KR20150066787A - Manufacturing method of Copper nano-zeolite and removing method of phenol using thereof - Google Patents

Abstract

The present invention relates to a method for manufacturing copper nano-zeolite, copper nano-zeolite manufactured by the same method and a method for removing phenol using the copper nano-zeolite. The present invention may manufacture the copper nano-zeolite by immersing nano-zeolite in a solution containing copper, and make the copper nano-zeolite have a large surface area and a large quantity of active portions, thereby increasing absorption efficiency of phenol to efficiently remove the phenol from an aqueous solution.

Description

[0001] The present invention relates to a process for preparing copper-nano-zeolite,

 The present invention relates to a process for producing copper-nano-zeolite, a process for removing phenol using copper-nano-zeolite and copper-nano-zeolite produced by this process.

Zeolite is a generic name of aluminosilicate and refers to natural and synthetic minerals having various physicochemical properties industrially useful because of the pore structure that is usually present inside the crystal. Zeolites can be broadly classified into natural zeolites and synthetic zeolites. Since the discovery of natural zeolites, synthetic zeolites were first studied by Besser et al. In 1938 and mass produced after 1945. As a result of many scholars' research, 46 kinds of natural zeolite and 200 kinds of synthetic zeolite are known. Although they are different in terms of crystal structure, chemical composition, and physicochemical properties, they have a common feature that they form a space large enough to allow molecules to easily enter into the structure depending on the surrounding conditions. Today, zeolite is used as a community name for natural and synthetic minerals with such crystal structure characteristics.

Zeolites are characterized by the way in which constituent atoms are bonded. The central atoms, silicon and aluminum, are coordinated in tetragonal form with four oxygen atoms. The central atom has four oxygen atoms and the TO unit, which is a double unit, is bonded while sharing an oxygen atom. There are many ways to combine and share corners so that various structures are possible. This is called a secondary bonding structure, and zeolite is a crystalline material formed by combining one or more types of secondary bonding structures while maintaining three-dimensional regularity. Since zeolite is a crystalline material, the crystal structure is not easily broken even when heated or exhausted. When the material is exhausted while heating, the material adsorbed in the pores is desorbed and the pores are emptied. In other words, zeolite has many fine pores and can be reversibly adsorbed and desorbed through heating and exhausting operations, and thus can be used repeatedly. Due to its excellent adsorption-desorption properties, many applications are being made in the separation process.

In addition, zeolite is a porous material with pores of uniform shape and size. The pores are very small, and the pores are developed throughout the crystal from the surface to the inside. Depending on the type of zeolite, the pore shape and the inlet size are different, but there are many pores in any zeolite. Molecules smaller than the pore openings can enter the pore and adsorb and react and can be used as adsorbents or catalysts. Since the shape and size of the pores are fixed and the substances that can be adsorbed are limited, the molecular sieve effect is exhibited. In addition, the substances that can be reacted or produced are also different. Since the skeletal center atom of zeolite is composed of silicon and aluminum, it exhibits the cation exchange property due to the charge difference of the skeleton. The charge of the entire TO unit is -1. Thus, zeolites contain alkali or alkaline earth metal ions that are positively charged to maintain neutrality. Cations can be converted to other cations depending on the surrounding conditions. This phenomenon is called cation exchange. Replacing Na ions in water with zeolite ions increases the ability of the detergent. The exchange of specific cations in zeolites changes the physicochemical properties of zeolites.

In addition, it has an acid / basic property due to the presence of aluminum atoms in the zeolite skeleton. The skeleton made only of silicon atoms is electrically neutral, but if the aluminum atoms are mixed, the positive charge is insufficient and the skeleton is negatively charged. In order to neutralize this, a cation must be present, which causes a positively charged site and a negatively charged site in the zeolite. Since the acid / basicity differs depending on the type of zeolite, the Si / Al molar ratio of the skeleton, and the kind and content of the cation, this property is controlled and used as a catalyst or an adsorbent.

Zeolite is a polar material, so it absorbs water well. Since zeolite is synthesized in the presence of water, it usually contains water. Water is not a constituent element of the zeolite skeleton, but it fills the pores and makes zeolite a hydrate. On the other hand, zeolite is a porous inorganic compound which is used as a carrier of catalysts and catalysts, and can exist not only in nature but also in a variety of structures by synthesis. Since the activity and selectivity as a catalyst can be controlled by various methods, Can be used in a separation process requiring a large amount of water.

1. Japanese Laid-Open Patent Application No. 2005-0125193 2. U.S. Published Patent 2006-0226078

Thus, the present inventors prepared copper-nano-zeolites by immersing the nano-zeolite in a solution containing copper. Due to the high surface area and large amount of active sites of the copper-nano-zeolite, the phenol molecules were effectively adsorbed on the zeolite surface, The present invention has been completed.

