KR20170043952A

KR20170043952A - Titanium dioxide supported with carbon and nitrogen, preparation method thereof and photocatalyst using the same

Info

Publication number: KR20170043952A
Application number: KR1020150143674A
Authority: KR
Inventors: 이병규; 웬레민띠
Original assignee: 울산대학교 산학협력단
Priority date: 2015-10-14
Filing date: 2015-10-14
Publication date: 2017-04-24
Also published as: KR101817837B1

Abstract

The present invention relates to carbon dioxide and nitrogen-doped titanium dioxide, a method for producing the same, and a photocatalyst using the same. The titanium dioxide according to the present invention is doped with carbon and nitrogen at the same time and contains titanium dioxide in the form of anatase and titanate crystal so that the difference in the band gap energy is reduced to exhibit excellent photocatalytic activity even when irradiated with visible light and have a characteristic of porosity Carbon and nitrogen-doped titanium dioxide excellent in adsorptivity, a method for producing the same, and a photocatalyst using the same.

Description

TECHNICAL FIELD The present invention relates to carbon dioxide and nitrogen-doped titanium dioxide, a method for producing the same, and a photocatalyst using the same,

The present invention relates to carbon dioxide and nitrogen-doped titanium dioxide, a method for producing the same, and a photocatalyst using the same.

Photocatalyst superoxide anion (· O ₂ ^-) has a strong oxidizing power by absorbing light (光) generates a and hydroxyl radicals (· OH), these materials to decompose the oxidation of organic substances with water (H ₂ 0) and carbon dioxide Change it to gas (CO2) and decompose pollutants.

TiO ₂ (anatase), TiO ₂ (rutile), ZnO, CDS, ZRO ₂ , SNO ₂ , and V ₂ O ₂ can be used as the photocatalyst. WO ₃ and the like, and perovskite-type composite metal oxide (SRTIO ₃ ). However, the substances that can be used for the photocatalytic reaction of the substance must first be optically active and free from photocatalytic reaction. It must also be biologically and chemically inert and should not only be able to utilize light in the visible or ultraviolet region, but also economically.

In general, anatase crystal titanium dioxide is widely used as a photocatalyst. However, in the case of titanium dioxide crystal of anatase type, the band gap energy is relatively large, so that there is a disadvantage in that the photoactive efficiency is lowered when visible light is irradiated. Accordingly, in the present invention, titanium dioxide containing a titanate crystal type having a relatively smaller band gap energy than that of an anatase crystal type is prepared, and the photoactive efficiency is enhanced when the visible light is irradiated.

Korean Patent No. 10-0620076, Korean Patent Publication No. 2010-0025421.

The present invention is to provide carbon dioxide and nitrogen-doped titanium dioxide that exhibits excellent photocatalytic activity even when irradiated with visible light and has a porous property and excellent in adsorptivity, a method for producing the same, and a photocatalyst using the same.

According to the present invention,

Titanium dioxide in crystalline form in anatase and titanate; And

And carbon and nitrogen-doped titanium dioxide doped with titanium dioxide and comprising a dopant comprising a carbon element and a nitrogen element.

Further, according to the present invention,

Titanium precursor; And a chelate compound containing a carbon element and a nitrogen element to prepare a mixed solution; And

And a step of subjecting the mixed solution to a heat treatment, thereby producing a titanium dioxide doped with carbon and nitrogen.

Further, the present invention provides a photocatalyst comprising carbon and nitrogen-doped titanium dioxide according to the present invention.

The titanium dioxide according to the present invention is doped with carbon and nitrogen at the same time and contains titanium dioxide in the form of anatase and titanate crystal so that the difference in the band gap energy is reduced to exhibit excellent photocatalytic activity in the visible light region as well as a characteristic of porosity It is also excellent in adsorption and can be used as an adsorbent.

1 is an image showing a method for producing titanium dioxide according to the present invention.
2 is a graph showing the results of X-ray diffraction for each type of titanium dioxide.
FIG. 3 is a graph showing X-ray photoelectron spectroscopy (XPS) according to the type of the photocatalyst: (a) shows the binding energy for Ti2p, (b) shows the binding energy for O1s, (D) is the graph showing the binding energy for N1s.
FIG. 4 is a graph showing Fourier transform infrared absorption spectroscopy (FT-IR) for each type of titanium dioxide.
5 is a graph showing the UV-Vis spectra according to the types of titanium dioxide.
FIG. 6 is a graph showing the average pore volume and the adsorption amount of organic compounds measured for each type of titanium dioxide: (a) and (b) show the adsorption amounts of organic compounds according to the relative pressures of Example 1 and Comparative Example 1 (C) and (d) are graphs showing the average volume of pores according to the average diameters of the pores of Example 1 and Comparative Example 1, respectively.
7 is a graph showing a removal rate according to the number of times of repetition of reproduction in the first embodiment.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

In the present invention, the terms "comprising" or "having ", and the like, specify that the presence of a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Hereinafter, the present invention will be described in detail.

