KR20140048371A - Self rotating photocatalytic water treatment apparatus by immobilized nanotubular tio2 on ti substrate - Google Patents

Abstract

The present invention relates to a water treatment device in which a nanotube type catalyst fixed to a titanium support rotates alone. The purpose of the present invention is to provide a water treatment device in which a nanotube type catalyst fixed to a titanium support rotates alone so that excellent photochemical reaction is performed in a reactor by using, as a medium, a nanotube structured titania (TiO_2) optical catalyst, which is autonomously grown on the surface of a mesh type titanium (Ti) support through anodizing and heat treatment, so as to overcome the weaknesses of a particle type optical catalyst reacting system. The water treatment device in which a nanotube type catalyst fixed to a titanium support rotates alone according to the present invention comprises: an optical reactor of which the top and bottom sides of one side surface connect with an outlet pipe path and an inlet pipe path, respectively, and which includes a housing having a cylindrical shape of which the top part is opened; an optical catalyst installed inside the housing to be able to rotate with a rotation means as a medium and in which a nanotube titania is formed, which is obtained as the surface of a mesh type metal titanium support is anodized and integrated; a water tank in which hexavalent chromium and aqueous solution having an adjusted concentration of hydrogen ions, which are needed to react the optical catalyst, are stored and which connects with the housing through the outlet pipe path and the inlet pipe path; and a light source part irradiating ultraviolet rays to the side of the optical reactor so that the ultraviolet rays react with the optical catalyst and the hexavalent chromium is reduced.

Description

      BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a nanotube-type photocatalyst immobilized on a titanium support,

The present invention relates to a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support rotates by itself, and more particularly, to a water treatment apparatus in which a nanotube photocatalyst having optical activity is grown on a mesh type titanium by self- And a nanotube type photocatalyst immobilized on a titanium support capable of performing an excellent photochemical reaction through self rotation.

      In general, the photocatalyst is a material widely used as a material in various industrial fields, and is known as one of materials having high utility as a catalyst in energy and environment.

      In particular, hydrogen energy production technology, which is emerging as a future energy source in the development of new and renewable energy technologies due to global warming and fossil energy depletion due to recently emerging greenhouse gases, is a global concern, and photochemical hydrogen production is one of these technologies. Is known as a clean energy production technology that can produce hydrogen without the generation of greenhouse gases, the photocatalyst is known as a catalyst utilized at this time.

      In addition, as the interest of water reuse and advanced treatment due to environmental pollution including not only air pollution but also water shortage is increased, utilization as an environmental purification catalyst in combination process combined with ultraviolet rays is also increasing.

Meanwhile, in the conventional water treatment field, TiO ₂ / UV technology, which is one of the advanced oxidation processes (AOPs), is used to oxidize or reduce pollutants using light energy (ultraviolet rays) and powder type photocatalysts. Although it is widely known, the above-mentioned technique has an advantage of showing a high reaction rate with organic pollutants, but it requires a secondary process such as a filtration process in order to discard or recover a catalyst that can be used after the reaction. In the case of slurry type reaction, there is an uneconomic problem that the amount of photocatalyst should be injected more than necessary.

      In order to overcome the above problems, there have been various attempts for immobilization of the support, etc., but it is a situation that the secondary problem of detachment is accompanied, and thus, the practical stage has not been reached.

SUMMARY OF THE INVENTION The present invention has been made in order to overcome the above-mentioned problems of the prior art, and it is an object of the present invention to provide a photocatalytic reaction system, And a nanotube type photocatalyst immobilized on a titanium support for allowing an excellent photochemical reaction in a reactor to pass through a grown nanotube-structured TiO ₂ photocatalyst.