Accordingly, an object of the present invention is to provide a method for producing copper-nano-zeolite.

Another object of the present invention is to provide a copper-nano-zeolite produced by such a method and a method for removing phenol using the copper-nano-zeolite.

In order to accomplish the above object, the present invention provides a method for manufacturing a semiconductor device, comprising: preparing a reaction mixture by mixing an aluminum source, a silicon source and water; Heating the reaction mixture, centrifuging and washing to prepare a zeolite nano powder; And a step of immersing the zeolite nano powder in a solution containing copper to prepare a copper-nano-zeolite.

In one embodiment of the present invention, the aluminum source is selected from the group consisting of alumina, sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, sodium aluminate (NaAlO2), aluminum hydroxide boehmite, pseudoboehmite, aluminum alkoxide, , Aluminum hydrate, sodium aluminate (NaAlO ₂ ).

In one embodiment of the present invention, the silicon source is selected from the group consisting of silane _{(C 8 H 20 O 4 Si} ) on silica, sodium silicate, alkyl silicate, silicon oxide, silicon hydrate, tetraethylorthosilicate tetra Lt; / RTI >

In one embodiment of the present invention, the solution containing copper may be selected from the group consisting of copper nitrate, copper sulfate, copper chloride, and copper nitrate (Cu (NO ₃ ) ₂ ).

In one embodiment of the present invention, the step of preparing the zeolite nanopowder comprises heating the reaction mixture at a temperature of 150 to 200 ° C for 12 to 36 hours; Centrifuging the solid product and washing until the pH is 3 to 5; And drying at a temperature of 15 to 25 캜 for 6 to 24 hours to recover the nano-zeolite.

In one embodiment of the present invention, the copper-containing solution may have an initial concentration of 0.05 to 1M.

In one embodiment of the present invention, the pH of the solution containing copper may be 3 to 7.

In one embodiment of the present invention, the copper-nano zeolite may be immersed in the solution containing copper for 80 to 150 minutes.

In one embodiment of the present invention, the nano-zeolite may be selected from zeolite A, zeolite X or Y, ZSM-5, zeolite L, TS-1, TS-2 zeolite.

The present invention also provides a copper-nano zeolite produced according to the above method. In one embodiment of the present invention, the particle size of the copper-nano zeolite may be 60-150 nm.

The present invention also provides a method for removing phenol in an aqueous solution using copper-nano-zeolite produced according to the above method.

In one embodiment of the present invention, the copper-nano-zeolite may be used in an amount of 0.01 to 0.1 g.

According to the present invention, it is possible to prepare copper-nano-zeolite by immersing the nano-zeolite in a solution containing copper. The copper-nano-zeolite has a high surface area and a large amount of active sites to increase the adsorption efficiency of phenol, Phenol can be effectively removed.

FIG. 1 is a SEM image of a nano-zeolite according to an embodiment of the present invention.
2 shows an X-ray diffraction pattern of a nano-zeolite and a copper-nano-zeolite according to an embodiment of the present invention; (a) nanozeolite, (b) 0.1M Cu-NZ, (c) 0.3M Cu-NZ, (d) 0.5M Cu-NZ.
3 shows the specific surface areas of nano-zeolite and copper-nano-zeolite according to an embodiment of the present invention.
Figure 4 shows the pH effect of the solution on the adsorption of phenol of the nano-zeolite and the copper-nano-zeolite according to one embodiment of the present invention.
FIG. 5 shows the effect of adsorption reaction time on the adsorption of phenol of nano-zeolite and copper-nano-zeolite according to an embodiment of the present invention.
FIG. 6 shows adsorption reaction rates of nano-zeolite and copper-nano-zeolite according to an embodiment of the present invention; (b) the rate of reaction of the copper-nano-zeolite with the pseudo-first-order model of phenol adsorption, (c) the adsorption of phenol on the nano-zeolite by phenol adsorption (D) the reaction rate according to the pseudo-second-order model of phenol adsorption of copper-nano-zeolite.
FIG. 7 illustrates the effect of adsorbent amount on the adsorption of phenols of nano-zeolite and copper-nano-zeolite according to an embodiment of the present invention.
FIG. 8 shows the effect of initial concentration of phenol on the adsorption of phenol in nano-zeolite and copper-nano-zeolite according to an embodiment of the present invention.
FIG. 9 shows the results of adsorption isotherm analysis of phenol according to one embodiment of the present invention; (a) the Langmuir isotherm, (b) the Freundlich isotherm, and (c) the Temkin method.
FIG. 10 shows the removal mechanism of phenol according to one embodiment of the present invention.

The present invention relates to a process for producing copper-nano-zeolite, a process for removing phenol using copper-nano-zeolite and copper-nano-zeolite produced by this process.

