CN1583586A - Method for recovering powdery titania light catalyst - Google Patents
Method for recovering powdery titania light catalyst Download PDFInfo
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- CN1583586A CN1583586A CN 03153655 CN03153655A CN1583586A CN 1583586 A CN1583586 A CN 1583586A CN 03153655 CN03153655 CN 03153655 CN 03153655 A CN03153655 A CN 03153655A CN 1583586 A CN1583586 A CN 1583586A
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- photocatalyst
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Abstract
A process for recovering the powdered TiO2-type photocatalyst features that the aqueous solution of high-molecular flocculant is mixed with the sewage treated by photocatalyst to separate the photocatalyst from water, and the photocatalyst is washed several times for removing electrolyte.
Description
Technical field
The invention belongs to photocatalyst and reclaim the field, particularly the method for separating and reclaiming of powder-type titanium dioxide class photocatalyst and water.
Background technology
Separation and Recovery photocatalyst from the sewage of handling is that one of critical limitation factor of practical application is moved towards in the application of restriction photocatalyst technology in water treatment from laboratory technique.At present, laboratory pulverous TiO commonly used
2Photocatalyst is suspended in water or other solvents, research TiO
2The situation of photocatalysis to degrade organic matter and influence factor thereof.Although the Powdered TiO of small size
2Photocatalyst has with the pollutent contact surface big, the light utilization efficiency height, and photocatalytic activity advantages of higher, but in the face of practical application, its shortcoming also is conspicuous, promptly catalyzer and shipwreck are to separate and the expense costliness.[R.L. Pozzo such as Pozzo, M.Baltanas, A. Cassano Supported titanium oxide as photocatalyst inwater decontamination:state of the art, Catal. Today, 1997,39,219-231] the glass microballon loaded optic catalyst be studies show that the high expense that the small size photocatalyst reclaims after the sewage disposal is enough to offset the energy expenditure of utilizing sun power to dispose of sewage and saved.Be to solve the recovery problem of catalyzer, method commonly used at present be with photocatalyst-supporting in certain substrate as glass microballon, aluminum oxide, molecular sieve, glass, pottery, use as catalyzer on surfaces such as carbon fiber.Compare with pulverous photocatalyst, although the method for supporting has the advantage that catalyzer is easy to reclaim, but the method for supporting exists the utilization ratio of luminous energy lower, catalytic efficiency is low, specific surface area is less, and the catalyst loading amount is little, and there be the problem and the carrier surface coating thickness of aspects such as coming off in catalyzer, shape, shortcoming [preparation of the big woods loading nano-titania of state and performance characterization Postgraduate School, Chinese Academy of Sciences doctorate paper 2003] such as crystallization is restive.How to address these problems the further research that awaits.In water treatment procedure, the adding of small amount of flocculant can make the suspended particle in the water obviously reunite, and the particulate matter after loose the reunion can be removed from water by sedimentation or filtering method easily because of the obvious increase of size.Although flocculence is extensive use of in water treatment, uses it in the aftertreatment of the recycling of photocatalyst and photocatalyst and yet there are no report.
At preparation TiO
2There are a large amount of ionogen, compositions such as organism in the system of photocatalyst.Studies show that a lot of mineral ions such as Cl
-Existence be unfavorable for TiO
2The raising of photocatalytic activity [Kormann, C.; Bahemann, D.W.; Hoffmann, M.R.Photolysis of chloroform and other oganicmolecules in aqueous TiO
2Suspensions Environ. Sci. Technol. 1991,25,494-500].Simultaneously, a large amount of electrolytical existence also are to cause particle aggregation, reduce particle dispersive major reason.Therefore after the photocatalyst preparation is finished, need carry out post-processing steps such as repetitive scrubbing to it.But because highly active catalyzer requires less, the common filtration of particle size of catalyzer, modes such as sedimentation are difficult to be suitable for, and must replace high speed centrifugation, methods such as solvent extraction.But these method ubiquity energy consumption height are time-consuming or need shortcoming such as a large amount of expensive solvent.
Summary of the invention
One of purpose of the present invention be propose fast, the method for high efficiency separation and recovery powder-type titanium dioxide class photocatalyst.
Another object of the present invention is the post-processing step that polymeric flocculant is used for photocatalyst, to reach the purpose of simplifying post-processing step.
