CN1593750A - TiO#-[2] based photocatalyst used for organic matter natural light degradation and preparation method thereof - Google Patents

Abstract

The invention relates to titanium dioxide photocatalyst for natural light degradation of organic matter and its manufacturing method. The catalytic agent is composed with a lanthanide of the rare earth and the mixture of C element and a substratum of titanium dioxide. In the components, the mole content of lanthanide is 0.01%-5% and the C mole content is 0.01%-5%. C adulterates in the volume phase in order to replace the O of titanium dioxide; the rare earth element adulterates in the volume phase of titanium dioxide, or deposits in the surface, or the both. The catalytic agent is manufactured by the collosol and gelatinous way. The invention mixes the solution of fetrabutyl titanate, absolute alcohol and glacial acetic acid with the solution of absolute alcohol in the lanthanide nitrate. Under stirring the solution mentioned above, add the water solution of tetra butyl group ammonium hydroxide, in order to make the PH up to 4-6. Then after laying it until being the gel, make it be desiccated, abraded and roasted, so the photocatalyst can be required. The catalytic agent can be used for the natural light degradation of the organic matter, and has no impressed luminaire so that it can save energy.

Description

Be used for the organic TiO of natural photodegradation 2Based photocatalyst and preparation method thereof

Technical field

The present invention relates to a kind of organic TiO of natural photodegradation that is used for ₂Based photocatalyst and this Preparation of catalysts method.

Background technology

The world today is faced with population, resource and environment three big problems, and water resource is irreplaceable a kind of valuable source in the various resources.Water pollutes and makes then that originally just water resource very in short supply becomes more deficient.

The method of having developed at present multiple processing waste water is as, physical treatment process: precipitation, filtration, centrifugation, extraction, stripping, absorption, evaporative crystallization, counter-infiltration etc.; Method of chemical treatment: neutralization, redox, ion-exchange, electro-osmosis etc.; Biological treatment: aerobic treatment method (as active matter mud method, biofilter etc.), Anaerobic Treatment method (being mainly digester).But they have mostly energy consumption big, bring secondary pollution or can not deep purifying etc. defective.

