KR100262555B1 - The fabrication of spherical nano-size anatase TiO2 powder for photocatalysis - Google Patents
The fabrication of spherical nano-size anatase TiO2 powder for photocatalysis Download PDFInfo
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- KR100262555B1 KR100262555B1 KR1019970073817A KR19970073817A KR100262555B1 KR 100262555 B1 KR100262555 B1 KR 100262555B1 KR 1019970073817 A KR1019970073817 A KR 1019970073817A KR 19970073817 A KR19970073817 A KR 19970073817A KR 100262555 B1 KR100262555 B1 KR 100262555B1
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- 239000000843 powder Substances 0.000 title claims abstract description 49
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 title claims abstract description 23
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 14
- 230000001699 photocatalysis Effects 0.000 title claims 3
- 238000007146 photocatalysis Methods 0.000 title claims 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 17
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims abstract description 15
- 239000002105 nanoparticle Substances 0.000 claims abstract description 7
- 239000011941 photocatalyst Substances 0.000 claims abstract description 5
- 229910010413 TiO 2 Inorganic materials 0.000 claims description 16
- 239000010936 titanium Substances 0.000 claims description 15
- 238000004808 supercritical fluid chromatography Methods 0.000 claims description 8
- 125000000896 monocarboxylic acid group Chemical group 0.000 claims description 6
- 150000001298 alcohols Chemical class 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- -1 titanium alkoxides Chemical class 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 239000000203 mixture Substances 0.000 abstract description 7
- 238000002156 mixing Methods 0.000 abstract description 4
- 238000001311 chemical methods and process Methods 0.000 abstract description 2
- 239000012530 fluid Substances 0.000 description 19
- 239000002245 particle Substances 0.000 description 14
- 239000002904 solvent Substances 0.000 description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 230000000704 physical effect Effects 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000012071 phase Substances 0.000 description 5
- 239000000919 ceramic Substances 0.000 description 4
- 239000002244 precipitate Substances 0.000 description 4
- 239000011164 primary particle Substances 0.000 description 4
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 4
- JMXKSZRRTHPKDL-UHFFFAOYSA-N titanium ethoxide Chemical compound [Ti+4].CC[O-].CC[O-].CC[O-].CC[O-] JMXKSZRRTHPKDL-UHFFFAOYSA-N 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000000227 grinding Methods 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- 238000006460 hydrolysis reaction Methods 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 230000009257 reactivity Effects 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 230000000844 anti-bacterial effect Effects 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000012798 spherical particle Substances 0.000 description 2
- 239000011882 ultra-fine particle Substances 0.000 description 2
- 238000007704 wet chemistry method Methods 0.000 description 2
- 241000588724 Escherichia coli Species 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 150000004703 alkoxides Chemical class 0.000 description 1
- 230000000845 anti-microbial effect Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
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- 239000013078 crystal Substances 0.000 description 1
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- 239000012153 distilled water Substances 0.000 description 1
- 239000005447 environmental material Substances 0.000 description 1
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- 238000010438 heat treatment Methods 0.000 description 1
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- 238000004626 scanning electron microscopy Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000005549 size reduction Methods 0.000 description 1
- 238000003746 solid phase reaction Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
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- 239000003053 toxin Substances 0.000 description 1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/04—Mixing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
- B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
- B01J21/063—Titanium; Oxides or hydroxides thereof
-
- B01J35/30—
-
- B01J35/39—
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
Abstract
Description
본 발명은 초임계 유체법을 이용한 광촉매용 나노크기의 구형 아나타제 TiO2분말의 제조방법에 관한 것으로, 좀 더 상세하게는 기존의 습식화학법에서의 문제점들을 해결하기 위해 용질분자가 용액내에서 활발하게 움직여 분자수준(level)의 혼합이 가능하고, 용매의 점도가 낮아 용질분자의 움직임에 영향을 주지 않으며, 직접 결정질 분말을 얻을 수 있는 초임계 유체법을 이용한 나노크기의 구형 아나타제 TiO2분말의 제조방법에 관한 것이다.The present invention relates to a method for preparing nano-sized spherical anatase TiO 2 powder for photocatalyst using a supercritical fluid method. More specifically, in order to solve the problems of conventional wet chemistry, solute molecules are active in solution. Molecular level mixing is possible, and the viscosity of the solvent is low so that it does not affect the movement of solute molecules, and the nano-sized spherical anatase TiO 2 powder using supercritical fluid method can directly obtain crystalline powder. It relates to a manufacturing method.
