CN103084163B - Process for coating Bi2O3/TiO2 photocatalysis film on surface of hollow lightweight glass sphere - Google Patents
Process for coating Bi2O3/TiO2 photocatalysis film on surface of hollow lightweight glass sphere Download PDFInfo
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- CN103084163B CN103084163B CN201210545555.5A CN201210545555A CN103084163B CN 103084163 B CN103084163 B CN 103084163B CN 201210545555 A CN201210545555 A CN 201210545555A CN 103084163 B CN103084163 B CN 103084163B
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Abstract
The invention discloses a process for coating a Bi2O3/TiO2 photocatalysis film on the surface of a hollow lightweight glass sphere and discloses application of the hollow lightweight glass sphere with a surface coated with the Bi2O3/TiO2 photocatalysis film. According to the process, bismuth nitrate, titanium tetrabutoxide, nitric acid, water, pentanediol, polyethylene glycol, acetylacetone and the like are adopted for forming a precursor solution; the sphere is rotatably coated with a film and then is quickly dried to obtain the uniform Bi2O3/TiO2 catalyst film; the glass sphere with the Bi2O3/TiO2 photocatalysis film coated on the surface is placed into a suspending type photocatalysis reactor and can be used for degrading organic pollutants such as methyl orange under illumination, and the glass sphere is excellent in photocatalysis performance; the process has the advantages that the raw materials are easily available, the preparation cost is low, the film coating process is simple, and the condition is easy to control; and the liquid film on the surface of the glass sphere is thin, has high light transmittance and high transfer efficiency, does not need to be separated and recycled and is capable of continuously working; and simultaneously, the process provides reference value respect to other film coating technologies and brings basic theoretical basis for designing and amplifying the photocatalysis reactor in future.
Description
Technical field
The invention belongs to the preparation technique and application field of conductor photocatalysis reactor, be specifically related to a kind of hollow light glass marble plated surface Bi
2o
3/ TiO
2the technique of photocatalysis film.
Background technology
The high speed development of world industry also brings many environmental problems while providing enrich material life to people.The healthy living that discharge destroys the ecological balance, people in contaminated environment, serious threat of discarded object in industrial production.Wherein, waste water from dyestuff is one of industrial wastewater of current difficult degradation, and color and luster is dark, and toxicity is large, and have carcinogenicity, environmental pollution is serious.Conductor photocatalysis material due to Strong oxdiative ability can degrade multiple hazardous contaminant, environmental friendliness, can solar energy be utilized, the features such as the gentle and cost of reaction condition is low make it have extremely wide application prospect.Wherein, TiO
2material because photocatalytic activity is high, stable in properties, nontoxic and material cheap, become the current photochemical catalyst most with application potential.
But there are three major defects in powder catalysis material in wastewater treatment: 1) because organic matter itself is to " screen effect " of the absorption of exciting light and catalyst powder self, exciting light penetration depth is in the solution too shallow, thus the degradation efficiency of unit mass catalyst is declined; 2) light induced electron and hole make degradation efficiency decline in the easy compound voluntarily of powder catalyst surface; 3) powder catalyst is not easily separated with solution after disperseing in aqueous, is difficult to the recovery and reuse realizing catalyst.Compared with powder catalyst, TiO
2photocatalysis film can avoid loss because catalyst causes with being separated of reactant and energy waste in actual applications.Meanwhile, in the design of photo catalysis reactor if consider that the problems such as the low and mass-transfer efficiency of current ubiquitous irradiation light utilization efficiency is low will have using value more.
In floating type photo catalysis reactor designed by the present invention, glass marble surface thickness of liquid film is little, thus light transmittance is high and mass-transfer efficiency is high, simultaneously coating process is easy, without the need to separation and recovery catalysis material, has reference to the design of photo catalysis reactor from now on and coating technique.