Since John H.Carey in 1976 (Carey J.H., Lawrence J., Tosine H.M., Bull.Environ.Contam.Toxicol., 1976,16:697) with TiO ₂Photocatalysis technology is applied to the dechlorination of Polychlorinated biphenyls, and photocatalysis to degrade organic matter earns widespread respect to handle waste water.Use photocatalysis technology organic pollution in the degradation water fully, make organic matter finally be degraded to H ₂O, CO ₂And inorganic ions, can not bring secondary pollution, owing to it is with a wide range of applications, thereby comparatively fast developed.The eighties, Pruden (PrudenA.L., Ollis D.F., J.Catal., 1983,82:404) and (Ollis, D.F., NATO ASI Ser. such as Ollis, Ser.C, 1986,174:651) successively studied dichloroethylene, carrene, methylene bromide, chlorobenzene, dichloroacetic acid etc. at TiO ₂Photocatalytic degradation in the suspension, effect is remarkable.The nineties, photocatalysis to degrade organic matter obtains flourish especially, (Matthews R.W., Abdullah M., Low G.H.C., Anal.Chim.Acta., 1990,233 (2): 171) once adopted nano-TiO such as Matthew ₂Photocatalysis Decomposition to multiple organic pollutant in the water is carried out system research.Yet application of pure TiO ₂Degradation of organic substances has the shortcoming that the quantum conversion ratio is low, speed is slower, around improving this target of photocatalysis efficiency, with TiO ₂Be the matrix field, scholars have carried out extensive studies.Developed that noble metal loadings such as Pt, Pd, Ag, semiconductor are compound, a series of technology such as metal ion, nonmetallic ion-doped and surface modification, delivered serial paper.Hoffmann etc. (HoffmanM.R., Martin S.T., Choi w.et al.Chem.Rev., 1995,95:69) this has been done summary preferably.Yet research originally mainly is confined to utilize ultraviolet degradation, and sunshine medium ultraviolet light part only accounts for about 4% of whole energy, uses artificial light source such as high-pressure sodium lamp, black light lamp and bactericidal lamp to need to consume a large amount of energy again.So TiO of exploitation visible-light response type ₂Based photocatalyst just becomes the research emphasis of photocatalysis technology.At present, industrialized photocatalysis equipment includes light source and auxiliary equipment, and power consumption is big.The end of the seventies in last century, the beginning of the eighties, (Michael Graetzel, Academic Press, Inc. (London), Ltd., 1983,71) application surface dye sensitization technology such as Switzerland scholar Graetzel are first with TiO ₂The activity of based photocatalyst is introduced visible region, and it mainly is used on the photo-reduction degradation of contaminant, but can produce secondary pollution simultaneously, so there is not technical advantage.Some have appearred thereafter as CdS and CdS-TiO ₂Visible light catalysts such as composite semiconductor." Science " magazine had been delivered (Shahed U.M.Khan such as Khan in 2002, MofarehAl-Shahry, William B.Ingler Jr.et al.Science, 2002,297 (27): 2243) thus burn in natural gas with the Ti metal and to obtain mixing the TiO of C ₂The report of photochemical catalyst, he has reduced the energy gap of TiO2, and the photocatalytic activity of TiO2 is introduced visible region.(ShanmugasundaramSakthivel such as German Sakthivel in 2003, Horst Kisch, et al.Angew.Chem.Int.Ed. 2003,42,4908) using TiC14 is the TBAH solution hydrolysis of presoma at 0.25mol/L, and wet method makes the TiO that mixes C ₂, and carried out the research of indoor natural light degraded 4-chlorophenol, succeed.But the introducing of single nonmetalloid may destroy the generation that the system charge balance causes oxygen vacancy, and the oxygen room becomes the electron/hole-recombination center in the light-catalyzed reaction process, reduces the light quantum conversion ratio.

Summary of the invention

The purpose of this invention is to provide and a kind of natural daylight is had highly-responsive and the TiO of high catalytic activity is arranged ₂Based photocatalyst directly utilizes organic matter in the sunshine degradation water in the process of disposing of sewage, reduce energy resource consumption to save cost of water treatment.

Photochemical catalyst of the present invention is lanthanide series rare-earth elements, carbon and TiO ₂Substrate composed compound, wherein the lanthanide series molar content is 0.01%～5%, the best is 0.5%～1.5%; The molar content 0.01%～5.0% of carbon, the best are 1%～3%; Said lanthanide series is meant a kind of among element La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, the Lu.

In this TiO2 based photocatalyst, C is entrained in the body phase, replaces TiO ₂In part of O, rare earth element ion is entrained in TiO ₂Body mutually or be deposited on the surface, or the two has concurrently.

This catalyst is a dark gray powder, and particle diameter is distributed as 10～500nm, and specific area is 5～150m ²/ g.

The C that mixes has replaced matrix TiO ₂In part of O, reduced semi-conductive energy gap, enlarged its photoresponse scope; Mixing of lanthanide element kept the charge balance of system, reduced oxygen vacancy-promptly reduced the complex centre of electrons/, improved photocatalysis efficiency.Therefore, catalyst of the present invention is applied to the natural photodegradation organic matter, does not need to add light source, has reduced energy resource consumption.This photochemical catalyst can be in degradation water under the natural daylight organic matter, heavy metal ion in the reductive water is carried out industry, sanitary sewage disposal, also can be used for the deep purifying of drinking water.Simultaneously also can be used for decomposition water and produce hydrogen.