세라믹스용 미분말 제조에 관한 연구는 세라믹 소결체의 신뢰성(reliability)을 어떻게 달성하는가에 대해 진행되고 있다. 신뢰성은 공정(process)의 개선을 표현한 것으로 소결체의 균질성, 재현성을 위해서는 재료의 개선이 필요하다. 재료의 물성을 좌우하는 것은 미세구조이며, 이것을 개선하기 위해서는 소결후의 결함제거가 중요하게 되나, 실제적으로는 불가능할 뿐만아니라 그 원인이 성형공정에서 비롯하기 때문에 성형공정 제어가 중요하다. 성형공정제어는 분말의 물리적 성질에 크게 좌우되므로 분말의 제조가 중요하게 대두된다.Research into the manufacture of fine powder for ceramics is progressing on how to achieve the reliability of the ceramic sintered body. Reliability is an expression of process improvement, and material improvement is necessary for homogeneity and reproducibility of the sintered body. It is the microstructure that influences the physical properties of the material, and in order to improve this, it is important to remove the defects after sintering, but it is not practically possible and control of the molding process is important because the cause comes from the molding process. The control of the molding process is highly dependent on the physical properties of the powder, so the manufacture of the powder is important.
이상적인 세라믹 분말의 물성은 (1) 고순도일 것, (2) 화학적으로 균질할 것, (3) 1차입자가 치밀하여 조직이 균질할 것, (4) 1차입자의 입경이 작을 것, (5) 입도분포가 좁을 것, 그리고 (6) 형상이 구형일 것 등이 요구되며, 이것에 부응하기 위해서 습식화학법(Wet Chemical Technique)등이 많이 연구되어 왔다.Ideal physical properties of ceramic powders should be (1) high purity, (2) chemically homogeneous, (3) primary particles are dense and homogeneous in structure, (4) small particle size of primary particles, (5) It is required that the particle size distribution is narrow and (6) that the shape is spherical, and in order to cope with this, the wet chemical technique has been studied.
한편, 미분말의 제조 방법에는 크게 두가지로 구분되는데 그 첫번째로 큰 덩어리를 볼밀을 사용하여 세세히 분할하는 방법인 분쇄공정(size reduction process)이 있다. 이것은 응집의 파괴와 입도분포의 조절을 주목적으로 한다. 더욱이 분쇄는 분말의 표면에너지를 증가시키지만 입도가 어느 정도 작게 되면 분쇄에너지는 분체의 성질을 변화시키는 것으로 작용한다. 주로 고상반응으로서 화학적으로 조성이 불균질하며 기계적 분쇄법이 사용되어 1㎛ 이하의 입자를 효과적으로 제조하기는 어렵다. 두번째로 작은 입자를 크게 하는 방법인 입성장공정(particle growth process)는 액상이 관여하는 반응으로 이온과 분자에서 핵생성과 성장에 의해 입자를 형성시키는 방법(습식화학법)으로 생성조건의 조절에 따라 1㎛ 이하의 초미립자를 만드는 것이 용이하고 입도분포의 제어도 가능하다.On the other hand, there are two types of fine powder production method, the first of which is a size reduction process that is a method of finely dividing the large lumps using a ball mill. This is mainly aimed at breaking the aggregation and controlling the particle size distribution. Furthermore, the grinding increases the surface energy of the powder, but when the particle size is somewhat small, the grinding energy changes the properties of the powder. It is mainly a solid phase reaction, chemically heterogeneous in composition, and it is difficult to effectively produce particles having a size of 1 μm or less by using a mechanical grinding method. Secondly, the particle growth process, which is a method of enlarging small particles, is a reaction involving liquid phase, and forms particles by nucleation and growth in ions and molecules (wet chemistry). Therefore, it is easy to make ultra fine particles of 1 μm or less, and the particle size distribution can be controlled.
