components, parts, or combinations thereof.

The term “at least one” is to be understood as including all possible combinations from one or more related items. For example, the meaning of “at least one of the first item, the second item, and the third item” means 2 among the first item, the second item, and the third item as well as the first item, the second item, and the third item. It means a combination of all items that can be presented from more than one.

The term “and/or” is to be understood as including all possible combinations from one or more related items. For example, the meaning of “the first item, the second item and/or the third item” means two of the first item, the second item or the third item as well as the first item, the second item, or the third item. It means a combination of all items that can be presented from the above.

When a component is referred to as being "connected or installed" to another component, it should be understood that it may be directly connected or installed to the other component, but other components may exist in the middle. On the other hand, when a component is referred to as "directly connected or installed" to another component, it should be understood that there is no other component in the middle. On the other hand, other expressions describing the relationship between the constituent elements, that is, "between" and "directly between" or "adjacent to" and "directly adjacent to" should be interpreted as well.

On the other hand, when a component is referred to as "formed, combined, installed" in another component, a component and another component are separately prepared, formed, combined, or installed, as well as a component and It should be construed as including one in which other components are one body.

In each step, the identification code (e.g., S100, S110, S120, etc.) is used for convenience of explanation, and the identification code does not determine the order of each step, and each step is clearly specified in the context. Unless the order is specified, it may occur differently from the order specified. That is, each of the steps may be performed in the specified order, may be performed substantially simultaneously, or may be performed in the reverse order.

Hereinafter, a method for preparing a granular adsorbent for removing harmful ions using alum sludge according to an embodiment of the present invention and a granular adsorbent prepared thereby will be described in detail.

1 is a photograph showing a granular adsorbent prepared by a manufacturing method according to an embodiment of the present invention.

As shown, the adsorbent according to an embodiment of the present invention may be removed by adsorbing arsenic (As), which is a harmful substance contained in drinking water. The adsorbent according to an embodiment of the present invention may be formed in a granular form.

The present applicants have applied for a patent (application number 10-2017-0147752) for a method of manufacturing a powder adsorbent in a granular form disclosed in Patent Registration No. 10-1344235 registered by the present applicants. ) (2017.11.08), and the adsorbent according to the embodiment of the present invention is an improvement of the patent-applied invention and has more excellent adsorption performance.

A method of manufacturing an adsorbent according to an embodiment of the present invention will be described with reference to FIG. 2. Figure 2 is a flow chart showing a method of manufacturing a granular adsorbent according to an embodiment of the present invention.

In the water purification process, alum (Al ₂ (SO ₄ ) _3· 14H ₂ O) is added to agglomerate contaminants in order to remove solid suspended matter and organic matter. When alum is added to water, amorphous aluminum hydroxide (Al(OH) ₃ ) is produced, and aluminum hydroxide has high voids, so it can be used as an adsorbent for harmful substances.

As shown, in step S110, alum sludge may be obtained in a water treatment plant. In the water treatment process, not only alum but also various substances are added, so alum sludge contains aluminum (Al), silicon (Si), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), and iron (Fe ), copper (Cu), zinc (Zn), zirconium (Zr), tin (Sn), and the like may be contained. At this time, the alum sludge may contain only aluminum (Al), manganese (Mn) and iron (Fe).

Thereafter, in step S120, impurities of the alum sludge can be removed, and in step S130, the alum sludge from which the impurities have been removed is dried at 100 to 115° C. for 23 to 25 hours, and the surface area is 30 m ² /g to 50 m. ² / g, it can be pulverized so that the diameter is 50 μm to 200 μm.

Thereafter, in step S140, a binder may be added to the pulverized alum sludge, and water may be added to the mixture to be stirred. The binder is an additive for forming a granular form by combining alum sludge in powder form.

In the method for preparing an adsorbent according to an embodiment of the present invention, sodium alginate may be used as a binder, or sodium alginate and polyvinyl alcohol may be used as a binder.

Sodium alginate exists in association with sodium cations, and is a long polymeric material formed by successively bonding molecules. Sodium alginate is insoluble in water, but the alkali salt of sodium alginate dissolves in water to make a very viscous solution. In addition, sodium alginate has excellent film-forming ability, reacts quickly with moisture, and easily binds to form a net structure.

And, polyvinyl alcohol has the function of an adhesive.