The present invention, in one embodiment,

Titanium dioxide in crystalline form in anatase and titanate; And

At this time, the chelate compound may be ethylenediamine or ethylenediaminetetraacetic acid (EDTA). Specifically, C ₁₀ H ₁₄ N ₂ Na ₂ O ₈ .2H ₂ O (ethylenediaminetetraacetic acid disodium salt dihydrate) in the form of a sol may be used.

By having the above-mentioned contents including carbon and nitrogen-doped titanium dioxide according to the present invention and titanium dioxide showing catalytic activity when irradiated with light, it has excellent photocatalytic activity even when irradiating visible light with low energy as compared with ultraviolet rays .

For example, i) the pure titanium dioxide, ii) the carbon and nitrogen-doped titanium dioxide according to the present invention was evaluated for the degree of absorption for light in the region of 200 to 800 nm. As a result, At a wavelength of 350 nm or less, the optical absorption intensity is about 80% or more, and as the wavelength is increased, the optical absorption intensity is decreased. The degree of decrease is about 15 ± 0.5 au for pure titanium dioxide at a wavelength of 500 nm or more Or less and an average light absorption intensity of about 20 +/- 0.5 au for nickel-doped titanium dioxide. On the other hand, the carbon and nitrogen-doped titanium dioxide according to the present invention has a surface roughness of at least about 25. + -. 0.5 au, specifically at least 26. + -. 0.5 au at a wavelength of at least 500 nm; 27 ± 0.5 au or more; Or an average light absorption intensity of 28 +/- 0.5 au or more. This indicates that the titanium dioxide according to the present invention is doped with carbon and nitrogen at the same time to combine with each other, so that the excited photon energy is reduced, and the electrons easily perform 'charge transition'.

The carbon and nitrogen doped titanium dioxide according to the present invention can have a band gap of 2.60 to 3.00 eV in the wavelength range of 400 nm to 800 nm, specifically 2.60 to 2.95 eV, 2.65 to 2.95 eV or 2.65 to 2.92 eV. The light reaction by titanium dioxide excites electrons from the valence band to the conduction band to form electrons in the conduction band and to form holes in the valence band. Here, the formed electrons and holes are diffused to the surface of titanium dioxide and participate in the oxidation-reduction reaction to decompose contaminants remaining in the water. In the titanium dioxide of the present invention, the gap between the valence band and the conduction band, It is possible to perform a photoreaction with high efficiency even in visible light.

On the other hand, the carbon dioxide and nitrogen-doped titanium dioxide according to the present invention can have a high surface area including pores. The carbon dioxide and nitrogen-doped titanium dioxide may include pores, and accordingly, organic matter, contaminants, and dyes remaining in the water may be adsorbed on the surface thereof under a condition that the surface has a high surface area and no light is irradiated.

At this time, the particle size of the carbon and nitrogen-doped titanium dioxide according to the present invention may be 10 to 50 μm, specifically 10 to 40 μm, 10 to 30 μm or 15 to 30 μm.

Also, the pore size of carbon and nitrogen doped titanium dioxide is 15 to 25 nm, specifically 17.5 to 25 nm; Or 17.5 to 22.5 nm, wherein the pore volume is 0.2 to 0.35 cm < ³ > / g; 0.2 to 0.3 cm < ³ > / g; Or 0.25 to 0.3 cm < ³ > / g. In addition, the average BET specific surface area of the carbon and nitrogen-doped titanium dioxide can be 80 to 120 m ² / g, specifically 80 to 110 m ² / g; 85 to 110 m < ² > / g; 90 to 110 m < ² > / g; 90 to 105 m < ² > / g; Or from 90 to 100 m < ² > / g.