두번째 제조방법인 액상이 관여하는 습식화학법에서는 용액상태에서 분말을 얻기 위해 침전제의 첨가와 물 등을 첨가하여 침전물을 얻은후 열분해하여 분체를 얻는다. 이렇게 얻어진 침전물은 용액상태에서와는 달리 반응성의 차이 때문에 조성이 불균일해지고, 얻어지는 분말도 비정질이기 때문에 열처리하지 않으면 안되나, 열처리시 입자가 성장하거나 부분적인 소결이 일어나므로 분말의 물성에 좋지 못한 영향을 미친다.In the wet chemical method involving the liquid phase, which is a second manufacturing method, to obtain powder in solution, a precipitate is obtained by adding a precipitant and water, and then pyrolyzing to obtain powder. Unlike the solution state, the precipitate is uneven in composition due to the difference in reactivity, and the powder obtained must be heat treated because it is amorphous.
이러한 문제점을 해결하기 위해서는 용질분자가 용액내에서 활발하게 움직여 분자수준의 혼합이 가능하고 용매의 점도가 낮아 용질분자의 움직임에 영향을 주지 않아야 하며 직접 얻어진 분말도 결정질이어야 한다. 이를 해결하기 위해서는 용액반응의 단점을 개선한 새로운 공정의 대두가 필요하다. 이에 본 발명자는 광범위한 연구를 수행한 결과, 고온, 고압의 조건하에서 대부분의 알코올들은 디에틸에테르와 물을 형성시키고, 여기서 형성된 물을 초임계 유체의 큰 반응성을 활용하여 Ti(OC2H5)4를 초임계 상태에서 가수분해시켜 직접 결정질 아나타제 구형분말을 얻었고, 본 발명은 이에 기초하여 완성되었다.In order to solve this problem, the solute molecules can be actively moved in the solution to enable molecular mixing, the viscosity of the solvent should not affect the movement of the solute molecules, and the powder directly obtained should also be crystalline. To solve this problem, a new process to improve the disadvantage of solution reaction is needed. Accordingly, the inventors have conducted extensive research, and under the conditions of high temperature and high pressure, most alcohols form diethyl ether and water, and the water formed here utilizes the high reactivity of the supercritical fluid to obtain Ti (OC 2 H 5 ). 4 was hydrolyzed in a supercritical state to obtain crystalline anatase spherical powder directly, and the present invention was completed based on this.
따라서, 본 발명의 목적은 지금까지 TiO2분말의 제조에 이용되지 않았던 초임계 유체의 장점을 이용하여 나노크기의 구형 아나타제 TiO2분말을 결정질로 제조하는 방법을 제공하는데 있다.Accordingly, it is an object of the present invention to provide a method for the crystalline preparation of nanosized spherical anatase TiO 2 powders utilizing the advantages of supercritical fluids which have not been used in the manufacture of TiO 2 powders until now.
상기 목적을 달성하기 위한 본 발명의 제조방법은 알코올류, 티타늄 알콕사이드 및 초산을 혼합한 다음, 상기 알콜류의 초임계상태에서 반응시키는 것으로 이루어진다.The production method of the present invention for achieving the above object consists of mixing the alcohols, titanium alkoxide and acetic acid, and then reacting in the supercritical state of the alcohols.