Summary of the invention
The object of the invention is to solve in photo catalysis reactor design and irradiate the problems such as light utilization efficiency is low, mass-transfer efficiency is low and obtain the coating technique of simple and effective, a kind of novel photocatalysis reactor and with low cost, easy-operating coating process are provided.
The preparation method of photocatalyst film of the present invention comprises the following steps:
Hollow light glass marble plated surface Bi
2o
3/ TiO
2the technique of photocatalysis film, is characterized in that, comprises the following steps:
(1) precursor aqueous solution is prepared: the mixed solution A of preparation pentanediol, water, polyethylene glycol and ethanol, the mixed solution B of tetrabutyl titanate and acetylacetone,2,4-pentanedione, adds A in B, mixes rear red fuming nitric acid (RFNA) adjust ph to 3-4, then add five nitric hydrate bismuths, obtain precursor aqueous solution; In A, the amount ratio of pentanediol, water, polyethylene glycol and ethanol is (0.2-1.0) g:(0.5-1.5) g:(0.5-3.0) g:(70-150) mL, in B, the volume ratio of tetrabutyl titanate and acetylacetone,2,4-pentanedione is (1-20): (0.5-5), the volume ratio of A and B is 15-25:1, and the mol ratio of bismuth and titanium is 0.5-2.5%;
(2) hollow light glass marble being placed in precursor aqueous solution and rotating makes its surface fully contact with precursor liquid, takes out glass marble and dries up, obtain the glass marble of uniform coated, dry 1-2h at 100-110 DEG C;
(3) repeat step (2) 0-4 time, obtain the film of different-thickness;
(4) glass marble is placed at 450-550 DEG C of high-temperature calcination 3-5h in Muffle furnace, obtains surface and be coated with Bi
2o
3/ TiO
2the glass marble of photocatalysis film.
Described hollow light glass marble is simple glass hollow ball, and density is 2.5-2.6g/cm
3, glass marble diameter is 10-11mm, wall thickness 0.3-0.4mm.
In order to obtain better coating effects, first pretreatment can be carried out to glass marble surface:
First remove surface impurity, adopt 1.0M H
2sO
4cavity glass marble 24h is soaked, in 80 DEG C of dry 2h after deionized water and ethanol purge under solution room temperature;
Carry out surface active afterwards, under adopting 1.0M NaOH solution room temperature, soak cavity glass marble 24h, in 80 DEG C of dry 2h after deionized water and ethanol purge.
Preferably, the volume ratio of tetrabutyl titanate and acetylacetone,2,4-pentanedione is 4:1 in step (1), and the amount ratio of pentanediol, water, polyethylene glycol and ethanol is the volume ratio of 0.25g:0.7g:2.0g:100mL, A and B is 20:1, and the mol ratio of bismuth and titanium is 1%.
Preferably, in step (3), number of repetition is 2 times, i.e. plated film 3 layers.
Preferably, in step (4), calcining heat is 500 DEG C, and the time is 4h.
There is above-mentioned technique can obtain plated surface Bi
2o
3/ TiO
2the hollow light glass marble of photocatalysis film, in floating type reactor, places 60 surfaces and is coated with Bi in reactor
2o
3/ TiO
2the glass marble of photocatalysis film, reactor diameter 125mm, the bubbling loop diameter 85mm of bottom, is uniformly distributed 12 pores, each hole diameter 5mm.Can obtain different reaction conditions by changing different gas speed, the gas speed scope in reactor is 0.28-0.60m/s, and OGV optimum gas velocity is 0.47m/s, and corresponding gas holdup is 0.32-0.43, and wherein best gas holdup is 0.39.
Above-mentioned plated surface Bi
2o
3/ TiO
2the hollow light glass marble of photocatalysis film may be used for Photocatalytic Degradation of Methyl Orange.