The carbon dioxide and nitrogen-doped titanium dioxide according to the present invention can be regenerated by heating at a high temperature of 400 DEG C or more for 180 minutes or more. Specifically, the heating temperature may be 380 ° C or higher, 420 ° C or higher, 430 ° C or higher, 450 ° C or higher, 470 ° C or higher and 500 ° C or higher. , 200 minutes or more, 210 minutes or more, and 240 minutes or more. The heating is carried out at a heating rate of 6 ° C / minute, specifically at a rate of 5 ° C / minute, at a rate of 7 ° C / minute, at a rate of 9 ° C / minute, at a rate of 10 ° C / .

In addition, the carbon dioxide and nitrogen-doped titanium dioxide according to the present invention satisfy the condition represented by the following general formula (1).

[Formula 1]

X / Y? 0.1

Here, X is the concentration of methylene blue in the solution irradiated with light in the wavelength range of 400 nm to 800 nm by adding titanium dioxide for 1 hour, and Y is the concentration of methylene blue in the solution not irradiated with light .

Specifically, the X / Y value may be 0.098 or less, 0.095 or less, 0.092 or less, 0.090 or less, 0.088 or less, 0.085 or less, 0.082 or less, 0.080 or less and 0.078 or less.

In addition, the present invention, in one embodiment,

In the step of preparing the mixed solution, a dispersion in which a chelate containing a carbon element and a nitrogen element are dispersed and a titanium precursor are dispersed is mixed and aged in a dark place for 24 hours or longer to form a gel- Titanium dioxide (N-TiO ₂ -C) can be obtained. In addition, the pH of the mixed solution may be 8.5 or less. Specifically, the pH of the mixed solution may be 5 to 7.5, 5.5 to 7.3, 6.0 to 7.2, 7 to 8.5, 7.2 to 8.2, 7.4 to 7.9, or 7.2 to 7.9. Unlike the conventional synthesis methods in which an alkali reagent is added to make an alkali atmosphere, since the present invention uses EDTA (ethylenediaminetetraacetic acid), there is no need to additionally add an alkali reagent, which is economical.

At this time, the titanium precursor is not particularly limited as long as it is reduced to form titanium dioxide (TiO ₂ ). For example, the titanium precursor may be titanium isopropoxide, titanium alkoxide, titanium tetrachloride (TiCl ₄ ), or the like.

The step of subjecting the mixed solution to heat treatment is a step of heat-treating the carbon and nitrogen-doped titanium dioxide (N-TiO ₂ -C), and the heat treatment is performed at a temperature of 300 ° C to 500 ° C for 200 to 400 minutes . Specifically, the heat treatment temperature is from 350 ° C to 500 ° C; 350 DEG C to 450 DEG C; Or 375 < 0 > C to 425 < 0 > C. The heat treatment time is 200 to 380 minutes; 220 to 360 minutes; 240 to 360 minutes; Or from 260 to 320 minutes.

The present invention provides a photocatalyst comprising carbon and nitrogen doped titanium dioxide according to the present invention.

The present invention also provides a water treatment method characterized by removing organic compounds contained in water by using the photocatalyst.

The water treatment method is carried out by adsorbing an organic compound on a photocatalyst, and the photocatalyst on which an organic compound is adsorbed can be regenerated through a regeneration process of a photocatalyst heated to a temperature of 400 ° C or higher.

A photocatalyst containing titanium dioxide and carbon and nitrogen doped with nitrogen according to the present invention is contacted with an aqueous solution containing an organic compound to adsorb the organic compound contained in water and irradiate ultraviolet rays and / or visible rays having a wavelength of 200 to 800 nm The organic compound remaining in the aqueous solution can be removed with high efficiency.

At this time, in order to maximize the adsorption rate of the organic compound contained in the water and the photocatalyst, the pH of the aqueous solution containing the organic compound may be 8 to 12, and the concentration of the organic compound contained in the aqueous solution may be adjusted per 1 L of the aqueous solution containing the organic compound 200 mg or less. Specifically, the pH of the aqueous solution is 9 to 11; 9 to 10.75; 9.25 to 11; 9.25 to 10.75; 9 to 10.5; Or 9.5 to 10.5, and the concentration of the organic compound is 150 mg or less per liter of the aqueous solution containing the organic compound; 140 mg or less; 130 mg or less; Or 115 mg or less.