도 1은 일반적인 순수한 성분의 초임계 유체 영역을 나타낸 그래프,1 is a graph showing a supercritical fluid region of a typical pure component,
도 2는 본 발명에 따른 초임계 유체법에 사용되는 오토클레이브를 개략적으로 도시한 도면,2 schematically shows an autoclave used in a supercritical fluid method according to the present invention;
도 3은 본 발명에 따른 초임계 유체법(273℃, 7.3MPa, 2시간)으로 얻어진 분말의 X-선 회절분석,Figure 3 is an X-ray diffraction analysis of the powder obtained by the supercritical fluid method (273 ℃, 7.3MPa, 2 hours) according to the present invention,
도 4는 티타늄 에톡사이드 농도((a)는 0.230몰, (b)는 0.920몰 및 (c)는 1.840몰)에 따른 에탄올의 에탄올의 초임계 유체상태인 273℃, 7.3MPa에서 2시간동안 처리하여 얻어진 구형 아나타제(anatase) 분말의 전자현미경 사진,4 is treated for 2 hours at 273 ° C. and 7.3 MPa in the supercritical fluid state of ethanol according to the titanium ethoxide concentration ((a) is 0.230 mol, (b) is 0.920 mol and (c) is 1.840 mol) Electron micrograph of spherical anatase powder obtained by
도 5는 1000℃에서 1시간 동안 소결시킨 구형의 아나타제 분말의 전자현미경 사진.5 is an electron micrograph of the spherical anatase powder sintered for 1 hour at 1000 ℃.
이하 첨부된 도면을 참조하여 본 발명을 좀 더 구체적으로 살펴보면 다음과 같다.Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.
초임계 유체는 도 1에서와 같이 물질의 임계점보다 높은 온도, 압력에서 존재하는 응축된 가스 상태로 정의된다. 초임계 유체는 액체상도 기체상도 아닌 단일 유체상으로 액체상의 반응성 및 기체상의 침투성, 낮은 점도, 표면장력이 없고, 높은 용질 확산계수 등의 장점을 모두 갖추고 있다. 본 발명에 이용 가능한 유체의 임계조건을 하기 표 1에 기재하였다.Supercritical fluid is defined as the condensed gas state present at a temperature and pressure above the critical point of the material, as in FIG. Supercritical fluids are liquid or gaseous, not a single fluid phase, and have all the advantages of liquid phase reactivity and gas phase permeability, low viscosity, no surface tension, and high solute diffusion coefficient. The critical conditions of fluids usable in the present invention are listed in Table 1 below.
*1atm 1.013×105㎩.* 1atm 1.013 × 10 5 ㎩.
실험실적으로 용액반응에 많이 사용되는 에탄올의 임계밀도(=0.276g/㎤)는 액체밀도(=0.795g/㎤)의 약 ⅓ 정도이다(표 1 참조).The critical density (= 0.276 g / cm 3) of ethanol, which is widely used in laboratory solutions, is about 약 of the liquid density (= 0.795 g / cm 3) (see Table 1).
일반적으로 반응속도는 용질분자의 이동도와 관계가 깊다. 일반 용액 상태에서의 용질의 이동도는 10-5㎠/sec로 온도에는 큰 관계가 없다. 그러나 용매의 TC(임계온도) 및 PC(임계압력)가 넘는 초임계 유체상태가 되면 용질분자의 이동도가 10-4∼10-3㎠/sec로 최고 100배까지 증가하게 되며 이것을 잘 활용하여 용액반응의 결점을 보완한 결정질 분말을 직접얻을 수 있는 새로운 제조공정을 확립하였다.In general, the reaction rate is closely related to the mobility of solute molecules. The mobility of the solute in the general solution state is 10 -5
본 발명의 바람직한 일 실시예에 따르면, 티타늄 에톡사이드(Ti(OC2H5)4)와 용매로서 C2H5OH, 반응속도 제어로서 초산(CH3COOH)을 사용한다. 또한 본 발명에서 이용한 도 2와 같은 오토클레이브(Autoclave) 장치는 물의 임계점 이상인 400℃, 300atm(≒30.4MPa)에서 사용할 수 있도록 스테인레스 스틸로 제작한 것이다. 온도를 올려주면 용매로 사용한 에탄올이 증발하여 초임계 유체상태로 되고 이때 고온에서 에탄올의 분해로 생성된 물을 이용, 가수분해하여 분말을 제조한다. 에탄올의 초임계 유체상태는 상기 표 1에서와 같이 TC=243℃ 이상, 및 PC=63atm(≒6.4MPa) 이상이다.According to a preferred embodiment of the present invention, titanium ethoxide (Ti (OC 2 H 5 ) 4 ) and C 2 H 5 OH as a solvent, acetic acid (CH 3 COOH) is used as the reaction rate control. In addition, the autoclave (Autoclave) device as shown in Figure 2 used in the present invention is made of stainless steel to be used at 400 ℃, 300atm (≒ 30.4MPa) above the critical point of water. When the temperature is raised, the ethanol used as a solvent evaporates and becomes a supercritical fluid state. At this time, hydrolysis is performed using water generated by decomposition of ethanol at high temperature to prepare a powder. The supercritical fluid state of ethanol is T C = 243 ° C. or more, and P C = 63 atm (≒ 6.4 MPa) or more as shown in Table 1 above.