According to the present invention, there is provided a method for producing copper-nano zeolite by immersing a nano-zeolite in a solution containing copper, and since the copper-nano zeolite thus produced has a high surface area and a large amount of active sites, The present invention provides a method for removing phenol using copper-nano-zeolite because it can be effectively adsorbed on the surface to easily remove phenol.

Zeolites are crystalline aluminosilicates and are generally microporous materials containing pores of 0.4-1.0 nm diameter. Zeolites have been widely used as catalysts and adsorbents in the petrochemical and fine chemical industries. The micropores of zeolite exhibit molecular selectivity that selectively diffuses molecules according to size and shape. Therefore, zeolite is also called molecular sieve, and this property can be used to design adsorption and catalytic materials that can selectively adsorb or convert molecules.

The microporous structure of zeolite is advantageous when molecular selectivity is used, but sometimes the diffusion of target molecules is impossible or too slow to act as a limit for adsorption and catalytic applications. In general, the diffusion of molecules in the porous material is closely related to the diameter of the pores. As the diameter of the pores becomes smaller, the diffusion of the molecules becomes slower. The micropore structure of zeolite generally exhibits very slow diffusion characteristics, and when used as a catalyst, only the shell of the crystal is used in the reaction and its efficiency is often inferior. In addition, the product produced through the reaction may be deposited in the pores with byproducts such as coke due to overreaction, thereby shortening the life of the zeolite catalyst. Therefore, if the degree of molecular diffusion in the zeolite crystal can be dramatically enhanced, a catalyst having good activity and excellent catalyst stability can be produced.

Accordingly, the method for producing copper-nano-zeolite of the present invention comprises: preparing a reaction mixture by mixing an aluminum source, a silicon source and water; Heating the reaction mixture, centrifuging and washing to prepare a zeolite nano powder; And immersing the zeolite nano powder in a solution containing copper to prepare a copper-nano-zeolite.

First, an aluminum source, a silicon source and water are mixed. At this time, the aluminum source and water are firstly mixed and aged at a temperature of 15 to 25 ° C. for 3 to 8 hours, and then a silicon source may be added and the reaction may be carried out at a temperature of 15 to 25 ° C. for 10 to 15 hours.

According to the invention, the source of aluminum is selected from the group consisting of alumina, sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, sodium aluminate (NaAlO2), aluminum hydroxide boehmite, pseudoboehmite, aluminum alkoxide, aluminum oxide, Sodium aluminate (NaAlO ₂ ), but the present invention is not limited thereto.

According to the present invention, the silicon source may be selected from the group consisting of silica, sodium silicate, alkyl silicate, silicon oxide, silicon hydrate, tetraethylorthosilicate tetraethoxysilane (C ₈ H ₂₀ O ₄ Si) But is not limited thereto.

Next, the reaction mixture formed by the reaction of aluminum source, silicon source and water is heated, centrifuged and washed to prepare a zeolite nano powder. More specifically, the reaction mixture is first heated at a temperature of 150 to 200 DEG C for 12 to 36 hours. Thereafter, the solid product is centrifuged, washed with deionized water several times until the pH becomes 3 to 5, and dried at a temperature of 15 to 25 ° C. for 6 to 24 hours to obtain a nano-zeolite.

The nano-zeolite may be selected from zeolite A, zeolite X or Y, ZSM-5, zeolite L, TS-1, TS-2 zeolite.

Next, the thus obtained nano zeolite powder can be immersed in a solution containing copper to prepare copper-nano zeolite. At this time, it is preferable to prepare copper-nano-zeolite by immersing the copper-nano-zeolite in the solution containing copper for 80 to 150 minutes.

According to the present invention, the solution containing copper may be selected from the group consisting of copper nitrate, copper sulfate, copper chloride, copper nitrate (Cu (NO ₃ ) ₂ ), but is not limited thereto.

The solution containing copper may have an initial concentration of 0.05 to 1 M, and the pH of the solution containing copper may be 3 to 7. Outside of the above range, the adsorption ability of phenol deteriorates, which is not preferable.

Meanwhile, the present invention provides copper-nano-zeolite produced according to the above-described method.

The particle size of the copper-nano-zeolite according to the present invention is preferably 60 to 150 nm.

The present invention also provides a method for removing phenol in an aqueous solution using copper-nano-zeolite produced according to the above-described method. The copper-nano-zeolite is preferably used in an amount of 0.01 to 0.1 g in order to effectively remove phenol.

As a result of evaluating the ability of copper-nano-zeolite to adsorb phenol from an aqueous solution in the present invention, the adsorption capacity of phenol also increased when the concentration of copper-containing solution for modifying nano-zeolite was increased.