Product prepared by the present invention carries out structural characterization by following means: adopt the X ray diffracting spectrum measured on Japanese RigakuD/Max-RB type X-ray diffractometer to carry out the structural analysis of sample; The stereoscan photograph obtained at Japanese JEOL JSM-6380LV type ESEM is adopted to analyze the appearance structure of sample.Adopt light abstraction width and the optical absorption intensity of the UV-vis DRS spectrum analysis sample obtained on Shimadzu UV-2450 type spectrophotometer.
Degraded system provided by the present invention is 150mL 5 × 10
-6m methyl orange solution is placed in floating type photo catalysis reactor, investigates its catalytic performance.Concrete steps are: make glass marble rotate 30 minutes to reach adsorption equilibrium before illumination, open light source afterwards and start reaction.A 500W Xe lamp is positioned at reactant ullage 18cm place as light source, and reaction temperature is 30 DEG C, and the reaction time is 6 hours.The absorbance that methyl orange concentration after reaction in solution measures at 464nm place according to ultraviolet specrophotometer (UV 7504/PC) calculates.
The present invention, compared with existing photo catalysis reactor, has the following advantages: irradiate light utilization efficiency high, the features such as mass-transfer efficiency is high, and coating process is simple, easy to operate, solve the separation and recovery problem of powder photocatalyst.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of floating type photo catalysis reactor provided by the present invention.
Fig. 2 is Bi prepared by embodiment 1
2o
3/ TiO
2the XRD collection of illustrative plates of photocatalysis film under different sintering temperature.
Fig. 3 is Bi prepared by embodiment 1
2o
3/ TiO
2(a) surface and (b) side SEM photo of photocatalysis film.
Fig. 4 is Bi prepared by embodiment 1-5
2o
3/ TiO
2the UV-vis DRS collection of illustrative plates of photocatalysis film.
Fig. 5 is Bi prepared by embodiment 1-5
2o
3/ TiO
2the photocatalytic activity of photocatalysis film compares.
Fig. 6 is the Bi that embodiment 1 is prepared with embodiment 6-9
2o
3/ TiO
2the photocatalytic activity of photocatalysis film compares.
Fig. 7 is the Bi that embodiment 1 is prepared with embodiment 10-12
2o
3/ TiO
2the photocatalytic activity of photocatalysis film compares.
Fig. 8 is Bi prepared by embodiment 1
2o
3/ TiO
2the service life cycle test of photocatalysis film.
Detailed description of the invention
Be making further detailed, clear and complete description of how realizing below in conjunction with specific embodiment to the present invention, listed embodiment is only further described the present invention, not thereby limiting the invention:
Embodiment 1
After glass marble surface treatment, 0.25g pentanediol, 0.7g water, 1.0g polyethylene glycol, 100mL ethanol be made into solution A and stir 30min, 4mL tetrabutyl titanate and 1mL acetylacetone,2,4-pentanedione mix and blend 30min being made into B solution simultaneously.Solution A is joined in B solution, add 2mL red fuming nitric acid (RFNA) adjustment pH to 3-4 after mixing, add five nitric hydrate bismuths afterwards in the solution, make Bi/Ti mol ratio be 1.0%, can precursor aqueous solution be obtained.Glass marble being placed in precursor aqueous solution and rotating makes its surface fully contact with precursor liquid, and taking-up bead hair-dryer dries up rapidly and obtains homogeneous film and to be placed in baking oven dry 1h at 100 DEG C.Repeat aforesaid operations 2 times, namely coating times is after 3 times, glass marble is placed at 500 DEG C of roastings in Muffle furnace within 4 hours, namely to obtain surface and be coated with Bi
2o
3/ TiO
2the glass marble of photocatalysis film.Glass marble after plated film is placed in floating type reactor, reactor diameter 125mm, the bubbling loop diameter 85mm of bottom, is uniformly distributed 12 pores, each hole diameter 5mm, controls gas speed and carries out photocatalytic degradation reaction for 0.47m/s.
In Fig. 2, XRD collection of illustrative plates shows the Bi prepared by embodiment 1
2o
3/ TiO
2anatase structured all in pure phase after different temperatures roasting of photocatalysis film, along with the rising degree of crystallinity of temperature strengthens gradually.