따라서 본 발명에 맞는 에탄올의 초임계 유체상태를 찾기 위해 에탄올 양의 조절이 중요한데 이론치의 1.75배(≒150cc)를 넣어 에탄올 초임계 유체상태를 유지한다. 에탄올의 초임계 유체상태에서 생성되는 물과 Ti(OC2H5)4와의 가수분해 반응을 이용하여 초미립 분말을 제조하고 초임계 유체의 빠른 반응속도를 이용하여 결정화시킨다.Therefore, in order to find the supercritical fluid state of ethanol according to the present invention, it is important to adjust the amount of ethanol 1.75 times the theoretical value (≒ 150cc) to maintain the ethanol supercritical fluid state. Ultrafine powders are prepared by hydrolysis of water and Ti (OC 2 H 5 ) 4 produced in the supercritical fluid state of ethanol and crystallized using the rapid reaction rate of the supercritical fluid.
본 발명에서는 용질의 양을 조절하는 단계, 다시 용액의 양을 조절하는 단계로 구분하여 여러 가지 조건에서 제조된 분말중 물성이 좋은 조건을 채택하여 대량의 미분말을 제조하였다. 다시 말하면, 출발물질인 알콕사이드 원료의 특성은 습도와 온도에 매우 민감하기 때문에 글로브 박스(glove box)를 이용하여 30% 이하의 습도를 유지하면서 용질인 Ti(OC2H5)4, 용매인 알코올류(예를 들어, 에탄올), 가수분해 억제제와 초미립 입자크기 조절제로서 CH3COOH을 혼합한다. 이 혼합물을 균일 혼합하기 위해 자기교반장치로 약 2시간이상 혼합한다. 상기 혼합물과 용매인 알코올을 오토클레이브에 위치시킨후 상기 알코올의 임계점 이상에서 초임계 유체 처리한 후 침전물을 얻는다. 오토클레이브 처리한 용액에서 원심분리기를 사용하여 약 3000rpm 회전수로 10분간 처리한 후 침전물을 분리한다. 그 후 알코올로 세척한 후 다시 증류수로 세척, 건조하여 분말을 얻는다. 또한 구형입자의 형태를 유지하면서 한번에 최대로 처리할 수 있는 양을 알기 위해 용액의 양을 조절한다. 마지막으로 상기와 같이 여러조건에서 제조된 분말중 물성이 좋은 조건을 채택하여 대량의 미분말을 제조한다.In the present invention, by adjusting the amount of solute, and again to adjust the amount of the solution to adopt a good physical properties of the powder prepared under various conditions to prepare a large amount of fine powder. In other words, since the characteristics of the alkoxide raw material as a starting material are very sensitive to humidity and temperature, a solute Ti (OC 2 H 5 ) 4 and a solvent alcohol are maintained while maintaining a humidity of 30% or less using a glove box. (Eg ethanol), a hydrolysis inhibitor and CH 3 COOH as an ultrafine particle size regulator. The mixture is mixed for about 2 hours or more with a magnetic stirrer to uniformly mix the mixture. The mixture and the alcohol, which is the solvent, are placed in an autoclave and subjected to supercritical fluid treatment above the critical point of the alcohol to obtain a precipitate. In the autoclaved solution using a centrifugal separator for 10 minutes at about 3000rpm revolutions to separate the precipitate. After washing with alcohol and then again with distilled water and dried to obtain a powder. It also controls the amount of solution to know the maximum amount that can be processed at one time while maintaining the shape of the spherical particles. Finally, a large amount of fine powder is prepared by adopting conditions having good physical properties among the powders prepared under various conditions as described above.