Also, the process of adsorbing phenol from the aqueous solution is very rapid contact and equilibrium is reached within 3 hours. This is very rapid compared to other adsorbents used for the removal of phenol.

The main adsorption mechanism for phenol removal involves the phenol adsorption on the outer surface of the nano zeolite and the complexation between the Cu ^{2 +} ions and oxygen on phenolic molecules or phenolate anions. Therefore, the copper-nano zeolite according to the present invention based on a high adsorption capacity can be used as a good adsorbent which can replace expensive activated carbon for purifying contaminated phenol from wastewater.

Hereinafter, an embodiment of the present invention will be described in order to facilitate understanding of the present invention. It should be understood, however, that the following examples are for the purpose of promoting understanding of the present invention, but the present invention is not limited by the following examples.

< Example  1>

Synthesis of nano-zeolite

<1-1> Materials

Sodium aluminate salt (> 63% Al ₂ O ₃ ) was used as the aluminum source, and silica sol (Sigma-Aldrich) was used as the silicon source. Analytical grade sodium hydroxide, phenol and copper nitrate are available from Daejung Chemical and Metals Co. Lt; / RTI &gt;

<1-2> Synthesis of nano-zeolite template

0.35 g of NaOH and 0.147 g of sodium aluminate were mixed in water and aged at 200 DEG C for 5 hours. Next, 6.6 g of silica sol was added dropwise and the reaction mixture was stirred at room temperature for one day. Next, the homogeneous mixture was heated at 180 캜 for 24 hours under autogenously pressure. The solid product was centrifuged and washed with deionized water until a pH of 4 was reached.

<1-3> Synthesis of copper-nano zeolite

The nano zeolite crystals synthesized above were dried and then immersed in a Cu (NO ₃ ) ₂ solution to obtain a nano-zeolite solid doped with Cu ions. Cu ^{2 +} ions of different initial concentrations (0.1M, 0.3M, 0.5M) in order to obtain the nano zeolite loaded differently Cu (NO _{3) 2} three types of each of the different initial concentration of Cu (NO ₃ using ) ₂ -modified copper-nano-zeolite (0.1M Cu-NZ, 0.3M Cu-NZ 0.5M Cu-NZ)

< Example  2>

Characterization of nano-zeolite

<2-1> SEM analysis

The particle size and shape of the nano-zeolite crystals were analyzed by field emission scanning electron microscopy (FE-SEM, Hitachi / S-4800 model). An SEM image of the synthesized nano-zeolite (see FIG. 1) confirmed a spherical nanocrystal shape with an average particle size of 90 nm.

<2-2> XRD analysis

To confirm the crystallinity of nano-zeolite and copper-nano-zeolite, Cu kα radiation, voltage of 40 kV and current of 30 (mA) were analyzed using an X-ray diffractometer (ruker AXS, Germany Model D8 Advance). (2 [theta]) / min and 0.01 [theta] (2 [theta]) scan steps in the range of 5 [deg.] And 50 [

Fig. 2 shows an X-ray diffraction pattern of nano-zeolite before and after deformation into Cu (NO3) 2. The XRD pattern shows peaks in the range of 2? = 7 to 9 and 23 to 25, which is consistent with the specific peaks of the nano-zeolite (ZSM-5). From this analysis, it can be seen that the material prepared in the present invention is a typical zeolite ZSM-5 structure. The XRD pattern of Cu-ZSM-5 with different concentrations of Cu ^{2 +} ions shows strong peaks at 2θ = 35.6 ° and 38.9 °, which is consistent with the specific peak of Cu-loaded nano-zeolite . All Cu-ZSM-5 samples exhibit strong peaks at 2θ = 35.6 ° and 38.9 ° through impregnation, which is a result not seen in XRD patterns of pure nano-zeolite not modified with Cu.

<2-3> BET Surface analysis

The specific surface area (SBET) was measured using the Brunauer-Emmett-Teller (BET) method.

Surface area of nano-zeolite before and after deformation with Cu (NO ₃ ) ₂ Sample BET (m ² / g) Nano zeolite 691 0.1M copper-nano zeolite 724 0.3M copper-nano zeolite 795 0.5M copper-nano zeolite 860

As shown in Table 1 above, all nano zeolite samples were found to have a surface area of greater than 600 m ² / g, indicating that they have a well formed pore structure. The surface area of copper-nano-zeolite was larger than that of nano-zeolite. Especially, as the concentration of Cu (NO ₃ ) ₂ was increased, the surface area was further increased.

This phenomenon can be explained by a variety of causes, including the penetration of Cu ^{2 +} ions deposited into the pores of the sample due to the narrowing of the pore diameter as the surface area of the adsorbent increases and the blocking of some micropores have.