      According to an aspect of the present invention, there is provided a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support rotates by self-rotation, comprising: an outlet pipe and an inlet pipe connected to upper and lower sides of one side, A photoreactor including a cylindrical housing; A photocatalyst which is rotatably installed inside the housing via a rotating means, wherein the surface of the metal titanium support in the form of a mesh is anodized to form an integrated nanotube titania; A water tank in which an aqueous solution having a controlled concentration of hexavalent chromium and hydrogen ions necessary for the reaction of the photocatalyst is stored and connected to the housing through the outflow conduit and the inflow conduit; And a light source unit for irradiating ultraviolet rays to the photoreactor side and allowing the ultraviolet ray and the photocatalyst to react and reduce the hexavalent chromium.

      The rotating means provided in the photoreactor may include an impeller which is installed at an inlet side of the housing and receives a rotational force through an aqueous solution introduced from the water tank and a rotating shaft which is vertically fixed to the center of the impeller, And a rotating body fixing part for supporting the upper end of the rotating shaft.

      Preferably, the rotary shaft is provided with 2 to 8 photocatalysts attached to the surface of the metallic titanium support in the form of a mesh, a reflection tape is attached to a certain point of the impeller, a rotation speed meter is installed on the housing side of the reactor, And the rotation speed of the photocatalyst attached to the rotating shaft is preferably detected through this.

      A pump for controlling the flow rate and a flow meter are provided on the inflow portion side from which the aqueous solution is supplied from the water tank to the photoreactor side so that the rotational speed and the hydraulic retention time HRT of the rotating means are changed by controlling the flow rate supplied to the photoreactor side .

      It is preferable that a temperature control unit for maintaining the temperature of the aqueous solution through the circulation of the cooling water is connected to the water tank.

According to the present invention as described above, hexavalent chromium, which is known as a typical carcinogen in water, is treated as an object to be treated through a photocatalyst prepared by fixing to a titanium mesh through anodization, It is possible to solve all the problems of elimination of the catalyst after the slurry-type photocatalytic reaction or removal of the catalyst.

In addition, by using the momentum of the fluid in the inlet portion where the water containing the pollutant is supplied to the photoreactor, the titanium mesh rotation shaft having the photocatalyst immobilized therein is rotated according to the supply flow rate, The nanotube-type photocatalyst for fixing the unique characteristics of the photocatalyst that generates charge / charge pairs such as electrons / holes through optical absorption and fixing the nanotube-type photocatalyst for more effective use of the light energy, Or the photochemical oxidation / reduction reaction can be stably caused without any problem such as the recovery of particles.

In addition, it is possible to provide a reaction device which is easy to manufacture by size and maximizes the efficiency of light energy per unit area and unit time of light energy, and has high optical activity and economical treatment of contaminants, In order to more effectively utilize the activity of the nanotube type photocatalyst, there is an effect that the light energy passing through the pores of the mesh can be used more efficiently by rotating the plurality of mesh-type titanium plates fixed on the rotating shaft.

In addition, it is also easy to control the residence time (or reaction time) in the reactor in accordance with the change in the rotational speed of the rotating means with the photocatalyst has the advantage that can change the treatment efficiency of the pollutant according to the rotational speed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view schematically showing the overall structure of a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support according to the present invention rotates,
FIG. 2A and FIG. 2B are a perspective view and an exploded perspective view showing the structure of a photoreactor provided in a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support according to the present invention rotates,
FIG. 3 is a view showing an electron microscope (SEM) analysis state of a self-grown nanotube TiO ₂ photocatalyst on a mesh type titanium support applied to a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support according to the present invention is self-
FIG. 4 is an X-ray diffraction (XRD) analysis diagram of a self-growing nanotube TiO ₂ photocatalyst on a mesh-type titanium support applied to a water treatment apparatus in which a nanotubular photocatalyst immobilized on a titanium support according to the present invention is rotated Lt;
FIG. 5 is a graph showing a zeta potential value of a self-grown nanotube TiO ₂ photocatalyst on a mesh type titanium support applied to a self-rotating water treatment apparatus immersed in a nanotube type photocatalyst immobilized on a titanium support according to the present invention ,
FIG. 6 is a graph showing changes in inflow flow rate and HRT according to the rotation speed of a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support according to the present invention rotates itself,
FIG. 7 is a graph showing a change in the reduction efficiency of hexavalent chromium according to the rotation speed of the water treatment apparatus in which the nanotube type photocatalyst immobilized on the titanium support according to the present invention rotates.
8 is a graph showing a change in hexavalent chromium reduction depending on the number of adhered nanotubes TiO ₂ photocatalyst on a mesh type titanium support applied to a water treatment apparatus in which a nanotube type photocatalyst immobilized on a titanium support according to the present invention is rotated .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the structure and operation of an apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