이하 실시예를 통하여 본 발명을 좀더 상세히 설명하겠지만, 이에 본 발명의 범주가 한정되는 것은 아니다.Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited thereto.
실시예 1Example 1
본 실시예에서는 ALDRICH사의 티타늄(Ⅳ) 에톡사이드(Ti(OC2H5)4)와 용매로서 Hayman Limited사의 에틸올(C2H5OH) 99.9%, 반응속도 제어제로서 TEDIA사의 초산(CH3COOH) 99.7%를 사용한다. 에탄올의 초임계 유체상태(273℃, 7.3㎫)에서 Ti(OC2H5)4의 농도를 0.115∼1.840㏖/ℓ, C2H5OH는 16.420㏖/ℓ, CH3COOH는 Ti(OC2H5)4양의 절반으로 하고 전체용액의 양은 10㏄, 용매인 에탄올을 150cc로 하여 분말을 제조하였다. 얻어진 분말은 X-선 회절분석장치로 모두 결정질 아나타제 상인 것을 확인하였고, 주사전자현미경으로 측정한 결과 모두 구형형태 입자로 1차 입자크기가 20㎚이다. 응집입자의 크기조절도 가능하여 용질의 농도가 증가함에 따라 입자크기가 증가하였다.In this example, titanium (IV) ethoxide (Ti (OC 2 H 5 ) 4 ) of ALDRICH, 99.9% ethylol (C 2 H 5 OH) of Hayman Limited as a solvent, acetic acid (CH) of TEDIA as a reaction rate controlling agent. 3 COOH) 99.7%. In the supercritical fluid state of ethanol (273 ° C, 7.3 MPa), the concentration of Ti (OC 2 H 5 ) 4 was 0.115-1.840 mol / l, C 2 H 5 OH was 16.420 mol / l, and CH 3 COOH was Ti (OC 2 H 5 ) 4 was used as a half and the total amount of the solution was 10 cc, and 150 cc of ethanol as a solvent was used to prepare a powder. The obtained powders were all confirmed to be crystalline anatase phase by X-ray diffractometer. As a result of scanning electron microscopy, all powders were spherical particles having a primary particle size of 20 nm. The size of the aggregated particles can also be controlled so that the particle size increases with increasing solute concentration.
한편, 용질농도의 변화에 따른 결과에서 물성을 변화시키지 않고 한번에 최대로 처리할 수 있는 용액 양을 알기 위해 최적조건인 Ti(OC2H5)40.230㏖/ℓ, C2H5OH 16.420㏖/ℓ, CH3COOH는 Ti(OC2H5)4양의 절반으로 하여, 전체 용액의 양을 20∼80㏄로 조절하였다. 60㏄까지는 구형형태의 입자를 유지하나 80㏄ 이상에서는 구형이 아닌 다른 형태의 분말을 얻었다. 한편, 상기 에탄올 대신에 메탄올, 부탄올, 또는 프로판올을 사용할 수 있으며, 당업계에 통상의 지식을 가진자라면 그 최적 조건 또한 본 발명을 범주내에서 용이하게 구할 수 있다.On the other hand, the most suitable conditions to find the solution amounts that can handle up to at a time without changing the physical properties of the results according to the change in solute concentration of Ti (OC 2 H 5) 4 0.230㏖ / ℓ, C 2 H 5 OH 16.420㏖ / L, CH 3 COOH was adjusted to half of the Ti (OC 2 H 5 ) 4 amount, the amount of the total solution was adjusted to 20 ~ 80 kPa. The particles of spherical shape were maintained up to 60 Hz, but other than non-spherical powders were obtained above 80 Hz. On the other hand, methanol, butanol, or propanol may be used instead of the ethanol, and those skilled in the art can easily obtain the optimum conditions within the scope of the present invention.