< Example  3>

Adsorption Characteristics of Nano-zeolite

<3-1> Adsorption experiment

Experiments to remove the phenol from aqueous solution were carried out in a 250 mL Erlenmeyer flask and stirred in a shaking water bath (HST-205SW at 120 rpm) at room temperature of 20 ± 1 ° C.

The pH was measured with a digital pH meter (Orion 5Star) and the concentration of phenol was measured with a UV spectrometer (UV-2550, Shimadzu) at? max 270.

&Lt; 3-2 > pH Influence of

To determine the effect of pH on the adsorption of nano-zeolite and copper-nano-zeolite, 0.1 M HNO ₃ or 0.1 M NaOH was used to adjust the pH of the test solution to 3.0-10. To determine the optimum pH, a solution of 200 mg / L of initial phenol concentration and 0.05 g of adsorbent was used.

The pH of the solution generally affects adsorption over a wide range, affecting the properties of both the adsorbent (nano-zeolite and copper-nano-zeolite in the present invention) and absorbent quality (phenol in the present invention).

4 shows the pH effect of the solution on the adsorption of phenols of nano-zeolite and copper-nano-zeolite. It can be confirmed that the pH of the solution plays an important role in the adsorption of phenol to the adsorbent. Adsorption of phenol by adsorbent gradually increased when the pH was increased to 5.5 and decreased when the pH was increased to 5.5 or higher. In addition, as the pH increased from 3.0 to 5.5, the absorption of phenol by nano-zeolite and 0.5M copper-nano-zeolite increased to 46.78 mg / g and 98.89 mg / g, respectively. However, as the pH increased above 5.5, the uptake decreased gradually.

These results can be explained by the concentration of H ⁺ ion, the concentration of OH ^- ion, the pK _{a of} phenol (pK _a = 9.5), and the pH of the adsorbent _pzc (zero charge point, pH _pzc = 6.3 ± 0.1).

In acidic solutions below pH 6.0, the adsorption of phenol has a partial positive charge. Hydrogen ions with high mobility in the acid pH range (pH 3.0 to 5.5) compete with phenol, which has a partial positive charge that can be adsorbed onto the adsorbed sites on nano-zeolites and copper-nano-zeolites. Therefore, as pH increases, the adsorption of phenol increases, indicating a decrease in positive charge such as H ₃ O ⁺ .

At a slightly acidic pH such as pH 5.5, it exhibits a lower H ₃ O + concentration in the slightly acidic range of pH 3.0 to 5.0. Completion of adsorption sites on nano-zeolite and copper-nano-zeolite between H ₃ O ⁺ and phenol with partial positive charge is less important. Thus, phenol shows a high adsorption capacity around pH 5.5.

The surface of the adsorbent does not charge near pH 6.3 ± 0.1 and begins to have a partial negative charge at pH 6.5.

The basic pH range near or below neutrality (pH 6.0-9.0) is not sufficient for the surface of the adsorbent with negative charge to absorb the phenol with partial negative charge. In addition, the coupling between the hydroxyl group of the basic solution and the Cu ion in the copper-nano zeolite may lead to a decrease in the adsorption capacity of the phenol.

Increasing the pH in a basic solution (pH 6.5 to 9.0) increases the concentration of hydroxyl anion, which leads to an increase in the concentration of phenol anion. Therefore, phenol adsorption can decrease with increasing pH. However, copper-nano-zeolite adsorbents have a higher positive adsorption of phenol because they have a positive charge in the molecule as compared to nano-zeolites.

In strong basic solutions whose pH is higher than pK _a (pK _a = 9.5), there are more phenol anions, which reduces phenol adsorption. The pH change of the solution at pH 5.5 ~ 10 showed that the adsorption capacity of copper - nano - zeolite decreased more than nano - zeolite. Also, the adsorption capacity decreased with increasing Cu concentration. This is due to the greater binding between the hydroxyl anions and Cu ions, which is increased in the copper-nano zeolite, which leads to a decrease in phenol adsorption as the pH of the solution increases.

<3-3> Effect of adsorption reaction time

 Adsorption experiments were carried out with varying contact times from 200 mL of a solution containing 200 mg / L phenol for 30 minutes to 300 minutes. The reaction time after the adsorption, the concentration of phenol remaining in the aqueous solution was analyzed by UV spectroscopy (UV-2550, from Shimadzu) at λmax 270.

The effect of reaction time was determined to determine the equilibrium time required for the adsorption of phenol on nano-zeolite and copper-nano-zeolite modified with different initial concentrations of Cu (NO ₃ ) ₂ . Also, as the initial concentration of Cu (NO ₃ ) ₂ used to change the adsorption characteristics of nano-zeolite increased from 0.1 to 0.5 M, the amount of phenol adsorption increased at the same reaction time (see FIG. 5). Also, the amount of phenol adsorbed was higher than that of nano - zeolite (nano - zeolite modified with Cu (NO ₃ ) ₂ ).