In the present invention, we use for reference the successful experience that flocculation agent is removed suspended contaminant in the water, and flocculation agent is used for the recovery with catalyzer of separating of photocatalyst and water, can reach the purpose that rapidly and efficiently reclaims photocatalyst from water.Simultaneously, this method can also be used for the post-processing step of small size photocatalyst preparation process, has advantages such as easy, easily capable, quick equally.Except above-mentioned advantage, because flocculation agent is to use in the ending phase of light-catalyzed reaction, so photocatalyst still has the advantage of powder-type photocatalyst, is difficult to and water sepn the shortcoming that energy consumption is high but overcome the Powdered photocatalyst of small size again simultaneously.Our research finds that also the photocatalyst that reclaims after separating can be reused.
Separation of the present invention and the method that reclaims powder-type titanium dioxide class photocatalyst are that the aqueous solution of polymeric flocculant is mixed with waste water through titanium dioxide class photocatalyst treatment, continue to stir, utilize flocculence to make titanium dioxide class photocatalyst and water sepn, static, repeatedly wash the titanium dioxide class powder photocatalyst that can obtain containing small amount of impurities after incline supernatant liquid or the filtration.Perhaps, continue to stir, utilize the flocculence washing to remove the ionogen that exists in the catalyzer, only contained the electrolytical titanium dioxide class of minute quantity photocatalyst powder polymeric flocculant and the aqueous solution that contains titanium dioxide class photocatalyst.
The concrete steps of separation and recovery powder-type titanium dioxide class photocatalytic method are among the present invention:
(1) aqueous solution of preparation polymeric flocculant such as polyacrylamide, sodium polystyrene sulfonate or natural polymers such as Walocel MT 20.000PV etc.
The polymeric flocculant of 0.1～15 weight part is joined in the deionized water of 85～99.9 weight parts, stir, make it to dissolve fully;
(2) get the waste water of 50～99.9 weight parts through titanium dioxide class photocatalyst treatment, under agitation the flocculant aqueous solution with 0.1～50 weight part step (1) adds wherein.After continuing stirred for several minute, can find that photocatalyst obviously flocculates, short period of time static back solid catalyst is promptly in the container bottom sedimentation, and supernatant liquid or filter and photocatalyst can be separated from the waste water of having handled inclines.Water repeatedly washes the photocatalyst powder of recovery, and is removing the residual ion of catalyst surface, behind the organism fragment etc., dry or it is directly used in next time light-catalyzed reaction.
Polymeric flocculant can also be used for the post-processing step of photocatalyst, can reach the purpose of simplifying post-processing step equally.Concrete step is:
(1) the preparation polymeric flocculant aqueous solution;
The polymeric flocculant of 0.1～15 weight part is joined in the deionized water of 85～99.9 weight parts, stir, make it to dissolve fully;
(2) under agitation the polymeric flocculant aqueous solution of 0.1～50 weight part step (1) is joined in the aqueous solution that contains titanium dioxide class photocatalyst of 50～99.9 weight parts, continue stirred for several minute after; Leave standstill, since throwing out, the loose reunion of catalyzer, after the sedimentation, the supernatant liquid that inclines adds deionized water in lower floor's solid, after stirring, leaves standstill, and after the catalyzer rapid subsidence, supernatant liquid inclines.Repeat this step repeatedly and can remove a large amount of ionogen that exist in the catalyzer, only contained the electrolytical titanium dioxide class of minute quantity photocatalyst powder.
Flocculation agent recited above is that a class has the macromolecular compound that suspended particulate is reunited; The suitable flocculation agent kind and the selection of flocculation agent consumption are to improving the active favourable of photocatalyst; Studies show that the photocatalyst small-particle that flocculation agent brings is reunited and can be broken up by ultransonic method, can not bring obvious influence to the redispersion performance of photocatalyst.Flocculation agent can be eliminated by the illumination of certain hour the influence of catalyst activity.
Purposes of the present invention:
(1) use in the waste water of handling through photocatalysis method, the photocatalyst in the waste water is reunited rapidly, coagulation filters or standing sedimentation can separated light catalyzer and water.Obviously simplified separating of photocatalyst and water.
(2) at the TiO of hydrothermal method or other method preparation
2Use before the aftertreatment washing step of nanoparticle.Can make washing step simple.