In the step of stirring the pulverized alum sludge and sodium alginate as a binder in water (S141), 1 to 3 g of sodium alginate is added to 100 ml of water and stirred at 60 to 70°C for at least 1 hour to prepare a sodium alginate solution. Then, 5 to 15 g of alum sludge is added to 100 ml of water to prepare an alum sludge solution, and then the alum sludge solution is added to the sodium alginate solution, and the mixture is stirred for 25 to 35 minutes.

In the step of stirring the pulverized alum sludge and the binders sodium alginate and polyvinyl alcohol in water (S145), 1-3 g of sodium alginate was added to 100 ml of water and stirred at 60-70°C for 1 hour or more. A sodium alginate solution was prepared, and 1-3 g of polyvinyl alcohol was added to 100 ml of water to prepare a polyvinyl alcohol solution, and then the sodium alginate solution and the polyvinyl alcohol solution were stirred for 15 to 25 minutes. Then, 5 to 15 g of alum sludge is added to 100 ml of water to make an alum sludge solution. Then, add the alum sludge solution to the mixed solution of sodium alginate solution and polyvinyl alcohol solution, and stir for 25 to 35 minutes. .

Thereafter, in step S150, the solution in which the alum sludge and the binder are stirred may be hardened to form granules. In detail, the solution in which Alum sludge and binder are stirred is inhaled using a syringe, etc., and then dropped into 0.1-0.5M (Mole) calcium chloride (CaCl _{2 ·} 2H ₂ O) solution drop by drop and immersed. Let it. Then, the solution in which the alum sludge and the binder are stirred is immersed in a calcium chloride (CaCl _{2 ·} 2H ₂ O) solution in the form of water droplets to be cured, and it is preferable to immerse for 36 to 48 hours to maintain an appropriate hardness. Then, a cured granular adsorbent is prepared.

Then, in step (S160), the cured granular adsorbent may be washed with distilled water, and in step (S170), the washed granular adsorbent may be dried at 24-26°C for 24 hours or more.

Thereafter, in step S180, the dried granular adsorbent may be heat treated. Applicants have found through experiments that the adsorption performance is improved when the adsorbent is heat-treated at a predetermined temperature. Through these experimental results, in step S180, the dried granular adsorbent may be heat-treated at 490-510°C for 2 to 4 hours.

It is preferable that the heat-treated granular adsorbent has a particle diameter of 0.3-1.5 mm. In order to prepare a heat-treated granular adsorbent with a particle diameter of 0.3-1.5 mm, the particle diameter of the solution in which alum sludge and a binder, which are immersed in calcium chloride (CaCl _{2 ·} 2H ₂ O) and hardened (S150), are stirred is 2-3 mm It is desirable. Then, the particle diameter of the cured granular adsorbent is approximately 2-3 mm, the particle diameter of the dried granular adsorbent is reduced to approximately 1-2 mm, and the particle diameter of the heat-treated granular adsorbent is reduced to approximately 0.3-1.5 mm. .

Experimental Example 1

The results of the Isotherm Experiment conducted with the adsorbent prepared by the manufacturing method according to the embodiment of the present invention will be described with reference to FIG. 3. 3A and 3B are graphs showing the Langmuir Adsorption Iisotherm and the Friedrich Adsorption Isotherm of the adsorbent.

) 용액으로 각각 12시간동안 실험을 진행하였다.In order to investigate the adsorption capacity of the adsorbent depending on the concentration of arsenic, arsenate containing 5, 10, 40, 80, 120, 200 and 300 mg of pentavalent arsenic in 1 L of water, respectively.

) The experiment was conducted for 12 hours each.

In addition, 0.1 g of an adsorbent according to an embodiment of the present invention in which the binder is sodium alginate and polyvinyl alcohol (hereinafter, referred to as "the adsorbent") was added to 30 ml of an arsenic solution for each concentration in which pentavalent arsenic was dissolved, and the 0.1 g of the first adsorbent (hereinafter referred to as "first application adsorbent") disclosed in Patent Application No. 10-2017-0147752 was added to 30 ml of the arsenic solution at each concentration in which pentavalent arsenic was dissolved, and the patent application No. 10 -0.1 g of the second adsorbent disclosed in 2017-0147752 (hereinafter, "second application adsorbent") was added to 30 ml of the arsenic solution at each concentration in which pentavalent arsenic was dissolved.

Then, each solution was stirred at 30 rpm with an overhead shaker at room temperature, and then the solution was analyzed using ICP-OES (Agilent 7200, USA).