      The present invention relates to a nanotube type photocatalyst immobilized on a titanium support, and more particularly, to a nanotube type photocatalyst immobilized on a titanium support, A perspective view and an exploded perspective view showing the structure of a photoreactor provided in a rotating water treatment apparatus.

      First, in the water treatment apparatus in which the nanotube type photocatalyst immobilized on the titanium support according to the present invention rotates, the mesh type titanium immobilized with the photocatalyst 15 is mounted on the rotation axis 13 at the center of the photocatalytic reactor 1, (Rotation plate) 14 installed at the lower part of the reactor 13 and the momentum due to the flow rate supplied from the reactor inlet 11 perpendicular to the fluid in which the pollutant is dissolved.

      To this end, the water treatment apparatus in which the nanotube type photocatalyst immobilized on the titanium support according to the present invention rotates itself comprises: a photocatalyst 15 on which the nanotube titania is formed by the anodic oxidation of the surface of the metal titanium support in mesh form; A water tank (2) storing an aqueous solution in which hexavalent chromium and hydrogen ion concentrations necessary for the reaction of the photocatalyst (15) are stored; The photocatalyst 15 is installed inside the housing 10 in such a manner that the photocatalyst 15 can rotate by itself. The housing 10 has a cylindrical shape and a lid 16, (1) connected to the water tank (2) through a reactor outlet (12) and a reactor inlet (11), respectively; And a light source unit 7 for irradiating ultraviolet rays to the photocatalyst 1 and allowing the ultraviolet rays to react with the photocatalyst 15 to reduce hexavalent chromium.

      In addition, the water tank (2) side is configured to be further connected to the temperature control unit (3) for maintaining the temperature of the aqueous solution in the water tank through the circulation of the cooling water.

      The present invention is characterized in that titania, which is a photocatalyst oxide, is immobilized on a surface of a metal support to integrate the same, and the titania is densely formed on the surface of a support in the form of a tube to form a bond. And thus a reaction device having excellent efficiency can be made. First, a tubular photocatalyst will be described as follows.

      The photocatalyst 15 is a structure in which tubular titania as a photocatalyst material is integrally bonded to the surface of metallic titanium (Ti) as a support through an anodic oxidation reaction. At this time, the hollow shaft of each titania tube is opened to the outside while being perpendicular to the surface of the support. That is, the integrated photocatalyst of the present invention is a structure in which titania tubes, which are transition metal oxide layers, are laminated on a surface of a metal support in a densely packed state, and oxidation or reduction reaction can be caused according to conditions of an aqueous solution.

In the self-rotation type photoreaction device of the present invention, the mesh type photocatalyst may include a step of washing a conductive metal support, such as titanium, with a detergent; A copper or iron coil or foil is used as a counter electrode in a mixed electrolyte of ammonium fluoride (NH ₄ F), water (H ₂ O) and ethylene glycol (C ₂ H ₆ O ₂ ) ; And a step of heat-treating at 400 to 500 ° C. while supplying oxygen per unit surface area of the support to be oxidized in an amount of 350 to 450 ml per minute in a furnace capable of controlling the atmospheric gas and the treatment temperature.

      As described above, the steps of manufacturing the integrated photocatalyst according to the present invention will be described in detail. In the cleaning step in which the support is degreased, the oil and various contaminants deposited on the surface of the support are separated and removed. Various other methods such as washing with solvent or alkali may be applied.