Kinetic experiments clearly show that the adsorption of phenol to nano-zeolite and copper-nano-zeolite occurs following three steps. The initial adsorption site can be used further, and the phenol stunning rate is higher at the beginning of the experiment (30-100 min), since phenol ions are more easily adsorbed to these sites.

The second stage (100-150 min) where additional adsorption appears contributes to the diffusion of adsorbate from the surface through the pores of the adsorbent, and the adsorption capacity of the phenol gradually increases. It has been reported that it is difficult to occupy the remaining free surface area due to the repulsion between the phenol molecules adsorbed on the surface and the bulk phase. As a result, the adsorption rate decreases. The last step is the equilibrium step, the adsorption leads to equilibrium, and the phenol accumulates on the surface of zeolite and copper-nano zeolite within 2.5 hours. During this time, the amount of phenol adsorbed is shown as 76, 118, 139 and 160 mg / g of nano zeolite, 0.1M copper-nano zeolite, 0.3M copper-nano zeolite and 0.5M copper-nano zeolite, respectively.

<3-4> Study of adsorption reaction rate

Adsorption kinetics are the most important data for understanding the adsorption mechanism and for evaluating the performance of the adsorbent. Different reaction rate models including pseudo-first-order and pseudo-second-order models were applied to the experiments to predict adsorption kinetics. The constants of the reaction rate model for the adsorption of nano-zeolite and copper-nano-zeolite are shown in Table 2 below.

Reaction rate parameter for adsorption of nano-zeolite and copper-nano-zeolite Pseudo-first-order parameters absorbent q _e (mg / g) (exp) q _e cal (mg / g) R ² K ₁ Nano zeolite 20 8.78 0.879 1.84 x 10 ^-2 0.1M copper-nano zeolite 20 10.53 0.808 2.46 x 10 ^-2 0.3M copper-nano zeolite 20 13.35 0.826 1.79 x 10 ^-2 0.5M copper-nano zeolite 20 18.174 0.799 2.0 x 10 ^-2 Pseudo-second-order parameters absorbent q _e (mg / g) (exp) q _e cal (mg / g) R ² K ₁ Nano zeolite 20 20.14 0.999 1.63 × 10 ^-3 0.1M copper-nano zeolite 20 20.32 0.998 2.48 x 10 ^-3 0.3M copper-nano zeolite 20 20.48 0.979 1.44 x 10 ^-3 0.5M copper-nano zeolite 20 20.57 0.996 2.15 x 10 ^-3

The pseudo-second-order equation from FIG. 6 (a, b, c and d) provides the best correlation coefficient and the correspondence between the calculated q _e values and the experimental data, while the pseudo-first- Can not show the agreement of the experimental data with the test results.

<3-5> Effect of adsorbent amount

The effect of adsorbent amount on removal of phenol was confirmed. As shown in Fig. 7, when the amount of the adsorbent was increased from 0.01 to 0.2 g in 200 mL of 200 mg / L phenol solution under pH 5.5 at 20 rpm at 150 rpm for 3 hours, the binding capacity of the phenol by the adsorbent was 20.2 To 196.2 mg / g. The effect on adsorption was negligible when the amount was further increased. If the amount of adsorbent is very high, more adsorption sites can be used for adsorption of more phenol. However, some adsorption sites can be blocked in a very large amount of adsorbent. Therefore, in order to further increase the adsorption efficiency of phenol in the solution, the amount of adsorbed phenol to the unit weight of the adsorbent should be reduced.

<3-5> Influence of initial concentration of phenol

In order to confirm the effect of the initial concentration of phenol, batch experiments were carried out at various initial concentrations of phenol (10-300 mg / L) under 0.1 g of adsorbent and 100 min of reaction time. The equilibrium phenol capacity was calculated by the following equation (1).

Equation _{(1): q e (mgg} -1) = C o -C e (mgL -1) × V (L) / W (g)

Wherein, q _e is the absorption of phenol for the adsorbent (mg g ^-1), C _o is the initial concentration of the phenol (mg L ^-1), C _e is the equilibrium phenol concentrations (mg L ^-1) in the solution, V Is the volume of solution used (L), and W is the amount of adsorbent used.

The removal efficiency (R _e %) of the phenol by the adsorbent in the aqueous solution was calculated by the following equation (2).