(3) photocatalyst of Hui Shouing can reuse.Similar with purposes 1, in the waste water that photocatalysis method is handled, add flocculation agent in proportion after, reclaim photocatalyst behind separated light catalyzer and the water.
Advantage of the present invention and positively effect:
(1) as previously mentioned, make powder-type photocatalyst and separating of water become easy unusually, can reduce the high expense that is used for photocatalyst and water sepn greatly;
(2) because flocculation agent uses in the ending phase of light-catalyzed reaction, compare, kept that the powder photocatalyst specific surface area is big, photolytic activity is high, the advantage that light utilization efficiency is high with catalyzer fixation method commonly used at present;
(3) as shown in Figure 1, the photocatalyst after the recovery is reusable;
When (4) in the post-processing step of small size photocatalyst, using, simplify the last handling process of washing greatly;
(5) as shown in Figure 2, the use of flocculation agent does not bring obvious influence to the dispersing characteristic of photocatalyst in the post-processing step, therefore, has still kept the advantage of powder-type photocatalyst.Because the reunion that suitable flocculation agent adds the photocatalyst that causes can be broken up by ultransonic method of short period of time.
(6) as shown in Figure 4, select suitable flocculation agent kind and flocculation agent consumption, can obviously improve the photocatalytic activity of photocatalyst;
(7) because of the flocculation agent of selecting for use is some high molecular polymers, this base polymer can be removed by photocatalysis method.
(8) compare with water separating method with catalyzer commonly used at present, technology is simple, and is workable;
(8) convenient for washing of the photocatalyst of Hui Shouing.
Description of drawings
Fig. 1. the embodiment of the invention 3 be with azoic dyestuff tropeolin-D as probe molecule, homemade TiO
2Photocatalyst photocatalytic degradation tropeolin-D activity is with the variation of recovered frequency.Circulation 1 is the TiO of preparation
2Photocatalyst photocatalytic degradation tropeolin-D, the mark of remaining tropeolin-D is with the variation of light application time; Circulation 2 is TiO
2After reclaiming for the first time, photocatalytic degradation tropeolin-D, the mark of remaining tropeolin-D is with the variation of light application time; Circulation 3 is TiO
2After reclaiming for the second time, photocatalytic degradation tropeolin-D, the mark of remaining tropeolin-D is with the variation of light application time.The reduction of catalyst activity may be relevant with these two reasons: the loss in the catalyst recovery process; The influence of photocatalyst surface residual organic when light-catalyzed reaction is not thorough.
Fig. 2. after the different post-treating methods of the embodiment of the invention 7 usefulness were handled, photocatalyst is the electromicroscopic photograph behind the redispersion in water;
A washes sample; The b sample that flocculates
Fig. 3. the activity of the embodiment of the invention 7 photocatalyst photocatalytic degradation tropeolin-Ds is with the variation of flocculation agent consumption;
Fig. 4. the embodiment of the invention 8 post-treating methods change the active influence of photocatalyst for degrading tropeolin-D.
Embodiment
Embodiment 1
The polyacrylamide of 15 weight parts added in 85 parts the deionized water, stir and make it to dissolve fully.The above-mentioned polyacrylamide solution that in the waste water from dyestuff that contains commercialization photocatalyst P25 that photocatalysis method is handled, adds 0.1 weight part to 99.9 weight parts, after continuing stirred for several minute, naked eyes can be observed catalyzer and obviously reunite the very big aggregate of formation size.After leaving standstill this solution, photocatalyst is in the bottom deposit of solution.The incline clear liquid on upper strata keeps lower floor's solid and can reach the dried up purpose with photocatalyst of branchs.
Embodiment 2
The polyacrylamide of the hydrolysis of 12 weight parts added in 88 parts the deionized water, stir and make it to dissolve fully.The polyacrylamide solution that in the waste water that contains commercialization photocatalyst P25 that photocatalysis method is handled, adds the hydrolysis of 0.5 weight part to 99.5 weight parts, after continuing stirred for several minute, naked eyes can be observed catalyzer and obviously reunite the very big aggregate of formation size.Leave standstill, sedimentation is filtered, and lower floor's filtrate is treated water, the photocatalyst P25 for reclaiming that keeps in the upper screen.