As a result, as can be seen from Figures 3 (a) and (b) and Table 1, when judging the present adsorbent as a value of the correlation coefficient r ² , it was found to follow both Langmuir Isotherm and Freundlich Isotherm. Therefore, it can be seen that it can be used as an adsorbent.

In addition, the maximum adsorption capacity (q _max ) was the best in the second application adsorbent, and the present adsorbent was the lowest. However, from the numerical value of the maximum adsorption capacity of the present adsorbent, it can be seen that it can be used as an adsorbent since it can sufficiently perform its function as an adsorbent.

division
Langmuir Isotherm Freundlich Isotherm q _max (mg/g) k _L (L/mg) r ² k _F (mol/gxL) 1/n r ² First application adsorbent 18.49 0.03 0.94 2.54 0.35 0.99 2nd application adsorbent 21.20 0.03 0.94 3.31 0.33 0.99 This adsorbent 15.15 1.04 0.97 2.01 0.37 0.97

(q _max : maximum adsorption amount, k _L : Langmuir Isotherm constant,

k _F and n: Freundlich Isotherm constant, r ² : correlation coefficient)

The granular adsorbent prepared by the manufacturing method according to the embodiment of the present invention can be removed by adsorbing not only arsenic (As) ions, but also fluorine (F) ions and selenium (Se) ions. In addition, the results of the Isotherm Experiment for fluorine (F) ions and selenium (Se) ions were similar to those of the arsenic ions.

Experimental Example 2

A result of an experiment on the adsorption rate of the present adsorbent according to an embodiment of the present invention will be described with reference to FIG. 4. 4A and 4B show a Pseudo-first order kinetic model and a Pseudo-second order kinetic model of the present adsorbent according to an embodiment of the present invention. It is a graph.

) 용액 30ml에 상기 제1출원 흡착제,상기 제2출원 흡착제 및 상기 본 흡착제를 각각 0.1g을 넣은 다음, Overhead shaker를 이용하여 30rpm의 속도로 교반하였고, 상기 제1출원 흡착제, 상기 제2출원 흡착제 및 상기 본 흡착제를 용액으로부터 각각 분리하여 ICP-OES(Agilent 7200, USA)로 분석하였다.In order to investigate the adsorption rate of the adsorbent according to the contact time, arsenate containing 150 mg of pentavalent arsenic in 1 L of water

) 0.1 g of the first application adsorbent, the second application adsorbent, and the main adsorbent were added to 30 ml of solution, and then stirred at a speed of 30 rpm using an overhead shaker, and the first application adsorbent and the second application adsorbent And the present adsorbent was separated from the solution and analyzed by ICP-OES (Agilent 7200, USA).

division
Pseudo-first order Pseudo-second order q _e (mg/g) k ₁ (min ^-1 ) r ² q _e (mg/g) k ₂ [g/(mg·min)] r ² First application adsorbent 15.62 0.0011 0.99 26.39 0.00002 0.55 2nd application adsorbent 14.47 0.0023 0.96 17.48 0.00015 0.92 This adsorbent 9.43 0.0102 0.87 10.89 0.00123 0.99

(q _e : equilibrium adsorption amount, k ₁ and k ₂ : adsorption rate, r ² : correlation coefficient)

As a result, as can be seen from FIGS. 4A and 4B and Table 2, it can be seen that the adsorption rate of the present adsorbent is improved by at least 4 times compared to the first application adsorbent and the second application adsorbent. . Therefore, when applied in the field, the present adsorbent can be used in a relatively small amount and the contact time can be reduced.

Experimental Example 3

An experiment result performed by putting the present adsorbent according to an embodiment of the present invention into a column under conditions similar to that of an actual field will be described with reference to FIG. 5. 5A and 5B are graphs showing the results of a column experiment of the adsorbent according to an embodiment of the present invention.

) 용액를 상기 컬럼에 0.2ml/min의 유속으로 투입하였다.Experimental conditions are a column having a diameter of 1.5 cm and a length of 12 cm, each 2 g of the main adsorbent and Bayoxide E33, which is a ready-made adsorbent, are charged, and then 0.2 mg/L arsenate (

) The solution was added to the column at a flow rate of 0.2 ml/min.

As shown in (a) of FIG. 5, since the present adsorbent has an adsorption capacity similar to that of Bayoxide E33, it can be seen that it can be sufficiently used as an adsorbent for adsorbing arsenic.