The electrolyte for the anodic oxidation may include 1 to 3 parts by weight of ammonium fluoride (NH ₄ F), 2 to 4 parts by weight of water (H ₂ O) and 93 to 97 parts by weight of ethylene glycol (C ₂ H ₆ O ₂ ) is oxidized by using copper or iron as a counter electrode as a negative electrode to oxidize the titanium support in the form of a mesh.

      At this time, if the content of ammonium fluoride is less than 1 part by weight, it is difficult to form a tubular oxide film, and when it exceeds 3 parts by weight, the tubular oxide film is deformed into a non-uniform form. In addition, if the water content is less than 2 parts by weight, ammonium fluoride is difficult to dissolve. When the content is more than 4 parts by weight, the viscosity of the electrolyte may be lowered, thereby changing the rate of anodization. If ethylene glycol is less than 93 parts by weight, the etching rate of the oxide is increased, and if it exceeds 97 parts by weight, it is difficult to form a long oxide tube.

      In the anodic oxidation step, it is appropriate to set the voltage applied to the two electrodes in the range of 45 to 55 V. When the voltage does not reach 45 V, the generation of oxide becomes irregular, and when the voltage exceeds 55 V, the oxide layer is desorbed. The time required for oxidation is about 0.5 hours. In addition, the heat treatment performed after the anodic oxidation is a process for crystallizing the amorphous oxide layer formed by the anodic oxidation into an anatase structure, and if the heat treatment temperature is less than 400 ° C., crystallization into the anatase structure is difficult and exceeds 500 ° C. In this case, a rutile structure may be generated. As such, the crystals produced by the heat treatment temperature influence the treatment efficiency of pollutants, and the hexavalent chromium reduction reduction efficiency is excellent when the crystals of the anatase structure are present.

      At this time, if the amount of oxygen per unit surface area of the support supplied to form the oxidation atmosphere during heat treatment does not reach 350 ml / min, the time for forming the oxide layer may be long, and the oxide layer may be unstable. If the amount exceeds 450 ml / min, no further effect is seen. And, in the case of the heat treatment time, it changes depending on the oxygen supply amount, the heat treatment temperature, the surface area of the support, etc., and generally takes about 1 to 3 hours.

      The reaction efficiency of hexavalent chromium varies according to the method of installing the photocatalyst 15 having the nanotubes formed through the manufacturing process as described above in the photoreactor 1. In the case of the photocatalyst 15 produced by the titanium mesh, it is possible to install the photocatalyst 15 in the form of two to eight wings around the rotation axis 13, so that the reaction efficiency of hexavalent chromium can be varied depending on the rotation speed. This is because the light passing through the pores of the mesh in the same reactor area effectively contacts the portion where the photocatalyst is formed and the reaction efficiency is increased, and the change is remarkable according to the rotation speed (10 to 150 rpm). At a rotation speed of less than 10 rpm, the use of photocatalyst and light required for the reaction of hexavalent chromium was not effective and the reaction efficiency was more than 95% at 90 rpm or more.

      Through the above process, it is possible to produce a tubular oxide layer having proper photoresist on the surface of titanium. The oxide layer formed on the surface of titanium as a support generates electrons by receiving sunlight, ultraviolet rays, or some visible light. Will be.

      The rotating means provided in the photoreactor 1 including the housing 10 and the cover 16 is installed on the reactor inlet 11 side of the housing 10 and is connected to the inlet A rotating shaft 13 vertically fixed to the center of the impeller 14 and attached with a plurality of photocatalysts 15 mounted thereon and a rotating shaft 13 supporting the upper end of the rotating shaft 13, The rotating shaft 13 is provided with approximately 2 to 8 photocatalysts 15 attached to the surface of a metallic titanium support in the form of a mesh, And is rotated at a speed of 10 to 150 [rpm].

      In addition, a reflective tape 17 is attached to a predetermined point of the impeller 14, and rotation of the impeller 14 is detected by detecting the position of the reflective tape 17 on the housing 10 side of the photoreactor 1. Rotational speed measuring device 6 for detecting the speed is provided.