TiO of the present invention ₂The preparation method of based photocatalyst, following steps:

(1) butyl titanate, absolute ethyl alcohol, glacial acetic acid is made into mixed solution by 1: 1～30: 0.1～5 mol ratios, is stirred well to form uniform solution;

(2) lanthanide series metal nitrate hydrate is dissolved in 1～30 times in the absolute ethyl alcohol of butyl titanate mole, make even mixed solution; The addition of said lanthanide series metal nitrate hydrate gets according to the incorporation calculating of lanthanide series metal in the catalyst.

(3) solution that step (2) is made slowly adds in step (1) mixed solution, constantly stirs in the adition process, and solution temperature is constant in 10～50 ℃;

(4) solution mixes and to be stirred well to solution when finishing and to mix;

(5) under the mixed solution vigorous stirring with step (4), slowly add the TBAH aqueous solution, reach 4～6 until the pH value;

(6) continue to stir, leave standstill in the air until forming gel, ageing a couple of days;

(7) gel is put into baking oven in 60 ℃～120 ℃ dryings 5～20 hours, takes out, and grinds, and puts into the Muffle furnace roasting, is warming up to 260～600 ℃, is incubated 0.1～5 hour.Control sintering temperature and time, can obtain the catalyst that different carbon contents are mixed.

Description of drawings

Fig. 1 is the TiO of La, C codope ₂Photochemical catalyst XRD figure spectrum.Catalyst is single Detitanium-ore-type as seen from Figure 1.

Fig. 2 is pure TiO ₂, La, C codope TiO ₂The ultraviolet-visible diffuse reflection spectrum.A is the TiO that lanthanum 1.0%, carbon dope 0.6% are mixed in this patent preparation ₂Catalyst based, B is pure TiO ₂

Fig. 3 is indoor natural light degraded methyl orange curve map.

Fig. 4 is outdoor sunshine degraded methyl orange curve map.

Fig. 5 is a 300W visible light Xe lamp degraded rhodamine B curve map.

The abscissa of Fig. 1 is 2 times of angles of diffraction, and ordinate is a diffraction peak intensity.

The abscissa of Fig. 2 is for absorbing optical wavelength, and ordinate is an absorbance.

Among Fig. 3～Fig. 5, C ₀The expression initial concentration; C represents the concentration of not degrading; The C/C of ordinate ₀Be degradation rate not, abscissa is the time.

The specific embodiment

Embodiment 1 TiO of the present invention ₂The preparation of based photocatalyst

Embodiment 1 (1)

Be made into mixed solution I with 30ml butyl titanate, 50ml absolute ethyl alcohol and 5ml glacial acetic acid; 0.4 gram lanthanum nitrate hexahydrate is dissolved in the 50ml absolute ethyl alcohol, forms mixed solution I I; Solution II is added solution I, form mixed solution I II, drip 2.0ml TBAH solution to solution III, left standstill 2 days, and formed gel, 70 ℃ of freeze-day with constant temperature 12 hours, grind, put into Muffle furnace and heat up,, can obtain mixing the TiO of lanthanum 1.0%, carbon dope 0.6% (mole) 400 ℃ of insulations 1 hour ₂Based photocatalyst.

This catalyst and pure TiO ₂The ultraviolet-visible diffuse reflection spectrum see Fig. 2, pure as seen from Figure 2 TiO ₂There is not activity at visible region greater than the 400nm wavelength, and the TiO of present embodiment ₂Based photocatalyst has the catalytic activity of responding to visible light in that very strong absorption is arranged greater than the 400nm visible region.

Embodiment 1 (2)

Method is just changed into the input amount of nitric hydrate lanthanum 0.2 gram with embodiment 1 (1), and the roasting holding temperature changes 500 ℃ into, then can obtain mixing the TiO of lanthanum 0.5%, 0.08% (mole) ₂Based photocatalyst.

Change sintering temperature and temperature retention time, also can obtain the TiO of different carbon dope amounts ₂Based photocatalyst.