Embodiment 3
The sodium polystyrene sulfonate of 1 weight part added in 99 parts the deionized water, stir, make it to dissolve fully.The sodium polystyrene sulfonate aqueous solution that in the methyl orange aqueous solution that contains self-made photocatalyst that photocatalysis method is handled, adds 50 weight parts to 50 weight parts.After continuing stirred for several minute, leave standstill sedimentation solution.Clarifying supernatant liquid inclines.Lower floor be with water sepn after photocatalyst.Add the photocatalyst that water washing is reclaimed for several times.Use the photocatalyst that reclaims, the photoactivation method adds the sodium polystyrene sulfonate aqueous solution in identical ratio after handling and containing the waste water of dyestuff tropeolin-D in waste water from dyestuff, after continuing stirred for several minute, leave standstill, sedimentation, photocatalyst can separate from the waste water of handling once more.
Embodiment 4
In the deionized water with 99.5 parts of 0.5 part Walocel MT 20.000PV addings, stir, make it to dissolve fully.To 80 weight parts through photocatalysis method handle the waste water from dyestuff that contains self-made photocatalyst in add the Walocel MT 20.000PV aqueous solution of 20 weight parts.After continuing stirred for several minute, leave standstill sedimentation.Filtering can separated light catalyzer and water.
Embodiment 5
The polyacrylamide of 8 weight parts added in 92 parts the deionized water, stir and make it to dissolve fully.To 95 weight parts through photocatalysis method handle contain self-control TiO
2The polyacrylamide solution that adds 5 weight parts in the methyl orange aqueous solution of photocatalyst.After continuing stirred for several minute, leave standstill sedimentation.Filtering can separated light catalyzer and water.
Embodiment 6
The polyacrylamide of 3 weight parts added in 97 parts the deionized water, stir and make it to dissolve fully.After 90 weight parts have been finished the polyacrylamide solution that adds 10 weight parts in the sewage that contains commercialization photocatalyst UV-100 of light-catalyzed reaction, after continuing stirred for several minute, naked eyes can be observed catalyzer and obviously reunite the very big aggregate of formation size.Filtering can separating catalyst and water.
Embodiment 7
In the deionized water with 97 parts of 3 parts Walocel MT 20.000PVs addings, stirring makes it to dissolve fully.Under agitation contain without the homemade TiO of the hydrothermal method of aftertreatment to 99.5 weight parts
2The Walocel MT 20.000PV aqueous solution that adds 0.5 weight part in the aqueous solution of photocatalyst.After continuing stirred for several minute, leave standstill sedimentation.Photocatalyst is at the rapid coagulation in solution bottom.Inclining adds deionized water behind the supernatant liquid, stirs, leave standstill, and sedimentation, supernatant liquid inclines.Repeat this process and can reach the washing photocatalyst there to be a large amount of electrolytical purposes in the system of removing.After accompanying drawing 2 is conventional washing methods and flocculence washing photocatalyst, after ultrasound light-catalyzed in short-term dose, the dispersed comparison in water of its particle.TiO behind the change flocculation agent consumption
2Photocatalyst photocatalytic degradation tropeolin-D activity with the variation of flocculation agent consumption as shown in Figure 3.
Embodiment 8
In the deionized water with 95 parts of 5 parts sodium polystyrene sulfonates addings, stirring makes it to dissolve fully.Under agitation contain without the homemade TiO of the hydrothermal method of aftertreatment to 99.5 weight parts
2The sodium polystyrene sulfonate aqueous solution that adds 0.5 weight part in the aqueous solution of photocatalyst.After continuing stirred for several minute, leave standstill sedimentation.Photocatalyst is at the rapid coagulation in solution bottom.Inclining adds deionized water behind the supernatant liquid, stirs, and leaves standstill, and supernatant liquid inclines.Repeat this process and can reach the washing photocatalyst there to be a large amount of electrolytical purposes in the system of removing.Accompanying drawing 4 is handled with ordinary method for flocculence and is handled self-control TiO
2The specific activity of photocatalyst photocatalytic degradation tropeolin-D.
Claims (10)
1. method that reclaims powder-type titanium dioxide class photocatalyst, it is characterized in that: described method is that the aqueous solution of polymeric flocculant is mixed with waste water through titanium dioxide class photocatalyst treatment, continue to stir, utilize flocculence to make titanium dioxide class photocatalyst and water sepn, static, incline supernatant liquid or filter after promptly obtain powder-type titanium dioxide class photocatalyst after the solid that obtains repeatedly washed.