TiO2는 전자세라믹스용 재료로 널리 사용되고 있으며, MTiO3(M=Ba, Pb, Sr, ……)의 주요 구성물질이기도 하다. 또한 반도체 특성을 이용한 촉매로 활용되고 있는 매우 우수한 광촉매 TiO2는 강한 산화환원력 때문에 물을 수소와 산소로 분해시킬 수 있어 이때 발생되는 수소를 이용하여 청정에너지로 사용할 수 있다. 이러한 산화력을 이용하면 수중 및 공기중의 난분해성 유해화학물질이나 악취물질, 질소 산화물(NOx), 유분의 분해나 방균·방곰팡이 등 폭넓게 환경재료에 널리 사용될 가능성이 있는 재료이다. 최근 활용범위가 다양하여 유리에 TiO2를 코팅하여 90% 이상의 대장균을 사멸시키는 항균 TiO2유리컵 등장, 항균타일, 그리고 병원균 사해(死骸)나 독소까지 분해하는 사실이 확인되었고 그밖에 반도체특성과 온도특성을 이용 자동차 배기가스 산소센서와 습도센서에 널리 활용되고 있다. 따라서, 전술한 바와 같이 응용성이 많은 TiO2분말을 초미립 형태로 제조하는 것이 중요하다.TiO 2 is widely used as a material for electron ceramics, and is also a major component of MTiO 3 (M = Ba, Pb, Sr, ...). In addition, the excellent photocatalyst TiO 2, which is used as a catalyst using semiconductor characteristics, can decompose water into hydrogen and oxygen due to its strong redox power, and thus can be used as clean energy using hydrogen generated at this time. By using such oxidizing power, it is a material that can be widely used in environmental materials such as hardly decomposable harmful chemicals, odorous substances, nitrogen oxides (NO x ), oils, antibacterial and mildew in water and air. Recently Areas of the antimicrobial TiO 2 glass appeared to vary the death of over 90% of E. coli coated with TiO 2 in the glass, antibacterial tiles, and pathogens Dead (死骸) and this was confirmed in fact that break up toxin Other semiconductor characteristics and temperature It is widely used in automobile exhaust gas oxygen sensor and humidity sensor. Therefore, as described above, it is important to prepare a highly applicable TiO 2 powder in an ultrafine form.