The contact amount of the photocatalyst in contact with the organic compound in the aqueous solution may be 1 g or less per 1 L of the aqueous solution containing the organic compound, more specifically 0.9 g or less per 1 L of the aqueous solution containing the organic compound; 0.8 g or less; 0.7 g or less; Or 0.6 g or less. The water treatment method according to the present invention can prevent the photodegradation rate from being lowered due to the shielding effect caused by excessive titanium dioxide by controlling the contact amount of the photocatalyst in contact with the organic compound remaining in the aqueous solution within the above range have.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.

However, the following Examples and Experimental Examples are merely illustrative of the present invention, and the present invention is not limited to the following Examples and Experimental Examples.

Example 1.

First, deionized water and acetic acid were added to EDTA (ethylenediaminetetraacetic acid), and a mixture of titanium isopropoxide precursor and isopropanol at a ratio of 1: 2 was added dropwise at 4 ° C. and stirred for 3 hours. The mixed solution was aged in the dark for 24 hours. The aged mixed solution was dried in vacuum at 70 DEG C for 1 hour. Thereafter, calcination was performed at 400 ° C for 5 hours, and then the titanium dioxide was doped with carbon and nitrogen.

Comparative Example 1

Pure titanium dioxide was obtained and prepared.

Comparative Example 2

A P25 product from Degussa was obtained and prepared.

Experimental Example 1

X-ray diffraction (XRD) of the titanium dioxide prepared in Example 1 and Comparative Example 1 was measured in order to confirm the morphology, component content and the like of the carbon and nitrogen-doped titanium dioxide according to the present invention The measured results are shown in FIG.

Referring to FIG. 2, the titanium dioxide obtained in Example 1 has no distinct peak, and the titanium dioxide obtained in Comparative Example 1 has a clear peak on the anatase. From these results, it can be seen that the titanium dioxide according to the present invention has an amorphous structure because it has both an anatase and a titanate phase.

Experimental Example 2

The titanium dioxide prepared in Example 1 and Comparative Examples 1 and 2 was subjected to X-ray photoelectron spectroscopy (X-ray photoelectron spectroscopy) in order to confirm the binding properties between the components constituting the titanium dioxide doped with carbon and nitrogen according to the present invention. Photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR) were measured. The results are shown in FIG. 3 and FIG.

3 (a) and 3 (b), the titanium dioxide prepared in Example 1 exhibits the binding energies of Ti2p and O1s, which can confirm the respective bonding properties of the titanium element and the oxygen element, Which is lower than that of titanium dioxide. This means that the titanium element of the titanium dioxide of Example 1 chemically bonds to carbon to reduce the binding energy between the titanium element and the oxygen element relatively.

Also, referring to FIG. 3 (b), in the case of the titanium dioxide prepared in Example 1, the presence of Ti-O-Ti and C═O bonds at binding energies of about 529.8 ± 0.5 eV and about 531.2 ± 0.5 eV Can be confirmed. It can also be seen that Ti-O-N and Ti-N-O bonds are present at binding energies of about 532.0 ± 0.5 eV and about 533.6 ± 0.5 eV. That is, it indicates that the titanium dioxide prepared in Example 1 chemically bonds with carbon and nitrogen.

3 (c), the titanium dioxide produced in Example 1 had CO and C = 0 (or CO-Ti) bonds at bond energies of about 286.4 ± 0.5 eV and about 288.6 ± 0.5 eV . That is, it can be seen that the titanium element and the oxygen element in the titanium dioxide of Example 1 are bonded to the carbon component produced by the calcination of EDTA.

3 (d), the binding of N1s at a binding energy of about 393.1 ± 0.5 eV, the binding of Ti2p at a binding energy of 458.2 ± 0.5 eV, the binding of O1s at a binding energy of 530.1 ± 0.5 eV , Binding of C1s at binding energies of 285.1 ± 0.5 eV can be confirmed. It can be seen from this graph that the titanium dioxide of Example 1 is bound to a titanium element, a nitrogen element, an oxygen element, and a carbon element.

In addition, Fig. 4 (a) Referring to Comparative Example 1 of the titanium dioxide is about 3414 ± 10 cm ^- the vibration peak appeared in about ¹ and 1629 ± 10 cm ^-1. It can be seen that the titanium dioxide is bound to the water molecule, and at about 473 5 cm ^-1 The broad peaks shown indicate the presence of a bond between titanium and oxygen (Ti-O-Ti).