2. the method for claim 1, it is characterized in that: described titanium dioxide class photocatalyst and water sepn are to get the waste water of 50～99.9 weight parts through titanium dioxide class photocatalyst treatment, under agitation the aqueous solution with 0.1～50 weight part polymeric flocculant adds wherein, continue to stir, static, incline supernatant liquid or filter after promptly only contained the powder-type titanium dioxide class photocatalyst of trace impurity behind the solid that repeatedly washing obtains.
3. method as claimed in claim 1 or 2 is characterized in that: the aqueous solution of described polymeric flocculant is that the polymeric flocculant with 0.1～15 weight part joins in the deionized water of 85～99.9 weight parts, stirs, and makes it to dissolve fully.
4. claim 1 or 2 described methods, it is characterized in that: described polymeric flocculant is the high molecular polymer of polyacrylamide, sodium polystyrene sulfonate or Walocel MT 20.000PV class.
5. the described method of claim 3, it is characterized in that: described polymeric flocculant is the high molecular polymer of polyacrylamide, sodium polystyrene sulfonate or Walocel MT 20.000PV class.
6. method that reclaims powder-type titanium dioxide class photocatalyst, it is characterized in that: described method is the aqueous solution and the aqueous solution that contains titanium dioxide class photocatalyst with polymeric flocculant, stir, utilize the flocculence washing to remove the ionogen that exists in the catalyzer, promptly only contained the electrolytical powder-type titanium dioxide of minute quantity class photocatalyst.
7. method as claimed in claim 6, it is characterized in that: the described ionogen that exists in the catalyzer of removing is under agitation the aqueous solution of the polymeric flocculant of 0.1～50 weight part to be joined in the aqueous solution that contains titanium dioxide class photocatalyst of 50～99.9 weight parts, stirs; Leave standstill, behind the supernatant liquid that inclines, add deionized water in lower floor's solid, after stirring, leave standstill, the supernatant liquid that inclines repeats this step repeatedly and is promptly only contained the electrolytical powder-type titanium dioxide of minute quantity class photocatalyst.
8. as claim 6 or 7 described methods, it is characterized in that: the aqueous solution of described polymeric flocculant is that the polymeric flocculant with 0.1～15 weight part joins in the deionized water of 85～99.9 weight parts, stirs, and makes it to dissolve fully.
9. claim 6 or 7 described methods, it is characterized in that: described polymeric flocculant is the high molecular polymer of polyacrylamide, sodium polystyrene sulfonate or Walocel MT 20.000PV class.
10. the described method of claim 8, it is characterized in that: described polymeric flocculant is the high molecular polymer of polyacrylamide, sodium polystyrene sulfonate or Walocel MT 20.000PV class.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03153655 CN1583586A (en) | 2003-08-20 | 2003-08-20 | Method for recovering powdery titania light catalyst |
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| CN 03153655 CN1583586A (en) | 2003-08-20 | 2003-08-20 | Method for recovering powdery titania light catalyst |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101863571A (en) * | 2010-06-04 | 2010-10-20 | 厦门凯瑞尔数字环保科技有限公司 | Method for treating paper-making wastewater by utilizing photocatalytic oxidation film coagulation reactor |
| CN103232102A (en) * | 2013-05-09 | 2013-08-07 | 同济大学 | Method for accelerating solid-liquid separation of nanometer particle suspension |
| CN107715925A (en) * | 2017-10-26 | 2018-02-23 | 内蒙古科技大学 | The coagulation and recovery method of rare earth modified nano titanium dioxide optical catalyst |
-
2003
- 2003-08-20 CN CN 03153655 patent/CN1583586A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101863571A (en) * | 2010-06-04 | 2010-10-20 | 厦门凯瑞尔数字环保科技有限公司 | Method for treating paper-making wastewater by utilizing photocatalytic oxidation film coagulation reactor |
| CN101863571B (en) * | 2010-06-04 | 2012-07-04 | 厦门凯瑞尔数字环保科技有限公司 | Method for treating paper-making wastewater by utilizing photocatalytic oxidation film coagulation reactor |
| CN103232102A (en) * | 2013-05-09 | 2013-08-07 | 同济大学 | Method for accelerating solid-liquid separation of nanometer particle suspension |
| CN107715925A (en) * | 2017-10-26 | 2018-02-23 | 内蒙古科技大学 | The coagulation and recovery method of rare earth modified nano titanium dioxide optical catalyst |
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