(2): R _e % = [(C _o -C _e ) / C _o ] × 100

FIG. 8 shows the adsorption capacity of phenol according to the initial concentration of phenol in the range of 10 to 300 mg / L under optimum pH concentration at 20 DEG C for 0.05 g of nano-zeolite and copper-nano zeolite. The concentration of phenol reaches saturation at 200 mg / L. When the initial concentration of phenol is low, more surface area or adsorption sites can remove the phenol, so the phenol is easily adsorbed and removed. When the initial concentration of phenol is high (200 mg / L or more), the adsorption capacity of phenol is slightly improved and the adsorption capacity of phenol is almost constant. These results indicate that the majority of the adsorbed sites available in the adsorbent are mostly adsorbed by phenol. This phenomenon is due to the increase in saturated adsorption sites above a certain concentration of phenol. An increase in the ratio of phenol / adsorbent causes adsorption saturation of the binding site at the adsorbent surface, which is because the adsorption efficiency of phenol ion per unit adsorbent is decreased. The peak equilibrium adsorption capacity values of phenol were 125, 151, 188 and 217 mg when the initial concentration of phenol was 300 mg / L in nano-zeolite, 0.1 M copper-nano zeolite, 0.3 M copper-nano zeolite and 0.5 M copper- / g.

To explain how the adsorbent and solute interact, it is essential to identify the adsorption isotherm of the phenol to the adsorbent. In particular, it is important to determine the optimal amount of adsorbent to effectively remove phenol from the aqueous solution.

<3-6> Adsorption isotherm of phenol ( isotherm ) analysis

Isotherm analysis was performed using different concentrations of phenol (10-300 mg / L) at room temperature. To simulate adsorption isotherms, Langmuir and Freundlich isotherms, which are commonly used models, were used.

Adsorption equilibrium isotherm analysis is an important step to investigate the adsorption process. After equilibrium is reached due to adsorption isotherm, the relationship between adsorbent and adsorption amount in solution can be confirmed. In the present invention, a linear method was used to determine the Langmuir isothermal parameters and the Freundlich and Temkin methods were used to better understand the interaction between the nano-zeolite, copper-nano zeolite and phenol. Nano-zeolite, 0.1M copper nano-zeolite, 0.3M copper nano-zeolite and 0.5M copper nano-zeolite has a very high correlation coefficient (R ^2), respectively 0.996, 0.999, 0.998 and 0.997, C _e to C _e / q _{e The} Langmuir constants q _max obtained from the linear equations are shown at 125, 151.5, 188.67, and 217 mg / g, respectively (see FIG. 9 (a)). Their very high correlation coefficients fit well with the single layer Langmuir model for phenolic adsorption of two adsorbents.

The Freundlich constant values K _f and 1 / n can be obtained from the linear curve of lnq _e for lnC _e (see Figures 9 (b) and 9 (c)). The Freundlich constant 1 / n is small (0.31 to 0.58), indicating that it is advantageous in the adsorption process under study conditions.

  Comparison of Langmuir, Freundlich and Temkin constants for phenol adsorption of nano-zeolites absorbent Langmuir isotherm Freundlich isotherm Temkin isotherm Q _max
(mg / g) b R ² Q _max
(mg / g) b R ² Q _max
(mg / g) b R ² 0.5M Cu-NZ 217 7.486 0.997 0.3467 38.3 0.915 38.16 0.76 0.941 0.3M Cu-NZ 188.67 25.54 0.998 0.4817 14.91 0.922 36.02 0.53 0.918 0.1M Cu-NZ 151.51 45.45 0.999 0.5544 7.22 0.936 30.35 0.28 0.929 Nano zeolite 125 59.68 0.996 0.5885 4.605 0.942 25.24 0.21 0.938

As can be seen from Table 3, the correlation coefficient (R ² ) was 0.942, 0.936, 0.922 and 0.915 for nano-zeolite, 0.1M copper-nano zeolite, 0.3M copper-nano zeolite and 0.5M copper- . Therefore, the Freudlich model is inconsistent with the Langmuir model as well as phenol data for nano-zeolites and copper-nano-zeolites. However, the interaction of different adsorbents on the adsorbent was not considered in the Langmuir and Freudlich isotherms. Temkin motel takes into account the effect of adsorption interactions on the adsorbent. The determination coefficient of the Temkin isothermal equation (R ² = 0.91 to 0.94) is smaller than the Langmuir value. Thus, phenol absorption using nano-zeolites and copper-nano-zeolites does not closely follow the Temkin isotherm.

Table 4 summarizes the adsorption amounts of different types of adsorbents for phenol removal. This shows that nano-zeolite and copper-nano-zeolite have a large adsorption capacity of phenol.