      A pump 14 and a flow meter 5 for controlling the flow rate are provided on the inlet side of the water tank 2 from which the aqueous solution is supplied to the photocatalytic reactor 1, The rotational speed and the hydraulic retention time (HRT) of the rotating means can be changed through the supplied flow rate control.

That is, the rotational speed of the photocatalyst 15 is dependent on the velocity of the fluid flowing into the photoreactor 1 to measure the supply flow rate according to the rotational speed and to maintain the hydraulic volume according to the effective volume and supply flow rate of the photoreactor. The hydraulic retention time (HRT) can be calculated by the following [Equation 1].

      [Equation 1]

HRT = effective area of reactor / flow rate

      The rotating shaft 13 to which the photocatalyst 15 is attached has a proportional relationship in which the rotational speed increases when the supply flow rate from the water tank 2 increases and the rotational speed decreases when the supply flow rate decreases (HRT) of the photocatalyst 15 and the optimum retention time for the photocatalyst 15 to react on the surface are desirable.

      The water treatment apparatus in which the nanotube type photocatalyst immobilized on the titanium support according to the present invention rotates itself comprises a nanotube type photocatalyst which is self-grown by anodizing the surface of the metal titanium mesh support in the quartz optical reactor (1) 15) is attached to the rotating shaft (13) and embedded therein, the fluid supply from the water tank (2) storing the aqueous solution in which the concentration of hexavalent chromium and the hydrogen ion is contaminant is stored, and the irradiation of ultraviolet rays from the light source And the photocatalyst 15 is positioned so that a photochemical reaction can take place and a change in the hydraulic momentum transmitted to the impeller 14 depending on the flow rate of the fluid supplied to the reactor inlet 11 of the photoreactor 1 So that the rotation speed of the photocatalyst 15 can be changed.

At this time, the photocatalyst applied to the conventional apparatus is a photocatalyst including powdered TiO ₂ or a photocatalyst containing a noble metal (Pt or the like) to increase photoactivity, an ion such as indium tin oxide (InSn oxide) or tin oxide (FSn oxide) The conductive oxide film is coated with photocatalyst particles such as TiO ₂ , ZnO, and WO _{3. In} contrast, in the water treatment apparatus of the present invention, when the rotatable photoactive nanotube photocatalyst 15 is embedded in the photoreactor 1, And the photochemical reaction proceeds as light is irradiated from the light source unit 7.

The reduction efficiency of hexavalent chromium may vary considerably depending on the hydrogen ion concentration of the aqueous solution, the initial hexavalent chromium concentration, the size of the fixed or rotatable photocatalyst produced, and the heat treatment temperature. However, sunlight or ultraviolet light is reflected on the surface of the photocatalyst The electrons in the VB state in the photocatalyst are excited to serve as a charge pair source (electron donor) that continuously generates electron (e ^- ) and hole (h ⁺ ) in CB At this time, as shown in the following equation, hexavalent chromium, which is reacted with holes of water to be oxidized to oxygen and is highly toxic by the reaction with electrons, can be reduced to trivalent chromium with a low toxicity.

      [Chemical Formula 1]

TiO ₂ (light) → e ^- + h ⁺

      (2)

CrO ₄ ^2- + 8H ⁺ + 3e ^- ? Cr ³⁺ + 4H ₂ O

      (3)

2H ₂ O - > O ₂ + 4H ⁺ + 4e ^-

      [Chemical Formula 4]

_{^{4CrO 4 2- + 20H + → 4Cr}} 3+ + 10H 2 O + 3O 2

      Next, the operation of the present invention as described above will be described with reference to the drawings.

The nanotubular-type photocatalyst immobilized on the titanium support according to the present invention constructed as described above will have the following advantages over the self-rotating water treatment apparatus.