Further, in the case of titanium dioxide of Example 1, peaks were confirmed at about 1061 10 cm ^-1 , about 1347 10 cm ^-1 , about 1449 10 cm ^-1 and about 1563 10 cm ^-1 . Here, the vibration peak at about 1061 ± 10 cm ^-1 means that a bond (CC) between the carbon-carbon elements of the functional group exists, and the vibration peak at about 1347 ± 10 cm ^{-1 corresponds to} the titanium element And EDTA-derived CO ₃ is present, and a vibration peak at about 1449 ± 10 cm ^-1 and about 1563 ± 10 cm ^-1 means that there is a bond between the titanium element and COO ^- .

From these results, it can be seen that the carbon dioxide and nitrogen-doped titanium dioxide according to the present invention are chemically bonded to a carbon element and / or an oxygen element bonded to a carbon element by doping the surface with a cupric acid and a carbonate.

Experimental Example 3.

In order to evaluate the optical and surface properties of carbon and nitrogen doped titanium dioxide according to the present invention, the following experiment was conducted.

(1) Optical properties

The absorbance of the titanium dioxide prepared in Example 1 and Comparative Example 1 in a wavelength region of 200 to 800 nm was measured and the measured results are shown in FIG.

5 is a graph showing the absorbance of titanium dioxide with respect to a change in wavelength.

5, the titanium dioxide prepared in Example 1 and Comparative Example 1 exhibited a light absorption intensity of about 80% or more at a wavelength of 350 nm or less, and a light absorption intensity at a wavelength of more than 350 nm The strength of the However, the titanium dioxide prepared in Comparative Example 1 exhibited an average light absorption intensity of about 10 +/- 0.5 au and about 15 +/- 0.5 au, respectively, at wavelengths of 500 nm or more, while the photocatalyst of Example 1 was about 50 And an average light absorption intensity of 0.5 au. This indicates that the titanium dioxide of Example 1 is reduced in excited photon energy and the electrons are easily " charge transitioned. &Quot;

From these results, it can be seen that the photocatalyst according to the present invention has an excellent photocatalytic effect not only in the ultraviolet region but also in the visible light region of 400 to 800 nm wavelength region.

(2) Surface properties

The average diameter, average volume and average BET specific surface area of the pores were measured for the titanium dioxide prepared in Example 1 and Comparative Example 1. The adsorption amount of the photocatalyst was measured according to the relative pressure of the photocatalyst under the condition of increasing the relative pressure from 0 to 1 in a nitrogen atmosphere using a Micromeritics ASAP 2020 apparatus. The measured results are shown in Tables 1 and 6 .

Average diameter of pores
[nm] Average volume of pores
[cm ₃ / g] Average BET specific surface area
[m ² / g] Example 1 18.74 0.276 91.927 Comparative Example 1 3.60 0.016 29.809

Referring to Table 1 and FIG. 6, the titanium dioxide of Example 1 exhibits a high distribution in the pore diameter range of about 15 to 25 nm, while the titanium dioxide of Comparative Example 1 has a high distribution in the range of 5 nm or less It looked. In addition, the titanium dioxide of Example 1 had an average BET specific surface area of about 91.927 +/- 0.5 m < ² > / g, indicating that the adsorption amount of the organic compound with respect to the relative pressure was larger than that of the titanium dioxide of Comparative Example 1. [

From these results, it can be seen that the titanium dioxide according to the present invention contains pores having an average diameter of 15 to 25 nm, and thus has a large average BET specific surface area, and thus has an excellent effect of adsorbing organic compounds on the catalyst surface.

Experimental Example 4.

In order to evaluate the water treatment efficiency according to the titanium dioxide type of titanium dioxide according to the present invention, the following experiment was conducted.

Titanium dioxide (0.02 g) prepared in Example 1 and Comparative Examples 1 and 2 was added to an aqueous solution (20 ml) having a pH of 10 dissolved in methylene blue (MB, 3 ppm) in a 50 ml quartz tube reactor, Lt; / RTI > was stirred in the dark for photolysis reaction. As a result, the degree of adsorption of titanium dioxide is shown in Table 2.

Photocatalyst usage
[g] MB concentration
[mg / L] PH of aqueous solution Reaction time
[hr] Adsorption ratio
[%] Example 1 0.2 3 10 One 88 Comparative Example 1 0.2 3 10 One 30 Comparative Example 2 0.2 3 10 2 7

Further, the titanium dioxide of Examples 1 and 2 in which the adsorption was completed was placed in a place where visible light was irradiated, and a photocatalytic reaction was performed for 3 hours. As a result, the photocatalytic efficiency of titanium dioxide is shown in Table 3.