Fig. 3 is the SEM photo of embodiment 1 film, and can find out film surface even uniform, film thickness is about 210nm.
UV-vis DRS collection of illustrative plates in Fig. 4 shows due to Bi
2o
3modification make embodiment 1 at the purer TiO of visible region
2film has stronger optical absorption intensity.
Fig. 5-7 shows that embodiment 1 has better photocatalytic activity compared with other embodiment.
Fig. 8 is the life test result of the present embodiment, shows that photocatalysis film has stable photocatalytic activity, can repeatedly use.
Embodiment 2
Do not add bismuth nitrate in preparation process, namely Bi/Ti mol ratio is 0, and all the other contents are identical with described in embodiment 1.UV-vis DRS collection of illustrative plates in Fig. 4 shows the TiO in the present embodiment
2film at visible region without obvious absorption.
Embodiment 3
In preparation process, control Bi/Ti mol ratio is 0.5%, and all the other contents are identical with described in embodiment 1.UV-vis DRS collection of illustrative plates in Fig. 4 shows due to Bi
2o
3modification make the present embodiment at the purer TiO of visible region
2film has stronger optical absorption intensity.
Embodiment 4
In preparation process, control Bi/Ti mol ratio is 1.5%, and all the other contents are identical with described in embodiment 1.UV-vis DRS collection of illustrative plates in Fig. 4 shows due to Bi
2o
3modification make the present embodiment at the purer TiO of visible region
2film has stronger optical absorption intensity.
Embodiment 5
In preparation process, control Bi/Ti mol ratio is 2.5%, and all the other contents are identical with described in embodiment 1.UV-vis DRS collection of illustrative plates in Fig. 4 shows due to Bi
2o
3modification make the present embodiment at the purer TiO of visible region
2film has stronger optical absorption intensity.
Embodiment 6
Coating times is changed into 1 time, all the other contents are identical with described in embodiment 1.SEM photo shows the film surface even uniform in the present embodiment, and film thickness is about 110nm.
Embodiment 7
Coating times is changed into 2 times, all the other contents are identical with described in embodiment 1.SEM photo shows the film surface even uniform in the present embodiment, and film thickness is about 135nm.
Embodiment 8
Coating times is changed into 4 times, all the other contents are identical with described in embodiment 1.SEM photo shows that non-uniform phenomenon appears in the film surface in the present embodiment, and film thickness is about 600nm.
Embodiment 9
Coating times is changed into 5 times, all the other contents are identical with described in embodiment 1.SEM photo shows that irregular splitting appears in the film surface in the present embodiment, and film thickness is about 1.1 μm.
Embodiment 10
Carry out photocatalytic degradation reaction in not air-blowing i.e. gas speed under being the condition of 0.0m/s, all the other contents are identical with described in embodiment 1.
Embodiment 11
Gas speed is adjusted to 0.28m/s and carries out photocatalytic degradation reaction, all the other contents are identical with described in embodiment 1.
Embodiment 12
Gas speed is adjusted to 0.60m/s and carries out photocatalytic degradation reaction, all the other contents are identical with described in embodiment 1.
Embodiment 13
Get the photocatalysis film obtained in above-described embodiment 1-9, adopt 150mL 5 × 10
-6m methyl orange solution is placed in floating type photo catalysis reactor, is positioned at reactant ullage 18cm place using a 500W Xe lamp as light source, reacts 6 hours, investigate its Photocatalytic Degradation Property at 30 DEG C.Fig. 5 shows through Bi
2o
3the purer TiO of catalytic activity of each embodiment after modification
2film (i.e. embodiment 2) is all significantly improved, and wherein embodiment 1 has best catalytic activity.Fig. 6 shows that the increase of photocatalytic activity along with coating times is in the rear downward trend that first rises, and when wherein coating times is 3 times, (embodiment 1) has best catalytic activity.