Example 1

Mesh titanium Electrolyte (0.3M NH ₃ F + H ₂ O + 2% Ethylene glycol) oxide in the positive electrode 5 0 V used (maintaining the electrolyte temperature 25 ℃) in (Ti, 10cm x 10cm, porosity 20%) a FIG. 3 shows the result of analyzing the surface of the photocatalyst of nanotubular TiO ₂ self-grown at 450 ° C. for 2 hours at 400 ml / min in an oxygen atmosphere, by the electron microscope (SEM).

In order to confirm that the uniform nanotubes TiO ₂ are formed on the anodized titanium mesh, it is divided into five parts (A to E) and then analyzed by electron microscope. The tube-shaped TiO ₂ is self-growing in a uniform arrangement and has a diameter of about 55 to 60 nm, a thickness of about 10 to 20 nm, and a length of about 6.5 to 7.0 μm.

Figure 4 is an X-ray diffraction (XRD) results of the nanotubes TiO2 surface preparation of the above, the resulting TiO ₂ unique crystal structure was analyzed and each separated by sangjungha three portions (I ~ III) an anodized titanium mesh Anatase was detected and titanium metal (Ti) was also detected.

In addition, Figure 5 when a measurement of the zeta potential (zeta potential) of the nanotube TiO ₂ surface of the produced the result, nanotube TiO ₂ zeta potential value of the photocatalytic surface is the pH of the aqueous solution in particular three conditions of the acid amount (Positive charge) and a negative charge (pH 5 ~ 9).

Thus, the surface of the nanotube photocatalyst in contact with the aqueous solution has a positive value in the acidic condition where the pH value is low and exists in the anion state (HCrO ₄ ^- / CrO ₄ ^2- , pK _a = 6.5) in water It is known that hexavalent chromium increases the efficiency of reduction reaction by increasing the electrostatic attraction. On the other hand, when the pH is increased, the characteristic of the photocatalyst having a negative value of hexavalent chromium and surface charge in the negative ion state, Since the electrostatic repulsion is known to reduce the reaction efficiency, the present invention maintains pH 3 in the reaction condition setting.

Example 2

      FIG. 6 is a view illustrating the relationship between the rotation speed and the residence time according to the supply flow rate to the photoreactor side of the water treatment apparatus according to the present invention.

If the flow rate of the water through the pump after fixing four photocatalysts of 10 cm ² (2 cm x 5 cm) per one is fixed on the rotating shaft, the momentum of the fluid applied to the rotating plate can be changed, ). ≪ / RTI >

      As can be seen from the results of FIG. 6, as the rotation speed of the mesh changes from 10 to 150 rpm, the water supply flow rate is from 1.12 to 2.84 L / min, and the water retention time (HRT) Shows a difference of about 6 to 16 seconds.

      That is, when the rotation speed of the photocatalyst is low, the residence time (HRT) of water in the photoreactor is increased. On the contrary, when the rotation speed is high, the residence time of the water tends to decrease. Or the mixing of water and contaminants according to the rotation speed can be controlled.

Example 3

      FIG. 7 is a result of photochemical reaction by irradiating ultraviolet rays at an initial concentration of 2 mg / L of hexavalent chromium (Cr (VI)) as a target material under the conditions of the reaction apparatus described in Example 2 described above.

      As described in Example 1 above, the hydrogen ion concentration (pH) of the solution was adjusted to 3 to induce the reduction reaction of hexavalent chromium. The hydrogen ion concentration (pH) of the solution was adjusted to 3, Photochemical reactions were carried out.

      As a result, the reduction efficiency of hexavalent chromium increased with increasing rotational speed and showed high efficiency (over 95%) at 90 rpm or higher.

From these results, it can be seen that the mixing is uniform in the reactor as the rotation speed increases, and that the nanotube TiO ₂ formed on the mesh reacts with the ultraviolet ray effectively. When the rotation speed is lower than 90 rpm, The reduction efficiency was low.

Also, at 120 ~ 150 rpm, the reduction efficiency of hexavalent chromium was slightly lower than that at 90 rpm, which is not a problem for mixing and reacting with ultraviolet light and photocatalyst. However, HRT).