한편, 상기 실시예로 부터 알 수 있는 바와 같이, 얻어진 분말은 상당량이 아나타제 결정으로 합성되어 열처리 과정없이 직접 결정질 분말을 얻을 수 있었으며 온도와 압력을 조절하면 결정화도가 더욱 좋아진 분말을 얻을 수 있었다. 도 4는 용질의 농도 변화에 따른 에탄올의 초임계 유체 상태인 270℃, 7.3MPa에서 2시간 처리한 분말의 사진이다. 1차 입자크기가 20nm의 미분말들이 모여 구형 응집입자를 형성하고 있다. 도 5는 상기 실시예에서 얻어진 분말을 1000℃에서 1시간 동안 열처리 한 분말들의 사진이다. 구형형태를 유지하면서 하나의 구형 소결체내에 많은 나노크기의 입자가 소결되어 존재하는 것을 볼 수 있다. 그리고, 여러조건에서 제조된 분말중 물성이 좋은 조건을 채택하여 대량의 미분말을 제조하였다. 현재 시판되고 있는 TiO2와 비교하여 보면, 초임계 유체법으로 얻어진 TiO2는 알려진 상전이 온도(약 1000℃ 이상)보다 100℃ 낮은 890∼900℃의 온도에서 루틸(rutile) 상으로 완전히 상전이가 일어났고 또한 800℃의 상당히 낮은 온도에서도 치밀한 소결체를 얻을 수 있었다.On the other hand, as can be seen from the above examples, the obtained powder was synthesized in a significant amount of anatase crystals to obtain a crystalline powder directly without a heat treatment process, it was possible to obtain a powder with better crystallinity by adjusting the temperature and pressure. Figure 4 is a photograph of the powder treated for 2 hours at 270 ℃, 7.3MPa of the supercritical fluid state of ethanol according to the concentration change of the solute. Fine particles of 20 nm in primary particle size gather to form spherical aggregated particles. 5 is a photograph of powders obtained by heat-treating the powder obtained in the above example at 1000 ° C. for 1 hour. It can be seen that many nano-sized particles are sintered in one spherical body while maintaining the spherical shape. In addition, a large amount of fine powder was prepared by adopting conditions having good physical properties among powders prepared under various conditions. Compared with TiO 2 on the market, and second TiO 2 obtained by the supercritical fluid method is a completely up phase transition at a temperature of 100 ℃ low 890~900 ℃ than the known phase transition temperature (about 1000 ℃) onto rutile (rutile) In addition, a dense sintered body was obtained even at a considerably low temperature of 800 ° C.
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| KR100355572B1 (en) * | 2000-05-15 | 2002-10-11 | 주식회사 지투케이 | a particle catalyst manufaction method |
| KR100445387B1 (en) * | 2001-07-26 | 2004-08-25 | 학교법인 한양학원 | A method and an apparatus for prepararing titania particle |
| KR101054444B1 (en) | 2008-11-13 | 2011-08-05 | 한국과학기술연구원 | Continuous production method of surface-modified nanoparticles using supercritical fluid and surface-modified nanoparticles prepared by the method |
| CN105126800A (en) * | 2015-08-24 | 2015-12-09 | 苏州聚康新材料科技有限公司 | Granite-loaded nano titanium dioxide photo-catalytic material and preparation method therefor |
| CN105195125A (en) * | 2015-08-24 | 2015-12-30 | 苏州聚康新材料科技有限公司 | Feldspar loaded nano-titanium dioxide photocatalytic material and preparation method thereof |
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| KR100435314B1 (en) * | 2001-04-13 | 2004-06-10 | (주)나노닉스 | Method for preparation of inorganic nanoparticles |
| KR100446869B1 (en) * | 2001-09-08 | 2004-09-04 | 학교법인 한양학원 | Preparation method for metal oxide nanoparticles |
| KR101236969B1 (en) * | 2009-12-28 | 2013-02-25 | 주식회사 휘닉스소재 | Method of preparing titania nano-powder for dye-sensitized solar cell, method of preparing titania nano-dispersion, and photocatalyst |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100355572B1 (en) * | 2000-05-15 | 2002-10-11 | 주식회사 지투케이 | a particle catalyst manufaction method |
| KR100445387B1 (en) * | 2001-07-26 | 2004-08-25 | 학교법인 한양학원 | A method and an apparatus for prepararing titania particle |
| KR101054444B1 (en) | 2008-11-13 | 2011-08-05 | 한국과학기술연구원 | Continuous production method of surface-modified nanoparticles using supercritical fluid and surface-modified nanoparticles prepared by the method |
| CN105126800A (en) * | 2015-08-24 | 2015-12-09 | 苏州聚康新材料科技有限公司 | Granite-loaded nano titanium dioxide photo-catalytic material and preparation method therefor |
| CN105195125A (en) * | 2015-08-24 | 2015-12-30 | 苏州聚康新材料科技有限公司 | Feldspar loaded nano-titanium dioxide photocatalytic material and preparation method thereof |
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