And, as shown in (b) of FIG. 5, it is possible to confirm the breakthrough point of the bed volume (BV) exceeding 0.01mg/L (refer to the dotted line), which is the standard for drinking water of arsenic. At this time, Bayoxide E33 exceeded 0.01 mg/L at about 113 BV, but it can be seen that the present adsorbent exceeded 0.01 mg/L at about 200 BV. Therefore, it can be seen that the present adsorbent can be sufficiently used as an adsorbent for adsorbing arsenic, and can be used for a longer period of time than Bayoxide E33.

The results of Experimental Examples 2 and 3 of fluorine (F) ions and selenium (Se) ions of the present adsorbent were also almost similar to those of arsenic ions.

And, when the adsorbent according to the embodiment of the present invention prepared using sodium alginate as a binder was tested under the same conditions as in Experimental Examples 1 to 3, results were almost similar to the experimental results of the present adsorbent.

The method of manufacturing a granular adsorbent according to an embodiment of the present invention and the granular adsorbent prepared thereby form the adsorbent in a granular form. Then, even if the adsorbent is applied and used on the site, the adsorbent does not clump, so that the channeling of water can be prevented, and the flow path of the product in which the adsorbent is installed can be prevented from being blocked.

In addition, since the adsorbent is formed in the form of granules, it is possible to prevent the adsorbent from leaking out of the part of the product where the adsorbent is installed. Then, there is no need for an operation to treat the spilled adsorbent, which is convenient.

And, since the granular adsorbent according to the embodiment of the present invention is finally heat treated, the adsorption performance is further improved.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and that various substitutions, modifications, and changes are possible within the scope of the technical spirit of the present invention. It will be obvious to those who have the knowledge of. Therefore, the scope of the present invention is indicated by the claims to be described later, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

Claims (8)

In the adsorbent manufacturing method for adsorbing and removing at least one of arsenic (As) ions, fluorine (F) ions, and selenium (Se) ions,
(A) Remove impurities from Alum Sludge containing aluminum (Al), manganese (Mn) and iron (Fe), and remove the impurities from the Alum sludge at 100-115 °C for 23-25 hours Drying and then grinding;
(B) adding a binder to the alum sludge pulverized in (A) and stirring by adding water;
(C) hardening the solution stirred in (B) to form granules;
(D) drying the granules cured in (C) after washing;
(E) comprising the step of heat-treating the granules dried in (D),
Step (E) is a method for producing a granular adsorbent, characterized in that the heat treatment at 490-510 ℃ for 2-4 hours. delete The method of claim 1,
The binder is sodium alginate,
The (B) step,
1-3 g of sodium alginate was added to 100 ml of water and stirred at 60-70°C for 1 hour or more to prepare a sodium alginate solution,
After preparing an Alum sludge solution by adding 5-15 g of Alum sludge to 100 ml of water,
The method for producing a granular adsorbent, characterized in that the alum sludge solution is added to the sodium alginate solution and stirred for 25 to 35 minutes. The method of claim 1,
The binder is sodium alginate and polyvinyl alcohol,
The (B) step,
1-3 g of sodium alginate was added to 100 ml of water and stirred at 60-70°C for 1 hour or more to prepare a sodium alginate solution,
A polyvinyl alcohol solution was prepared by adding 1-3 g of polyvinyl alcohol to 100 ml of water,
The sodium alginate solution and the polyvinyl alcohol solution were stirred for 15-25 minutes,
5-15 g of Alum sludge was added to 100 ml of water to prepare an Alum sludge solution,
The method for producing a granular adsorbent, characterized in that the alum sludge solution is added to the mixed solution of the sodium alginate solution and the polyvinyl alcohol solution and stirred for 25 to 35 minutes. The method of claim 1,
The (C) step,
The method for producing a granular adsorbent, characterized in that the agitated solution is immersed in a 0.1-0.5M (Mole) calcium chloride (CaCl ₂ · 2H ₂ O) solution in the form of water droplets for 36-48 hours to cure. The method of claim 1,
The step (D),
The cured granules are washed with distilled water and dried at 24-26°C for 24 hours or more. The method of claim 1,
The method for producing a granular adsorbent, characterized in that the particle diameter of the granules heat-treated in step (E) is 0.3-1.5mm. A granular adsorbent prepared by the method according to any one of claims 1 and 3 to 7.

Images