Example 4

FIG. 8 shows the result of photochemical reaction in which the number of nanotubes TiO ₂ formed meshes at different rotational ratios of 90 rpm, where the hexavalent chromium reduction efficiency is highest, among the conditions of Example 3.

As the reaction condition is the same as all the conditions, the amount of TiO ₂ photocatalyst and the area of reacting with ultraviolet light increases as 2 ~ 8 number of TiO ₂ meshes are attached to the rotating shaft.

      That is, the amount of the TiO2 photocatalyst may be about 0.5 to 2 times larger than in the above-described embodiment in which four TiO2 meshes are attached.

As shown in the results of Figure 8 when the two TiO ₂ mesh 6 that becomes the reduction rate of chromium significantly can see the decrease, the reaction rate is fast, as TiO _2, the mesh is increased by the 8 TiO ₂ mesh final 2 hours And the diameter of the rotating shaft can be increased when the scale of the reactor is enlarged. Thus, it is considered that the efficiency can be increased by installing the TiO ₂ mesh having a wide effective area.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

Photoreactor, 10. housing,
11. reactor inlet, 12. reactor outlet,
13. axis of rotation, 14. impeller,
15. Photocatalyst, 16. Cover,
17. Reflective tape, 18. Rotor fixing part,
2. Water tank, 3. Temperature control unit,
4. pump, 5. flow meter,
6. Rotation speed meter, 7. Light source.

Claims (6)

An optical reactor (1) including an outlet pipe path and an inlet pipe connected to upper and lower sides of one side, respectively, and including a cylindrical housing 10 having an open top;
A photocatalyst 15 which is rotatably installed inside the housing 10 by means of a rotating means, wherein the surface of the metal titanium support in the form of a mesh is anodized to form an integrated nanotube titania;
A water tank 2 storing an aqueous solution having a controlled concentration of hexavalent chromium and hydrogen ions necessary for the reaction of the photocatalyst 15 and connected to the housing through the outflow conduit and the inflow conduit;
The nanotube-type photocatalyst immobilized on the titanium support, comprising a light source unit 7 for irradiating ultraviolet light to the photoreactor 1 and reacting the ultraviolet light with the photocatalyst 15 to reduce hexavalent chromium. Self-rotating water treatment device. The method of claim 1,
Rotating means provided in the photoreactor 1,
An impeller 14 installed at the reactor inlet 11 side of the housing 10 and receiving rotational force through an aqueous solution flowing from the water tank 2;
A rotary shaft 13 fixedly installed at the center of the impeller 14 and having a plurality of photocatalysts 15 attached thereto;
The nanotube type photocatalyst immobilized on the titanium support is self-rotating water treatment apparatus, characterized in that consisting of a rotating body fixing part (18) for supporting the upper end of the rotating shaft (13). 3. The method of claim 2,
Wherein the rotating shaft (13) is provided with 2 to 8 photocatalysts attached to the surface of a metallic titanium support in the form of a mesh, wherein the nanotubular photocatalyst immobilized on the titanium support rotates by itself. 3. The method of claim 2,
A reflective tape 17 is attached to a certain point of the impeller 14, and a rotation speed measuring device 6 is installed at the housing 10 side of the photoreactor 1, and is attached to the rotation shaft 13 through this. Water treatment apparatus for self-rotating nanotube-type photocatalyst immobilized on a titanium support, characterized in that configured to detect the rotational speed of the photocatalyst 15. The method of claim 1,
A pump 14 and a flow meter 5 for controlling the flow rate are provided on the inlet side of the water tank 2 from which the aqueous solution is supplied to the photoreactor 1, Wherein the rotating speed of the rotating means and the HRT are changed. The water treatment apparatus of claim 1, wherein the nanotubular photocatalyst is immobilized on the titanium support. The method of claim 1,
Wherein the nanotube type photocatalyst immobilized on the titanium support rotates by itself, wherein a temperature regulating part (3) is connected to the water tank (2) side to maintain the temperature of the aqueous solution through the circulation of the cooling water.

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