Comparing adsorption amount of phenol by adsorbent type absorbent Isothermic Adsorption amount (mg / g) Example Nano zeolite Langmuir 125 0.5M copper-nano zeolite Langmuir 217 0.3M copper-nano zeolite Langmuir 188.67 0.1M copper-nano zeolite Langmuir 151.51 Comparative Example Natural zeolite Langmuir 34.5 Activated carbon fiber Langmuir 262 League Night Langmuir 10 Activated carbon Langmuir 49.72 Granular activated carbon Langmuir 165.80 Hydroxyapatite nano powder Langmuir 10.33 Bentonite Langmuir 1.712

< Example  4>

Nano-zeolite and copper - removing phenol from aqueous solution of nano-zeolite Mechanism

The adsorption mechanism for phenol removal depends on the physical and chemical properties of the adsorbents (nano-zeolite, copper-nano-zeolite) and absorbent quality (phenol). Factors influencing the interaction between phenol and adsorbent are the solubility of phenol in water, the repulsion between phenol anion and negatively charged zeolite, and the complex between the hydroxyl group of phenol and Cu ^{2 + on the} surface of nano-zeolite.

Particularly, the adsorption process for removing phenol from an aqueous solution is very important. They can be classified by various criteria and can be divided into the following mechanisms.

1) Phenol adsorption on the outer surface of nano-zeolite

2) Formation of complex between Cu ^{2 +} ion and oxygen in the phenol molecule or phenolate anion shown in FIG. 10

Nano-zeolites and copper-nano-zeolites are adsorbents having a high surface area, a large number of pores and active sites, and phenol molecules are easily adsorbed on the outer surface of the zeolite and into the pores of the adsorbent. These factors can explain the increase in adsorption capacity (qmax) in the Langmuir equation. Reaction rate studies suggest phenol adsorption on nano-zeolites and copper-nano-zeolites with physical and chemical adsorption. The reaction mechanism may be partly a result of complexation between Cu ^{2 +} ions and oxygen in phenol molecules or phenolate anions. This type of compounding can take place from the oxygen on the phenol or phenolate anion through charge transfer to the vacant d-orbital of the copper ion on the surface of the nano-zeolite.

In a complexing process, the electrostatic interactions between phenol (or phenolate anions) and copper ions are strongly affected by the pH of the solution.

Of all the nanosized zeolites modified with Cu (NO ₃ ) ₂ tested with an adsorbent, 0.5M copper-nano zeolite shows a very high affinity for phenol adsorbents. This is because more complexation between copper ion and phenol occurs, which increases the phenol adsorption capacity.

However, an increase in the concentration of Cu ^{2 +} ions on the adsorbent surface increases the positive charge density and increases the oxygen binding capacity of the phenol due to the significant adsorption capacity generation of phenol.

The present invention has been described with reference to the preferred embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.

Claims (13)

Mixing an aluminum source, a silicon source and water to produce a reaction mixture;
Heating the reaction mixture, centrifuging and washing to prepare a zeolite nano powder; And
And dipping said zeolite nano powder in a solution containing copper to produce copper-nano-zeolite. The method according to claim 1,
The aluminum source can be selected from the group consisting of alumina, sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, sodium aluminate (NaAlO2), aluminum aluminum boehmite, pseudoboehmite, aluminum alkoxide, aluminum oxide, aluminum hydrate, sodium aluminate ₂ ). The method for producing copper-nano zeolite according to claim 1, The method according to claim 1,
The silicon source is silica, sodium silicate, alkyl silicate, silicon oxide, silicon hydrate or tetraethylorthosilicate tetrahydro copper, characterized in that is selected from the group consisting of silane _{(C 8 H 20 O 4 Si} ) on-the nano zeolite How to make The method according to claim 1,
Wherein the copper-containing solution is selected from the group consisting of copper nitrate, copper sulfate, copper chloride, copper nitrate (Cu (NO ₃ ) ₂ ). The method according to claim 1,
Wherein the step of preparing the zeolite nanopowder comprises:
Heating the reaction mixture at a temperature of 150 to 200 DEG C for 12 to 36 hours;
Centrifuging the solid product and washing until the pH is 3 to 5; And
And drying at a temperature of 15 to 25 ° C for 6 to 24 hours to recover the nano-zeolite. The method according to claim 1,
Wherein the copper-containing solution has an initial concentration of 0.05 to 1 M. 2. The copper-nano-zeolite according to claim 1, The method according to claim 1,
Wherein the copper-containing solution has a pH of 3 to 7. The method according to claim 1,
Wherein the copper-nano-zeolite is immersed in the solution containing copper for 80 to 150 minutes. The method according to claim 1,
Wherein the nano-zeolite is selected from zeolite A, zeolite X or Y, ZSM-5, zeolite L, TS-1, TS-2 zeolite. A copper-nano zeolite produced according to the method of any one of claims 1 to 9. 11. The method of claim 10,
Wherein the copper-nano-zeolite has a particle size of 60 to 150 nm. A process for removing phenol in an aqueous solution using copper-nano-zeolite prepared according to the process of any one of claims 1 to 9. 13. The method of claim 12,
Wherein the copper-nano-zeolite is used in an amount of 0.01 to 0.1 g.

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