Embodiment 14
Adopt embodiment 1 and the Bi prepared by embodiment 10-12
2o
3/ TiO
2photocatalysis film carries out the photocatalytic activity contrast under different gas speed, and other reaction conditions are with embodiment 13.Embodiment 1 has best catalytic activity as can be seen from Figure 7.
Embodiment 15
Adopt the Bi prepared by embodiment 1
2o
3/ TiO
2photocatalysis film carries out life experiment, is taken out by each reacted glass marble and dries 12h in 100 DEG C after using washed with de-ionized water 3 times, continue afterwards to use in life experiment.The reaction time of each life experiment is 6h, the results are shown in Figure 8.Can find out that the product that the present invention obtains has stable photocatalytic activity.
Claims (7)
1. hollow light glass marble plated surface Bi
2o
3/ TiO
2the technique of photocatalysis film, is characterized in that, comprises the following steps:
(1) precursor aqueous solution is prepared: the mixed solution A of preparation pentanediol, water, polyethylene glycol and ethanol, the mixed solution B of tetrabutyl titanate and acetylacetone,2,4-pentanedione, adds A in B, mixes rear red fuming nitric acid (RFNA) adjust ph to 3-4, then add five nitric hydrate bismuths, obtain precursor aqueous solution; In A, the amount ratio of pentanediol, water, polyethylene glycol and ethanol is (0.2-1.0) g:(0.5-1.5) g:(0.5-3.0) g:(70-150) mL, in B, the volume ratio of tetrabutyl titanate and acetylacetone,2,4-pentanedione is (1-20): (0.5-5), the volume ratio of A and B is 15-25:1, and the mol ratio of bismuth and titanium is 0.5-2.5%;
(2) hollow light glass marble being placed in precursor aqueous solution and rotating makes its surface fully contact with precursor liquid, takes out glass marble and dries up, obtain the glass marble of uniform coated, dry 1-2h at 100-110 DEG C; Described hollow light glass marble is simple glass hollow ball, and density is 2.5-2.6g/cm
3, glass marble diameter is 10-11mm, wall thickness 0.3-0.4mm;
(3) repeat step (2) 0-4 time, obtain the film of different-thickness;
(4) glass marble is placed at 450-550 DEG C of high-temperature calcination 3-5h in Muffle furnace, obtains surface and be coated with Bi
2o
3/ TiO
2the glass marble of photocatalysis film.
2. hollow light glass marble plated surface Bi according to claim 1
2o
3/ TiO
2the technique of photocatalysis film, it is characterized in that, in step (1), the volume ratio of tetrabutyl titanate and acetylacetone,2,4-pentanedione is 4:1, and the amount ratio of pentanediol, water, polyethylene glycol and ethanol is 0.25g:0.7g:2.0g:100mL, the volume ratio of A and B is 20:1, and the mol ratio of bismuth and titanium is 1%.
3. hollow light glass marble plated surface Bi according to claim 1
2o
3/ TiO
2the technique of photocatalysis film, is characterized in that, in step (3), number of repetition is 2 times.
4. hollow light glass marble plated surface Bi according to claim 1
2o
3/ TiO
2the technique of photocatalysis film, is characterized in that, in step (4), calcining heat is 500 DEG C, and the time is 4h.
5. plated surface Bi
2o
3/ TiO
2the hollow light glass marble of photocatalysis film, is characterized in that, is prepared by the technique described in claim 1-4 any one.
6. plated surface Bi according to claim 5
2o
3/ TiO
2the hollow light glass marble of photocatalysis film is used for floating type reactor.
7. plated surface Bi according to claim 5
2o
3/ TiO
2the hollow light glass marble of photocatalysis film is used for Photocatalytic Degradation of Methyl Orange.
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CN104909579B (en) * | 2015-05-22 | 2017-03-01 | 上海师范大学 | The glass bead of plated surface Ag/BiOCl silica membrane and its technique and purposes |
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