Catalyst is a grey black, specific area 60.9m ²/ g, XRD figure spectrum is seen Fig. 1, is characterized as seen by the XRD of Fig. 1, crystal formation is single Detitanium-ore-type.

Embodiment 2 TiO of the present invention ₂The based photocatalyst organic example of under Different Light, degrading

TiO with mixed 1% (mol) La, 1 hour La of 400 ℃ of roastings, C codope ₂Based photocatalyst carries out the methyl orange with indoor natural light, outdoor sunshine degraded 5mg/L respectively, and is as follows with the experiment of 300W xenon lamp simulated solar light degradation 5mg/L rhodamine B:

Embodiment 2 (1):

The place: Nanjing, weather is fine, 20～27 ℃ of temperature

Time: the 13:20～17:20 on May 6th, 2004, the 8:00～12:00 on May 7,

Light source: inject indoor natural daylight by 230 * 210cm window

With methyl orange is the target degradation product, gets the methyl orange solution 400ml with 5mg/L, adds the photochemical catalyst of 0.4g, places indoorly, stir and make catalyst be suspended in solution, and degradation time 8 hours, measuring methyl orange content subsequently is 1.26mg/L, degradation rate is 74.6%.The methyl orange degradation curve is seen Fig. 3.

Embodiment 2 (2)

The place: Nanjing, weather is fine, 25～30 ℃ of temperature

Time: on May 18th, 2004 10:15～13:15

Light source: direct sunlight

5mg/L methyl orange solution 200ml is injected beaker, add photochemical catalyst of the present invention, cover glass sheet on the beaker in the degraded down of outdoor sunshine, then gets degradation rate about 75% after 3 hours.Sunshine methyl orange degradation curve is seen Fig. 4.

Embodiment 2 (3)

With the Xe lamp simulated solar irradiation of 300W, the rhodamine B of degraded 5mg/L, behind the 80min, the rhodamine B degradation rate reaches more than 98%.Xe lamp degraded rhodamine B curve map is seen Fig. 5.

Claims (4)

1. one kind is used for the organic TiO of natural photodegradation ₂Based photocatalyst is characterized in that by lanthanide series rare-earth elements, carbon and TiO ₂Substrate composed compound, wherein the lanthanide series molar content is 0.01%～5%, the molar content 0.01%～5.0% of carbon, said lanthanide series are meant a kind of among element La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, the Lu.

2. be used for the organic TiO of natural photodegradation according to claim 1 ₂Based photocatalyst is characterized in that the lanthanide series molar content is 0.5%～1.5%, and the molar content of carbon is 1%～3%.

3. be used for the organic TiO of natural photodegradation according to claim 1 ₂Based photocatalyst is characterized in that C is entrained in the body phase, replaces TiO ₂In part of O, rare earth element ion is entrained in TiO ₂Body mutually or be deposited on the surface, or the two has concurrently.

4. the TiO of a claim 1 ₂The preparation method of based photocatalyst is characterized in that as follows:

(1) butyl titanate, absolute ethyl alcohol, glacial acetic acid is made into mixed solution by 1: 1～30: 0.1～5 mol ratios, is stirred well to form uniform solution;

(2) lanthanide series metal nitrate hydrate is dissolved in 1～30 times in the absolute ethyl alcohol of butyl titanate mole, make even mixed solution;

(3) solution that step (2) is made slowly adds in step (1) mixed solution, constantly stirs in the adition process, and solution temperature is constant in 10～50 ℃;

(4) fully stir after the solution mixing is finished and mix until solution;

(5) under the mixed solution vigorous stirring with step (4), slowly add the TBAH aqueous solution, reach 4～6 until the pH value;

(6) continue fully to stir, leave standstill in the air, until forming gel, ageing a couple of days:

(7) gel is put into baking oven in 60 ℃～120 ℃, and dry 5～20 hours, take out, grind, put into the Muffle furnace roasting, be warming up to 260～600 ℃, be incubated 0.1～5 hour.

Images