Photocatalyst usage
[g] MB concentration
[mg / L] PH of aqueous solution Reaction time
[hr] Photocatalytic efficiency
[%] Example 1 0.2 3 10 3 95 Comparative Example 1 0.2 3 10 3 3 Comparative Example 2 0.2 3 10 3 18

First, in Table 2, the titanium dioxide prepared in Example 1 exhibited an adsorption capacity of about 88% for methylene blue remaining in the aqueous solution, whereas the photocatalysts prepared in Comparative Examples 1 and 2 exhibited adsorption capacities of about 30% and 7 %.

As shown in Table 3, the photocatalytic efficiency of titanium dioxide prepared in Example 1 was 91% at 1 hour and 95% at 3 hours after visible light irradiation. On the other hand, the photocatalytic efficiency of the titanium dioxide of Comparative Example 2 is 18%, which is lower than that of the titanium dioxide according to the present invention.

From these results, it can be seen that the titanium dioxide according to the present invention is a titanium dioxide which is simultaneously doped with carbon and nitrogen, and has a lower melting point in the wavelength region of 400 to 800 nm remaining in the aqueous solution as compared with the case of using pure titanium dioxide and commercially available titanium dioxide. It can be seen that the photodegradation efficiency is excellent.

Experimental Example 5

In order to evaluate the reproducibility of carbon and nitrogen doped titanium dioxide according to the present invention, the following experiment was conducted on titanium dioxide prepared in Example 1.

The methylene blue dye-adsorbed carbon and nitrogen-doped titanium dioxide solution was centrifuged at 3000 rpm for 5 minutes to remove the supernatant, and the temperature was increased by 6 ° C. per minute and calcined at 400 ° C. for 3 hours to regenerate. The regenerated carbon and nitrogen doped titanium dioxide was added to the methylene blue solution to adsorb the dye to determine the removal rate. The above procedure was repeated and the results are shown in FIG.

Referring to FIG. 7, the titanium dioxide of Example 1 was found to have a methylene blue dye removal rate of 80% or more even after 5 repetitions of regeneration.

From these results, it can be seen that the carbon dioxide and nitrogen-doped titanium dioxide according to the present invention are regenerated when heated to a temperature of 400 ° C or higher, and the adsorption rate is also excellent.

Claims

Titanium dioxide in crystalline form in anatase and titanate; And
Carbon and nitrogen-doped titanium dioxide doped with titanium dioxide and comprising a dopant comprising a carbon element and a nitrogen element.

The method according to claim 1,
Carbon and nitrogen-doped titanium dioxide having a band gap of 2.60 to 3.00 eV in a wavelength range of 400 nm to 800 nm.

The method according to claim 1,
Carbon and nitrogen-doped titanium dioxide satisfying the conditions represented by the following general formula:
[Formula 1]
X / Y? 0.1
Here, X is the concentration of methylene blue in the solution irradiated with light in the wavelength range of 400 nm to 800 nm by adding titanium dioxide for 1 hour, and Y is the concentration of methylene blue in the solution not irradiated with light .

The method according to claim 1,
Characterized in that the average particle size of the carbon and nitrogen doped titanium dioxide is between 10 and 50 mu m.

Titanium precursor; And a chelate compound containing a carbon element and a nitrogen element to prepare a mixed solution; And
And then heat treating the mixed solution. &Lt; RTI ID = 0.0 > 11. < / RTI >

6. The method of claim 5,
Wherein the heat treatment is performed for 200 to 400 minutes in a temperature range of 300 to 500 占 폚.

6. The method of claim 5,
Wherein the pH of the mixed solution is 8.5 or less.

6. The method of claim 5,
Wherein the titanium precursor is at least one selected from the group consisting of titanium isopropoxide, titanium alkoxide, and titanium tetrachloride (TiCl ₄ ).

A photocatalyst comprising carbon and nitrogen-doped titanium dioxide according to claim 1.

A water treatment method characterized by removing an organic compound contained in water by using the photocatalyst according to claim 9.

11. The method of claim 10,
The water treatment method is carried out by adsorbing an organic compound on a photocatalyst,
The photocatalyst on which the organic compound is adsorbed,
Wherein the photocatalyst is regenerated through a regeneration step of a photocatalyst heated to a temperature of 400 DEG C or higher.